Lotus Elan

zenith stromberg rebuild

PostPost by: rdssdi » Tue Mar 19, 2013 1:45 pm

I have never been content with the way my TC runs in my +2. Besides running hot, the engine never ran well. Difficult starting poor idle quality, excessive fuel consumption etc. I developed a trans problem so the engine and trans has to come out. I plan on disassembling the engine to have a look as well as repair the trans. I sent the carbs out for rebuilding. The shop reported that the temperature enrichment devices were installed backwards. Therefore the carb was lean when it should be rich and rich when it should be lean as well as creating a vacuum leak. This was not the shop who originally rebuilt the carbs. Apparently some ZS carbs do not have a tab or some sort of :registering" device so these parts can be installed improperly.

They also reported a lot of rust coating the interior of the carbs. I am also removing the entire fuel system to determine the source of the rust. It is perplexing as I have a new alloy tank, all aeroquip fuel line and no steel or iron in the system.
If anyone is having engine running problems have a look at these parts. I have no idea what is correct and how to determine if it is installed and adjusted properly. I relied on specialists to rebuild the carb. I suspect that when it was serviced at a shop the enrichment assemblies were removed and installed backwards. This was done immediately prior to my picking up the car after restoration. So it has been wrong from day 1.

When I get the engine apart that may also reveal some problems.

Bob
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PostPost by: 69S4 » Tue Mar 19, 2013 3:35 pm

[quote="rdssdi" The shop reported that the temperature enrichment devices were installed backwards. Therefore the carb was lean when it should be rich and rich when it should be lean as well as creating a vacuum leak. This was not the shop who originally rebuilt the carbs. Apparently some ZS carbs do not have a tab or some sort of :registering" device so these parts can be installed improperly.

I relied on specialists to rebuild the carb. I suspect that when it was serviced at a shop the enrichment assemblies were removed and installed backwards. This was done immediately prior to my picking up the car after restoration.

Bob[/quote]

Do you mean the temperature compensators? The bimetalic spring on those only bends one way, going from "blocked" to "unblocked" by bending outwards as they heat up. If you turned them round and adjusted them to be shut when cold they'd go from "blocked" to "really blocked".
Stuart Holding
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PostPost by: oldelanman » Tue Mar 19, 2013 4:04 pm

Hi Bob,
I would guess they are talking about the choke (cold start device) as that's the only part that I think could be assembled "backwards". The operating lever is located on the spindle by two parallel flats so they will fit together in two positions 180 degrees apart, fitted wrongly the metering holes in the disc will be presented to the wrong drilling in the body of the carburettor and it will effectively work backwards.
Carburettor overhaul 002.jpg and
Carburettor overhaul 003(a).JPG and


Before you go tearing your fuel system apart are you sure it's rust they've found in your carbs ? I would expect large particles would not get through the filter in your fuel pump and fine particles would leave a brown sludge in the bottom of the float bowl not coat the inside of the carb as they say. Could it just be fuel staining perhaps ?
Roger
S4 DHC
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PostPost by: rdssdi » Tue Mar 19, 2013 5:50 pm

I am relying on my memory which is poor at best. I will enquire and write down the rebuilder's response. These are "Federal" emission era carbs. I do not know if they are the same as the carbs you have.

I do know that I was told the engine would run poorly the way the carbs were assembled.

It is entirely possible that both items were installed improperly!

More later.

Bob
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PostPost by: rdssdi » Tue Mar 19, 2013 5:52 pm

Forgot. Yes I was told it was rust. I have no doubts that the rebuilder is correct. His past work on other cars (he did not rebuild the +2 carbs originally) has been superb. I am confident it was a coating of rust he encountered.

Bob
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PostPost by: 69S4 » Wed Mar 20, 2013 7:28 am

Yes, it's very easy to assemble the cold start disc 180 degrees out - I just tracked my cold start problems to having done exactly that on one of the carbs. :oops: If you do it though the mechanism doesn't work backwards ie enriched when off, lean when the cable is pulled out, it just doesn't, for the most part, work at all because the holes and the slots don't line up. I've just run my car like this for about three years and not noticed it except for winter cold start problems.
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PostPost by: rdssdi » Wed Mar 20, 2013 6:58 pm

I spoke with Jeff Palya (Paltech Technologies Brunswick OH 44212 USA) . He said the temperature compensators were installed improperly and would be open all the time.

I have been very pleased with other carb rebuilds he has done for me. If you are having difficulties with your ZS carbs or others call him to discuss your problem. (440)570-1932.

I look forward to re-installing the carbs with a clean fuel tank and fuel system with a rebuilt trans. I anticipate finally my +2 will run properly and be fun to drive. Maybe I am getting a bit carried away!

I will report once all that is accomplished.

Bob
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