Discussion Forum - Northstar Chevelle Club

SShink · 3K+ Club

Re-use head bolts?

Tony Hoffer · Moderator

For a stocker yes... for anything else why not buy some ARP's?

dashboard · 2K+ Club

That's a heavy bolt it's not going to stretch very much with only 65/75 ft lbs of torque. I'd also tend to trust older proven hardware more than something new off the shelf today. I would however clean the threads in the block and on the bolts with a tap and die set. Most important thing is the highest quality head gasket kit.

Save the $25 here $50 there cost and have the ENGINE run on a test cell prior to installation. Then you can tweak the carb, timing and know the results, then you will know what you have and not spend the summer trying to find the right tune settings.

But then, there I go again spending your money.

SShink · 3K+ Club

dashboard wrote:

That's a heavy bolt it's not going to stretch very much with only 65/75 ft lbs of torque. I'd also tend to trust older proven hardware more than something new off the shelf today. I would however clean the threads in the block and on the bolts with a tap and die set. Most important thing is the highest quality head gasket kit.

Save the $25 here $50 there cost and have the ENGINE run on a test cell prior to installation. Then you can tweak the carb, timing and know the results, then you will know what you have and not spend the summer trying to find the right tune settings.

But then, there I go again spending your money.

Good advice Kevin. I decided to take the heads to Competition Engines in Eagan instead so that I can have the engine dyno'd there after it's reassembled. The peace of mind of putting in an engine that has already been broken in/run is worth the dyno cost. Plus I will have documentation on it's output plus be able to tweak it for optimum performance.

dashboard · 2K+ Club

I like spending your money more than watching the Vikings!

Tony Hoffer · Moderator

Thats Bob Kisons' dyno..
Applied Dyno Technology...
Good guy bob..

Lost in the 60s · President

SShink wrote:

dashboard wrote:

That's a heavy bolt it's not going to stretch very much with only 65/75 ft lbs of torque. I'd also tend to trust older proven hardware more than something new off the shelf today. I would however clean the threads in the block and on the bolts with a tap and die set. Most important thing is the highest quality head gasket kit.

Save the $25 here $50 there cost and have the ENGINE run on a test cell prior to installation. Then you can tweak the carb, timing and know the results, then you will know what you have and not spend the summer trying to find the right tune settings.

But then, there I go again spending your money.

Good advice Kevin. I decided to take the heads to Competition Engines in Eagan instead so that I can have the engine dyno'd there after it's reassembled. The peace of mind of putting in an engine that has already been broken in/run is worth the dyno cost. Plus I will have documentation on it's output plus be able to tweak it for optimum performance.

Good way to go now that you are going to change the cam too. A dyno break-in is almost a must in today's world. I will be changing my cam too but breaking it in, in the car. I have 12 bottles of ZDDP and will put 2 in for the break-in and keep my fingers crossed.

I've never bought a new head bolt in my life, but it does seem a worthwhile investment if they are rusty. Most I've removed still looked like new once they were cleaned.

bowtie · Secretary

On newer stuff, GM says to replace them, but they're not anywhere near the same as the old stuff. New ones are M12 size or so. We're doing a ton of Saturn timing jobs that get new head bolts and those even have some M8 bolts.

Dave Seitz · Mega Poster

I used the Joe Gibbs Breakin Oil on mine and had no issues. Stuff is expensive but it works well and you don't need any additives with it.

On the head bolts, it would depend on how many times they have been used in the past and how big of # you were shooting for. If the worst thing that happens with a head bolt is you loose a gasket not that big of deal, a rob bolt now that gets expensive. What Bryan said about head bolts the new style are torque plus 1/4-1/2 turn and 1 time use bolts. I know this as I have had to buy a few sets for newr cars PIA if you ask me.

Dyno is worth every penny to avoid having to yank an engine that was just installed due to oil leak or some BS of that nature. Plus it is nice to get the base tune in the car for initial romp.

Chris R · 2K+ Club

I reused my bolts when I had my heads done.

jim larson · 2K+ Club

I just cleaned the old head bolts last night. I wonder if the new gm head bolts from venders like Paragon that are stamped with the "M" headmark are any better than the new ones discussed above.?

Kevin, why not run a thread chaser in the block bolt holes, etc?

John D · 2K+ Club

If I recall correctly the advise is to use a thread chaser as opposed to a true thread-cutting tap.

A thread chaser does not "cut" new material, just cleans the existing hole. I'm guessing it has something to do with the existing "percentage of thread" on the existing hole. By using a tap you may be altering the original spec of thread engagement.

By no means run a die over the existing head bolts! Again, recollection serves that bolts of this caliber have "rolled" threads, as opposed to "cut" threads. By running a cutting die over them you may open up stress cracks/fissures in the material.

jim larson · 2K+ Club

John D wrote:

If I recall correctly the advise is to use a thread chaser as opposed to a true thread-cutting tap.

A thread chaser does not "cut" new material, just cleans the existing hole. I'm guessing it has something to do with the existing "percentage of thread" on the existing hole. By using a tap you may be altering the original spec of thread engagement.

By no means run a die over the existing head bolts! Again, recollection serves that bolts of this caliber have "rolled" threads, as opposed to "cut" threads. By running a cutting die over them you may open up stress cracks/fissures in the material.

Think I used a thread cutter on the block threads, Is that going to be a big problem?

How do you tell the difference between a thread cutter and a chaser? I have an old set I inherited from my dad?

Lost in the 60s · President

John is correct about the bolts having rolled threads. I've never used a die on them. All I use is a wire wheel to clean the threads.

Jim, if you used an old tap that has seen many years of use, it has already lost it's edge and may only be a "chaser" now... wink

If it went in with little resistance, I doubt you removed enough material to hurt anything.

On re-assembly, the specs call for motor oil on the threads to reduce drag for a more accurate torque. I have used silver anti-seize for this for many years now instead to avoid getting oil on the head gasket.

jim larson · 2K+ Club

Lost in the 60s wrote:

John is correct about the bolts having rolled threads. I've never used a die on them. All I use is a wire wheel to clean the threads.

Jim, if you used an old tap that has seen many years of use, it has already lost it's edge and may only be a "chaser" now... If it went in with little resistance, I doubt you removed enough material to hurt anything.

On re-assembly, the specs call for motor oil on the threads to reduce drag for a more accurate torque. I have used silver anti-seize for this for many years now instead to avoid getting oil on the head gasket.

Thanks for the silver anti-seize tip. When I gook the head bolts out there was a bunch of a RTV/Silicone sealer, down on the threads that go in the block and all the way up into the head and underneath the bolt head. Is this necessary? I see some bolts are sold with the sealer installed on the bolts and some bolts without the sealer.

The tap and die set if from my dad's farm machine garage in the 1040'-50's. I think its called the Little Giant.

-- Edited by jim larson on Monday 3rd of January 2011 04:37:34 PM

dashboard · 2K+ Club

I stand corrected use a thread chaser as opposed to a true thread-cutting tap. Jim I would also do the bolt holes in the block also.

Lost in the 60s · President

Some of the bolts do go thru into the water jacket but the factory never used sealer on them. Once torqued, the head gasket was supposed to contain any leakage. I have had to use sealer on the upper shank of the bolt, above the gasket, to seal the head of the bolt to the cylinder head to stop seapages in the past. Same with a couple intake bolts.

SShink · 3K+ Club

Randy at Comp Engines said I could re-use the head bolts with just a brush up with a wire wheel and some new thread sealer.

That will help save a few $ for all the other 'unexpected' costs on this rebuild...

Lost in the 60s · President

SShink wrote:

Randy at Comp Engines said I could re-use the head bolts with just a brush up with a wire wheel and some new thread sealer.

That will help save a few $ for all the other 'unexpected' costs on this rebuild...

Can't say it was "unexpected". I suggested you plan on a COMPLETE overhaul and anything less is a bonus.... biggrin

At least you aren't paying for a bore and hone job with new pistons................

.....................................yet......... wink

-- Edited by Lost in the 60s on Monday 3rd of January 2011 08:01:05 PM

SShink · 3K+ Club

Lost in the 60s wrote:

SShink wrote:

Randy at Comp Engines said I could re-use the head bolts with just a brush up with a wire wheel and some new thread sealer.

That will help save a few $ for all the other 'unexpected' costs on this rebuild...

Can't say it was "unexpected". I suggested you plan on a COMPLETE overhaul and anything less is a bonus.... At least you aren't paying for a bore and hone job with new pistons.....................................................yet.........

Anything needing work forward of the transmission on this project was 'unexpected' last Fall when I bought it. Remember, this was 'just' going to be a 'pull the engine for cleaning up on the outside and swapping in a 200-4r' project... ALL the rest is 'unexpected'! biggrin

You'd think I'd figure out to plan for the 'unexpected' by now on these cars!!! wink

Tony Hoffer · Moderator

SShink wrote:

Anything needing work forward of the transmission on this project was 'unexpected' last Fall when I bought it. Remember, this was 'just' going to be a 'pull the engine for cleaning up on the outside and swapping in a 200-4r' project... ALL the rest is 'unexpected'!
You'd think I'd figure out to plan for the 'unexpected' by now on these cars!!!

Its starting to..

SShink · 3K+ Club

Tony Hoffer wrote:

SShink wrote:

Anything needing work forward of the transmission on this project was 'unexpected' last Fall when I bought it. Remember, this was 'just' going to be a 'pull the engine for cleaning up on the outside and swapping in a 200-4r' project... ALL the rest is 'unexpected'!
You'd think I'd figure out to plan for the 'unexpected' by now on these cars!!!

Its starting to..

Yep, I'm starting to look around the house and garage for things to sell to support my habit, er.... hobby! I even went through the couch looking for loose change! wink

-- Edited by SShink on Tuesday 4th of January 2011 07:40:02 PM

Lost in the 60s · President

I've already got a list of "stuff" to bring to Karls to sell.

Scott Parkhurst · Super Poster

I've made a habit of upgrading to studs. I just don't trust old factory head bolts anymore...especially if they pass through water jackets. I've seen some pretty rusty/corroded ones in my time.

The ARP studs I like to use are stronger, coated, and I feel they torque more accurately because you apply torque to a finer thread than what's in the block. Oddly, I've seen studs leak more than bolts, so I always use the white goopy sealant in addition to thread lube.

jim larson · 2K+ Club

Looked like there was sealer both on the threads that go into the block and on the shank part of the bolt that goes though the heads and just under the head of the bolt. What do you mean by white goopy sealant Scott? Thanks.