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Tips

Help with Tuning Stromberg 175CD Carbs in Houston

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So,.., the engine will rev up and run with choke, just not hold a decent idle. Is that right ?
 
Exactly. With only minimal choke it holds a nice idle and revs beautifully. As soon as the choke is completely pushed in it stalls.
 
Don't let me push this off-track, but could that be a symptom of incorrect float height? Too low a fuel level, so it leans out too much off choke?
 
Try this just for heck.
On the 76 you'll find a "banjo fitting" on the intake manifold. It has 3 hoses attached to it. One, to the brake booster, another to the Anti Run-on Valve that's under the Carbon Canister, and the third hose is smaller going to a diverter valve.
Disconnect all the hoses attached to the "banjo fitting" and cap just the nipples, don't worry about plugging the hoses.
If the engine starts to act normal, then replace the hoses one at a time to see which may have a vacuum leak.
Alternately, and probably easier, you can remove one at a time and cap that nipple, but start with the one going to the Anti Run-on Valve.
 
TR4nut --- I set the float height at the recommended 17mm at the full closed position. I think if I had an issue with the float level I would have hesitation or stalling when the engien is reved.

Poolboy --- I will check the hoses on the "banjo fitting" tonight. Thanks for the suggestion.

One of the only parts of the carb I did not replace during the rebuild is the diaphram in the carb bypass valve assembly. Any chance a bad diaphram in the bypass valve would effect non-choked idle?
 
It wouldn't affect what you're seeing.
If it fails to open, nothing happens except perhaps during a downshift to decelerate. Then you might notice popping in the exhaust system,
sometimes not,however. A lot of people have them blocked off entirely with no side effects.
If it happens to be open, the idle speed would be about 2-300 rpms above normal because of the excess fuel mixture bypassing the nearly close throttle disc in idle position, and going directly into the manifold/combustion chambers.
Those are the 2 scenarios for a faulty or maladjusted TBV.
 
I am not that familiar with the TR6 either, but it sounds like the problem I had with my TR7. The rubber carb mounts had started to split and leak air. I installed aluminum mounts and never looked back. Also, I understand that the Stromburg carbs will wear at the butterfly stems and cause air leaks.

I have a teck tip article on the carbs on my download site.
https://homepage.mac.com/WebObjects/FileS...=US&lang=en

You can also find out more about the Texas clubs on the VTRSCR website.

https://web.me.com/jclaythompson/VTRSCR/Home.html

There is a guy I met whose wife inhereted her fathers TR6. They live down in Angleton. I only talked to him once. I wonder where my TR7 & TR8 will go when I am gone?

Get yours running and come to the SC Region meet in New Braunfels at the end of April!
 
So last night I finally had a chance to look into the non-idle problem I am having on the TR6. I found that I have a rust hole on the metal tube between the EGR valve and the intake manifold. Bingo .... no idle without choke.

Problem now is I cant find a replacement part. Not offered at VB and listed as Not Available on Moss. Any suggestions?
 
Could you use JB Weld for now to plug the hole?

I might take the pipe to the local NAPA store and see if they have similar ID pipe you could make a replacement out of?

Or:
Find a cheap carb set on ebay or craigslist you can get your part from? I bought a cheap speedometer so I could canabalize the parts I needed to get my original back to operational.

Or possibly:
Some kind forum member would offer you up that special tube?
 
Do away with the EGR altogether. The fitting on the intake manifold takes a 1/2" NPT brass hex head plug. I forget what the fitting in the head is exactly, but you'll find it.
 
TRF has the tube listed as available, P/N UKC2316.

When I had a similar problem with the Stag, I bought some suitable thin-wall steel tubing through McMaster-Carr and bent it to shape. Note that you are more worried about the outside diameter than inside, since that is where the fittings seal.

I don't know that this would apply to a TR6, but on my Chevy, disconnecting the EGR without making other changes really messed up the fuel economy.
 
Thanks for the input. I'm going with the "Do away with the EGR approach". Have heard from several people that eliminating the EGR does not impact performance or fuel consumption so I'm convinced.

After 15 years of storage, the TR6 should be on the road this weekend! Keep your fingers crossed.
 
One question though. If I remove the EGR Valve, plug the ports on both the intake and exhaust manifolds, what do I do with the line between the rear carb and the top of the EGR?
 
I have one if you want the metal tube. I took it off when I eliminated the EGR valve. If you want it let me know as it will be in the dump when I clean up.
 
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