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Farmall Super A

P

Philip Rosenberg

New User
I have just reworked the head with new guides and grinding.
The magneto has good spark.
However, I have 0 compression and I thought it was the stuck valves, which now are in perfect condition, is it worth doing a wet compression test, or just remove the pistons to look at the rings?

Any help would be great.
 
Have you reset the valve stem clearance? Did you grind the valves to the correct angle? How about the head gasket? Did you torque it correctly? Zero compression is an indication of something drastic. If the rings had blowby you would have SOME compression. Especially if you had compression before the valve job.
 
Compression is determined with the throttle wide open, spark plugs out so that your battery can turn the engine over rapidly. Unless you have made some major error, you will not get 0 compression.
 
Zero compression in all cylinders is dramatic.
Does the gauge work!?
Are the valves adjusted correctly while in the correct cam rotation.
Are there rags left in the intake track?
Are the gaskets put on wrong?
Are the rockers moving at all when the engine turns?
let us know these answers please. Jim
 
Zero compression in all cylinders is dramatic.
Does the gauge work!?
Are the valves adjusted correctly while in the correct cam rotation.
Are there rags left in the intake track?
Are the gaskets put on wrong?
Are the rockers moving at all when the engine turns?
let us know these answers please. Jim
 
If you had no compression before reworking the head I think you need to take a look at one of your pistons to see if the rings are stuck and measure that sleeve for wear. You may need a new sleeve & piston kit. Hal
PS: If you need a new sleeve kit I would pull that crankshaft and have it measured for wear. You don't want to have to pull that engine apart again.
 
The gauge is brand new.
I don"t feel any air pressure with my thumb when I crank the engine.
No rags
New exhaust gasket and new head gasket and torques to 65Ft. Lbs.
 
Nothing to do with compression, but IH upgraded the head torque to 80 ft lbs -- too late for the latest edition of the manuals.
 
I had the head redone at a head shop and they found several stuck valves because of bad gas.

I am going to remove one of the pistons and check out the rings. I need the experience.
 
Before you go any further I would start looking at the basics. If you
have 0psi compression then there is something really wrong, even
very leaky rings will make 'some' compression. The only times I've
seen zero compression were valves stuck open. For what a few
tablespoons of oil cost it's well worth doing a wet compression
test. Something else you can try - remove all the rocker arms,
remove the spark plugs, take a blow nozzle on your air compressor
and blow air in each spark plug hole (you may need to wrap a rag
around it to get a seal) then all you have to do is see where the air
leaks out and that's your problem spot. Sam
 
Unless the pistons are rattling around loose in the cylinders like marbles, the problem is NOT in the pistons, rings, or sleeves.
 
You should check your rotor & valves to make sure they're working when cranking. You may have something sheared or broken on the cam gear. Hal
 
Before you pull a piston check the rotor and valves to see if they're all moving when cranking the engine. You may have a broken cam or camgear. Hal
 
If you did not reset the valve clearance after reinstalling the head most likely the valves will not be closing completely.

The machine shop will have removed material from both the valve face and the seat in the head resulting in the valve stems extending higher above the head. If the valves are not reset the rocker arms will hold the valves open slightly which could result in no compression on any cylinder.
 
Before you tear it down to remove a piston, I'd set the valve clearances to see what you've got.

You haven't said what else you've done with the motor, but as another said, if it will turn over and even if the rings are stuck, you should get some level of compression once the valves are set properly.

Try that first. The shop that worked on your head can only put the parts back in place when it comes to valve/rocker clearances. Go over it, and you'll find them all over the place, from minor adjustments needed in or out, to completely out of whack in either direction.
 
It may be difficult to find your No1 piston at TDC on the compression stroke since you don't have any compression. Drop a long plastic straw on top of No1 piston and have someone hand crank the engine while you watch the straw rise. When it quits rising check to see if your
timing mark is aligned. If it isn't aligned rotate it one more full turn and see if it's aligned now. Set the clearance at .017" cold.

When the engine is at TDC on No1 piston you can
adjust valves 1,2,3 & 5 counting from the radiator, then rotate the engine one full turn and adjust valves 4,6,7 & 8. Hal
 
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