F20 failure

1070BK · Aug 8, 2016

Finally got some help to try to start the F20 I've been working on for what seems like years. I couldn't start it so thought we'd give it a pull. After skidding the rear wheels, I decided my overhauled engine was just to tight to turn. I'm thinking about loosening the rod caps and installing extra shims. Could this help?

DeltaRed · Aug 8, 2016

Can you crank it by Hand?If so,shims are probably not needed. Were you pulling it in low gear? Try High.Those old tractors are geared pretty low.Takes a lot to turn the motor through the wheels.Before you add shims,you need to acctually check/measure clearance.IIRC,3 to 4 thousands is fine for an F20.

1070BK · Aug 8, 2016

I can't turn it by hand. I can put a pipe wrench on the rear of the engine where it connects to the transmission and turn the motor. We pulled it in fourth gear.

teddy52food · Aug 8, 2016

So did it turn normally when you were putting it together? Did you use a good assembly lube that hangs in there?

BruceS · Aug 8, 2016

My f20s and 30 that were rebuilt all turned over with crank after rebuild and started up that way.

Ron Weber · Aug 8, 2016

Here is what I would do. I would start by loosening all of the conrods and then see of it turned over easy by hand. If it does, then tighten one and see what changes happen. Just one journal that is too tight can cause this problem. Shim the tight journal. From past experience, if you have too tight of a journal, it will heat up and melt out the babbitt in the shells. You can see the babbitt squeeze out the sides of the bearing. These old engines, f-20, regular, f-30, 10-20, 15-30, etc. are World War I technology and are crude by today's standards (F-12, w-40, etc. were the first high performance style engine - WWII Technology); they run best being a little loose. I have seen a regular with egged shaped journals .010 still run like a champ and plow up fields.

1070BK · Aug 8, 2016

Think I'll try what you say Ron. Everything was lubed up pretty well. I could turn it over easily as it was assembled but got tight after it was all together. I've been told by others that they can run fine a little loose.

36F30 · Aug 8, 2016

(quoted from post at 14:02:12 08/08/16) Think I'll try what you say Ron. Everything was lubed up pretty well. I could turn it over easily as it was assembled but got tight after it was all together. I've been told by others that they can run fine a little loose.

New felt oil seals, especially if put in dry, can lock them up tight too. I know some guys are trimming them for a better fit. My 30 tightened up to the point I couldn't crank it after new seals ( soaked in oil overnight). Once we pulled it and got it running they loosened up, then about a month later they started leaking. These old girls like to mark their territory.

robgIN · Aug 8, 2016

if you can barely turn it with a pipe wrench something is way too tight. As you were assembling it did you keep turning it after each part was installed ? When did it stop being able to turn by hand ? Also how fast are you trying to pull it? You need to go slow like first gear with the pulling tractor and 4th gear in the F-20 being pulled otherwise you are just going to slide tires or over rev the engine. If it turns that hard you are going to have to start taking things back apart until you find what is keeping it from turning. You should be able to turn it over with the plugs out with the crank . If not you have a problem. Dragging it around with another tractor is just going to compound your problem , like maybe bend rods,

Mark-Ia · Aug 8, 2016

If you didn't have it in high gear when attempting to pull it, the tires will just skid.

F-Dean · Aug 8, 2016

Take the plugs out and turn it over with a "Twisted Belt." That is easier and safer. That should let you know if the engine is too tight.
Did you oil the crank and bearings as you re-assembled the motor? A dry crank with dry bearings can be tough to turn. Did you use pasti-guage to get the clearance? Accidentally leaving a piece in between the rod and crank can lock things up.
Yes, this advice is based on experience! Often, you learn much from your errors!
Keep trying and do NOT be afraid to ask questions.

1070BK · Aug 8, 2016

Thanks for all the info guys. I will try these suggestions but not right away. Gotta get some combining done now. There's always that problem of work getting in the way of play.

ericlb · Aug 10, 2016

my take as wth any engine, if its that tight something is wrong, you probably dont want it to turn until you find out what it is,or all your work will be ruined , id start with the seals, if its still tight after you check those ,then plastigauge the bearings until you find the tight one , was the crank turned? it may be out of round if it wasnt, which will cause that even if bearing clearance is right, say if it was measured with plastigauge on where the cap goes on, but is our of round on the side of the journal it will be locked in place when the caps are torqued

1070BK · Aug 10, 2016

Crank was turned

redforlife · Aug 13, 2016

Should be able to turn it over by hand with the hand crank, or something is wrong and you don't won't to force it. If you can turn it over by hand, and just having trouble getting it to fire over, I would pull start it in the highest gear, but otherwise I would not pull start it.

F20 failure

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BruceS

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Ron Weber

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