I'm finally starting assembly on my LSx motor and ran into a snag. I'm using the Howards Billet connecting rods with a set of Custom diamond pistons for the LSx. The problem is in the area between the small end of the connecting rod and the piston. When you put the wrist pin in there isn't enough clearance between the piston and the rod, the rod actually rubs the bottom of the piston. What is the best solution for this type of problem? Thanks for any help!

 

Mll the under side of the piston to clear the rod.

 

I wouldnt risk weakening the piston.

Get the correct pistons.

 

what is your clearance? like six speed said, you might have to shave a little off. the rod is very thick on that end obviously. What size pin did you order for the piston, .927 or .944? just curious.

 

The wrist pin is a .927, comparing them to some other diamond pistons I have they have more aluminum than the others under the wrist pin. How much clearance do you need between the two? I can mill .005 off and see what that does.

 

I took a couple 120 grit sanding rolls and removed the CNC ridges and the rods float now but I need to check the clearance. The rod was hitting the high spots from the 3 CNC paths.

 

.050 min.

 

Thanks, I talked to Kurt from Wheel 2 Wheel last night and he said the min my combo needs is .020 so we're close.
Phil

 

Are your rods SBC or LS1?

 

Howards LS1 Billet rods

 

So Diamond just has a very narrow pin boss spacing in the piston you have now then probably. I got a set like that for big NOS with the pin boss spacing only like 1.095 ish with the 1.060 wide rods made for a very tight fit indeed. The ones I have are a taller compression height deal and they still worked alright but it was very close. I had some older SBC rods so I had to mill the rod back on one side a small amount to make them happy.