Theres a small plug that I removed prior to cleaning the block. I used a long dowel to knock it out through a top rear oil hole. (The hole the intake is notched for) This is the plug that is underneath the rear main cap and I believe it is there to make sure oil goes through the filter from the pump. ??? I noticed that there is another hole underneath it that looks like it feeds the rear main bearing. Is the purpose of this plug just to isolate the feed for the oil pump from the rest of the galley? Does it need to block anything else off? I have it installed now and it clears both the main cap hole and the filter hole, does it need to be deeper in? (About 1in down in hole now) Thanks.

 

If you look down into the vertical passage (from the rear main cap up to the oil pressure sending unit) with the plug not there, you will see 2 horizontal passages that intersect it. One carries oil to the filter from the pump, the other carries clean oil from the filter up to the rear cam bearing where it gets distributed throughout the engine.

The plug belongs between those 2 holes. Seems to me it should be a little farther down in there than 1"; but as long as it's between those 2 horizontal passages, it's OK. If you can't tell where it is, knock it out and go to the store and get another one. I think it's some real common size, like ½".

 

Its supposed to make sure that oil is routed to the filter so there is sufficient oil pressure. Maybe this drawing will help.

 

Thanks guys, thats exactly what I was looking for.

 

Mr. RB is again correct. The hole is drilled about 9/16" to a depth of about 0.800" as a lead-in, then drilled at 0.494" from that point on to retain the ½" expansion plug. This prevents installing the plug too shallow, since it falls right through the 9/16" lead-in area. The plug is installed to a depth of about 1.00" from the bearing deck to the shoulder of the plug, or about 1.300" from the deck to the head of the plug.



Thos Aquinas,

Do you have the rest of that drawing?