head bolt mistake

[wired]

I over tightened my head bolts to 60 ft lb. Now I wonder if I should leave them alone as the head gasket is already mashed, and if I redo it there might be a problem with it. Or should I replace the bolts with new ones. I really was trying to be frugal by not replacing bearings and rings and then I did this.

[Jim Becker]

Did you tighten them in multiple steps following the sequence specified in the shop manual or did you tighten each bolt once over? If done in steps and the proper sequence, I'd leave it alone. If done once over, I would go to each bolt in REVERSE of the specified sequence and break it loose and bring it back to slightly snug. Then start over retorquing them in normal sequence in multiple steps.

[ricky racer]

I guess my question would be, were you able to verify that the antifreeze in the cylinder was there due to a leaking head gasket and not a crack in the cylinder wall or head?

[wired]

I am pretty sure that the head gasket was the problem. I tightened all bolts to 40ftlb. in sequence and then went to 60 ft lb in sequence as I replaced the head gasket and proceeded to replace the head.

[ricky racer]

I am pretty sure that the head gasket was the problem. I tightened all bolts to 40ftlb. in sequence and then went to 60 ft lb in sequence as I replaced the head gasket and proceeded to replace the head.

If you didn't twist off any bolts or pull the threads out of any of the holes, I leave them tight. Did you put any sealant on the bolt threads?

[inairam]

Did you use the Permatex thread sealant on the bolts? Using a sealant can impact the "dry" torque values usually to a lower number. What grade bolts did you use?

The main purpose of the toque spec with a head bolt, or any bolt subject to fatigue cycles, is to stress the bolt so it does not see or feel the cycles and fatigue and fail. The secondary issue is the clamping force for the seal.

I do not think you have to replace the bolts. I would run the engine for the 30 minutes and do the retorque and check for leaks. If the bolts were torqued evenly and in the order, I personally probably would not redo it. I would be more concerned if you think a few of the bolts were tighter than the others maybe causing the head to bend/ warp.

[wired]

I did use a sealant on the lower half of the threads.

[goxu1]

Did you use the Permatex thread sealant on the bolts? Using a sealant can impact the "dry" torque values usually to a lower number. What grade bolts did you use?

The main purpose of the toque spec with a head bolt, or any bolt subject to fatigue cycles, is to stress the bolt so it does not see or feel the cycles and fatigue and fail. The secondary issue is the clamping force for the seal.

I do not think you have to replace the bolts. I would run the engine for the 30 minutes and do the retorque and check for leaks. If the bolts were torqued evenly and in the order, I personally probably would not redo it. I would be more concerned if you think a few of the bolts were tighter than the others maybe causing the head to bend/ warp.

What's the torque number when using a thread sealant ?

And what grade were the bolts ??

[wired]

bolts were grade 8 from Rural King and I put grade 8 flat washers on them because they were longer than the old bolts

[inairam]

I found this on the engineering toolbox web site

Reduced Torque with Lubricated Bolts Lubrication effect on bolt tension and torque.
https://www.engineeringtoolbox.com/torq ... _1693.html

and this pdf from Anti-Seize Technology https://www.antiseize.com/PDFs/torque_s ... ations.pdf

A lot of people do not like washers under head bolts. You can grind them down to make this shorter and chase the threads

[inairam]

I sent an email to Permatex tech support here is the response:

"We do not have bolt torque specifications regarding thread sealants.

Thread torque is normally related to anti-seize lubricants.

Don Sutliff
ITW Engine Repair | Senior Product Support Specialist "


So there is a difference but there is not a published number.

I suggest 25% less based on the above links.

[inairam]

"The Way Bolts Work Is Far More Fastenating Than You Think: Tech-Talk With A Suspension Engineer"

https://www.theautopian.com/a-suspensio ... -friction/

[wired]

Thanks for all of your help. This is a great place for information and a great group of people. Gratefully Larry [formally Barbwire}