Crank dimensions

[Tom P]

After struggling with low oil pressure it's time to pull the crank and have it ground.
Does any one have the dimensions and tolerances for the the crank they can share?
I've done a couple searches with no luck.


Thanks!
Tom

[JC]

I had to read through the Fordson manual a couple of times to find it. Here's the I&T numbers and the Fordson ones.

I&T__ Crankpin dia. 2.4988" .001-.003" clearance
Fordson__Big end bore (with liners) 2.5015-2.5025" Wear limit-2.5035" Clearance-.001-.0028"

I&T__ Main journal dia. 2.9993" Clearance .0025-.004"
Fordson__ Main journal dia. 3.0002-3.0010" Wear limit taper .001" Out of round .0015" Clearance .001-.0028"

Sorry that the Fordson book wasn't more specific on rod journal dia., but that's all I could find, and I wouldn't trust the I&T info. Maybe someone else has a little better info. from Fords.

[Tubal Cain]

I mis read the post and quoted the dimensions for a Dexta.

Gerald

[Tom P]

Thanks for the info. I now know why I have about 5 psi of oil pressure. i'm getting about .005" per side with plastigage. Looks like i'll be splitting the tractor and getting the crank ground.

[JC]

Is that .005 measurement with new bearing shells or the old ones, Tom? Do the crank journals look worn, except for a high ridge around the center?

[Tom P]

That is with new bearing shells.It does look a little wore, but it doesn't have a ridge in the center. I didn't have any crank dimensions and without the ridge i didn't think it was very worn. I will be able to look it over and measure it better when I get it completely apart.

[Millwall Paul]

I've just rebuilt the bottom end of my major, the crank and con rod journals were both reground and .01 oversize bearings refitted. It now runs with a very steady 40 psi oil pressure all day long. it was well worth the effort and a lot easier to do than I expected. I didn't split the tractor I pulled the engine out in stead which was easier for me and my limited facilities. One thing I did learn though was to make sure you mark up which way up the bearing caps go. My father stripped the engine for me and didn't mark them. When I put them back together 1 was 180 deggrees out and the engine wouldn't turn at all. Put it the way it was meant to be and happy days.