[SD455DJ]

We got the machined engine block, heads, and rotating assembly back a couple weeks ago and yesterday Dan & I (more Dan than I) got busy and assembled the YZ short block with the dished (14cc) Icon forged pistons (+.030” over) and Eagle H-beam rods. The rods bearings have .0023” clearance and the mains are at .0026”. The cam bearings went in without a hitch and the original 068 cam spun easily without any tight spots or having to mess with the bearings.

You may have noticed that there are 2-bolt mains where there should be 4-bolt mains. When the engine was getting cleaned and magged, the shop discovered an interesting factory “issue” with the #4 main thrust cap. It appears the factory used a bad casting that had to machined further on one side eliminating the inset the thrust bearing shoulders sit in. The factory “repaired” it by spray welding (or some other process of building up metal) around the saddle so the thrust bearing still would fit and sit correctly. The engine has never been apart until now for this rebuild, so this main cap is from the factory. Why the factory didn’t replace the cap, or a new set of caps, is a mystery. It must have been cheaper to ‘fix’ it this way than to re-line hone the block for new caps (?).

The machinist was surprised to see a different material (metal) that appeared was welded to the cap face and had never seen anything like it before. He did scrap/blast some off with a bit of difficulty, so it adhered pretty well after all the years. After debating whether to reuse the caps, or just replace the ‘weird’ one, we went with neither and substituted a set of 2-bolt main caps we had on hand for the original 4-bolt caps and line-honed the mains for them. We have no fear of using 2-bolt mains as they are more than strong enough for the 3” main blocks. The original 4-bolt mains will stay with the car.

The pistons are an average of .013” in-the-hole after the decks were squared up, so we’ll be using a set of .027” Cometic head gaskets to achieve .040” quench depth. Dan will be cc’ing the heads soon to see where we end up with the static compression.

Dennis