VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1929-1932 1931 Chevrolet Head

What usually goes wrong with the heads on these 194 CID engines? I am having some engine problems and have seen alot of discussions on how hard it is to find a good used head. What is usually wrong with these heads that make it so hard to find a good used one?

Cracks.....lots of them or large cracks that are usually not repairable.

:) :grin:

You could try a repair by using this link:

http://www.metalockinternational.org/

USA: http://www.inplace.com/

They drill holes in the cracks and plug them, and been able to save quite a lot of heads normally wrecked.

the problem is they crack where it can't be drilled there is some other repair methods being tried back later with more results

If my head is cracked it has to be internal since there is no water leaking from the block that I can see. Is there a way to find out if the head is cracked without removing it? The symtoms that I have is that the engine seems to smoke out the tail pipe more after the engine gets hot. The smoke appears more white than blue. The plugs, after removing them, all look the same and are not wet. The compression in all of the cylinders is the same.

Sounds like poor valve seals or badly worn guides.

When checking, are any of the fluids missing? Water or oil? Or is there an increase in contents when checked?

The 1931 cylinder head doesn't have valve seals.

:) :grin:

Yes. But you will need to be creative. If I am not mistaken the radiator cap is a screw on type not like new cars. you need to find a old cap or some way to pressurize the cooling system to NO MORE THAN 10 PSI ( you don't want to blow the radiator ) a gage that reads 0 to 20 psi a HAND TYPE PUMP. If it holds the 10 psi for 30 to 45 min no cracked head. If not pull the intake, exhaust, manifolds, and plugs. look for water to confirm crack or head gasket. good luck

I would try retorqueing the head bolts (carefully) with the motor hot. If I was going to pressure check it, I would just check the motor. Unhook all the hoses, radiator and heater, plug the holes and pressurize. I use short pieces of hose, hose clamps and core/freeze plugs. Remember that the water pump will leak some air.

If you are getting white smoke out of the tail pipe particularily when hot the head is likely cracked. Cracks at the valve seats or in the exhaust passage is most likely. If that is the case then the cylinders will not get wet or show moisture (that includes the plugs) until the cracks get bigger. You can pressure check the head in place by removing the lower hose from the radiator, putting in a plug and tightening the clamp. A 1 1/4" diameter rubber stopper from the hardware will work. So will a short piece of pipe with a cap or just the cap if it fits tightly. Do the same with the top hose (remove from radiator, plug the end) but add a "T" with air connection or other means to add air pressure and a guage. Add enough water to fill the block and water pump with water. That will help prevent air leakage at the pump and let you know if you are getting water leakage at that location. If you don't have water in the head it is better but a little is ok. Pressure the head to 10 psi or more and close the valve. Watch the guage for prssure drop and water pump for water leaks. If the pump only leaks water in slow drips it is ok and will not effect the test. Noticeable pressure drop (more that a couple of pounds)over a 10-15 minute period indicates crack(s). Performing the test when the engine is hot is best. Running the engine, draining the water, fitting the plugs and other hardware, refilling with some of the hot water should give a good test. Running the engine for a short period partially drained is risky but if for only a few seconds at a time should be ok.

Thanks for all the info. I have another chevy engine with the head on it that maybe I will take off and have it checked for cracks. According to the number stamped on the block it is a 1930 engine though. Is there any problems putting it on my 1931?

The 1930 and 1931 heads are the same and they both have the same casting number. The only difference is the casting date.

:) :grin:

i would have it pressure checked along with magnaflux