Farmall Cub

i have a farmall super c and i think it has a burnt valve. ive done everything and it still won't run right so here is my question. should i have the head remaned? or not

As far as having the head completely reworked, unknown until head is removed, condition of the valves and seats checked, valve stem and guide clearance, warpage, etc..

Compression tests results were? Vacuum test results?

What tests and procedures have you conducted to diagnose the problem(s).

If you're confident in your fuel and ignition troubleshooting skill, the next logical step is to pull the head and see what's going on. You might be able to get by with just cleaning up the valve seats and lapping in some new valves like I did on my 240 last spring.

i did a compression test they were all around 95 so i know everything else is good this tractor has very low hours it was owned by my grandpa (rest his soul) and he had a good collection of working IH tractors. so i need to do a leak down test is Wat i am thinking. but it had a stuck exhaust valve wen i got it but all i did to fix it was free it up but it is adjusted properly also. the guy said it would b starting at $175 to re cut all of them and machine it. wat do u guys think (you guys r always a good help) im only 14 and i use this tractor at my job so its needed thanks.

also i tried posting pictures buy i dont know how can someone walk me throught it. thanks

Is this the C113 or C123?

If all 4 cylinders were 95psi on a compression test (cranking with starter, all plugs out and throttle wide open) you do NOT have a valve problem to amount to anything. I suggest going deeper into ignition and carburetor.

farmallfarms wrote:I'm only 14 and i use this tractor at my job so its needed thanks.

Is this your tractor or someone else's? If you or your family do not own the tractor, let the owner fix the problems.

John *.?-!.* cub owner wrote:If all 4 cylinders were 95psi on a compression test you do NOT have a valve problem to amount to anything. I suggest going deeper into ignition and carburetor.

Concur. Tractor should run smoothly with those numbers and have good power.

What are the symptoms? What is the tractor doing and when does it do it?

I would start with a complete ignition tune up.

On my 240, I had two cylinders with 100PSI and two with 75PSI. That's how I knew I had a problem. After the valve job it was 100PSI across the board. So yeah, if you've got 95PSI across the board, the head is ok.

Given the fact that you're presumably inexperienced with tractors, I would go back to the ignition and fuel system.

it is my tractor and me and my dad own a profession mechanics shop so the way we test it is while its running we hold a piece of paper an inch away from the exhaust and if it pulls it in a little bit then its a valve probloem. the only reason i put my problem on here is because i wanted to see if anyone knew better. the cylender that had the stuck valve is lower than the others. its also a C123

i pt a comlpete ignition tune up in it already. wen it runs it has a slight miss. we are pretty sure thats wat it is.

Since your are a professional shop - - oscilloscope the ignition system, vacuum test and leak down test.

About 95 psi per cylinder. Might be a sticking valve. Have you tried SeaFoam or other upper cylinder lubricants.

Have you removed the valve cover, checked the valve rocker arm clearance? Watched the valve action while cranking over the engine?

Occasional or slight miss - - could be a problem other than a burnt valve.

thats a good point i had been running sea foam and then i stopped. do u think i could just put some into the breather on top of the valve cover?

Why don't we try some of the diagnostic tools I suggested.

If it is a sticking valve, it can be lubricated with the valve cover removed.

I realize you are 14 years old. I have been wrenching for 60 plus years and use to teach auto mechanics and engine tune and diagnosis at high schools and junior college trade schools.

All I'm pointing out is that I don't know the specific problem and that you can not diagnose the problem with out a step by step procedure. Take the time to diagnose the problem - - - much cheaper than throwing parts at the tractor - - - or unnecessarily removing parts then having the expense of replacing them.

Seafoam is a one- or two-time treatment. If it doesn't work after that, more is just throwing money away.