Hello Chris, thanks for your reply of Jan 15 to my posting.

(My problem was both oil leaking out the front main seal and marginally low oil pressure.) I ordered a plug for that hole from the crankcase into the timing gear cover area that my posting discussed.  

To my surprise, the plug (came from AGCO) has a 3/4&quot; hole in what would be the closed end.

The OD is 1 and 3/8&quot;, which will fit the hole in the block.  But with a 3/4&quot; hole remaining, I don't think that will solve the problem of too much oil up front.

Then I noticed that I already have a plug, like the one I bought, in that hole.  It's in &quot;head&quot; first, and pushed in far enough that the whole thing is about 5/8&quot; into the block hole.  So there is currently a 3/4&quot; hole into the crankcase.  

The packing slip from AGCO says this is part # K110, which is what my parts book shows for this plug.   In the parts book it does appear that the plug has a hole in it, though it's hard to tell from the parts book.

In my service manual volume 1, page 2-53, it also appears that the plug, on the right, has a hole in it like the one I have.  

Various people have told me that to make sure the 3 small threaded plugs inside the timing cover have been installed after overhaul.   There are three in place, looking ok, under the cam gear.     Since it is important for oil pressure to have these in place, I'd think the 3/4&quot; hole in the K110 plug would definitely be a problem.  But, I don't know. 

So, I don't know what to try next.   I was going to replace the timing cover and bought one ($500+) but returned it when this matter of the hole and plug seemed to be my problem.  The old timing cover is somewhat worn, but looks pretty decent in the front main seal area.  An experienced Oliver mechanic also thought it looks quite good.

Maybe I need to go get that new cover again and put it on.  But that doesn't seem to explain the low oil pressure problem, even if it might answer the oil leak problem.  

As always, I would appreciate any thoughts from you.

Tom