cold engine problems

[pierpaolo]

My 1955 V8 301 poly engine (1955 chrysler windsor) doesn't keep the idle and makes black heavy smoke that leaves thick spots on the tarmac when is cold, which could be the problem?

It happens also if I am driving (first 10 minutes), I had some "exciting" moments at crosses with the engine off and sudden loss of power steering and brakes....

Thank you,

Pierpaolo

[NTX5467]

If it's putting out black smoke during warmup, the automatic choke is not coming off soon enough. Not sure what helps the thermostatic spring work on that particular carb, but it could be gummed up and need cleaning plus making sure the vacuum portion of the pull off assist is working too. If it gets heat from the intake manifold, make sure the center part of the manifold under the carb is hot (hotter than engine temperature from heating by exhaust gases). If it's not, then the intake manifold will need to be removed to clean out the heat crossover passage (later 318s were bad about getting plugged up in short trip driving, from what I've seen) but it can happen on any engine over time.

At approximately 70 degrees F. ambient (all engine parts), the choke should just close fully, with just enough tension to make it close instead of a hard snap closed. Use that as a baseline adjustment for the choke thermostatic coil spring.

It could also be a plugged calibration air bleed in the carburetor's venturi cluster area. Plugging or decreasing the size of the air bleed (with deposits or such) will make the circuit go full rich.

Might also be, a somewhat remote chance, but still a chance, that the igniton points need to be replaced. I saw that happen on a friend's '58 Buick one time--acted just like a carb issue but was the ignition points. Get some quality points and make sure to lube the rubbing block on the points and the contact cam too. Set them to specs (gap AND dwell) for best performance and durability. See that the coil is up to snuff too.

When an engine runs that rich for that long, it's not good for the engine as it can wash the oil off of the cylinder walls and result in more wear over time as the lubrication is being washed away, not to mention oil dilution by the excess fuel. Get the carb working right and do an oil change too. Followed by a full length highway driving situation of at least 10 miles at highway speed to get everything back up to temp and such. Might need to do another oil change after that too, for good measure.

Hope this helps,

NTX5467

[pierpaolo]

The problem is the choke, it doesn't warm up. It gets heat from the exaust manifold, but the hose is completely obstructed. It has been joint in the past with fiberglass to the portion inside the manifold, so i'm afraid to damage it trying to remove the fiberglass, and also don't know if i can remove the part inside the manifold. The shop manual says only "..remove the hose..." very helpful!

However, I have set the choke fully open and regulated the idle mixture with warm engine, and now everything seems ok. I just need to pump some gas at start and in 2-3 minutes the engine runs well. No black smoke but only some healthy white fluffs.

Do you think that the engine running always well with choke fully open could mean sometingh else is badly tuned (as i've sad i' ve already tuned the idle mixture with warm engine)?

I have found another problem: the vaacum advance hose is cut in two and has been rejoint with a piece of rubber hose. Could this affect heavily the performance of the distributor?

Thanks Piero