[Lee]

Stock bolts, or ARP?

I've never had to retorque heads on a Pontiac. I've seen some 1016 head gaskets do this long ago, but would hope that issue is long gone.

[geeteeohguy]

I think Lee is on to something here. Very possible the bolts are too long and bottoming out. These gaskets are leaking along their length, indicative of the heads not being tight enough or seriously out of true. Regardless, the heads must come off, the surfaces and bolt length checked, and NEW gaskets must be installed. There have been incidents involving ARP bolts that are a hair too long, with the same result. Trying to simply re-torque and run is a shortcut and not in the best interest of the newly rebuilt engine.

[chiphead]

In theory, I agree with the "breakaway torque" discussion on a properly torqued fastener without a gasket, like a main journal bolt or something. A clamped joint is held together by the bolt, which is stretched by being torqued to a given value. The amount of rotational torque applied to the bolt gives a predictable amount of stretch, and thus a given clamping force for thread pitch, bolt diameter and bolt material. When a bolt is torqued to X value, it will require more than X value to further turn the bolt against friction in the threads and under the head.

This is why the type of lubricant on the threads is critical when torquing bolts. ARP suggests the use of their lubricant, since the amount of torque with lubed threads will more reliably produce the expected amount of stretch in the fastener.

However, when re-torquing head gaskets, you are RE-tightening fasteners that could have less than the correct torque value when you re-torque them. Torquing to the correct torque (without loosening) should properly stretch the bolts that are at less than rated torque. The loose bolts will be readily apparent by rotating but the tight fasteners will simply "click" when you torque with a clicker style torque wrench.

When retorquing, I watch for bolts that never seem to stop turning, they just keep going and going as you try to reach rated torque. Those bolts are likely stretched beyond yield and may break in half. I remove and replace those.

If you back the bolts off first, you will have no idea if the bolt was near rated torque or not. I do back off head bolts if I suspect that the original installer did not jump around and tighten the head bolts in the correct pattern, which does not evenly clamp the gasket.

If re-torquing does not shut the leaks up, it's time to pull the heads and see what's up. Could be too long bolts, improper deck surface (pits, etc), uneven deck, cheap head gaskets, fatigued bolts, bad install procedure, dowel pin issues, etc.

my .02, anyways......

[charlie66]

Originally Posted by chiphead

In theory, I agree with the "breakaway torque" discussion on a properly torqued fastener without a gasket, like a main journal bolt or something. A clamped joint is held together by the bolt, which is stretched by being torqued to a given value. The amount of rotational torque applied to the bolt gives a predictable amount of stretch, and thus a given clamping force for thread pitch, bolt diameter and bolt material. When a bolt is torqued to X value, it will require more than X value to further turn the bolt against friction in the threads and under the head.

This is why the type of lubricant on the threads is critical when torquing bolts. ARP suggests the use of their lubricant, since the amount of torque with lubed threads will more reliably produce the expected amount of stretch in the fastener.

However, when re-torquing head gaskets, you are RE-tightening fasteners that could have less than the correct torque value when you re-torque them. Torquing to the correct torque (without loosening) should properly stretch the bolts that are at less than rated torque. The loose bolts will be readily apparent by rotating but the tight fasteners will simply "click" when you torque with a clicker style torque wrench.

When retorquing, I watch for bolts that never seem to stop turning, they just keep going and going as you try to reach rated torque. Those bolts are likely stretched beyond yield and may break in half. I remove and replace those.

If you back the bolts off first, you will have no idea if the bolt was near rated torque or not. I do back off head bolts if I suspect that the original installer did not jump around and tighten the head bolts in the correct pattern, which does not evenly clamp the gasket.

If re-torquing does not shut the leaks up, it's time to pull the heads and see what's up. Could be too long bolts, improper deck surface (pits, etc), uneven deck, cheap head gaskets, fatigued bolts, bad install procedure, dowel pin issues, etc.

my .02, anyways......

Very well put.

When I called ARP they told me when re torquing NOT to loosen the bolt and to do it cold....

[FASTGOAT66]

I went to the machine shop today and showed the builder my pics. He looked at the pics and said it looks like the leak is above the front head bolt leaking through the bolt threads down the gasket. He said I could try to retorque the bolts and add those gm seal tablets.

[gtofreek]

I hope he's not suggesting that the head bolt threads go into the water jacket like a Chevy does, therefore leaking up the threads and out around the head of the bolt. That's kind of what it sounds like you're saying. Pontiac head bolts don't go into water.

[69Goatee]

I had the exact same leaks on my 1969 GTO. It was the ARP head bolts being too long and bottoming out in the block. I had not run mine yet, so I reused the head gaskets. I read the way to check is to put the bolts in hand tight without the washer and check the clearance. If the bolt head touches the cylinder head, the bolt is fine, if not you need to put two washers on those bolts. I had 7 bolts too long, 4 on the pass, 3 drivers. I put extra grade8 washers on the long bolts and torqued the heads down, broke the cam in, and have about an hour of run time with no leaks so far.

[lust4speed]

As far as not loosening or loosening head bolts, I think the phrase "an object at rest tends to stay at rest" can be tweaked a little to apply here. In the real world, a head bolt will resist moving until the torque load is considerably higher than the actual load. A bolt might be at 85 foot pounds, but won't move when 100 foot pounds is applied - and therefore the bolt is left under torqued. By loosening the bolt and taking a clean run, the actual torque will be re-set to 100 foot pounds. This has happened to me even when using of ARP's Ultra Torque after engine break-in. Just one of those facts of life that can either be accepted or rejected.

I have never had a gasket leak from head bolts not being retorqued, but I loosen and set them again before the engine comes off the engine stand.

I've seen blocks that looked like they've been decked with a belt sander and the head gaskets didn't leak. Long head bolts could be the culprit, but I'll throw another possibility out. Are these Felpro gaskets the normal blue color, or could they possibly be the black with orange Printoseal? I ask because we had two engines using the black gaskets leak the same way. After taking things apart we found that the fire rings were .012" thicker than the remainder of the gasket - and this was after torquing things down and then tightening things up again. The rings were holding the head far enough away from the block that the coolant leaked out. I always wondered how many more bad gaskets were out there.

[J.C.you]

fel-pro gaskets should be re-named fail-pro. Install a set of the Butler oem repop gaskets, copper coat the metal side and the problem will go away. Do a couple of re-torques after the first two heat cycles.

[gtofreek]

I've never had a problem with Fel-Pro gaskets not sealing that I can ever remember. I even re-used stock Fel-Pro replacement head gaskets on my 12.5:1 compressioned 428, 3 times without them ever leaking.

[J.C.you]

Originally Posted by gtofreek

I've never had a problem with Fel-Pro gaskets not sealing that I can ever remember. I even re-used stock Fel-Pro replacement head gaskets on my 12.5:1 compressioned 428, 3 times without them ever leaking.

I bet you went to the trouble of decking the heads and block on all your apps, which is a great thing to do. In your instances, fail pros will suffice in many cases, but will not seal like a composite, metal oem type gasket where the deck and head have not been trued. GM knew what they were doing when they made head gaskets where the surfaces were not perfect as in fastgoat66 engine.

[gtofreek]

Actually, my 428 was back before I was a machinist and it looked like it had a factory surface on the deck. Don't know about the heads.

[geeteeohguy]

I'm betting that this issue has nothing to do with Fel Pro gaskets that were used. I've personally used them a lot over the past 35 years with zero failures. I've also done a bunch of head jobs with them that never got re-torqued and never had a problem. No, the problem here is faulty machine work or over-long fasteners. Whenever an aftermarket part is introduced, it is the first thing I suspect when a failure occurs. This has been learned from decades of experience. The fact that the machine shop is advocating the use of stop leak in a brand new build would make me choose a different machine shop. It's a cop out of an answer, not a real fix. Measure the bolt length.

[78w72]

holy cow, enough with the opinions of head gaskets & guesses on how to retorque a head bolt... just re-torque the bolts & see what it does. chances are it will fix the problem, if not there is no harm done & very little effort involved. who knows, maybe the shop didnt tighten to the right spec, or had a crappy torque wrench? the time spent going back & forth is pointless. no offense intended to anyone who posted but to start calling gaskets "fail-pro" is hilarious & contributes nothing to helping the guy fix his leak. i have used felpros for over 20 years & never had a problem, had friends use them just as long too, on stock low buck rebuilds with no block decking to a 10.7 aluminum head stroker engine, all were just fine with thousands & thousands of miles. & GM didnt use this style gasket because its more expensive than basic metal gaskets that went on millions of cars, plus that design probably didnt exist back in the 60's & early 70's.

also never heard of backing off a bolt when retorquing head bolts or any bolt with a gasket between 2 surfaces... where is that written by any head gasket manufacturer or suggested by any knowledgable machine shop??? not saying its right or wrong, just sayin i've never heard of it untill reading this thread.

& actually i think most gasket companies specifically say to retorque head gaskets after a few heat cycles, simply due to the physics of expanding & contracting metals. or at least edelbrock says to do it regardless of the gasket used. & they dont say anything about backing off the bolt first.

however, on my 78 400 iron head engine with the basic fel-pro head gasket i did have a slight leak of coolant during the first winter storage, nothing as bad as the OP showed, but it seemed to be from the cold, which contracted the metal enough to let some coolant weep out.... without thinking twice i simply retorqued the gaskets to what wallace racing suggests, (a little tighter than stock) & the leak stopped instantly for the next few months of storage without starting the engine. come spring it was leak free & has been for almost 5 years now & thousands of miles.

bottom line, retorque the dang bolts before adding any stop leak or pulling the heads etc... & don't back off the bolts just to go to the same torque spec, seems like that will just put you back exactly where it is now. i agree with chiphead, when you retorque a head bolt you need to do it from where its at to get more clamping force. its not rocket science. if that simple step doesnt work then by all means do what others mention like checking bolt length & head/block surfaces etc. just my .02 since everyone else put in their .02

[charlie66]

Originally Posted by 78w72

holy cow, enough with the opinions of head gaskets & guesses on how to retorque a head bolt... just re-torque the bolts & see what it does. chances are it will fix the problem, if not there is no harm done & very little effort involved. who knows, maybe the shop didnt tighten to the right spec, or had a crappy torque wrench? the time spent going back & forth is pointless. no offense intended to anyone who posted but to start calling gaskets "fail-pro" is hilarious & contributes nothing to helping the guy fix his leak. i have used felpros for over 20 years & never had a problem, had friends use them just as long too, on stock low buck rebuilds with no block decking to a 10.7 aluminum head stroker engine, all were just fine with thousands & thousands of miles. & GM didnt use this style gasket because its more expensive than basic metal gaskets that went on millions of cars, plus that design probably didnt exist back in the 60's & early 70's.

also never heard of backing off a bolt when retorquing head bolts or any bolt with a gasket between 2 surfaces... where is that written by any head gasket manufacturer or suggested by any knowledgable machine shop??? not saying its right or wrong, just sayin i've never heard of it untill reading this thread.

& actually i think most gasket companies specifically say to retorque head gaskets after a few heat cycles, simply due to the physics of expanding & contracting metals. or at least edelbrock says to do it regardless of the gasket used. & they dont say anything about backing off the bolt first.

however, on my 78 400 iron head engine with the basic fel-pro head gasket i did have a slight leak of coolant during the first winter storage, nothing as bad as the OP showed, but it seemed to be from the cold, which contracted the metal enough to let some coolant weep out.... without thinking twice i simply retorqued the gaskets to what wallace racing suggests, (a little tighter than stock) & the leak stopped instantly for the next few months of storage without starting the engine. come spring it was leak free & has been for almost 5 years now & thousands of miles.

bottom line, retorque the dang bolts before adding any stop leak or pulling the heads etc... & don't back off the bolts just to go to the same torque spec, seems like that will just put you back exactly where it is now. i agree with chiphead, when you retorque a head bolt you need to do it from where its at to get more clamping force. its not rocket science. if that simple step doesnt work then by all means do what others mention like checking bolt length & head/block surfaces etc. just my .02 since everyone else put in their .02

Well said.

If a bolt losses its torque value it wouldn't need to be turned back to get it back to its original torque setting... Because its now lower in torque value.... So all you need to do is set the wrench an torque it back..,...

Just sayin.....

[Lee]

Originally Posted by lust4speed

As far as not loosening or loosening head bolts, I think the phrase "an object at rest tends to stay at rest" can be tweaked a little to apply here. In the real world, a head bolt will resist moving until the torque load is considerably higher than the actual load. A bolt might be at 85 foot pounds, but won't move when 100 foot pounds is applied - and therefore the bolt is left under torqued. By loosening the bolt and taking a clean run, the actual torque will be re-set to 100 foot pounds. This has happened to me even when using of ARP's Ultra Torque after engine break-in. Just one of those facts of life that can either be accepted or rejected..

Coefficients of friction, that is what you are referring to. CoF for items STATIC is higher than KINETIC.

That is, once you STOP turning a bolt at certain torque, say 90lb-ft, then it is static. To get it to move again, it will take MORE than 90 to get it moving. If you want it to be a small step above 90, then you will have to loosen the bolt enough to compensate for the CoFstatic. This why you don't baby-step the torques on cylinder heads and other higher-torque items.

[geeteeohguy]

As a technician who's done a fair amount of engine repair over the past 35 years, I have to say that I never have loosened any fastener on a re-torque job. You simply apply the wrench and verify the setting. I've had VERY FEW fasteners over the years (head bolts) come loose or lose initial torque, even after heat cycling, unless the fastener was stretched beyond its service limits by previous over-torqueing to begin with. This has always been the industry standard....nowhere can I find written verification that you need to loosen a tight fastener to 're torque' it.....I know that I personally won't be doing this, as I never have and have never had an issue. Over the past 35 years doing engine and automotive repair, I have never even worked with another tech who loosened before re-torqueing. IMO, it would do more harm than good.

[Lee]

Jeff, I never retorque head gasket either. Maybe with copper head gaskets, or other "non-normal" situations it is required, but not on street-strip motors using normal gaskets.

But, if you torque all the head bolts to 95, then "retorque" them to 100, you will find many of them do not move at all. Does that mean they were already "100"? No, it means the static CoF is higher than 5lb-ft for those. The ONLY way to get them 100 (from 95) is to back them off SLIGHTLY, then re-torque to 100.

I DO NOT make a practice of doing this myself, but I've seen it mentioned several times in my life.

[charlie66]

When tryed to re-torque ,If they don't move from original torque setting then they didn't need to be re-torqued...

[pugslyx234]

take it apart it will ease your brain and check the length of all head bolts. Remember coolant thats gets into the oil will gel and clog passages just sayin.