Sorry fellows but my last message did not go to the right place. I thought I had all like new parts in this old D4 2T 4400 engine but then found two liners are like new with a 020 ring gap with a new ring but the other two have a 1/16 th gap with the new ring. I do not have an inside mike but this seems way out of limits don't you agree? Someone must have recently overhauled this engine and taken the top ridge off so they all just looked new. All the rings are the same gap as one new one I bought.
If you confirm this 1/16 gap way out of limits I need to post a wanted liner message also.

From the manual:
Compression ring gap .012 - .022
Oil ring gap .012 - .020

At .020 it's time to renew the works.

Thanks Old Magnet,
I feel foolish now even thinking 1/16 could be still usable. My Rd4 book just told me 020 wear maximum as measured in the liner with an inside mike and gave no ring gap.
It may be another engine for the scrap because liners do not seem to be available so I need to look for a parts engine.
Do you or anyone else know if a D4 7U10386 engine that I have would fit in the D4 7J8926 tractor? It is in a HT4 trackson loader.
It may be that I just need to start selling all my D4 parts now because the liners seem to be the end of restoring these models.
Even Brent at Motor Warehouse could not find any and he is an exceptionally good man.

Yes, the D315 engines can be fitted to the earlier D4's.
Also have heard of the D4400 engines being rebored to accept D315 liners, pistons and rods modified to work. (can't remember what the rod issue was)
I didn't realize the 4-1/4 in liner sources had dried up. They were available from Regal for awhile but I'm sure that source was checked.

Specs on ring gaps do seem to vary a couple of thousands depending on what source you use. This manual says .015 is the limit on the liner bore.

If you can, get a micrometer reading on the actual bore dimension as that seems to be the main limiter for reuse.

In doing a little research on end gaps it may not be all that critical.
Apparently a standard ring in a .010 oversize bore has little significance in blow by with as much as .070 increase in end gap. The limit would be an .020 oversize at which point the end gap is significant and not acceptable.
Your 0.0625 (1/16) may be acceptable depending on the actual bore diameter and if it is no more than 0.015 oversize it would still be usable. But....your getting out there with the limits. Certainly two of those liners are good to reuse.

Old Magnet,
Thank you very much for your advice, it is greatly appreciated. Yes I did check Regal. I will be checking out the other engine and also getting an inside mike to better know the liner wear. There is an excellent machine shop here in case I find it can be re bored. Perhaps all is not lost yet.