Farmall Cub

I’m having a tough time with my C113 sticking valves.

The engine was completely rebuilt by a pretty reputable person who had done nice work on my Cub in the past. When I got the tractor back from him, there was a little head gasket water leak. I replaced the gasket, and the tractor ran like a champ for 3 or 4 hours. The tractor only gets used about 6 hours a year. The next spring, 4 valves were stuck and 4 pushrods bent when I fired it up. I took the head to a local motor builder who is not a Farmall guy, but does a LOT of local race car motors. He said that 2 of the valves were so stuck that the guides came out with them when he pressed them out. He went through the head, checked everything, and opened up the valve guide clearances. The motor went back together and ran great for another 3 hours. 4 weeks later, when I started the tractor, 2 more valves, different ones, were stuck. Same routine with the same result. I brought the head back for a second time and got the same result. The head has been off 3 or 4 times – I loose count – and I now keep head gaskets and pushrods in stock!

There seems to be plenty of oil pressure, my gauge isn’t calibrated, but runs about ¾ of the way into the white area. When I run the engine with the valve cover off, oil seems to be seeping out of everywhere is should be, but I have no idea of how much is enough. The center rocker arm bolt is the correct one with the hole up the center and out the side. The engine rebuild kit came from one or the reputable suppliers, and some if not all of the guides were replaced with ones from the engine builder.

I’m stumped.

Any thoughts?

Thanks,

Ed

when I replace guides and valves many times they have to be sized to the correct clearance after they are pressed in, to tight and they will get stuck

I agree with Tim! Stuck valves on newly rebuilt engines is pretty common. I like to have a tad more clearance, especially on the exhaust valve, than what the book calls out. Your race engine shop probably does just that.

Dont forget that one center (I think!) stud has a hole for the oil to flow through into the rocker arm shaft.

There is a write up on here somewhere all about it.

I had the chance to read about it before I ever took a C113 apart.

I was on the look out when I came to toying with one of those motors..... and low and behold........ someone placed a bolt in that hole and the oil stud was not there!

SamsFarm wrote:Dont forget that one center (I think!) stud has a hole for the oil to flow through into the rocker arm shaft.

It is the stud for the center support.

Have valve seals been put on it? A fresh overhaul of the head probably doesn't need them.

No valve seals.

The center stud does have the hole and it's right side up, with the center hole down. At one point last March (during the spring of 22 head rebuild) there was discussion about a washer under the center stud nut, but since it wasn't shown in the parts book, Jim Becker suggested, and I agree, that it wasn't necessary. I can't see where it would change the oil flow rate.

The engine guy said he opened up the clearances, so hopefully, this time, it will work.

There was at least one helpful write up on this issue, one in May of 19.

Thanks for helping out. Let me know if anyone has any other good ideas.

EdHarbur wrote:Let me know if anyone has any other good ideas.

Run it more...... more often!

Would if I could get it to run more than 2-3 hours at a time!