I'm working on recovering from an unfortunate Comp R incident, and I'm hoping to get my short block back together this weekend.

It's only my second build, and the first time around, between the machine shop marking the rods and the markings on the piston I was able to figure out how things went together pretty well. This time is a little different.

I'm using Mahle Powerpak pistons, and Eagle 5.7" rods, and I'm not really sure that I know how to match them up properly. I've done some reading, and some looking, and I think I have the pistons right. Both of the assembly books I'm using caution on 2 valve relief pistons there's an exhaust and intake valve relief, and putting them in the right spot is critical. I have 2 valve reliefs and they look to be identical, so I'm guessing that as long as the reliefs are at the top of the engine I'm golden. So can I safely ignore the books?



Also, I can't figure out how to hang the rods. I remember from last time that there was a specific way that they were supposed to go on, but again I can't really find any markings that would help me figure it out. I'm thinking the matched numbers on the cap and rod are key, but I don't really understand how to orient them. One of the books says that the rods are offset slightly, and that the offset needs to be oriented towards the center of the crank. Unfortunately I need a better explanation. I snapped some pics of the one piston & rod I've assembled, can anyone use the markings to help me understand how to install the rods better?








Thanks for any help!

 

you should check that piston to wall clearance,is that just the picture or is there .20+ around the piston?i think the mahle dont have a ''right'' or left'', both the intake and exaust valve reliefs look the same size.

 

For the orientation of the connecting rods, check the rod bearing mounting surface on the rod. There should be a a small and a large chamfer. The large chamfer should face the crankshaft and the small champher should face the other connecting rod and that journal.

 

Looking at the pic of the rods, it looks like pic 1 has the large chamfer, pic 2 the small.

 

Ok, thanks. I can see what you and sssalah are talking about. The side with scat57 has a large chamfer machined into it, and the other (blank) side has a very small/no visible chamfer (at least in the picture).

Just to make sure I understand, the blank side with no chamfer should be facing in, so that both rods have the small chamfer on the inside, next to each other when installed on the journal. Right?

If that's it, I'm excited, because it sounds like at a minimum I can get the shortblock together this weekend.

As for the pistons, they're just set in the bore, and I think that extra clearance that was being seen is just shadow and camera tricks.

Any tips for installing the wristpin circlips?

Thanks