Specs for LT1 crank bolt?
08-04-2005, 10:09 PM
#2
TECH Apprentice
Join Date: Feb 2005
Posts: 384
Likes: 0
Received 0 Likes
on
0 Posts
Are you referring to one of the bolts, or bolt w/ stud?
Main cap bolt: GM part number 12561388. Size is 7/16"-14 x 3.34" length.
Main cap bolt/stud: GM part number 12561389. Block side is again 7/16"-14 X 3.34". The windage tray side is 3/8"-14 thread (-Stud portion is raised 2" above bolt head, but only the last 1/2" is threaded).
Of course, if the bolt threads are messed up, you'll want to tap/chase the threads in the engine block as well. -Which, you were probably going to do anyway -- if you are rebuilding the bottom end...
Main cap bolt: GM part number 12561388. Size is 7/16"-14 x 3.34" length.
Main cap bolt/stud: GM part number 12561389. Block side is again 7/16"-14 X 3.34". The windage tray side is 3/8"-14 thread (-Stud portion is raised 2" above bolt head, but only the last 1/2" is threaded).
Of course, if the bolt threads are messed up, you'll want to tap/chase the threads in the engine block as well. -Which, you were probably going to do anyway -- if you are rebuilding the bottom end...
Last edited by Alex94TAGT; 08-04-2005 at 10:19 PM.
08-06-2005, 05:03 PM
#4
Teching In
Join Date: Jul 2005
Posts: 32
Likes: 0
Received 0 Likes
on
0 Posts
Originally Posted by matt94z
No I meant the hub bolt that goes into the crank. It's 7/16-20 x 2 1/4
Buy a new bolt. It is a single use crank bolt to keep the crank hub on the crankshaft. I reused mine and guess what... blower motor.. came loose and when tightened the head broke off. I will check the torque but if I remember it was a lot... like 90 foot pounds.
gary
