Head bolt torque

[mudnutt]

Finnaly getting my truck put back together. Anyone know the torque #'s for the head bolts?

[ronniejoe]

It takes a 4-step procedure, torquing in the right pattern. The first step is to torque all to 20 lb-ft. Second step, torque to 50 lb-ft. Repeat. Final torque is 1/4 turn more to yield the bolts. New head bolts must be used.

The pattern essentially starts in the center and radiates outward in a clockwise circular pattern.

[Robyn]

Hi
Be sure and get a new set of Bolts. The head bolts are a one time through game.
The bolts are a torque to yield type.
Most parts stores can get you a set. Be sure they have the sealer on the threads as well as under the head.
If they are bare use high temp silicone or High tack red goop will work. These bolts go into water so they must be sealed.
Torque with the factory pattern to 20 lbs then go back and torque to 55 pounds.
Now grasshopper pay attention!!!!!!
Draw a horizontal line on the bolt head with a felt pen you can see. (___)like so
Tighten each bolt in the pattern 1/4 turn more and thats it. when you are done all the lines should be verticle ( l ) like so.
Make sure you dont have to take the heads back off or your new head bolts are scrap.
Hope this helps

[NH2112]

How do you see the line on the bolt if the socket's on the bolt head? I recommend spending a little money for a torque angle meter instead.

[ronniejoe]

My book clearly says 50 lb-ft for the second step...

[DmaxMaverick]

How do you see the line on the bolt if the socket's on the bolt head? I recommend spending a little money for a torque angle meter instead.

Regardless of your method of actually tightening the bolts, the marks ensure you don't do one twice. You should be able to tell what 1/4 turn is by the position of your wrench handle. Use a protractor (or other suitable device) if you aren't that confident. Once the bolt yields, there's not much torque difference with one more 1/4 turn, so you may not notice it if you hit one twice. The torque for the final turn is irrelevant.

I've reused TTY head bolts, but I don't recommend it. Sometimes, the shadetree, get it out of my yard build didn't justify the cost of new bolts (and sometimes new gaskets, belts, hoses, etc.). Strangely enough, none of them ever failed because of the recycled or omitted parts.

[Robyn]

The bolt set that I just installed 3 days ago in my 94 engine speced 55 on the second step. My 94 chevy C-K manual says 50 Hmmmmm maybe these clowns should talk to one another??

I usually just put my large break bar on for the last round and set it up so I can get a good visual on what is a quarter turn. The spec on my bolt set was 90- 100 degrees so I really dont think its all that big of a deal.
What ever happend to good old head bolts. I have built a buttload of Big block chevies and never needed a torque to yield bolt. I think its a plot to sell head bolts. ?????????? :0)

[Robyn]

OH BTW
The line is my way of being sure that all the bolts got the final tweek. When Im all done U can visually see that every bolt has been turned 90 degrees.
Just a gimick, but it works. Justr like when I torque rodsa and mains. After I torque a bearing set I mark the cap with an X from my marker. Never a doubt when it comes time to bolt the pan on whether things are tight or not. Many times in the shop someone walks up and needs some thing ot the bloody phone rings.
Just my 2 cents worth. Been at this almost 40 years now and have developed some habits that work for me and have made many people ask questions or simply shake their heads. :0)

[NH2112]

A friend who has been a mechanic for close to 20 years told me that an error as small as 10 degrees when you TTY will result in insufficient clamping force being applied. Plus, if you don"t TTY in 1 smooth and continuous motion you risk inaccurate torquing. A torque angle meter isn't necessary but it does make for better accuracy when you TTY.

[mudnutt]

thanks for all the replies. i have a new set of bolts. was just wondering about the torque. i like the idea about the line. will help me make sure all have been tty.

[Craig M]

One item not mentioned. Does one soak the bolts in 30 wt oil prior to installation?

[JeepSJ]

Not soak, but put some oil on the threads and under the head of the bolt. Also make sure the threads in the block are clean enough that you can insert the bolt all the way with just your fingers. Run a tap through the threads first if you need to clean them out.

**EDIT** - forgot that the bolts go into water passages in these engines, so use thread sealer instead of oil on the threads. Get some of the teflon based thread sealer (NOT the tape) and use that on the threads, and a couple drops of oil under the head of the bolt.

[NH2112]

Torque values are for clean, unlubed bolts unless otherwise specified. If you lube a bolt and and torque it to the unlubed spec it'll be clamping too tightly because the oil lets it turn easier (and the torque value is just resistance to turning.) Somewhere I have a chart that gives torque equivalents for clean dry bolts, plated bolts, and oiled bolts. If I can find it I'll scan it and post it, or just type it in.

[Patrick m.]

a few years back i built a 383 stroker (Chevy), and used Lunati rods.
They came with a "molly" lube for the bolts the torque spec was .060" bolt stretch!
Now that is even clamp force.