From:Dave Hennessey
Subject:RE: RE: Torque of head bolts on 165cc Date:Tue Oct 9 10:23:02 2012
Response to:17859
I found this torque chart on Engineer's Handbook (very wonderful site)

Standard hardware store nuts and bolts are grade 5 (3 lines on the head). Not sure what grade those CP 1035 and 1038 bolts/nuts are, but I would go with grade 5.

Those Sportster instructions are probably for a NEW sportster that uses NEW type stretchable bolts. NEW cars (well, probably for the last 15 years) use these stretchable bolts on the cylinder heads, and require a torque-angle gauge to install. These NEW head bolts are designed to be used only ONCE - after they stretch, they're useless - throw them away. So don't follow these instructions on your Hummer.



I have gone through my manual and can find nothing about the head bolt
torque. Don't know if it will help, but has a page on torque
specs. They indicate that, if you don't know, torque based on fastener size.
I think that the studs are 5/16", so should be 19 ft lbs (if you buy this).

Don't know how the process on the lightweights compares to the Sportster,
but this outlines that process - remember that the Sportster uses 7/16"

Head Bolt Installation
Factory Method

For each cylinder head, start with head bolt numbered one. In increasing
number sequence (1-2-3-4), tighten the head bolt in three stages.

1. Tighten each bolt to 7-9 foot pounds of torque.

2, Tighten each bolt to 12-14 foot pounds of torque.

3. Mark each head bolt and head with aligning marks. Tighten each bolt 1/4
turn (90 degrees).

Hard to believe that the manual doesn't cover this.


What is the proper torque value for the head bolts Also what is the
best gasket sealant to use?