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JFairman JFairman is offline
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Join Date: Jul 2006
Location: S. Florida
Posts: 7,289
Checking new piston and wristpin balance

Set up my old triple beam in my little kitchen today and I'm checking the weights of my new Mahle 3.3 turbo pistons and wristpins that were in the cylinders inside a sealed Mahle box when I bought the set 6 years ago. If there's any differences I'll shuffle around the wristpins to get them as close as possible and then get out the die grinder and make them all weigh the same down to 1/10 of a gram.

When you pull a new Mahle piston out of the cylinder it came in all the ring gaps are lined up in a row. I'll stagger them oil ring at 12 noon and the compression rings at 4 and 8 o clock when I install them back into the cylinders unless someone says there's a better position for them.
I numbered the pistons and cylinders so they'll go back together where they were inside the sealed box.

When I eventually get the rods out of the motor I'll balance all the rod caps to the same weight and then the rods all the same weight down to 1/10 of a gram with the caps installed.
I've done this before on old 4 and 6 cylinder SOHC BMW motors and they run and rev so smooth when you take the time to balance the reciprocating parts down to .1 gram.
I have ARP headstuds, 40mm aluminum injector blocks, and another set of turbo heads I ported matched the intake ports to 40mm last spring. I'll port match the flat intake manfold to 40mm when I remove it.

Meanwhile the car is still on the road and running great!

Old 02-13-2014, 10:55 AM
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