29-27 starting problem

[jps]

Last summer I drove my car several times and although it was not a great starter I always could get it going.  However, since last September I have not been able to start my car.  I replaced the heat riser tube, and confirmed that I have spark at all 6 plugs and at least minimal compression on all cylinders (compression was about 55, 55, 55, 30, 50, 50 psi on cylinders 1 - 6).  I also am positive that gas gets to the carb bowl.  I try starting 4-5 times and the engine cranks but never fires.  Starting fluid does not help.  Also, I removed the spark plugs afterwards and they are dry.  However, gas drips out of the air cleaner by the time I stop attempting to start. 

 

I just took apart and cleaned the carburetor.  The nozzles do not appear cracked and after cleaning they are not plugged.  The float is OK.  I do not see anything that looks wrong although I am a newbie.  My guess is that the low-speed nozzle was plugged with dirt, and now I have cleaned it out.  I will try to start again tomorrow, but can anybody think of something else that might explain dry plugs while the air cleaner drips fuel after several start attempts?

 

Thanks.

[28-27-buick]

 Do you have spark at the plugs? have you checked the timing?

Herb  28-27 buick

[carbking]

Based on what you have posted, I would suspect the compression. With an updraft carburetor, the vacuum must be sufficient to draw the fuel UP into the cylinders.

 

Dry plugs, but fuel in the air intake indicates the fuel is not being drawn into the cylinders.

 

The oldest compression information I have on Buick is 1931, so might be slightly different from the 1929; factory compression pressure on the 1931 was 97 psi (from old Motors manual).

 

EDIT: telephone interrupted this post. The anomaly is that you posted starting fluid did not help. Generally, even with low compression, the engine should fire on starting fluid if the timing and spark are good, even if the carb was removed. It may be that you have multiple issues. As to the compression, if the 97 were correct for 1929, then I would like to see a minimum of 60/cylinder if it were my vehicle.

 

Jon

Edited June 2, 2015 by carbking (see edit history)

[trimacar]

Not long ago I bought a car that had a good engine, but had been sitting for a long time.

 

Started it up after checking/changing fluids, car ran great, drove it into my warehouse and turned it off.

 

Next day, and for weeks after, no matter what I did, car wouldn't start.

 

The valve stems had varnish (or whatever coating would be called that gums up the works) on them from gas, the heat of that run turned the varnish to hard gum, and most pushrods were bent like pretzels.

 

Make sure you don't have numerous stuck valves, just something else to check...

[Roger Barrett]

These cars are prone to shorting the spark plugs on the cover, especially if you have longer plugs than the originals. Have you changed anything on the engine since the last time it ran? If so, that's where to look first. Hold your hand over the carb intake with the choke open and have a helper crank the engine. Suction should be pretty strong. If not, with decent compression numbers, I would be looking for a big vacuum leak. Look at the butterfly valves in the Marvel heat system to be sure you don't have both of them blocked, which will effectively strangle the engine. No air out, no air in. Just some thoughts. Good luck.

[Mark Shaw]

Also, I suggest you plug the vacuum line to the wiper.

[jps]

Thanks everyone for all of the ideas.  I got it started yesterday and it sounds great now.  I think the carburetor needed a good cleaning because that seems to be what made it go.

 

However, while re-assembling the manifold last week after replacing the heat riser tube, I put a crack in the exhaust manufold starting at the heat riser port.  My first try using high-heat JB Weld to fix it didn't hold, but I will try again.  I am also working to get a replacement manifold.  So I can't drive it yet, but getting it to start again was a big deal so overall I am happy.

 

John

[AzBob]

John, Glad to hear you got it started. A major accomplishment!

 

I had a crack in my heat riser casting where it bolts to the exhaust manifold. Took it to a guy who was good at brazing and welding cast iron. So far, the repairs have held.