wrist pins

Randy Webb · 11-04-2003, 12:02 PM

Does anyone know the weight of the stock piston wrist pins in the 3.2L engine? Thanks.

Rot 911 · 11-04-2003, 12:04 PM

You could call John Walker, he has two of mine in the shop right now and could probably weigh them. If not I can weigh one of mine tonight.

ChrisBennet · ChrisBennet's Garage

I have to hold the umbrella for my sweetie while she does an after vote (exit) poll but I can weigh a stock one later tonight. I have some JE ones (for a 3.2) I can weigh also. I've been itchin to use my new scale...
A friend of mine told me he was surprised at the differences in weight between "identical" 3.2 wrist pins.
-Chris

RoninLB · 11-04-2003, 12:48 PM

I shave the inside of the pins to balance......Ron

ChrisBennet · ChrisBennet's Garage

I only had a stock 3.2 wrist pin: 127.8 grams
(I forgot I used the JE ones.)
-Chris

Bill Verburg · Bill Verburg's Garage

the wrist pins and valve train recipricatring components are a great place to save weight. Mahle offers some very nice lightweight tapered wrist pins w/ some of their p/c kits.
Mine

stock 993

They may be available for a 3.2 as well.

J&E also has a very nice lightweight w/p option for their p/c sets. No personal experience but they were reccommended by most of the engine builders I spoke w/ .

Leland Pate · 11-04-2003, 02:52 PM

I read this whole thread and everytime I read "wristpin", my mind said, wrist pin "Circlip!

Talk about being confused!
When I had my pistons and rods balanced, the machinist used the rods, bolts, bearings, pistons, rings, wrist pins and circlips.

Randy Webb · 11-04-2003, 04:45 PM

Thx - I'll fwd to seeing some of those wts. when you guys get home.

ChrisBennet · ChrisBennet's Garage

Quote:

Originally posted by Randy Webb
Thx - I'll fwd to seeing some of those wts. when you guys get home.

See my post above.
-Chris

Rot 911 · 11-04-2003, 05:36 PM

Quote:

Originally posted by ChrisBennet
See my post above.
-Chris

Yes Chris, but you don't have official photographs certifying the weight!

I weighed 4 of my wrist pins (John Walker has the other two)

1 weighed 127 grams and the other three weighed in at 128 grams each:

ChrisBennet · ChrisBennet's Garage

Drat, Foiled again!

Randy Webb · 11-04-2003, 09:07 PM

?? THe light JE pins only save 10 grams? Don't the JE pins weigh 117 g.? So if the stock ones weigh 127 or 128....

I thought the wt. savings was more. (?)

rw7810 · rw7810's Garage

RoninLB - How do you shave your wrist pins, with what kinda of tool??

1fastredsc · 11-05-2003, 05:50 AM

It's not much now, but when reciprocating inside of an engine it can become a big gain. The faster the engine moves the more the acceleration force will multiply. So the 8% saving can be more profound at 8k rpm as opposed to sitting in your hand.

Randy Webb · 11-05-2003, 10:00 AM

Yes, I understand the physics -- but I thought there would be a much greater difference.

kepperly · kepperly's Garage

I read through Wayne's engine book and was shocked that was the way you balance 911 pistons was by variying the weight of the wrist pin. on any motor I have ever had done they shaved some meat out of the bottom of the piston dome's.

keith epperly

RoninLB · 11-06-2003, 03:25 AM

Quote:

Originally posted by kepperly
I read through Wayne's engine book and was shocked that was the way you balance 911 pistons was by variying the weight of the wrist pin. on any motor I have ever had done they shaved some meat out of the bottom of the piston dome's.

that's how I balanced mine.. way before the book was published