Still getting some run on and exhaust backfire when I shut the car off.
For those not familiar, it's a Ford 302 with aluminum GT40 heads, B303 cam, and Edelbrock carb, 10* initial timing, mechanical advance.
What should I check first?
sounds like your carb is adjusted a little too rich and probably have some carbon buildup in your cyl heads
Its easy to clean the carbon, warm up your engine and remove the air cleaner lid, use a soda can full of water and open throttle enough to keep running while dribbling water down the primaries then take it out on the street and drive it hard letting the engine rev.
getting the carb adjusted correctly is important also just dont go too lean
Rob,Throttle plates might be open too far, check the secondary stop also.
How about excess fuel? I noticed fuel dribbling from the nozzles at the front of the primaries. Read that means the floats are stuck. Make sense? What about if fuel pressure is too high? Gauge says 5lbs but no idea if it's accurate. Thinking it's easier to back down the pressure a little than getting at the floats.
Rob, you're moving air over the venturies, enough to siphon out the fuel, but not enough to fully atomize it. Throttle plates have to be open a bit but I wouldn't think the floats were stuck or the needles leaking, I'd lower the float level a bit to increase the amount of vacuum needed to siphon fuel out of the bowls to start with. Drop it about an eighth of an inch to start and see what happens.
Ok, I pulled the top of the carb - have a few questions...
there's a little varnish around the float bowl vents and the upper part of the metering rod hole where the cover is. Seems very thin but want to clean it while I have it apart. Is it ok to use carb cleaner with the accelerator pump attached or will it damage the rubber (or whatever that material is)?
There's carbon or something (a thin black build up) around the middle inch or so on the metering rods. Will clean them but assume that's a good sign there's more & I should follow Kevin's water suggestion.
The floats seem to be set right on the "up" travel - right about 7/16" from the surface the gasket sits on when the carb lid is held upside down.
Not sure about the amount the floats are dropping. Thought I'd read that should be close to 1" but not sure. Mine drop almost 1 5/16" on one side and 1 1/4" on the other. Do I need to adjust that?
It doesn't look like the throttle plates are fully closed but the only thing that appears to be affecting that is the idle speed screw. Should they be fully closed and still be able to get a good idle?
Rob, it's not how far they drop, that would be limited by the depth of the float bowls when installed anyway. It's the distance they are from the face of the carb top when it's inverted, that's what the little fiber gauges that come with a rebuild kit check. Check the height with a small rule or even cut some light cardboard and make a gauge to fit between the float and the top surface. To lower the float you'd increase the distance the float rests above the carb surface by bending the little lever that pushes in the needle. I wish I had pictures, I'll try to find something on line about how to rebuild a Carter style carb and send them to you. Try this link to see how the floats are adjusted. http://www.laroke.com/larryk4674/2009/AFB_Rebuild_Guide.pdf
Figure 8 shows the float height adjustment and how it's measured. That's the critical adjustment as it determines the fuel level in the bowls, too little and you can get fuel starvation at high rpm or wide open throttle for sustained periods, too high and you may get gas dribble into the venturies because even with low vacuum there's just enough to siphon gas out of the bowl. In your case I'd make sure the floats are set to normal spec to begin with then lower them (actually raise them as seen in figure 8) about 1/8" and see if that stops the fuel dribble you're seeing in the venturies.
Well, I just got back from a test run & it didn't backfire when I shut it off. It was just about a mile so we'll see if I fixed it or not with the next couple of runs. I called Edelbrock to see if there's any sort of extended warranty on their "Endurashine" finish and while on the line their support guy started diagnosing the fuel dribble... He was pretty clear that only 4 things can cause it...
1. Float level on the rise. Should be 7/16". Mine were pretty close but I went ahead and adjusted them a bit - maybe 1/16" higher at most. I think this was 1/2 of my problem.
2. Fuel getting into the floats. Mine were dry.
3. Dirt in/on the valve or valve seat. They looked clean but I sprayed some carb cleaner, let it set a few mins and then sprayed a little more.
4. Throttle plates not fully closed. I think this was the other part of the problem because when I put it back together, it was still dribbling some - but less. I decided to reset idle air mixture to where they were out of the box thinking maybe my idle screw was forcing the throttle open (looked like the only mechanical thing keeping them from closing 100%) to compensate for too much gas getting in on the idle circuit. It was just a guess, but once I reset the idle air mixture, I was able to back the idle speed screw out a little and maintain idle - and the rest of the dribbling into the venturis stopped.
Assuming this did fix the over rich/backfire, I'll follow the book to adjust the idle air properly.
The next item is I now noticed a little bit of hesitation or missing when I was accelerating in 1st and 2nd and a little popping from the exhaust on quick deceleration. Likely causes for that?
Probably need a bit more ramp on the accelerator pump cam as I remember about the stumbling under acceleration, leaning out just a bit most likely. I'm not sure what options Edlebrock carbs have, but Holly has a lot of different pump cam profiles, Edlebrock should as well. You might also need to work on the timing and adjust the vacuum advance for a bit less vacuum to retard that input a bit, sounds like it may be over advancing when the vacuum rises as the throttle plates close.
Thanks Bill. The Edelbrock has 3 positions that the accelerator pump linkage can connect to. It's easy enough to try adjusting that, but the more I think about it, the more I think it felt more like ignition - like it was missing. Would the accellerator pump make it feel like that or would it feel like it's bogging down? As far as vacuum advance, my distributor is all mechanical advance; no vacuum advance.
Hey Rob,
After running the engine that rich you have probably fouled up the plugs pretty good.
I would start with a good inspection of the ignition system before I went any further.
Pull the plugs and make sure they are clean and not blackened.
Double check the rest of the tune and check your oil for fuel contamination.
Warm up the engine fully and set the idle speed with the screw at the throttle stop.
Pick one of the idle mixture screws and adjust it for the highest idle speed that it will provide.
Now do the same for the other idle mixture screw.
Reset the idle speed with the throttle screw and go through the idle mix screws one more time.
Now turn both mixture screws in 1/4 turn. this should cause your idle speed to drop. If it doesn't then you are still too rich.
Now that you are idling right, get a vacuum gauge and check the idle vacuum. If it's anything less than 8" you will need to change your step up springs.
For your cam a pink or possibly orange spring would be appropriate.
Once you get to this point see how the car drives. If it's still off we'll have to start rejetting before we play with the accel pump.
Keep us informed and we'll go from there.
Cheers
Fred
Rob, sounds like you are making great progress. Bet the car looks great also. Maybe EFI was not too big of a project,heh :)?
Nice Kelly! But honestly this kind of stuff is fun to me. I like learning by doing. I plan to switch to FI sometime down the road, that's why I ran the high pressure fuel pump & return line (with a bypass valve to cut the pressure down for carb use. I'd only messed with SU and ZS carbs in the past. The Edelbrock & all the stories about carb problems intimidated me so I put off messing with it. When I pulled the top off yesterday, I was pleasantly surprised with how simple it was.
Fred, I had the plugs out when I used the piston stop to find TDC. Now that you've reminded me, they all looked ok - a light grey - except one. #5 plug was black and I meant to clean it but I had my son put the plugs back while put the radiator back.
Hadn't thought about fuel getting into oil.
Guess my weekend is shaping up!
An air leak in the exhaust will cause that to happen as well, when I had a header gasket blow out on me and run up the rpms in 1st then engine brake a little ways it would backfire, 10* initial timing sounds low for a mechanical advance, how about trying the vacuum gauge trick as was discussed over on MGE to get optimum settings. Just a thought!
Quote.....to change your step up springs. For your cam a pink.......
I'll second Fred's recommendation on the step up spring change to compensate for reduced available vacuum with your B303 cam - that was the first thing that was changed on my Edelbrock 600cfm and B303 combo. (pink if memory serves)
Tan is the color that you are looking for Rob.
Unless you are running a 10% or more blended fuel in which case they will just turn white.
Grey generally indicates contaminants that are burnt onto the plugs.
Clean them all or better replace them. If you clean them it needs to be with a media blaster not a wire brush.
Short gap them @ around .028" until you get the carb sorted out.
Once the carb is close then you can open up the gap and fine tune everything else.
Cheers
Fred
Our gas does say "Contains up to 10% Ethenol" year round. Not sure if we have any sort of winter mix down here but I doubt it; there's never any mention of it at the pumps or anyone talking about it.
The mixture in the pumps isn't ever mentioned, but almost all parts of the country now get specific mixtures for summer and winter with more volitle elements for winter driving to help it atomize, and less volitle elements in summer to help reduce evaporation and air pollution. Fuel containing 10% ethanol will burn cleaner on the plugs. Since we're starting to get more blended fuel around here I'm starting to use products like Sta-Bil to help reduce the corrosive effects of the alcohol.
Methanol-yes, 10% ehtanol- not likely. I suggest a peep at the" Performance E85" webbsite. Very informative without being corrosive/ lol. roverman.
Bill is right about Stabil. Not so much corrosive but alcohol draws moisture and separates from the gas. If not driven regularly or stored ,highly recommended.
Didn't have a lot of time this weekend to work on the car, but did do a little...
Pulled the plugs (#8 was a pain -- had to shift the steering u-joint to get a socket on it), cleaned, regapped (.028 for now per Fred). They looked good to me except #5 but I'm interested in your opinion of the color & especially likely reasons for #5 being so fouled compared to the rest. I guess I need to watch the valve/spring on that cylinder and check compression? What else to check?
A couple of additional updates...
*Carb is an Edelbrock 1405 (600 CFM)
*Plugs were gapped way too much. They were around .044; I didn't check them all, but #5 was a bit more - about .050
I'm hoping that's why it was fouled so much more. What do you think?
*I'm going to change the oil -- didn't smell a strong fuel smel in it but did smell some.
Plugs.jpg
Hey Rob,
Your engine is probably just fine.
What happens is, when your fuel mix goes way rich the plugs soot up like # 5 and the engine starts to misfire and stutter.
The misfire happens because the soot is a conductor and shorts the plug out.
Back in the old days this didn't happen as much.
Mostly because the ignition systems couldn't tolerate today's wide plug gaps. And partly due to today's very high additive load.
With the shorter gap the plug will still fire even when fouled.
Once the engine starts to warm up and the plug starts to fire the soot burns off leaving the grey contamination that you see on the other plugs.
That's why you short gap the plugs while you are dialing in your fuel mix.
It makes the ignition less of a variable while tuning.
Once you get the mix closer you can open the gaps back up so that the engine will tolerate a leaner idle and cruise setting.
What does your ign. consist of? It just might be happier with the smaller gap anyway.
Cheers
Fred
Ignition is MSD6AL; MSD 8579 distributor; plug wires are Taylor 8MM (one of which has the silicone melted from coming in contact w/header, but it's not #5. I have new plug wires to replace them) and, plugs are AGSP32C.
Note, there is something wrong with the MSD box I think -- the tach output on the side is suspect (either that or I have two bad tachs). I will be testing the tach output tomorrow or Wed evening after work but am pretty sure it's broken or has come loose.. the 1/4" spade connector feels loose in the box and neither my dash mounted tach (autometer) nor a SunTech one I've used under the hood when timing in the past show any RPM's. According to the MSD tech, if that output is bad, it shouldn't be affecting the rest of the ignition - including the info just in case you guys have had different experience.
Did some adjustment today...
1. Unrelated, but because I needed a tach, I checked the tach output on the MSD box & it was working... So next checked the voltage at the other end of the wire... Or at least went to do that... That's when I realized I'd connected my Speedo sender to the tach & vice versa. Tach now works & assuming Speedo will too but didn't go for a drive.
2. Checked the advance. Remember, mechanical advance only, no vacuum advance on the distributor. Result:
- 10° @ idle (600 rpm)
- 10° @ 1000 rpm
- 10° @ 1500
- 17° @ 2000
- 20° @ 2500
- erratic, bouncing between 30 & 10 very rapidly @ 3000
3. Idle reasonably smooth @ 500; have it set to 600 rpm; 1/4 turn in of an idle air screw drops rpm by 50-75 rpm
4. Manifold vacuum @ idle was generally moving between 8 & 9.5. Every few seconds it'd drop down to 7 for about a second and then return to about 8.
5. There's a noticeable popping in the exhaust on deceleration if I quickly rev it to about 2000 rpm and immediately drop it back to idle, but it did rev better and transition from idle was smoother (no real load, just opening the throttle by hand in the driveway)
6. My son was playing with a non-contact thermometer @ noticed the header primaries were all running 250-310° except #5. It was about 190. Not sure if the ceramic coating might be thicker there but since #5 was the plug that was way more fouled, thought I'd mention it. Engine has only been run for about 20 minutes since cleaning the plugs (blast cabinet) & gapped them at .028; I didn't pull the plug to look at it again.
I haven't changed the step-up spring, rods or jets from the way the carb came (orange spring, .100 mains, .070x.047 rods.)
So, what do you recommend as the next step?
I would turn in both idle mix screws 1/4 turn re adjust the idle speed and take it out for a drive.
That should help out with the backfiring and make the idle more stable.
The erratic timing at 3000 is a concern but it might just be your timing light.
If it's really moving around, you will feel it on the drive.
You might need some more initial timing but lets get the carb set up first.
I'm surprised that your carb has orange springs. These are probably a little too weak. Sadly pink is your colour Rob.
The orange springs will probably cause a flat spot on moderate acceleration. They won't affect full throttle power though.
cheers
Fred
Adjusted air/fuel screws in 1/4 turn each & replaced orange step up springs with pink. Hard to describe how it's running now. Idle is about the same. More lope than I remember other B cam 302's but the idle is consistent. Feels like it doesn't have the power it should, almost like it's missing a little until about 2500 rpm. Accelerating moderately hard to 5k it felt strong.
What to check next?
Oh, and I did check our local gas station & the pumps do say "Contains Ethanol. This product may contain up to 10% ethanol by volume."
Rob, I'm no mechanic-but, is it possible your getting some "cam phasing" due to timing chain wear/stretch ? If so, this will contribute to timing wander. I suspect #5 exhaust is cooler because of misfire. I know it's a partial band aid, but have you considered platinum or irridium plugs ? Good Luck, roverman.
I won't rule timing out... In fact, I'm wondering if the next step should be to adjust timing either using the vacuum method or just increasing a degree or two at a time & testing... My thinking is without vacuum advance, I'm not getting enough advance off Idle till I get into the 3k range. But, my only experience is with stock MG's, Triumphs, and a few Jags while helping out at a small British repair shop when I was in school (and that was over 25yrs ago) so, I hoping to hear from others before doing that.
As for wear/stretch, I don't think so. The motor was bought 2nd hand, but, it was a new Ford Racing Parts crate motor that had never been installed. (was bought for a customer's 57 T-bird resto-mod. He ended up in a divorce and the wife got the money. Shop was selling off all the parts they'd bought. I got a copy of the receipt from when they bought the motor.). My odometer isn't working, but I doubt I have more than 30 miles on it at this point.
Rob, Try 12-14 initial,back off if pinging. I'd check the connections on both ends of #5 plug wire.
Rob, take your car for a run in 2nd or third gear and accelerate @ 3/4 or more throttle from 1500 to 5000 rpm.
Does it pull smoothly all the way through?
If it does. then drive it at a steady 2000 rpm in the highest gear that you can. How is it now?
Just trying to narrow down the variables and avoid the shotgun approach to tuning.
Cheers
Fred
I didn't have the note above with me so went off memory and messed up the detail... but what I did will probably give some good info...
third gear, held it at 1500 rpm for a few seconds, then floored it to about 4000. Spits & pops out of the exhaust till it gets around 2000 or a bit more, then spitting goes away and accelerates more smoothly.
third gear, held it at 2000 for a few seconds, then floored to about 4000 - no spitting or popping.
Will redo the test tomorrow all te way to 5k & also do the steady 2k test.
Ran Fred's tests...
* 1500 rpm to 5000... Initially bogs down, low power, then a bit more power (but not full power) & bucks & pops out of the exhaust up till around 2300 or so (one run did it thru about 3000), pulls strong from then to 5000. Pops every second or two out of the exhaust as it decellerates (I took my foot completely off the gas after each run).
* 2000 steady in 3rd or 4th isn't as smooth as when it is accelerating but doesn't buck or pop.
I'm assuming that means it's rich under load (power mode?) but not in cruise mode, right?
Edit: Forgot to mention, I checked the plug wire connections & they were good. Also checked compression on a few cylinders to see if #5 was different and it isn't. #1, #2, and #5 all showed 110.
Hey, where'd everyone go? Did I bore you with this?
I got a PM that got me thinking about the basics & suggested I check a few things so I did.
* retested header primary tube temps since plugs are short gapped - should be firing but #5 is still significantly cooler than the rest.
* swapped #5 & #6 plug wires (@ both distributor ends & plug ends) to see if low temp moved from #5 to #6. It didn't; #5 is still cooler.
* pulled #5 and it is already starting to foul.
* pulled the left side valve cover & ran the engine for a few seconds. Can't tell for sure of cours, but valves on #5 appear to be moving as much as the other cylinders.
* also checked distributor cap - still looks pretty much brand new. No signs of arching, moisture, cracks, wear, etc. Same with the rotor.
* while swapping plug wires, I noticed my header bolts had loosened up - most of them were loose, not just the ones near #5. I'll clearly need different header bolts (they're currently Allen head & even with an allen that I cut shorter it's still really hard to tighten a few of the bolts due to the tube locations)
* while I was at it, I checked for exhaust leaks at my band clamps. I knew it was leaking some because I could hear it but it didn't sound bad. Turns out oval pipe and band clamps don't seem to mix well - they are all leaking enough I can feel the exhaust where the band clamps come together on all 4 (before & after each muffler). Will have to come up with a better answer for that too.
So, at this point I'm thinking I need to sort out the exhaust & figure out why #5 isn't firing right before I go back to trying to tune the carb.
Since compression on #5 is the same as #1 & 2, I'm assuming it is not a head gasket problem. Make sense?
Similarly, I think the compression test suggests the rings have seated on #5 too. Right?
And since it is just #5 it's not likely to be the ignition box or coil (my thought is those would tend to be more random than clearly/consistently #5)
And, since distributor cap/rotor look good and swapping 5/6 plug wires had no effect, seems like the only ignition cause would be the plug, right?
I ran out of time to see if it is firing, but will do that next. If it's not that, what would you check next.. After I closed it up for tonight, I thought about rockers. They're stud mount. Seems like if the nut was loose or there was too much preload, that would show up in the compression... Or would it?
Rob,I suspect you would lose "a lot" of valve lift to measurably affect compression reading,(low cranking speed). Just for giggles, swap on another carb ? "Color Tune" spark plugs may still be available,(ising glass). Cheaper than (8) wide band O2 sensors.#5 definately sounds fat, perhaps part of the backfire problem. Had the distributor on a dyno ? Good Luck, roverman.
Sorry Rob,
Been out shoveling snow and fixing my shop roof for the last week.
I would be inclined to replace your plugs at this point. # 5 is probably dead.
Also try another timing light and see if your timing is still erratic @3000 rpm.
Set your total timing to around 34' for now and let the base timing fall where it may.
listen carefully for any signs of detonation and back off accordingly.
With all your exhaust leaks it's going to backfire on decel for sure.
Compression tests are not very accurate and will only show major faults.
A better test is a leak down test but I don't think you need one just yet.
Cheers
Fred
I've got a feeling something simple is wrong and you'll smack your forehead pretty hard when you find it. Happens to all of us from time to time... Possibly two things are wrong at the same time; and that can really confuse diagnosis (sometimes especially if one is ignition and the other is fuel system related.) Without reviewing what other people have already suggested, I can tell you three of the things I would have done a long time ago:
(a) Put a brand new spark plug in the number five hole. It will be nice to scratch "defective/damaged spark plug" off the list of possible problems.
(b) Clamp your timing light on the number five spark plug lead just to make sure you're getting a good steady spark there, just like on number one.
(c) Back at the beginning of the process, I would have removed the MSD box and the fancy coil you're probably using with it... because even though they're almost certainly NOT causing your symptoms, they may well be masking other symptoms. Maybe it's still a worthwhile idea. (MSD boxes cause lots of problems too, but mostly at high load / rpm. You've got it well grounded, don't you?)
My personal experience is that OEM quality control beats aftermarket quality control hands down. Based on what I've heard in your last post, I wouldn't rule out the possibility of a manufacturing defect in the distributor or distributor cap. If you have one laying around, now would be a great time to plug-in a Motorcraft distributor. If not, I'd think about changing caps. One day you'll need a change of spark plugs, a new cap, and a new rotor... you might as well invest in them now. Swapping parts isn't the most elegant way of diagnosing engine problems but sometimes it's the the most pragmatic. For that matter, swapping a "known good" spark plug wires from your pick-up truck or commuter-car for that number five lead might not be a bad idea. It only takes a second.
Just another off-the-cuff thought, but on a late Ford HO engine, cylinders 6 & 5 fire sequentially - you're not getting cross firing going on between HT leads are you?
I'd also check resistance of #5 HT plug wire to see if it jives with the others - maybe a bad end connector or something?.
If a new plug works for a while then goes south again it might be a marginal piston oil ring or a margin valve guide or seal.
This site might be some help.
http://www.autotap.com/techlibrary/diagnosing_misfires.asp
Ok, you guys have redeemed yourselves -- no one gets fired today ;)
I've got locking header bolts on the way. They're a double hex style so should be able to get them all properly tightened & with luck they'll be there when I get home from work Friday.
Haven't figured out what I'm going to do on the exhaust. If I weld it at the mufflers, it'll be solid from the headers all the way to the tail pipes. Not even sure I could get it back on like that. I guess it'd be too easy to have something that could wrap around the pipe under the band clamps. Probably have to get some flanges & put them in before the oval starts & again where I transition back to round to go through the rear suspension. Any other way to effectively seal the joints? The oval pipe slips into oval inlet/outlets on the mufflers.
Plugs are easy; probably should have swapped #5 out earlier - at least to see if it fires. I also like Curtis' idea about putting the timing light on #5 -- that'd tell me the plug is getting voltage consistently -- not necessarily that the plug is firing, right?
Don't think I'm getting cross firing -- at least no signs of it. And, since I swapped #5 & #6 leads and #5 stayed cold, I think that rules out a bad plug wire.
Don't have a stock points distributor, but will probably keep an eye out for one next time I'm at the pick-a-part. Wonder if parts stores even stock points any more? Don't want to go on a tangent, but what would it take to convert a stock distributor to work with the MSD ignition -- is there a magnetic pick-up module that'd work? Thinking out loud here - don't recall why I got a mechanical only distributor.
Rob, You still may have an issue with #5 distributor cap terminal. You can test if the cold exhaust moves by moving your wires one terminal and retiming. Late 70's Duraspark II(magnetic breaker type) will work fine with MSD and has vaccuum advance. You can lose the adapter and use the old style small cap and rotor if you like. I have an article on setting up the advance curve for one if you go that route.
Curtis said "I've got a feeling something simple is wrong and you'll smack your forehead pretty hard when you find it"
So...........Double check to make sure you don't have #5 and #6 plug wires switched. IE #5 fires when #6 should and #6 fires when #5 should.
I double checked the firing order on Monday -- 1-3-7-2-6-5-4-8 so I'm good there.
QuoteI also like Curtis' idea about putting the timing light on #5 -- that'd tell me the plug is getting voltage consistently -- not necessarily that the plug is firing, right?
No. A timing light can be very handy for finding a misfire. I've used a light to simply and quickly verify which cylinder a misfire is occurring on... you can put that inductive pick-up on any of the eight leads, or even on the coil lead for that matter. But the light will ONLY blink when there's a spark.
I'm almost embarrassed to admit it, but for most of my life I haven't owned a timing light. For years and years I set timing statically, and maybe tweaked it a little by ear. I only bought a light of my own when I wanted the dial-back feature... to verify the advance curve of a distributor. (Sure enough, the curve wasn't good.) I bring this up because I don't think Rob's symptoms point to timing per se. If I set his timing statically, I wouldn't expect his engine to miss. It might not make ultimate power, but it would behave nicely. Perhaps something is wonky and causing very erratic ignition timing. That's a different issue.
QuoteDon't want to go on a tangent, but what would it take to convert a stock distributor to work with the MSD ignition -- is there a magnetic pick-up module that'd work?
I publish so many racecar articles... don't you read them? Probably better than half those vintage racecars have a Pertronix Ignitor module hidden inside their distributors, used in conjunction with an (often hidden) MSD box (or Lucas ignition amplifier). Lumenition's breakerless ignition module would work fine too.
This is a roller cam motor?
JB
Thanks Curtis - I didn't realize the light was sensing actual spark firing vs. just voltage on the line. That's great to know.
Educate me on dial back timing lights... don't think I need one. My balancer is marked from 0 to about 40 degrees... so I can see total timing at various RPM's without using a dial back. Aside from determining total timing when you don't have sufficient markings, what's the benefit of a dial back light over a regular one?
As for the vintage race car articles, I have to admit I skim them but don't read them. I'll have to start looking at them more closely though.
Yes Jim, roller cam motor.
That's good. The way it's acting it sounds like a wiped cam lobe but I don't think a roller cam would do that.
Jim
Is the only difference between a Motorcraft AGSP32C and a AGSF32C that the AGSP uses a washer and the AGSF seals w/o the washer? While I was out of town (w/o access to the car) I called Ford Racing to ask what plugs I should be using & the tech told me AGSP32C.
I also checked for spark on #5 - holding the plug to the engine, the spark looked strong, blue, & consistent. Same with the timing light on #5 with the plug back in the engine.
I rearranged the band clamps on the oval pipe today too. I'm confident they're probably still leaking some, but it's way better than it was -- at least I can't feel the exhaust coming from the clamps any more.
Going to let it cool & then replace the header bolts w/the locking ones - they came in today's mail -- and will double check to see whether timing bounces around at higher RPMs using a newer timing light.
Also, drained the radiator fluid & draining the oil so I can see what they look like too. More later tonight or tomorrow.
Oil looked fine. A bit darker than I'd have expected for as few miles were on it, but no signs of water or metal.
The radiator water on the other hand didn't look as good. When I drained it, I noticed it was discolored when it first came out (e.g. the water at the bottom of the radiator), then cleared up within a few seconds of draining. I let the tub sit over night & the radiator water looked pretty good - pretty clean & green. I knew whatever was in it must have settled so I poured off the top -- about a gallon & here's what was left.
I know it looks like oil in the picture, but doesn't look it in "real life"; more like either fine rust or maybe carbon -- although I'm not sure how to tell which? Unless there's a way to tell, I'm guessing the next step is to pull the head?
Radiatorwater.jpg
Rob, that's an iron block motor so you'll have some particulate in the coolant no matter how thoroughly you cleaned the block. I don't think that's anything to worry about.
Jim
Would it make sense for the cooling system to be pressurized after just a few minutes of running the engine? I ran it long enough to get the temp up to about 175 or 180 before draining the oil and drained the radiator at the same time. I was surprised that the radiator was under pressure - nothing excessive, but noticed it when I took the radiator drain plug out.
Absolutely normal Rob. Pressure builds up as your engine heats up. Your engine is near it's running temp and should be very close to your rad cap rating. The stuff in your coolant is also pretty normal. Rust from the block, corrosion from the heads and oils from assembly all accumulate to contaminate the coolant some.
Have you changed out the plugs yet?
Your timing light will still fire whether your plug is good or not, it just confirms that voltage is present. So don't count on that to confirm a good plug. I'm with Curtis I think your problem is going to be something simple.
If you are using one of the more popular stainless steel band clamps for your exhaust. Position it so that the aluminum block is on the short radius of your oval pipe. Lube the nuts and crank them down tight. Somewhere around 40ftlbs. You should see the stainless band deform to take on the shape of the joint. The aluminum block will do the same. If this is a butt joint it will be hard to seal perfectly but it can be done. A slip joint is much easier.
Good luck
Fred
Sounds like concensus is nothing wrong with the radiator water which means nothing is pointing to a bad intake or head gasket. That's good. I hadn't refilled the fluids because I was assuming the next step was going to be to pull the intake & heads. I'd read several posts on the mustang & factory five boards where apparently the Fel-Pro printo seal gaskets - especially intake gaskets - were failing & there's a replacement out that's been redesigned (steel core gasket) that supposedly holds up better. A few members of this board have had the intake gaskets fail & had luck with the updated gaskets. Also several posts talk about using RTV on both sides around the water passage openings on the gaskets which I didn't do.
I'll probably pull the intake & replace the gaskets for peace of mind - but, since I'll have to order them, I'm going to proceed with with trying to isolate the #5 problem assuming the gaskets are ok - at least till the new ones come in.
I did already turn the band clamps so the aluminum blocks are on the short radius & they are sealing better. I didn't do a smoke test or anything but I don't feel the exhaust at the clamps any more.
So, seems like the next step is reflill the fluids, replace #5 plug & retest.
Rob,
Re the RTV silicone. Don't do it!
Silicone is grossly overused and generally for the wrong purpose.
Gaskets these days are pretty high tech, and don't require any "help" in sealing. Proper prep and assembly is all that's needed.
Most gaskets have some form of sealant built into them and adding another product usually defeats that sealants ability to work.
I use the Felpro gaskets all the time. As in several times every day. And haven't run into sealing problems yet.
If the surfaces are clean and flat and the proper torque procedure is used they will work well for you.
If you need silicone to make it work then something is wrong and you should fix that problem first.
Cheers
Fred
X2
X3
I have been a mechanic for 30+ years(yes I am old) and you can usually tell how good a mechanic is as an inverse proportion to the amount of silicone he uses
Rob, Just try retorqueing the intake first and try your new plugs.
Actually, Jim, that idea hit me today. I re-torqued the intake and checked the heads after the first heat cycle but haven't touched them since. It also occurred to me that my torque wrench is at least 30yrs old & while it was a good brand (Snap On) and hasn't been used much in the past 20 or so, it's hasn't been calibrated in that time. So, I picked up a rental one today (my AutoZone says they send them out to have them re-calibrated on a regular schedule). I'm going to check both as well as replace just #5. My kids have scouts tomorrow night so it'll probably be Wednesday before I can do that.
As for the silicone, what do you guys make of these intake & head gasket instructions for Ford 302's from AFR's web site? http://www.airflowresearch.com/sbf_install.php
I would call that a blatantly irresponsible comment by AFR.
#1 why would you ever not torque a bolt when you have the opportunity? Torque specs are provided by the manufacturer for good reason. In particular this instance where the load is spread over such a large area. Doesn't it just make sense to have all the clamping forces the same over all the sealing surfaces? In this day and age of precision fasteners "just tighten it up by hand" doesn't cut it anymore. Pick up any engine assembly manual. Every bolt and nut has a torque spec.
#2 Read the instructions for any gasket installation. They all say tighten to manufactures recommendation. No manufacturer says tighten it up until it feels good. As well they all say do not use any coatings or sealants on the gasket and apply to a clean properly prepared surface. I would be inclined to follow the guy who makes millions of gaskets rather than the guy who makes a few heads. Possibly the tighten by hand recommendation leads to the need for the silicone use.
Cheers
Fred
Rob, just for reference sake, Ford Racing recommends intake gasket M-9439-A50 for use with GT40 alum heads - the cheaper alternative is Felpro #1262S3 - both are steel backed Print-O-Seal gaskets.
If you decide on gasket replacement, do not use supplemental silicone on the head faces but certainly use at the front and back seal to gasket joints (as per Felpro instructions).
You should also instal 4 threaded rods to guide the intake manifold as it is lowered onto the cyl heads - this prevents distortion of the print-o-seal. If you don't use the guide rods, you'll risk seal damage and potential leakage.
Sorry Rob,
I should have mentioned that a little dab of silicone at the interface of the intake gasket and the valley seals is proper procedure.
I guess I was too busy frothing at the mouth to notice.
Also please note that all RTV silicone's are not the same.
They have grown from a one size fits all into very specialized applications.
Make sure that you are using the correct product.
Cheers
Fred
I like the "new and improved Kryptonite Fortified". This stuff would break Superman's ba$#@^'S ! Previous owner of my "Huff" car used enough on intake manifold to create "stallagmites" in the inlet ports. This was beneficial in helping the car get , off the turns, by not slipping the rear tires soo easy. More is always better. Cheers, roverman.
Thanks again guys. New gaskets are on the way; haven't come in yet. Did re-torque the intake bolts in the meantime, they were all loose. Also swapped out my header bolts for locking ones - guess I should say started to. Right side had burned through the front most portion of #1 sealing surface (remember header bolts had worked loose) so will pick up new exhaust gaskets tomorrow & retest once back together.
My experience with header bolts is that they require periodic tightening for a few weeks until the gasket 'settles in' - after that, bolts retain their torque.
If you run EFI with oxygen sensors or have a A/F ratio meter, be very careful about using silicone around the induction system as it could ruin your expensive sensors; food for though........
Pulled the intake; no sign of a gasket problem. Ran out of time between church & the Superbowl and flying out in the morning so won't get to reassemble till Friday. Had planned to do it Saturday afternoon, but of 14 people who signed up to help replace soffit and facia wood on a deserving lady's house, only two of us showed up. What was supposed to be a few hrs was an all day job & I was worn out by the time I got home!
Anyway, before I pulled the intake I re-torqued the intake and exhaust & ran the engine for a while. Runs the same but noticed 2 things this time...
1. Pops every now & then thru exhaust when turning btwn about 2k and about 3.5k (didn't rev it more than that).
2. Checked temps on header primaries and they weren't as consistent as I remembered from before. No's 5 & 6 down in the 150 - 180 range. 7 up around 300 and #8 a bit over 400. #1 was also down around 170. Don't recall 2-4 but pattern was same in that forward cylinders were cooler than rear ones. I'm wondering if the ceramic coating might not be even thickness?
Rob, Another idea. Valve adjustment (rocker arms actually). If adjusted too tight and valve barely seating could cause a miss. I adjust mine in the normal manor initially but ,after breakin put the little clips on the rockers to prevent oil spraying everywhere,with the engine warmed up and running. Loosen until slight clatter,tighten slowly until no more clatter and tighten another 1/2 turn.
Quote...Loosen until slight clatter,tighten slowly until no more clatter and tighten another 1/2 turn.
That method works great for a Chevy, but the std Ford 302 valvetrain is not adjustable. It relies on achieving a lifter preload range while the rocker nut is torqued to value (18-20 ft.lb). If the preload falls out of range either longer pushrods or pedestal shims are required.
It's unfortunate that Ford hasn't caught up to GM with their adjustable rocker assemblies - they sure make life easy!
I am using an aluminum exhaust gasket. It stays soft and will reseal even if reused many times. It solved my exhaust leak problems.
Graham, I had assumed Rob had upgraded to adjustable rockers. I always do,same adjustment as with Chevy.
Replacing the intake gasket today & noticed something I hadn't when I first put it on... Don't think it has anything to do with the #5 fouling issue, but this center port is a water port, right? My old gasket had the cut-out for it so it never occurred to me to compare it to the intake. The new gaskets (Fel-Pro 1262S3) don't have a cut-out for it so I looked @ my intake and sure enough, there's no port there. What's the implication of having it on the heads but not on the intake?
Cylinderhead.jpg
That might be an exhaust crossover port.
Jim
Turns out it's an EGR port. Still not sure if I should cut the gasket there. May not matter but seems like it might seal better with the exhaust gasses hitting the edge of the gasket vs that whole area?
that is an exhaust crossover and the gasket you have is correct dont cut it
As usual, there are arguments both ways to retain or eliminate the exhaust crossover...keep in mind that this feature was designed to improve the driveability of carburetted engines operating in colder climates .
PRO: Cooler intake manifold allowing a denser intake charge and more power
Mitigates vapor lock in Summer
CON: Less fuel vaporization resulting in poorer distribution to cylinders
Increased air density changes A/F ratio, possibly requiring a jet/rod change
Since Rob is domociled in Houston, blocking the exhaust ports shouldn't create a problem (mine are blocked off, BTW)
The heads (X-303 Ford Racing heads) have one crossover only, I cked this very closely and used the blocking plate on my install also. The EFI is not effected since the EGR is behind the T/B. I agree with Graham, the X-over is for cold weather driveability only. The 1862s3 were the Spec gaskets listed in their cat.
SAFETY FASTER!
Graham, how does the crossover reduce intake temps? Seems like routing some of the exhaust gasses through the intake would transfer heat to the intake?
Kelly, what do you mean by "the blocking plate"? I've already re-installed my intake -- there's no blocking plate; just the head (with port on each head) to the intake gaskets (no cut-out on the gaskets) to the intake (no port)... so the exhaust cross-over ports on the heads (one on each head). are "open" to the back side of the intake gasket. Also, is 1862s3 the gasket set for the EFI intake? The ones I got for my carb intake were 1262s3.
QuoteGraham, how does the crossover reduce intake temps? Seems like routing some of the exhaust gasses through the intake would transfer heat to the intake?
You've got it right Rob, eliminating the crossover feature keeps intake temps down.The PROS & CONS that I listed above are for crossover elimination.
Rob, my 1st gasket set came with 2 SS block off plates that fit over the X-over port and block the gases. my intake had only one opening and I used the SS plate to block it. Originally the X-over was to warm the intake and carb to prevent icing in cool damp weather and promote better driveability. You are OK w/o it.
I blocked the cross-over ports in my manifold. Even in winter weather, with no choke, the car runs fine. The only differencve is full warm-up, in terms of acheiving perfect throttle response, takes slightly longer,
The cross-over passage helped animize the fuel for cold weather drivability; on older cars, it also worked in conjunction with a heat riser trap on one exhaust manifold to help create an exhaust bridge to channel the exhaust to the open side. Later on, it became part of the EGR system and also help with cold start with a surrounding water jacket to neutralize the resulting heat once the engine warmed up and helped cool the intake down. This passage would mostly end up getting blocked with nasty carbon and cause cracks at the bottom of some intake designs.
The guys are right, don't use it as you don't need it, besides, your intake is not designed for it.
I've been on and off reading your thread about your backfiring problem so, I don't remember what has been suggested or not. However, here's my 2 cents on some suggestions:
(1) Have you done a cylinder balance check?
(2) Have you performed a "cylinder leak down test"?
(3) I once had a newly rebuilt engine that would have a certain valve stem (on the intake side) occasionally hangi up in the guide, hence, causing popping (backfiring) through the carburetor. I don't imagine that would be your problem but just in case.
(4) Point a hand held digital pyrometer at each exhaust header outgoing tubes and read the difference in thermal efficiency of each cylinder; it could tell you a lot
I hope the comments help you diagnose the issue as I know how frustrating it can be.......
Jac
QuotePoint a hand held digital pyrometer at each exhaust header outgoing tubes and read the difference in thermal efficiency of each cylinder; it could tell you a lot..
That would be a great idea.....unfortunately, typical infrared laser exhaust pyrometers (like the HF unit) won't read an exhaust header/manifold temperature > 500-600F. Normal running exhaust temps are in the1000F range.
You've got to be kidding; exhaust headers temperature readings are directly related to engine load. I don't think that Rob would be doing dyno pull in his driveway; all he needs to do is keep the R.P.M. up to around 2,000 to 2,500 RPM to come off the idle circuit (if carburated) and,, he should get readings around 600 degrees or below; every engine is different, I also assume his headers are Jet coated as it can reduce temperatures quite a bit. I've done this many times and it is an excellent way of picking out lean (or rich) cylinders.
I don't doubt that temperatures inside the headers (coming out the heads) exceeds 1,000 degrees, but we're talking sensible approach here. If someone wants to measure close to combustion temperature then he needs to install EGT probes; again, we're talking diagnostic tool.
I don't know what IR gun you own but mine goes up to 1,200 degrees and I only paid $150.00 for it and if you want to go up higher (2,000 degrees) you also can get one at a modest cost. My IR gun has helped me diagnose all sort of issues varying from A/C to, cooling, exhaust catalytic converter efficiency, tuning, brakes, and etc., etc., Here's a link to tons of IR type guns :
http://www.transcat.com/Catalog/ProductSearch.aspx?SearchType=Combo&Mfg=FLUKE&Cat=TE&SubCat=T3&gclid=CKOCrbvApa4CFUbc4AodgkZ4Pg
Here's also a Raytek owner's manual that depicts the different usefulness of such a great tool: http://www.instrumart.com/assets/108/ST25-infrared-thermometers-man.pdf (good reading material)
I hope that this clarifies the limits of a decent IR gun....... Good luck Rob!
Cheers,
Jac
Didn't realize that you had one of the fancy IR type guns, Jacques......most of the "budget' guns don't go past 600F. The better guns, like yours, are a great tool for isolating cylinder issues.
If anyone is interested, Harbor Freight is having a sale on a IR gun for $34.99. It goes up to 968 degrees F. Not the best quality but you can't beat the price.
http://www.harborfreight.com/non-contact-laser-thermometer-96451.html
Jac
Thanks Jacques, I'm pretty sure that's the same one I have. I didn't realize it goes that high though. It does seem to eat the battery even when it's off/not used so if you get one, take the battery out when you're not using it.
So, in the way of an update... With the plugs short gapped, they were all fouled or fouling -- not sure if they should have been or if that was maybe a symptom of the intake & headers loosening more while trying to diagnose things earlier?
But, I did get everything back together today & ran the car up to temp so I can retorque the intake & headers when it cools. I put the plugs (AGSF32C) at .044 [Have read that 302's seem to do better around .050 but sticking w/specs for now], reinstalled the intake and replaced my plug wires. Initial timing still @ 10*. I also worked on the header to exhaust pipe coupling to try & eliminate a leak there.
Won't know more till I take it back out on the road (waiting for my son to get home so I can check the speedo sensor wire while it's on the jack stands), but running it for a few mins in the garage, here's what I observed:
1. All 8 cylinders seem to be firing -- ranged from 350-425*. That was just random idle with occasional runs to 2500 or 3k RPM.
2. Played with accelleration & rapid decelleration & didn't hear any pinging, popping or backfiring.
3. Not sure it's 100% sealed, but the exhaust leak @ the header couplings is either fixed or very close to it. It's hard to tell in the garage, but I think I still have some exhaust leaks back by the muffler but will check those later.
I do have some oil & water on the garage floor I need to check out. I think the water came from a heater hose that was loose & I'm guessing the oil came from a socket that fell in my drain pan (it was barely big enough; oil was very close to the lip). But, will clean that up & see if there's any more when I run it again.
Since the intake gasket didn't show signs of a problem back when I pulled it, I'm hopeful that all that was wrong was the loose intake & headers, exhaust leaks, & probably one or more plug wires (haven't checked them w/ohm meter yet put plan to out of curiousity).
Will post an update when I get to run it later in the week.
Played with accelleration/rapid decelleration and didn't hear any
Has this story got a happy ending yet? Can't wait to hear.......I'm thinking air leak was the biggest problem
Quote: Has this story got a happy ending yet? Can't wait to hear.......I'm thinking air leak was the biggest problem
Well I'm delinquent in posting an update... But yes, this story does have a happy ending. Took two tries, but it is running much better now. I'm pretty sure it was a combination of both air leak and a couple of bad plug wires. Here's what I did:
Re-did the intake gasket using the fel-pro 1262S3 gaskets. Turned out the combination of the bigger ports in the gasket and my world products air gap clone weren't a good match. Remember I'd said I had some water on the floor? Well, th 2nd time I started it I had a spray of water shooting 10' across the garage. The intake casting curved down toward the back bolt by #8. I didn't notice when installing the intake but it left a pin size portion at the upper back corner of the water port in the gasket uncovered.
Since I had to pull it, & I was still concerned my drop base was contributing to the rich condition (I only had about 3/16" between the top of the choke horn & the bottom of the air cleaner cover so was worried I wasn't getting enough air in) - so, I did a sarch on craigslist & there was good condition Edelbrock Performer 289 intake for sale. I got that installed it - this time using fel-pro MS93334 gasket. It has similar composition but ports matched the intake & heads better.
I also replaced the plug wires. Later tested them & two are suspect. They're two of the shorter wires but resistance on them was double the longest wire.
And last, I took some time to get the exhaust leaks sealed up.
Net is it's running way better. All 8 cylinders are showing similar temps @ the header tubes, it's pulling stronger, the popping on deceleration
is gone, and the tendency to run on when I shut it off is also gone.
I'm going to drive it for about a week and then have another look at the plugs, but there's no doubt it's way better than it was. Thanks to all for your help!
Great job Rob. We all like a happy ending. Nothing conquers like persistance. I'm still working on the concept. Cheers, roverman.