mccormick deering 10-20 engine problem

josh j noel · Nov 25, 2011

have a 1927 M-D 10-20 new to me, just got it running it runs good for about 20 minutes or so than loses power gradually, problem found is extremely excessive valve lash due to bottoms of pushrods being worn off, i checked the tappets and cam lobes all that is in check and i am oiling the valves/oil cups, all felts in oil troughs are correct, i cannot imagine what is wearing these pushrods to the point of needing replacements, that happens at almost a quarter inch worn off, seems like the tappets and pushrods are turning properly when running, any info is appreciated thanks josh

Nebraska Kirk · Nov 25, 2011

I find that hard to believe, are you sure that the push rods have really worn that much?

Readjust the valve lash to .019" cold and then see how well it runs. It would not hurt to squirt some oil down the push rod hole so that the bottom end of the rod gets oil.

rustred · Nov 25, 2011

anytime you have excessive valve clearance you will get excessive wear on pushrods, tappets, rockers, and valve stem ends.

josh j noel · Nov 25, 2011

kirk, i also find it hard to believe,ive done the oiling and setting the lash using a wire type feeler gauge because of worn rocker arms,im comparing the pushrods to my spares, have swapped them in and out measure and remeasured all and yes they"re definately getting alot shorter in a hurry, not all of them but most, you can set the lash to spec or there abouts, .020 and it"ll get to about .100 in about a half hour of running

rustred · Nov 25, 2011

just a stupid thought, but did you remove the tappets, (cam followers) and look at them maybe the rods are running right on the camshaft.

josh j noel · Nov 25, 2011

rustyred, i had that same thought, so i removed the rockershaft pulled the pushrods out and reached through the inspection covers on the block with a pick and or little finger and actually felt the bottoms of all the tappets, they all felt excellent and the cam lobes look good and are all even, to the eye anyway.

Oldiron29 · Nov 26, 2011

josh, scence you say they change in a half hour.
That is not ware, That is junk stuck in the bottom of the rod lifter! you must clean out the lifters befroe installing rods. I have used a coat hanger and a copper tube taped to my shop vac. Yes I have seen difference in rod lenght on tractors that are over 80 years old. But that happened over along time of heavy us. oldiron29

Tom Fleming · Nov 26, 2011

I absolutely agree with oldiron29. There is crud in the lifters. Over the years I have seen some pretty solidified oil/grease that is just down right HARD. I would suggest flushing them out or rig up a rifle cleaning brush that you can run on a drill witht the cleaning rod at moderate to slow RPM's.

rustred · Nov 26, 2011

thats for sure, but when he says all was checked makes a person wonder.i guess experience takes over and have to dought what you are told.

Nebraska Cowman · Nov 26, 2011

Yeah, I'd say dirt in the tappets that is being worked out.

36F30 · Nov 26, 2011

I have pulled a couple of these engines apart where the push rods were rusted tight into the lifter. Once you get the push rod out the rod doesn't look too bad but the pocket in the lifter was destroyed by the rust. They were bad enough I threw them in the iron pile. This could possibly be the problem.

How many pushrods are being chewed up, or is it all of them? Wrong push rods maybe?

No matter what I would now pull the cam and lifters and clean all the metal filings out that are now in those lifter bores. Or if they are just full of dirt you can clean them properly.

James Williams · Nov 26, 2011

Josh,Ill bet you have dirt in the tappets.I found a old pushrod and with a grinder cut a groove in the end of it, put it in the tappet and turned it around by hand and did this untill all of the dirt was cleaned out,Then every thing worked good

jimmy

Bill Krosnicki · Nov 27, 2011

I've had this happen twice, the dirt worked it's way out, readjusted the valves and everything was fine.

josh j noel · Dec 4, 2011

Thanks for the help. I'll see what happens, but I definately have pushrods that I have measured and compared, ran & re-measured the pushrod length, not just the valve lash. In doing so I have found that they are not all worn equally on the bottom, some are worse than others. Thanks again for all the input, anymore tips you have are welcome and I will keep you posted. Thanks, Josh

mccormick deering 10-20 engine problem

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