Stromberg 175 CD carbs - setting, balancing and idle question

[TRip]

Hi everyone,

I've been working on setting up the Stromberg 175 CD carbs on my 7 and have also set the timing.

However, I can't seem to get the idle to drop to 800 RPM. where it should be.  It's idling at 1200.  I've adjusted the idle trim screws, etc. but nothing seems to help.

Is there a trick to it?

Another thing - the shop manual says that an infrared CO meter is needed to set the lean/rich mixture.  I don't have one of those.  Is there an alternate method?

Could this be the reason for the high idle?

I have a balancing meter and adusting tool.

Can anyone suggest a way to fix these issues?

I know, I know... It's nothing an LS1 with EFI couldn't fix - Ha, Ha!

Thanks, guys.

Trip

[tr8todd]

It's probably the choke.  There is a wax filled acorn looking thing inside the choke assembly that goes bad.  Prevents the idle from going any lower than what you described even with the idle adjusted all the way down.  That little bugger is the main reason you see so many TR7s converted back to manual chokes.

[Dan B]

I have an article I found on FASD that is pretty good.  I can email it to you if you want.

Dan

[TRip]

Hi Todd,

I should have mentioned that the chokes are manual.  

I disconneced the cables and made sure both choke levers were all the way down before reattaching.  So the choke on both carbs are completely off with the high idle.

Trip

[castlesid]

Trip,

Check that the diaphrams are not perished, if so you can replace them but better still swap to a pair of SU's which are far better.

Kevin.

[TRip]

Hello Kevin,

I had completely rebuilt the carbs not to long ago and replaced all the bits so everything is new.  

You've given me an idea that maybe there's a tear or a separation causing the problem. I'll check that out.

Yes you're right, SU's would be very nice.  They're quite tough to find here in Canada, though.  The few that are available are very pricey and require rebuilds.

If I can get these CD's to balance, I guess I'll be okay with them for now.

Thanks Kevin,

Trip

[tr8todd]

Also check the carb mounting rubber blocks for air leaks.

[WedgeWorks1]

Todd tell him all about the Datsun 240Z Hitachi carb conversion......thats the way to go!

[tr8todd]

If you can find some of the early 240Z Hitachi carbs, they rock.  They are 1.75" licensed knockoffs of the SU.  They look just like a SU.  The later 240Z carbs looked like coffee cans and they suck.  Add a nice cam, and a set of headers, and you would be surprised how quick a TR7 can be.  Not as fast as the full race weber carbed Dolomite Sprint engined TR7 I had, but  quick non the less.  Mike should know.  He and another buddy of mine were dumb enough to try and race one of the guys from Aerosmith in his Ferrari with the TR7.  Howd that turn out for you Mike?  At least the TR7 came back in one piece.

[WedgeWorks1]

The Ferrari deal was fun at on my end and trouble free. At a light we took off and he was more than surprised I got a good jump on him and then when we went to second it was all high pitched grind and that was the Ferrari! I pulled away a little bit but when he skipped into 3rd he ran me down and was off. From rumors around the area he completely lost 2nd.......$5,000 TR7 and $??? Ferrari 308 2nd gear.........priceless!

[TRip]

Todd and Mike.

Todd, I  hadn't considered a leaking carb mount. I'll check it too.

The 240 carbs are an interesting idea.  I'll see if there's anything in this area.  

Mike, just the thought of going up against a Ferrari is verrrry cool! What's also cool is that you encountered one of the guys from Aerosmith!  Woo hooo!

Trip

[WedgeWorks1]

One of the guys from Aerosmith had about 2 or 3 lotus esprits that were AERO1, AERO2 & AERO3 for license plates. I had a TR7 going down the highway and he came up on me like I was standing still and gave the headlamp flash to move over and he beeped as he went by! I thought one of these times that is not going to happen! Well a few years later I had Woody Cooper's BAD8 with that plate still on the car and there the Lotus was again and up poped the lights. I droped down to 3rd and went. I looked and he was way back and I was at about 130 and started to slow down since my exit was coming up.....yeah right more like missed and just looking for the next one to turn around. He came by gingerly beeped again and gave me a big thumbs up. From time to time going from Kingston to Marshfield we would see Steven Tyler driving his Maroon original Shelby Cobra....what a ruff life!

Now back to the 240Z carbs you will need alinkage piece which I have a spare from 1991! and you if you go the Hitachi way can make one up from mine. You can retain the stock air cleaner box and throttle cable too

[TRip]

Hey Mike,

Must be nice rubbin' shoulders or should I say... rubbin' door handles with rock stars!!

I have a pair of K+Ns on the CDs.  They would bolt right up wouldn't they?  I'm really liking this Z carb idea!  

I did promise myself that I woudn't to get too carried away on this car, but......

Trip

[Dan B]

Trip,
I am betting on the carb mounts leaking!  I didn't think of that, but since Todd mentioned it, you really need to check that.  Start the car and take some carb cleaner and spray around the mounts.  See if the engine changes pitch.  If it does, you gotta leak.  When I first got my 7, the guy I bought it from said it had FASD problems.  We took it to Jim's place, took the carbs off, checked everything and it was all good.  After putting them back on, I was tightening the air cleaner and felt it move!  I said, "Hey Jim, this can't be right.."  He leaned over the engine while I pushed down on the air cleaners and could see all the way through.  TRF had the mounts back ordered and told me the ones they had been selling were crap.  I got a pair from a friend.  They are not easy to install.

Dan

[WedgeWorks1]

The K&Ns will fit. I think that was what Todd had on his blue TR7.

[TRip]

Hello Dan,

I had been wondering over the weekend how I was going to check for leaks on the carb mounts.  Your carb cleaner idea is perfect.  I'll try that.

I agree that they're not an easy install.  I realized that when I rebuilt the carbs and went to install them.  This should be fun!

Thanks for the advice.

Trip

[TRip]

Hi Mike,

Will I have to rig up a linkage to fit or will the CD linkage work between the Z carbs?

The Z set up looks like the carbs are much further apart (longer linkage).

I'm guessing that some sort of mod. will be needed.

Trip

[WedgeWorks1]

We had to make a linkage peice. You can possibly make it from the Z carbs or like I said loan you mine to have one made up or have you make somehting up?

[TRip]

Okay, thanks Mike.

Trip

[apg]

Hey Guys,

I have another question for you regarding the stromberg carb.

 I decided to go with the manual choke from Moss Motors for my '80 TR7.  I got the part and it fit fine until I put the 2nd carb on...then it wouldn't rotate.  It was all bound up.  I am looking for a manual choke that will actually fit and not bind up.  

Any suggestions?  I've already wasted a bunch of money on this and thought I should talk with the "experts".  Can somebody help me out?

[DiDueColpi]

Hi Al,

Lots of manual choke 175CDs are out there. They got put on tons of stuff like Volvo, Lotus, Saab, MG, etc.
Just take off your old water choke completely (three screws) and remove the high idle linkage from the throttle shaft.
Install your new found choke and high idle link and your good to go. It's a direct bolt on affair with no mods whatsoever.
You only need a choke on one carb. If you happen to have two disable the second one, or make a small blocking plate or flip the gasket to block off the vaccum port. If you need one I've got a few kicking around, just let me know.

Cheers
Fred

Hey Anthony did you ever solve your carb probs?