I just got my block back from the machine shop. The oil galleys above the camshaft have been tapped and plugged. I remember that, when I took it in, it had pressed in plugs in those spots. One or two of the plugs had a small hole (maybe .020), that I assume, were to give a little oil to the back of the timing chain gear where it rides against the cam retention plate. The pipe plugs that are in there now don't have these holes. Is this going to cause a problem? I bought a new timing chain that has the torrington bearing behind it that rides against the cam retention plate. Will these holes need to be drilled in the plugs to supply oil to the torrington bearing? If so, is it the top hole or the two side holes that has the hole? Any help greatly appreciated. Thanks.

 

Whoever built your motor before must have known what they were doing. Those don't come from the factory like that; that's one of those little tricks to help stuff last longer.

I use about a #65 or #70 drill bit, which is in the .020"-.030" range. Do it to the 2 side ones. DO NOT do it to the top one, only the top one: the side ones are the lifter feeds, the top one feeds al the bearings, and you want to keep as much oil going to them as possible.

 

RB83L69,

Thanks for the reply. I have also heard that the factory may have put the holes there to bleed the air out of the oil galley. The engine was totally stock. All parts that came out were stock. Stock bore 48,000 miles. The block is from '92. Maybe this is something the factory started doing? Regardless, I'll drill the holes. Thanks again.