Stuck\Broken Valves ?

marc hildebrant

marc hildebrant

Well-known member
Group,

Car started to idle\run rough without any reason. So, I checked the fuel flow, was O.K. Next, I checked the timing, O.K.

Shorting out Cylinder 1, the engine slowed. Shorting out 2, the engine slowed.

Shorting out either 3 or 4, NO effect. Nice spark though on all cylinders.

Would stuck valves happen on two cylinders at once ? Cam shaft broken ?

Marc
 
Usually when valves start sticking all of a sudden its from trying to burn off the old stale gummy gas in the tank. If you have old gas always drain it out.
If you must use it pour it on weeds.
 
I agree with the ohters, BUT just too throw this out there, haven't some people had problems with crossfire between 3&4 in the distributor cap? Lot less work and $ than a blown head gasket !
 
Big hammer said:
I agree with the ohters, BUT just too throw this out there, haven't some people had problems with crossfire between 3&4 in the distributor cap? Lot less work and $ than a blown head gasket !
Click to expand...

Yes, that's why I'd do a compression check, and check the distributor. I would use a vacuum gauge to check for a slow to close valve, and if you find one or two slow to close, then I'd add Sea-Foam to the gas and oil.
 
check comp. I had this happen with a head gasket. look at the plugs 3 and 4 they may be slightly wet with water after you run the car. with my bad head gasket the car would start after it dryed out for a day. then foul out on 3 and 4 after 20min of run time. if you do a head gasket replace head studs they are cheap.
 
Group,

I checked the engine compression. Cylinders 1 and 2 are good (80 lbs.) and 3 and 4 have NO compression. I could see some valve action in 3 and 4. Both intake and exhaust in 4. Note: 3 is probably O.K., just had a hard time looking into the spark hole.

So...the Head Gasket broke between 3 and 4 most likely. What to do next ? I have replaced head gaskets in my old 1933 Chev many years ago. But I have a feeling that once I start into this car, I will fine more stuff to fix. Replacing a head gasket I can do. Milling the head, pulling out the motor I can not as I'm an electrical person by nature.

First step...any good shops in Cape Cod\Mass that could replace the head gasket ?

Marc
 
Marc, With 1 & 2 @ 80 psig I would venture to say the rest of the engine may be in good shape.

Go slow removing the head. They like to stick sometimes. There are a lot of threads on Ford Barn offering plenty of tips.

Are there any Model A Clubs nearby that can offer help and/or advice? Good luck on your 'adventure'.
 
Don't pull the head until you do some basic checks. Blow compressed air into each cylinder and see where it comes out. You might just have a couple stuck valves, and maybe they would loosen up with some Kroil and using a bent screwdriver to push them down. Remember while trying to push them down be sure the piston is TDC and ready to fire, so you aren't trying to push against a cam lobe.
 
head is easy if it isnt stuck. Put penatrant around the head studs rusting of the stud can stick the head. I used high tack on my gasket you can do them dry. DONT OVER TORQUE. you risk breaking a stud and the water neck. check your head for warp.
 
Why do PROPER DIAGNOSTIC tests come LAST???---After 3 pages of "WHAT IFs????????????????? or "IT'S THE CONDENSOR"---or "ALL CARB PROBLEMS ARE ELECTRICAL"--or "MINE WUZ THE FUEL FLITTER"--or "IT'S A GYP MUFFLER BEARING HOLDER"---or "TIMING AIN'T RIGHT"---or "ADJUST THE VAG VALVE 1/4 TURN CCCW"---or--------??????
Bill Amazed!
 
if after further testing you still decide to do a head gasket. dont forget to order a water pump gasket and water neck gasket.
 
marc hildebrant said:
Bill W.

Sorry, I have no idea what you are saying. Please explain.

Marc
Click to expand...
Sorry To confuse you, Marc,
I just meant that common sense DIAGNOSIS, should always be done before any attempted repair.
Some just rattle on with ridiculous approaches that don't get the problem solved & repaired.
Bill W.
 
An easy way to determine if you have combustion is with the engine running, if it will run, is put your radiator cap on tight and your should have a lot of air pressure from your overflow tube. Be careful and stick a long hose on the tube before you start the engine so you don't get caught in the fan or better yet take the fan belt off. Like Bill said, diagnotics, diagnostics, diagnostics.

My experience with removing a head that had a bunch of pinholes in the head on the manifold side so it wasn't worth saving but the block was. 9 broken studs later to extract was no fun and you want to avoid that at all costs.:( I was lucky I saved the threads in the block but it was time consuming and required a lot of patience. Drill and dremel die grind everyone of them out. Heat did absolutely no good except harden the studs more.
 
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Group,

I will look into more diagnostics if possible as I do not have many "shop" tools.

When the car started to run rough, I checked the plugs and they all looked nice with white insulators. After running now, black.

When running rough and I give the engine some throttle and then idle, much backfires in intake and exhaust.

Running on two cylinders doesn't allow much driving !

Marc
 
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