ok,
i've always read that in order to mount the b16a (pr3) pistons on LS (b18a) rods that you have to machine off 1mm on each side of the rod, or, out of the piston for the rod to fit in..
well..
i have a PR3 rod/piston and a PR4 rod/piston sitting here.
in comparison:
- the wristpins are same
- both are 81mm in diameter
- the thickness of the rod where it connects to the piston is the same size
---pr3 = .787
---pr4 = .787

and before you say well maybe they have already been modded.
well each rod is stamped with PR3, and PR4
and each piston is stamped pr3 and pr4.
they are completely stock.. nothing modded.

the only difference is the pistons (one raised deck(pr3,10.2:1CR), the other flattop(pr4, 9.2:1CR)), and the rod lengths. as the pr4 is 3mm longer than the pr3.
the PR3 is definately a more beefy rod and the rod bolts are bigger in the pr3.

anyway,
whats up with machining off 1mm from each side of the rod where it goes in the piston? if they are identical?
anyone?, katman??

 

you are confused sir, that mod you refer to is only for putting gsr or itr pistons on ls/b16 rods.

 

it's the ITR or CTR pistions that will require the modifications of the LS rods to make them fit.

the USDM B16 pistion will fit with no modifications at all.

 

That is right, any R series piston on any non R series rod requires the mod...


Jason

 

ahhhh, ok. thanks.
your replies are much appriciated.