We took Phillip Leonard's RV8 racer out this weekend. Didn't do very well. The car ran great, but it had a problem with loss of oil pressure after about 7 laps on the Heartland Park track. When the driver slowed down after switching off the engine and then restarted it had good oil pressure and he was able to drive it back to the pits without problems. We found that we had pumped about 2 quarts of oil into the vent tank and some other loss around almost every point on the valve covers. No leaks and didn't show any signs of excessive blow by in the pits. I suspect that we were pumping all the oil up to the top of the engine and it couldn't drain back quick enough. Anyone have any experience with similar problems or any ideas on how to restrict the oil flow to the upper end without risking damage to the valve train?
Engine is basically a pretty stock 3.5 with around 10'5:1 compression and a single 4 barrel intake. Currently running a V8 T5 with a 3.9 rear gear and a 6500 rpm redline. Driver was running the whole track in third and fourth gears.
Bill,
I am so glad you encapsulated the oil problem we ran into Saturday (4/30/11). Here you've described to the V8 Forum group our problem and maybe we will get many suggestions of solutions and then a consensus of what corrections need to first be made.
Seems to me that the oiling, breathing and venting problem has been around for many years with various early Rover 3.5 and 3.9 aluminum block V8 engines.
Suggestions - please - anybody ...
keep them on the track,
phillip g
Holes in rocker shafts are pointing "downward" ? Exact clearance between shafts and rockers is ? Perhaps run-only motor with "splash tray/cut-out cover", to observe ? Type of rockers/shafts ? If the're "needles", you will need restricted oil feeds.I 'm hoping your NOT using stockers. Good Luck, roverman.
Thanks Art, don't know what type of rocker arms are being used, another guy built the engine but I'd bet it mostly stock parts as it is only a test "mule" to get the chassis sorted. Hard to find the source as the problem has only come up after 5 or 6 race laps on the track, in the pits and on the dyno there was never a trace of oil problems. We ran the car last year, but only a very few laps and at relative low speeds because of the rear gear ratio at the time.
Hey Bill,
I've battled the same problem on a friends BGT 3.5v8. It is a street car but gets used on some track days when he's bored with his race car.
To me the problem has been threefold.
#1 the block doesn't breath. The only ventilation that it has is through the cam shaft area which is quite small with the cam and lifters in place.
This leads to problem #2. With the engine running at high speed the cam picks up a lot of oil, which aided by the crankcase pressure and the sharp edge of the block opening, fills the valley with oil.
Which leads to problem #3. The design of the cylinder head causes it to collect oil. For some reason the drain back holes are at the top of the head. When running, the valve covers have a litre or more of oil in each one. Couple this with a valley full of oil and little drain back area from the heads and you puke oil out everywhere.
So what worked for me was, venting the block through the timing cover ( didn't want to drill the side of the block ), opened up the drain back area around the cam and gave the edges a good big radius biased back into the block, drilled the sides of both heads and put in two drains per side back down to the oilpan ( must terminate below the oil level).
Haven't had a problem since.
Hope that helps
Fred
That's what I was hoping for, someone who had seen the same symptoms. Fred, your reasoning and solutions sound right on, definitely something we will try.
This car "should" be generating over 1G lateral. This is tough territory for a wet sump to work in.The outboard bank/ cylinder head,(in a turn), will tend to flood with oil ,as it easily climbs out of the 45deg lifter valley and approx. 45deg. drain back angle in the heads. I strongly suggest you build a proffessional quality "race" engine, including a dry sump. A proper dry sump system will make more hp. AND save the motor ! Did I mention, you can "lower" the engine ? You guys have a beautiful/aero car, that is built well. Let's do the motor, just as impressive.I suspect your "serious" competititors, are using dry sumps. Phillip, please pm. me. Sincerely, roverman.
That's the plan for the future Art, a true race motor. Clancey Schmidt built a very nice wet sump pan for the engine with an extended sump and bafflels, should be fine as a wet sump engine if we can keep the oil down in the pan. Phil want's to find a 4 bolt main block to build the "race" engine with, the one in the car now is basically a warmed over stock Rover. Judging from the other racing MGB V8s in the photo area our venting system and pan should do the job if we can get the oil to drain back better, but that's Phillip's call, his car and his money. I figure we have all this season to run the present engine and get the rest of the car sorted out and hopefully install a better motor for next year and compete in earnest at that time. Our regular driver, Robert Malpins is recovering from rotator cuff surgery and won't be ready to drive until late this year or next spring so we have some development time ahead anyway.
Years ago, I obtained a small block Chevy that was used in dirt track racing. The entire block valley was polished smooth to facilitate oil drain back - an expensive proposition but perhaps worth the investment.
You can polish the valley to "mirror finish", it will only help the oil climb up the 45 deg walls ! We're chasing an issue here, that is correctly solved with a dry sump system, end of story. What works for dirt track does not apply, as they don't generate the lateral g's of asphalt. Cheers, roverman.
A dry sump surely must be the ultimate solution... but for short term / partial improvement, I think Fred is on the right track. In addition to improving the Accusump installation, these two changes in particular could easily be implemented before the next outing:
1) Plug the vent bung on the driver-side valve cover:
(http://www.britishracecar.com/PhilLeonard-MG-RV8/PhilLeonard-MG-RV8-BF.jpg)
2) Install as big a vent bung as feasible on the plate that covers the old mechanical fuel pump port:
(http://www.britishracecar.com/PhilLeonard-MG-RV8/PhilLeonard-MG-RV8-BK.jpg)
(I've been meaning to implement these two changes on my own engine...)
One way or another, what this car really needs is track time. I bet some clubs are already renting Heartland Park for track days, and surely they wouldn't mind sharing the track and the expense of renting it. Porsche club? Corvette club? Z club? Make some inquiries. I get invitations to join my local Miata club for their track days quite frequently - they're very happy to have something different to chase around the local tracks. There are going to be other problems to sort out and refinements to be made.
Hey Art,
I'm going to have to dissagree.
Dry sump systems are not the be all end all of oil supply.
Several factors could lead you to use a wet sump system.
#1 is class rules. Often you just aren't allowed to use a dry sump.
#2 is cost. Dry sump setups are expensive to build and maintain.
#3 is weight. Extra pounds are added precisely where you don't want them.
#4 is complexity. As the parts count goes up so does the chance of something going wrong. With all the pumps, hoses, fittings, tanks, belts and brackets something is going to fail. Possibly not often but enough to put you out for the day.
#5 is safety. You carry more than double the oil capacity with a dry sump system and some day you are going to oil down the track or the car.
#6 is space. Dry systems take up a lot of precious room the may not be available.
Granted a lot of my opinion is based on rally racing where simple and light is better. You can't race a broken car. So the fewer things to break the more you win.
Besides wet sump systems have come a long way. Oil management in a wet system is light years ahead of what it used to be.
So for me, unless the situation absolulely demands a dry sump, I would favour the wet.
Cheers
Fred
Sounds like the same problem many people have been having after installing shaft mount roller rockers. We solved our problems by installing bushings in the head oil galleys.
Curtis, what would be the point in removing the large vent from the valve cover? I checked the files and several of the MGB V8 race cars use vents from both valve covers, although they aren't as large as this one. I do agree that the fuel pump block off plate is an ideal spot to run a vent line from. Easy to make a new block off plate from some aluminum and drill and tap it to take the necessary fitting. We already have a small -6 AN fitting to the oil catch tank, we could T off that very easily although I tend to think a larger than -6 line would be prefereable. I figure at least 1" if we can fit it to the block off plate.
Todd, can you give me details on how and where those bushings were installed? I'm not sure what type of rockers we have but that might be a factor as well. Thanks.
Hey Bill,
I would put the same great big vent on the passenger valve cover as well. Small hoses, with some crankcase pressure, make fantastic oil pumps. Angle it inwards just like the left one so that if the valve cover does fill with oil it won't dump into the catch tank on a hard turn.
Also put a drain from the catch tank back into the oilpan. This can be a relatively small hose if it enters the pan below the oil level.
You will need some sort of deflector or baffle at the fuel pump flange as the timing chain will be firing oil right at it.
Use the biggest dia hose possible from the pump flange. And if it enters the catch can on the bottom it could be used to drain any captured oil back to the engine instead of a separate drain hose.
By the way I love that car.
"Go get em".
Cheers
Fred
You might consider a blow-by gage, in that excessive amounts will aggravate oil control, out the breathers/etc. You might want to consider using a modified EGR pump, for negative crankcase pressure. roverman.
Art, we thought about excessive blow by as a cause at first, but the loss of oil pressure means that the pan has to be getting low and blow-by by itself wouldn't account for that except as a cause of the oil not draining back into the pan. With the valve covers full of oil then with the venting system we currently have any crankcase pressure would have to force oil out of the engine. The idea Curtis had on venting the timing cover at the fuel pump block off would vent the crankcase below the valley and hopefully not force any oil out of the engine, but would it also solve the drain back issue? We'll have to experiment a bit and find out. Since we have limited track time available we'll probably try several of the suggested solutions before going back to the track in hopes one or all will solve the problem. The car seems pretty good but until we get the oil under control we won't be finishing any races.
For those of you with more experience on the Rover/Buick engine, is the sheet metal valley cover strong enough to install a fitting for a drain back or vent? For the car that would be an easy place to install a drain back line from the oil catch tank. I know it wouldn't drain back during engine operation, but at least after the engine is shut down we wouldn't loose the oil in the tank as we do now when we manually have to remove the tank and drain it.
Bill, your rocker shaft oiling holes are rather critical with roller rockers, since the needle bearings offer no restriction to oil flow whatsoever. If used with stock shafts oil flow will be completely uncontrollable. The feed holes in the shaft are the correct restriction point, as restricting oil to the shaft will result in uneven oiling front to rear. Sorry I can't advise you on the correct feed hole size, but a 1/16" diameter hole may be quite a bit too large. Needle bearings require very little oil and even a .010" hole should be enough as long as there is nothing in the oil to clog it. That would be my main concern with small feed holes.
A stock shaft can have feed holes as large as 1/8" but they are on the bottom and the bushing provides plenty of restriction. The same shaft with rollers would have about the equivalent of nearly a 3/8" open oil galley firing 45 psi oil into the valve cover which I'm sure you agree would be a problem.
JB
Bill Davidson, who assembled the engine, is back from Key West and I just got off the phone with him. The engine is running stock rockers, shafts, etc. so excessive oil from those shouldn't be the cause of the problem. We'll address the venting and drain back issues as soon as we can and report back. Thanks to all for the help and information.
Sounds like you don't want to pull the motor-understandable. Draining the catch tank into a modified sheet metal gasket sounds problematic.When you need to replace that gasket ? Fred's idea of draining excess oil into the pan, is a good one. Taking oil out of eack outboard corner, of the heads ,and draining into the pan should work. If you choose not to pull the heads,, "maybe"draining, just above, with ports in the valve covers, would work. Consider draining the catch tank (a) into the pan or (b) through a pipe tapped hole in the fron/rear China wall,(each end of the lifter valley).I wonder if a small electric scavenger pump,ie. fuel or water, sucking oil from the problem areas/discharging into the pan, would work ? Good Luck, roverman.
Hi Bill,
I'm with Art.
Putting a fitting into the valley cover will be a problem.
It can't support any weight or vibration and it's a problem when you need to change gaskets.
As well you'd be draining oil right into the area thats giving you the problem and venting an area that the valve cover vents service adequately now.
The oil return needs to be below the valley opening along with the new vent.
If your using anything smaller than a -10 line for the drain, then it needs to terminate in the pan below the oil level. Or it will push oil back up into the tank. A bigger hose will let the air pass by without taking the oil with it so it can go anywhere. Such as the fuel pump flange.
Cheers
Fred
Using the fuel pump cover as a vent/drain might be helpful, but I suspect the 4 corner drains to the pan are going to work out the best. Are you using a baffled/trapped oil pan and scraper? That car undoubtedly generates enough G's to slosh the oil up around the crank where it'll promptly get thrown everywhere except where you want it. Under those conditions even the best drain back system may not be enough. If you use the 4 corner system you can also baffle the rocker box to direct the oil down the drains. I'd put the drains in the heads themselves since the outer flange rises up to meet the valve cover. You could also put baffles in the lifter valley to keep oil from being thrown up into the rocker boxes. Lay one over on it's sides and you'll see where you need them.
JB
Thanks guys. I'll pass the information on to the rest of the crew. As for me, enought to do for my own car to get ready for the trip to Townsend so I'll have to let the race car wait until I get back.
Many modern V8's, like Lexus, Gen III hemi,etc, have 4+ large drain-back ports cast into the block, that dump inside the pan rails. The latest winner of Engine Masters(Gen III hemi), extended these ports downward with extension tubes.Cheers, roverman.
Under the rocker stantions in the head, you will see an oil galley front and rear. Only one is used per side as the heads are reversible. I bushed all four just so I wouldn't have to remember which head for which side. I had my machinist tap the oil hole and thread in a brass plug with a hole drilled into it. It will be loose, but not to worry, the stantions hold it in place so it won't back out. The oiling hole is about 190 thousandths originally. First I tried reducing it to around 90. Still too much oil pouring into the valve covers. Next I tried drilling .055 holes in the bushings. That seemed to do the trick. Oil is now manageable. Originally there was so much oil it couldn't drain back to the pan fast enough. The blow by from the bottom end was forcing the oil up and out of the breather at higher RPMs. Remember this was with shaft mounted roller rockers, and we also had one of the oiling holes in the rollers welded shut. Too much trouble in my opinion. Next time were going to use plate mounted rollers. A buddy of mine had the same problem and he plugged the hole in the head completely and is oiling up thru chevy hollow pushrods. Seems to be working as well, but not a lot of miles on that engine yet.
With roller rockers, pushrod oiling is a pretty good option, provided the rockers are designed to channel splash oil into the needle bearings. If they are not, a depression of some sort in the top and a hole draining into the bearing area should do the trick.
When using bushed rockers the amount of oil delivered depends on bushing clearances so obviously tight clearances mean better oil control. But, I've seen worn out engines that did just fine because the bushings had worn on the bottoms to the shape of the shaft, which had also worn, leaving as much as a 1/16" gap at the top. This still worked because the oil feed holes were at the bottom and spring and lifter tension kept the bushing pressed against the shaft, mostly blocking off the feed hole. Odd as it sounds, something like this can actually leak less oil than a brand new shaft and rockers. But it'd be less than ideal for a high speed motor because of the change in geometry from wear.
Restriction of rocker shaft oiling has in the past been a very common method used to keep oil in the bottom end. Early on it was recognized that oiling at high speeds was markedly more than what was needed and that there were benefits to restricting the flow. The usual method was as Todd described for his roller rockers, but it should be understood that the risk of this method is poor distribution from front to rear. Of course on a road coarse this may not be a problem.
Pushrod oiling also has been used successfully with shaft mounted rockers of the more conventional type, but often this was done by using pressed steel unbushed rockers where the rocker itself forms an oil reservoir that collects splash oil from the pushrod. You see these in the 350 SBB for instance, and it is a system that works very well. You might be able to adapt 350 rocker shafts to your engine, although the spacing would need to change some. The center pushrods on the 350 are moved over about 3/8" and the intermediate ones a bit less. The outer ones are unchanged. So it may be possible to juggle things around enough to match up properly. The stands should block off the oiling ports in the heads, and then hollow pushrods and correct lifters to finish the job. May not make a lot of sense on the test motor though.
JB
"Maybe" we should ask the guy who built the motor, for his solution ? I'm going to risk some more objecture here ,and go on record to say, needle roller rockers are best suited for a mech. roller cammed, 3.5L Rover, to be a serious contender in GT 2. My Huffaker GT1 car used Volvo adjustables,(I think they were allowed at the time), non roller, and while strong, they produced a LOT of scrub on the valve tips ! These would run up to 8k rpm., but at the price of quick wearing valve tips.Requred changing "chain" after every race ! Of course now,I would use a gear or belt drive, on the cam. Good Luck, roverman.
Art
What gear drive is availible?
Art, Bill Davidson built the engine and it's basically a stock Rover long block at this point. It was just a budget piece to get the car on the track so we could sort out the chassis without putting hours on a real "race" type motor. We'll keep this mule engine in the car for this year I suspect and finish all the sorting of problems such as the oil problem we're addressing now as well as some handling issues Jessie reported, then we'll build a more highly modified engine for the car. That engine will require a lot more thought and engineering. As Phillip reported in another thread we have to run a restrictor plate under the carb and that will have a lot to do with determining just how much cam and head work we should run. Having the intake valves open longer won't help much if you can't fill the cylinders because of the restrictor plate. Finding the right combination in that area will take some tiral and error I suspect and we don't have the resources like the big boys in NASCAR do to try different combinations for their restrictor plate motors.
Milodon did make them,(Buick V6 with odd-fire nose). I had (2) roller cam blanks made with (3) bolt mounting, to use sbc belt or gear. Cam/crank centerlines are closer on B.O.P.'s, idler bar will need a mod. Cheers, roverman.
QuoteYou will need some sort of deflector or baffle at the fuel pump flange as the timing chain will be firing oil right at it.
Maybe. Not sure there is much oil in that area. One of the mods I see in all the books is to drill holes in the block to better oil the timing chain.
Jim Blackwood suggested this mod for my badly blowing 215 last Summer. By coming out, then up with the hose any oil should drain back. Or, run it to the catch can, then back to the oil pan (as mentioned).
Not having run a Rover on a dyno with a "clear" valley cover, I suspect oil is actually try to fling/levitate up/out of the valley drain slots. Why?, crankcase pressure and throw-off from the cam, lifters and rotating assembly.Of course this impedes drainback from everything, above this area. I like the idea of welding/closing these slots,(stronger), and draining valley at each end, yes,rear would need a port added. IMHO, roverman.
So where would be the ideal places to scavenge oil from on these motors, specifically the 4.0l varient?
I ask this having just picked up a 5 stage oil pump. My plan was to run two pickups in the pan, and one on either side of the lifter valley, but maybe I should be pulling from the heads instead? Maybe just one pickup in the valley and 3 in the pan, bye bye crankcase pressure...
Jeremy, road course or oval ? For my build, I would seal-up the lifter valley and use one scavenge in it. 5 stages is a lot for a Rover. I would limit bleed-off from rockers. My Huffaker GT1 motor has 2 in the pan. I suspect a clear valley cover, on engine dyno, will tell you where, IMHO.Good Luck, roverman.
Road course, and street driven for that matter. 5 stages is a lot, I was looking for a 3 stage but found this one for $300, practically new. I'm thinking about doing Chevy stud mounted rockers, but either way I was planning on oiling through the pushrods, that should limit oil to the valve covers.
I wish the clear valley cover wasn't so hard to do on these motors, on the LS1 it couldn't be easier, has anyone fabbed up a valley cover independent of the intake gasket? I was thinking of doing one out of UHMW polyethylene, but I guess I could use acrylic or similar for a few dyno runs. R&D budget is small for this project, might end up doing the dry sump and find out later if I need to change the scavenge pickups.
Just a thought
Didn't Group 44 racing have to resolve this problem when they raced TR8s......If any of their alum is on maybe they could comment. What oil pan should I put on my street/auto cross V8 B?
Jeremy, I would try .06" polycarbonate,(Lexan). "temporary" on engine test stand-only ! Possible to use extra stages for trans or rear end ? Modify pump to "remove' un-needed stages ? David, I would get pic's of "Phillips" wet sump pan in his RV8 GT 2 .car. A crank scraper is a good addidion to any motor. I would also use 1/more, Moroso 1.5qt., verticle "bottle" accumulator. Street and Slalom is is easier for oil control. The duration and severity of lateral G's is less. IMHO, roverman.
I will give the Lexan a try. Using one stage to pump trans fluid through a cooler is a good idea, otherwise I am thinking I will be using 3 stages on the pan and one in the lifter valley. I'm not sure of you can have a problem with too much crankcase vacuum? Am I going to suck my combustion gases into the pan?
Kevin Johnson makes a crank scraper for our motors for a good price, including a zero clearance teflon scraper.
Jeremy, each stage produces vacum and pressure, so I think it could "dry sump" the trans, pump through a cooler and into "spray bars", like Bonneville racers use ?
Most modern manual transmissions don't need much over 30 wt. for racing, your results may vary. I think I might "slow" the pump down, to where it produces just enough psi at lower rpm. If your gaskets impload(lol),OR your getting inlet charge into the crankcase, I would check with a "blowby" gage. IMHO, roverman.
Yes the idea will be to size the sprockets to produce the minimum hot idle pressure. Peak power on this motor will likely be at 6000rpm, so at least I don't have to worry about dealing with an 8k+ rpm range. I could always route one stage back into the pan, that should cancel out...
I'm not sure if I want to pull apart a T-5 to add spray bars, seems like overkill, but then so is a 5 stage oil pump on a rover...or ITBs for that matter. Lol
Checking for blow-by will be a must, I'm going to be upset if I'm not making at least 300hp with this hunk of junk...
Jeremy, According to Dynomation, using my ported Merlin heads, single plane intake,830 cfm 4bbl, 290" would power peak at approx. 7k rpm.,mech. roller cam. We are soo jacking this thread-sorry Phillip. Cheers, roverman.
Was watching this and was just going to let it ride out but.........
A 5 stage pump is waaaay too much for this situation.
Each stage costs you power to run so you only want the minimum needed to accomplish your goal.
I don't know what pump you have but most are modular so just remove the excess modules.
I for one would not multiplex the engine pump for the trans and rear end.
#1 it's not needed
#2 if the sealing between stages is not perfect (which it mostly isn't) you run the risk of cross contaminating the various lubricants.
And #3 Thats a lot of hardware, lines, oil and weight that you don't need to carry around.
Running one stage for the oil cooler also has it's problems. The individual stages when used as pumps are un regulated.
You run the risk of blowing up your oil cooler unless you install a pressure regulator.
Expecting these pumps to control blowby or cause a vaccum in a properly vented engine just ain't gonna happen.
If this were mine I would seriously evaluate whether a dry sump is needed and if it was, limit the pull to the heads and the oil pan. A proper crank scraper and a windage tray will take care of the valley oiling and still give enough oil to keep the cam alive.
All in all remember simpler is better.
The lovely Lynne says thats why she married me.
Cheers
Fred
Fred,
Thanks for chiming in, I post on these forums to get input from guys like you and Art, it is much appreciated.
The only reason I am considering a 5 stage pump is the price I picked this up for, you're right though, I can just get some shorter bolts and turn it into a 3 stage. Would it be worth it to have two pickups in the pan and one in each head? I am planning on oiling through the pushrods so I don't anticipate having the same oil control issues.
I will be running a Kevin Johnson Teflon bladed crank scraper and windage tray. Honestly the main reason for the dry sump is to gain that extra couple of inches of ground clearance so that I can mount my engine lower. I am shooting for an intake runner length of 12.121" (3rd Harmonic with peak power at 6500) and I would like to keep the TBs themselves under the hood, though I expect the trumpets to protrude...
So you're planning on cutting down your crossmember and lowering the steering rack? The engine angle will change so the axle angle should also, and then what of your bellhousing and flywheel? Cut down flywheel, multi disc clutch and custom starter maybe? The oil pump itself doesn't seem to me to be the primary restriction on lowering the engine. I'm like Fred, I like simple. Adding an external pump and an external reservoir is anything but.
JB
This topic was started to help Phillip's oil control problem. Are we any closer to a solution ? To me, it appears his problem, is lost in committee ! I suspect most serious cars in GT2, are running dry sumps. Why, because they need them ! I've listened to all the negatives of dry sump systems, interestingly-enough, Porsche has been using them on production 911's for 40+ years and production Vettes for 6+ years ? I don't believe Porshe or GM use these foolishly. Real racing in SCCA is expensive. If you can't afford it, or are unwilling to shop for "deals", there are many cheaper forms of racing. There are bargins on dry sump components and other serious race parts, on ebay, and other onlines and auto swaps, all the time. Sometimes, you have to dig, if you want bargains-it's own reward. Cheers, roverman.
Art, I just got home from this year's V8 Meet and haven't had a chance to get together with Phillip yet, but as far as I know no progress has been made on the original problem except for some great suggestions here on the forum. I'm not sure that a dry sump would help us much as the problem seems to be a drain back problem to the sump, so wheither wet or dry if the oil doesn't get back to the sump to recycle then we'd still have oil problems. I don't know what Phillip's budget is, but I suspect that he's much like the rest of us and will have to keep things simple for a while yet in terms of cost. All the guys on the team will get together and decide on what direction to move and I'll keep you guys up to date on what's going on when I have news. Thanks for all your suggestions and experience.
Sorry if these drysump questions are getting off topic, but it is a potential oil control solution, so hopefully it is not too far off...
Jim,
I am using a tubular subframe and relocating the steering rack to give myself some more room, I might even explore some alternate steering rack options to move the steering shaft outside of the subframe if necessary.
I'm not sure how familiar you are with the Miata, but it seems like I have a bit more room than you MGB guys. I'm using a d&d fabrications bell housing, the kind that is open at the bottom, so clearance there is fine, we'll cross the flywheel and clutch bridge when I get there, but I have a few options. Actually where I want the motor right now should straighten out the drive-train to be almost level, I don't anticipate many problems with the suspension geometry (no more than what I can expect with a stock car anyway).
I really have the engine where I need it, I'm just trying to regain some ground clearance. My other option I have explored is building an extra wide and shallow oil pan. The C5 vettes seemed to do fairly well with them, but that still leaves us with a few quarts of oil in the heads unless we fix the drainback problem or scavenge oil directly from the heads.
Again, I hope I'm not getting too far off topic, my major question is with the viability of a drysump in fixing this oiling problem?
Update. We have finished the vent line from the fuel pump block off plate area up to the line leading to the catch tank. Used -12 AN line and fittings. Should vent enough pressure from below the cam area to allow oil drainback but we won't know until we can get it on the track. Right now we're shooting for July 15th if we can get the new 8" Ford rear installed by then. Thanks guys for all the help and ideas to cure this problem for us.
IMG_0646.jpg
IMG_0647.jpg
IMG_0648.jpg
Phil and Bill
Looking at these photos and if I understand the problem, it looks like you are trying to create a negative pressure on new tube to fuel pump plate to pull oil to the bottom end of engine. Where does this negative pressure get produced in this system? Hope it takes care of the problem. If not is an engine vacumn pump an option in your class?
I don't mean pull oil through the tube but depressurizing the bottom end for better drainback.
The latter is the idea David. If you go back to the first of this thread you'll find the original problems we had at our first actual race with the oil drainback. I looked at the V8s shown in the British Racecar section and it appeared that we had enough venting on the top of the engine compared to others but we still had drainback problems. IIRC Curtis suggested venting from the timing cover at the fuel pump block off and that's what we decided to try first as it didn't require removing the heads or the oil pan as some of the other solutions did. If this doesn't work then we'll add oil drainback lines to the heads leading directly into the oil pan. We also took care of several other items that caused problems last time out.
I really like the oil pump block off plate, Bill. I could use one of those to help my blow-by issues.
That air filter has got to go, though.
Carl, send me a gasket and I'll make you one minus the AN fitting. Just a chunk of 1/2" aluminum plate I cut out on the band saw and drilled for the fitting.
As for the air filter, that's something we're working on. When Phillip got the restrictor plate made he had to space up the carb about 1/2" so that the butterflys would clear the restrictor, that didn't leave us enough room between the hood and the carb for anything else other than this cut down filter for now. A new hood is coming we hope with a bit more "hump" that will allow for a remote air filter and cool air intake system. For now this keeps the larger stones and birds out of the intake. Bill Davidson trimmed off the choke housing and smoothed out the upper carb areas for better air flow so the filter even though it's low isn't too restrictive.
Hi
I have the same oil drainback problem with my 3port drysumped rally TR7V8. It seems that when I get over 6000 rpm the oil have great diffuculties getting back to the sumppan.
Now the engine is out of the car for service and I have made an oil baffle plate above the camshaft. I have noticed that when engine is running above 2000 rpm the oil is splashing all over, inside the Vee and up into the rocker covers.
Some ford and chevy engines have such an oil baffle plate.
I have also drilled 2 10mm holes behind the timing wheel and into the valley, for faster oil drainback. Unfortunatly this fix properly only works when braking (G-force)
I like the idea of venting via the timing cover, because I think that the venting air is not going to press additional oil up in the direction of the rocker covers. Also crankcase blowby air will maybe enter timing cover via the gap under the front main bearing and into the timing cover venting.
P1010758.jpg
Do you have any photos of the oil baffle for the cam and placement? Just thinking about it wouldn't the valley intake/heads gasket function the same way?
Hi
Picture of oil baffle plate
IMAG0317.jpg
Per, I would have thought that type of plate would have made the oil drain back problem worse. Stock the only drain back from the heads is via the valley, there are troughs built into the ends of the head specifically for that purpose. I suppose you're running roller lifters as well, I would think that flat tappets would need the oil flow from the valley to keep well lubricated against the cam.
My Huffaker GT1 engine has a syphon line from the dry sump pump, mounted in right rear of lifter valley(4 stage). I would not assume there is more bleed-off from the rocker assemblies than say, the cam and lifters(will vary greatly with cam bearing and lifter clearances). We seem to be rehashing what has been proven in racing circles, for decades. Dry sumps cost some hp. to run. They also save hp. in other ways, like keeping a motor from destroying itself due to oil pressure loss. Blowers cost hp. to run, so why use them ? Good Luck, roverman.
I had the same thought Bill.
The oils only avenue back to the oilpan is now blocked.
This plate will stop the cam from throwing oil up into the valley so maybe at the end of the day it's a wash?
I had an idea while looking at this, feel free to tell me what you think.
What if you designed some sort of scraper for the cam similar to a crank scraper?
This scraper would shed oil from the cam back into the crank case.
This would then turn the cam into a rudimentary pump that would pull oil from the valley back into the sump.
You would need to leave some oil on the cam, but not much in a race engine.
It's just crazy enough to work!
Cheers
Fred
I think the oil that flies up into the lifter valley is coming from the crank. At 7000 rpm the cam is turning 3500 rpm and is much smaller in diameter. It would have to be swimming in oil to throw enough up into the lifter valley to make much of a difference, and as big as the crank is and as fast as it is turning, that is probably correct. If you eliminate enough of the oil coming off the crank it may not be that much of an issue. With the smaller cranks (5L and under) there should be enough room for a deflector or scraper between the crank and cam. Properly designed and located it should be able to deal with the windage.
JB
I run forged rocker setup on this race engine (not rollers). I have also reduced both the cylinder head oil feed to the rockers from 4.7mm hole to 1.5mm.
Engine has been leakdown tested and all cylinders has 1-1½% blowby, so the rings is sealing well.
Still some oil find it's way up into the rocker cover breathers (is also baffled) at high RPM.
The oil fumes that the catch tank contains (approx ½ litre after one race) is totally dark grey, but engine oil is fine and as new. (oil temp is 85 degrees).
I hope the camshaft splash guard (oil baffle) will prevent oil splash from cam and crank to splash up into the valley and cylinder heads. If oil can run down into the big hole above the camshaft it can also go the other way in form of splash.
Cam lobes should still be lubricated from splash oil from crank and oil from oil baffle sealing dripping.
If you look at an engine from below you will see that the oil will have great difficulties getting back to the sump due to the rotating camshaft lobes and crankshaft counterweights and conrods spinning. Combined with that engine blowby only can enter the breathers via the cam valley holes you have upward moving air at the same time oil tries to go down. Can't be a good coctail :-)
Thats why I now have drilled two 10mm holes from timing chain area into the valley. Maybe the holes are to small ?
Well, I have to try all this out when race season starts, but it is nice to hear some suggestions.
Per, are you using a crank scraper ? Drainback holes in the front "china wall", are a good idea. There is ample room behind the rear china wall to run 1+ drain lines into sump area. Do your connecting rods have "squirt holes" at their parting lines, aimed at the camshaft ? Roller cam ? They require much less lube than flat tappet,(no need for squirt holes). Good Luck, roverman.
Thanks for your reply
>>Per, are you using a crank scraper ?
The one that is fitted to the JE sump does not reach very far. I have now extended it some 40mm without interference problem.
I also think part of the problem lies here.
>>Drainback holes in the front "china wall", are a good idea.
>>There is ample room behind the rear china wall to run 1+ drain lines into sump area.
I have to look further into the rear drainback option. Remember my drysump pan is flat so it is difficult to make a drainback.
>>Do your connecting rods have "squirt holes" at their parting lines, aimed at the camshaft ?
No. they are JE steel rods. Don't know manufacturer.
>>Roller cam ? They require much less lube than flat tappet,(no need for squirt holes).
No. Crane 248 cam and oil supply to heads is limited from 4.7mm to 1.5mm.
One time when I had the rocker cover off I noticed that at above 2000 rpm there starts to come many squirts of oil from the camshaft area and up through the cylinder head drainback holes and out on my garage floor. Didn't have the courage to rev it past 2500 rpm, because I would have been shoot all over with oil bullits.
By the way engine has only done some 2000 miles from new.
Per
Per,
You have experienced the breathing problem that these engines suffer from, first hand.
Pressure from the crankcase has nowhere to go except up through the slots at the camshaft and into the valley.
Once the spinning cam picks up a good load of oil it effectively blocks any drain back through the slots.
The pressure from the crankcase picks up this oil and blows it up through these slots.
The way the slots are laid out causes them to scrape some of the oil from the cam and pump it up into the valley as well, making the drain back even worse. On top of all that the oil then gets heavily aerated from all this and turns up in your catch can as a grey looking fluid. If you let that fluid sit long enough it will separate back out into oil and probably some moisture.
My experience says that you need to provide some significant breathing to the crankcase below the valley. Add a proper crank scraper and provide oil drains back from the heads. They hold a significant amount of oil when the engine is running.
Others will disagree, but I would be reluctant to drill the "china wall". These engines have very little meat connecting the two banks together and the two walls constitute a large part of what little there is.
Later this spring I'm going to try out my cam scraper idea. I'll let you know how it works out
Cheers
Fred
Hi Fred
I have the same thoughts as you. That's why I think it was a good idea with a breather at the timing cover combined with two drilled holes through to the front end of the valley. Then you get an extra air route to the crankcase. Just hope that the timing cover don't get filled up, but I think that is most unlikely.
Have not thought of the bottom of the valley as a cam scraber, but I can now see that it proberly will work that way. That is not good....I have seen some big US V8 engines where the valley area is totally closed above the cam, with only 2 drainback holes, front+rear.
About drilling the "china wall", remember the inlet manifold provide some rigidity to the block.
Per
Looking at this as a system, it should be possible without great difficulty to make a few changes which will have it pumping air and suspended oil back towards the pan. Let's start with the idea that two things create positive pressure in the crankcase: blow-by, and aeration in the area of the crankshaft. The valve covers and to a lesser degree the lifter valley become an area of lower relative pressure. Venting the engine from the valve covers only encourages the oil to go upwards. So the first order of business it to provide large diameter equalization lines from the valve covers back to the crankcase, preferably to the pan below the level of the crank scraper and either on the opposite side or provided with a baffle, or both. If this is not possible the front cover would possibly be the next best as it is vented to the pan, provided the lower openings are large enough. This is to let the crankcase pressure pressurize the valve covers but without carrying oil up. Next would be a series of passive flow inducers in the downwards direction, taking the form of modified scraper/deflectors. The idea being that rotation of the cam and crank can be used to create a centrifugal pump which will pump the air and oil downwards. Starting at the top, where you now have your fabricated shield, if you were to do no more than make a sheet which projects into the slots at an angle upwards to the left a bit and more or less completely blocking oil from the cam from being flung to the right through the slot, extending downwards as close to the cam as you can get it without touching, then the rotation of the cam will suck oil through that gap and cause it to be flung downwards. Then a second scraper below and to the right of the cam, angled downwards to the left relative to cam rotation, will peel the oil off the cam and direct it downwards where it will be picked up by the crank windage. If the downward edge of this scraper is matched to the crank and it is bent downwards to the right it too will act to pump the oil downwards like the one above the cam. (With the right angle and placement, the use of a flat scraper/deflecter should be possible) Then a scraper on the opposite side of the pan will help to keep the oil in the pan where it belongs. Finally, a deflector can be used below and to the left of the cam to keep windage away from the cam, however you must determine what your oiling requirements are for the cam lobes and whether this is going too far. In a race engine I would think it would be a help. A second crank scraper part way up the block may be a good idea too, as on hard left hand turns the oil in the pan (if it is a wet sump) will overcome the first scraper.
I've not built this system, but I'm sure you can see how it would work. Once you have equalized the pressures the centrifugal forces would be very effective at making the oil go where you want it if directed properly, bearing in mind the direction of rotation.
Bear in mind too that anything you do with the vent lines which causes an upwards instead of a downward air flow will counteract these devices to some degree. With that in mind, it would be best to vent the engine from the crankcase level if possible, using lines which do not connect to the valve covers. We are trying to get the air to flow downwards. The blowby creates a special problem in this regard. If it can be drawn off directly from the crankcase that would seem the most direct, but if it is drawn off from the pan level it creates a downward flow. On one hand reason dictates that it should be separated as much as possible from the equalization lines, but on the other, if we are using pressure rather than vacuum to remove crankcase gasses we want the valve covers to be at the same pressure as the pan, meaning that pressure from blowby gasses must be transmitted as directly as possible (externally) to the valve covers. Obviously minds will differ on the best way to do this.
Jim
Hi Jim
I agree with you in theory. In practice I think I will get into space problem with the cam scrapers and how to fasten them.
Also my drysump is a flat cast alu-pan. There is less than 1" from crank weights to bottom of the sumppan.
Anyway your suggestions sounds right and I will look more into what is possible, within the engine space avaible.
Thanks for your suggestions
Per
Jim,
You were awake all night figuring that one out . . . :-) The part that got me hooked is figuring out how some of us can use an efi manifold and vent from the crankcase instead of the valve covers. After reading all about these engines over the last few years, I don't know why anyone wants to vent from the valve covers. (Sorry-Rocker Covers, I'm showing my age).
I think I'm working this out but wonder if I could use a port on the cold-air intake behind the K&N filter to aspirate the rocker covers to the crankcase and then to the EFI intake manifold. The restrictor hole recommended from Rover is awfully small for the 14CUX system.
Using a Buick front cover with a fuel pump plate vent (and appropriate back-flow reducer) I could see how this might work. How would you route the vent from the CC to the the manifold?
Tim
Tim, the small Rover vent orifice is there only to restrict the fresh air that is circulated through the engine, and only for the purpose of allowing good A/F mixture control at idle. (above that it is more or less insignificant) Because this oxygen laden air is eventually ingested it does affect the mixture. At WOT and max blowby manifold vacuum drops to near zero so little or no fresh air is ingested.
If you plumb the large vent line to manifold vacuum in keeping with British practice then you certainly do not want to increase the size of the orifice, as you would lose all control of idle speed and mixture. Then in your large vent line you want to be very certain to include a flame trap of some sort. A canister stuffed with a metal dish scrubber is excellent and does not restrict flow.
Some intakes have a threaded port into one of the runners, or a boss for such a port that can be drilled and tapped. Such a port with 1/2 or 3/4" pipe threads would be ideal.
Jim
After the above modifications, I have been running the engine for 2 years without any oil problems at all. The oil catch tank connected to the rocker covers, dont get filled with oil anymore.
I only have one 15mm vent hose from each rocker cover to the oil catch tank. The catch tank never gets filled with oil any more.
The engine runs to 7200 rpm.
Before the modifications the engine filled the catch tanks very quickly. Now I never emtyes them.
Modifications done to resolve my drainback problem.
--------------------------------------------------------------------------
1: Camshaft splash guard
2. Crankshaft scraper
3. Two 12mm drainback holes behind the camshaft timing Wheel
4. Reduced oil to rockers (1.5mm feed hole)
------------------------------------------------------------------------------------------
That solved my drainback problem
Per
Per, thank you for the follow-up and congratulations for finding a solution!
I had forgotten about this thread, and I'm especially happy to re-read Jim B's last two posts. My engine is worlds away from your racer, but I think Jim's PCV ideas might help me improve it. So that got me surfing through the 300 pages or so of Jim's "340" thread, where I found this killer photo and helpful caption:
MVC-019F.JPG
QuoteThis PCV system uses the British format with an orifice breather on the opposite corner of the engine. The stainless line was sand packed and formed using a custom fabricated bender. It draws filtered air through the engine via the orifice and then into the blower inlet under vacuum under normal conditions (also assisting in sealing small oil seepages) and vents blowby directly to the inlet under WOT. The inner diameter of the tube is about 9/16". The large canister below the tube is the stock Rover flame trap which prevents crankcase explosion in the event of a backfire and also separates oil vapors and droplets and returns them to the rocker box.
One more consideration, what amount of cubic inches, you have circulating on top of the pistons, has equal amount circulating, undernath. How/where is all of this transfer ? Food for thought. roverman.