Cylinder head bolts - reuse or replace?

[The73vetteman]

Having had the heads from my high mileage '73 350 rebuilt (new valves, springs etc) I am just about to reassemble everything. I've bought myself some new gaskets and some copper spray and was just about to start work when I read two things:

1. put teflon tape on the threads of the head bolts.

2. buy new cylinder head bolts.

What do people think about these two suggestions? Worth doing, and if so why?

Any other tips for sucessful reassembly?

the73vetteman

 

[Scooter76]

While in the past I have reused head bolts without any problems, unless you are on a very tight budget, I'd get new ones. They are relitively inexpensive. High mileage bolts tend to get corroded since some of them extend into the water jacket of the block.
I have always used permatex #2 sealer on the threads.
Good luck on your assembly.

 

[motorman]

DO NOT USE teflon tape use non hardening permatex formagasket in the white bottle. clean the threads with a wire brush and if the threads are not corroded use them over.

 

[JonM]

If you have "torque-to-yield" bolts, Yes change them. Otherwise here are some tips.

http://www.federal-mogul.com/cda/content/front/0,2194,2442_7359_7465,00.html

 

[The73vetteman]

Thanks for the suggestions.

One follow up question, if I may:

How do I know if my bolts are "torque to yield"?

The Federal-Mogul link JonM gave above mentions that these are found on newer engines, so I'm not likely to have them on my 1973 vintage small block, am I?

 

[motorman]

no you do not have "torque to yield" bolts

 

[JonM]

The TTY bolts are easily distinguished from the others because they have a flange under the hex head.

 

[RMS73]

If the bolt has been torqued so that its yield stress has been reached then the threads will be deformed. To verify the condition of the threads run a new nut up the threads to check for any tight fit between the threads. If the nut stops or a high torque on the nut is required to turn the nut on the bolt then the threads on the bolt have been deformed and the bolts should be trashed. You can also use a die nut or thread gage to verify the bolt thread condition, but running a new nut is the easiest. Likewise verify that the threads in the block are in good condition by running a bolt with good threads into it by hand. If the bolt does go in easily then there may be some thread damage to the internal threads in the block. If this is the case then the threads may have to be retapped.

When installing the bolts make certain that you use the proper torque value. The torque value will change based on if a lubricate is used on the bolt threads or if the bolts are used dry. A quality lubricant can decrease the needed torque value by up to 60% over a dry bolt.

Roger

 

[JohnZ]

I've bought myself some new gaskets and some copper spray
the73vetteman

If you're using good quality Fel-Pro composition head gaskets, they don't require any sealer. OEM-type steel shim head gaskets aren't a good idea unless both the block and heads have been re-surfaced; they're designed to seal dead-flat freshly-machined surfaces.

Buy new head bolts - they're cheap compared to having to do this job over again, and use thread sealer on every bolt. Follow the Shop Manual torquing sequence, and do it in three steps.

 

[resto75]

Just replaced my head and used new bolts( about 12 bucks), permatex #2 sealer, Fel pro gaskets. No problems at all.

 

[brusso]

Are these TTY bolts the same thing that we use to call "stretch bolts"? It's been about 15 years since I've worked in the trade for a living, but I always thought that head bolts were considered a one time use kind of thing. I curious to find out, so I'll watch this thread. Thanks in advance for anyone who can clear this up.

 

[JonM]

Are these TTY bolts the same thing that we use to call "stretch bolts"? It's been about 15 years since I've worked in the trade for a living, but I always thought that head bolts were considered a one time use kind of thing. I curious to find out, so I'll watch this thread. Thanks in advance for anyone who can clear this up.

If I recall, I think that is what they called them back in the day...(I was still an embryo back then) I think for the price of new bolts its cheap insurance. Its like the old oil filter commercial...You can pay me now...or pay me later.

http://www.arp-bolts.com/