Farmall m

1939farmallm · Sep 13, 2018

Hey guys. I have a 1939 farmall M. I have recently rebuilt it. It is 263 cubic inch with lp head. New cam and lifters. The problem I am having is when warmed up going down the road in 5th gear at full throttle or under a load as in going up a hill it knocks and I can't seem to figure it out. I h ave played with the timing. It also has electronic ignition

rustred · Sep 13, 2018

played with timing means nothing... you must set it to spec. and go from there. then post some timing degree's. where u set it and where it is now. is it ignition knock or rod knock?? ignition knock is known as pinging.. so to cure that which is caused by too much advance you retard the timing. nothing to go by in your statement. a person is not there to listen to it running so need info.

Steinkamp sales · Sep 13, 2018

I had the same problem. Overhauled an m with a bad head. Replaced head with a brand new high compression
head since that was all that was available. Used it to grind feed to break in engine. I thought it
sounded that way also. This tractor also had domed pistons. I did verify that the piston could not hit
head before I put it together. I think it is an ignition knock?

Old weldor · Sep 13, 2018

A friend of mine had a Farmall H with a knock, it sounded like it was in the upper part of the engine. Didn?t sound like a rod. Turned out to be a
sleeve that was moving up and down. Every time it moved up it hit the head hard enough to make the knock.

robgIN · Sep 13, 2018

like rusted said need more info. How many total degrees of advance does it have and where it is set, usually when higher compression the advance plate was changed for
less total advance . Hard to tell without hearing what it may be. Pistons don't like detonation , especially cast ones. Where is your carb set ?

teddy52food · Sep 13, 2018

Tractor Vet would tell you to put better gas in it among other things.

1939farmallm · Sep 14, 2018

(quoted from post at 19:55:25 09/13/18) Tractor Vet would tell you to put better gas in it among other things.

Timing is set to stock settings. When I said played with timing I meant turning the distributor to advance and turned it to retard. I don't believe it is a rod knock I believe it is a timing knock or ping. I run super in it. I have pulled the head off to see if I have enough clearance and I do

John M · Sep 14, 2018

What plugs are you running?

1939farmallm · Sep 14, 2018

(quoted from post at 04:50:21 09/14/18) What plugs are you running?

Plugs are autolite byt can't think of the number at the moment. They came in the electronic ignition kit

1939farmallm · Sep 14, 2018

(quoted from post at 04:50:21 09/14/18) What plugs are you running?

It has ngk ab-6 in it

1939farmallm · Sep 14, 2018

It is set at stock timing marks. I just set the carburetor back to stock specs and then played with the air adjustment screw. The tractor was on a dyno to break it in and has roughly 40 hours on it at this point. I've had this problem before and brought it to a guy and he played with it and told me it was the carb and for a while it ran without any issues until now. To me it sounds like a spark knock. The tractor runs great at an idle or full throttle until it's under a load

fastfarmall · Sep 14, 2018

Just curious what kind of hammer mill do u have, i had a Gehl and a Arts Way, i used my M on a Gehl, 20 inch very seldome pulled down with it, it would change tones, but kept the rpm,up!

John M · Sep 15, 2018

Those will be a good plug, I was thinking maybe you had one too hot. Without being in front of it, I cant be much good.

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