Farmall h pistons

[jonathan Brown]

I need help i bought a farmall h 179130x1 off a neighbor with a stuck motor awhile back. Well i finally got the head of it this week. It has two stuck and well rusted pistons. I want to replace them. My problem is the pistons on the tractor are flat and all i can find are stepped pistons. Do i need to change all 4 to stepped ones? On a side note would i be money ahead in the long run to take the motor to a shop and let a real expert fix it.

 

[rustred]

yes, all 4 pistons must be the same.
that all depends on your experince and mechanical ability . or get someone with experince to guide you through if you dont feel comfortable. i would be consentrating on removing the stuck pistons then look them over and make a decision on if they need replacing.

 

[WellWorn]

Jonathan, it depends not just on what you are going to use your H for, but how bad the sleeves are. If you can get it freed up, and this isn't going to see regular farm work, you may get by with honing the sleeves, cleaning up pistons and a new set of rings. If you expect to be using it for real work, figure on saving yourself taking it apart twice, and just rebuild it correctly once.

First off, soak each piston with some good penetrating oil for a few days. Put the tractor in 5th and try rocking it gently back and forth to see if you can get any movement on the pistons. Don't "bash" it with rocking, as you can pound the rod bearings and add to it's woes. If it starts pushing up a sleeve with a stuck piston, figure that you'd have to replace that piston/sleeve anyway. If they won't come loose, you'll have to pull the rod caps and drive the pistons up from the bottom, probably with the sleeves (use a length of hard wood against the bottom of the piston - don't drive against the rod, unless you're replacing that too).

Before you get too far into it, you'll probably want to check rod and crank bearing clearances (you can get plastigage from NAPA or from ebay). Crank and rod bearing clearances run from .0009 min to .0039 max.To do that, unbolt a rod or journal cap, put a short piece of plastigage across the bearing surface, then put the cap back on and snug it up. Remove the cap again and 'read' the plastigage according to widths printed on the plastigage wrapper.

Again, depending on what you expect to be doing with this tractor, you may get by going 'cheap'. There is a good chance someone from the forum has a couple sleeves and flat top pistons left over from a rebuild. Just ask.

hope that helps

 

[PretendFarmer]

Overbore pistons are about the only thing you can get now for
most Farmalls. There aren't too many Farmalls around with stock pistons.