candlelit

iTrader: (21)

So we pull the 24mm bolt off and put the new 16mm bolt on??? Why are they two different sizes???? 240 lbs TQ on the 16mm bolt doesn't seem possible

HavATampa

iTrader: (49)

Did you buy a GM stock bolt or aftermarket?

01ssreda4

iTrader: (96)

4 dollars at the dealership

conan

iTrader: (5)

The reason for the the 240ft pound is to seat the pully all the way into the engine. To make your life easier put the pully in a oven. and heat to 200 deg. for 15 to 20 min. dont go above 200 for risk of melting the timeing cover seal. I have never got my bolt to 240ft pounds. With swetting the pully on i'll torque to 180-190ft pounds. then remove bolt and torque in NEW bolt to spec's.

vjo90rs8

iTrader: (9)

the thread size should be M16 x 2.0.

GM part #: 12557840

2000WS6ICK

iTrader: (2)

My stock bolt was 24mm.

candlelit

iTrader: (21)

right, guys. the old one is 24mm. the new one I got from gm is 16mm. I just want to make sure it's the correct bolt, guess they changed bolts since they put these motors in at the factory?

DaddySS

No, I think you have the wrong bolt. The replacement is also 24mm

candlelit

iTrader: (21)

so these are the wrong bolts???

http://www.byunspeed.com/product_inf...d738cbd5ed0493

http://cgi.ebay.com/ebaymotors/Chevy...807251153r9226

HavATampa

iTrader: (49)

That is odd. You are talking about the bolt head size was different for the socket wrench right? The stock replacement is part number 12557840 and the specs are m16x2x103mm. I've bought several of these and the head bolt size has always been the same, 24mm like DaddySS stated.

HavATampa

iTrader: (49)

Those are the correct part numbers, maybe GM redesigned it? Is the thread pitch and length the same? You do realize you should be using your old bolt to pull the pulley on to 240 ft. lbs. and then remove it and put your new bolt in and tighten it to just 37 ft. lbs. plus another 140 degrees or so?

2000WS6ICK

iTrader: (2)

I bought mine from the dealership, not sure what part number it was. The old one I took off with a 24mm socket and the new one I put on with the same 24mm socket. Not sure what the thread size is, I am just saying what size the socket I used.

candlelit

iTrader: (21)

take that back guys. I went and measured the new bolt this afternoon and the head IS 24mm. thanks for everyone's input!

drivinsidewayz

i felt like bringing up a dead thread to clarify since im going through swapping dampener... the HEAD of the bolt is 24mm, but the thread size is 16mm. sounds like he was confusing the thread description with the head size.