Wrist pin size

[brighton911]

Can someone please supply me the size range for a 3.2 wrist pin. And to my dismay, I see wrist pins are not available. Does this mean to correct a loose pin to bushing issue, my only option is to replace the bushing and hope to make up the difference there. Both the pins and the bushing look very good, just the slightest scuffing on the bushing at the bottom or towards the big end, yet I have about .0025 clearance. Should be more like .0008. Darn it all.

[Gordo2]

From what I'm seeing - the specs you are referencing are incorrect. I think the piston pin clearances for a 3.2L should be 0.020 to 0.037mm - which would put your 0.025mm right in the ballpark.

Another thought - are you mixing inches and mm (0.0008" corresponds to .020mm).

Referencing my specs from Wayne's engine rebuild book - which if you don't have already, I strongly recommend picking it up...

BTW - I do believe the only way to correct for an out of spec pin clearance is to have new bushings installed and honed ("pin fit") to the correct clearances.

Good luck, Gordo

[brighton911]

Thanks Don My mikes are all in inches but to avoid confusion, I will go all metric . Yes, I have Wayne's book but I believe there is a typo. On page 205 under G it has the heading:

"Rod bushing/Piston Pin Diameter 23.020 - 23.033" Of course, this does not makes sense as the stated pin size is larger than the bushing size. I assume he meant it was the range for the bushing size and there was no pin size. Confirming this, the Bentley manual states the rod bushing size as 23.020 - 23.033 but again, no number for pin size.

My pins all measure out at 22.99 mm. Does anyone have the range for a new pin? Are new pins available from anyone?

Thanks

[Flat6pac]

Carrera pin size is 23mm
Bruce

[cgarr]

22.99 warm them up 10 degrees and they will be in spec lol

[brighton911]

Found the one metric micrometer I own and the pins measured out at 23.00 The 22.99 was with a digital caliper, not as exact as a good mike. So, pretty obvious, rod bushings are out of spec. Can I use a bolt and nut method to draw the new bushings into the rod or is it strictly presswork?

[Mark Henry]

Originally Posted by brighton911

Found the one metric micrometer I own and the pins measured out at 23.00 The 22.99 was with a digital caliper, not as exact as a good mike. So, pretty obvious, rod bushings are out of spec. Can I use a bolt and nut method to draw the new bushings into the rod or is it strictly presswork?

The rod small end is heated then pressed in, then it needs to be reamed to size and it better be dead nuts square on the pin. Machine shops have special equipment for this job and will want a pin for size. If you are going ARP bolts you need to have the big end done as well.

I have reams and I could probably fake it through this job, but at $40-45 per rod (big and small end) from the machine shop why would I chance it?
This is a 3.2? The rods are the weak link in this engine, I wouldn't cheap out in this area. ARP bolts and doing the big end is about the cheapest I'd go.

[Mitch1]

This thread kinda has me concerned. When I sent my rods off to be rebuilt I didn't think about sending my wrist pins with them. I assumed machinist would hone the wrist pin bushing to factory spec.

[Mark Henry]

My guy wants a pin to be sure.
The down and dirty test is to stick a pin in and try to rock it, it should have no play that you can feel, yet still slip in and spin with no effort.

[Mitch1]

I'll check. I bet Ollie's has a few wrist pins lying around.

[Mark Henry]

Yep, Ollie's isn't just a local MS, it 's a Porsche shop. You should be good to go.

[brighton911]

Thanks Mark Yes, for sure the rod bushing must be done on a Sunnen pin machine or similar. I figure if I can install the bushings and do the oil hole work, just the final finish is need = less cost!

Dave