Rebuilt engine over heating

R

RJ

Member
I have a 1930 AA, engine was rebuilt and it has a new radiator,engine boils over after running for 10 minutes. I had a original radiator on it that was cleaned out at a local shop and it was over heating . I decide to bite the bullet and buy the new radiator.
Much to my dismay it still over heating, engine has a high compresion head and premium head gasket.I dont see any water in oil, engine is tight but will start up with only a 6 volt battery.
Any help would be appreciated. Thanks
 
How long ago was it rebuilt? If the engine is tight, it may take a couple of hundred miles to run without heating...


Frank
 
Have you checked the temperature of the water with a thermometer to verify the actual temperature?
Have you checked the torque on the head? It may be low and allowing gases to push water out of the radiator.
I have found that the torque needs to be checked several times on a fresh head install.

Is your timing correct? Could be that it is retarded and is causing your trouble.
 
I have not checked water temp, but was running it yesterday without radiator cap and after ten minutes water was boiling out of radiator. I had a thermostat in it but I have taken that out made no difference. Timing seems alright checked several times, car will go to a slow idle when retarded.
Engine was rebuilt 5 years ago , I will recheck torque but I dont see any signs of water leaking. Someone has suggested that exhaust leak into coolant?
 
As you state that the radiator is new, the issue seems to be one of timing/retarded spark. Be sure that you are advancing the spark correctly when driving, but not excessive as you have a high compression head. Points set correctly and plugs gaped correctly?
 
Railcarmover said:
It was a question...I thought Ryan ran this place,if he left you in charge he should give you moderator status.

Not wannabe status...
Click to expand...


Respectfully,


I posted info/a response without thoroughly reading the entire Post String, and when reread considered info I posted as not relevant and possibly confusing. So removed it. My info followed posting guidelines for content. I did not delete others info, and am unaware that I should not in this case be able to do this.


If I did a no-no please someone explain why I should not have done this and in the future will refrain from doing it again if the same situation happens again.
 
After rereading again, looks like I mistakenly left your original question in the deletion post. My apologies. I did not intend to question the validity of your original question. My mistake. :(
 
Bob C said:
Is it actually boiling or just puking coolant out. How full is the radiator when cold?


Bob
Click to expand...

X2 on this. Some of the new water pumps move too much water. Even with the cold coolant level at or below the top plate in the radiator, when the coolant expands when warm, the water pump is powerful enough to start puking coolant out the overflow, and often out the cap.

Get one of those inexpensive Harbor Freight laser thermometers...

https://www.harborfreight.com/infrared-thermometer-93984.html

...and check the actual temperature of the water, block, head. If it is not boiling, get one of those thermostats that fit in the top hose that all the vendors sell. That slows the flow down enough that it no longer pukes it out.
 
The riley steel crank pulley cures two issues,it slows the water pump by 30% and eliminates the chance of catastrophic failure by the cast pulley
 
Do some basic resistance testing if you want.remove sparkplugs and hand crank the engine,it should turn easy and smoothly.You mention the engine is a fresh rebuild,a number of your issues can arise from that.
 
Thanks to all, I,m going back and rechecking time re torque head and will try again. I did try hand crank last night without spark plugs . I can crank by hand now but it is still very tight. Timing was checked seems ok, points had closed up a little ,reset points. I was running in advanced position. I will try again this weekend.
 
If concerned about effort to hand crank.
I have a fresh rebuilt motor, very difficult at 65 years old to hand crank with the plugs in, and even with the plugs out takes a little grunt . When motor is fresh is difficult to do a continuous motor spin via the hand crank even with the plugs out. Probably not as difficult back when I was 20-30 years old.


My opinion is what you have is normal for a rebuilt engine with few miles.
 
Timing " seems right" is not a good answer and would very likely contribute to your problem. Consider telling what procedure you followed so that it could be eliminated. The whole process is first to be aware what the possible causes might be. Then test and verify one at a time to be eliminated as a cause.
 
Tight engine without plugs can mean a few thing,one is that the builder set up the main bearings tight,which means they have to burnish,or 'run' in. Another is a failure to measure piston ring gap,which results in a tight piston in the bore.That needs to be fixed.
Hopefully its tight bearings that will burnish,thats the hoped for solution.timing and radiators wont cure an engine friction issue
 
Good Model 'A' morning. If you know who the engine builder was/is, can you contact him and ask for advice. If the builder is close enough, can you take the car to him on a trailer or have him make a house call. Often we guess when we should go to the source if the source is available...otherwise...Our father who arte in heaven....Ernie in Arizona
 
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