1000 miles on rebuilt engine leaking head gaskets WHY?
 

My 389 was rebuilt from a engine shop here in Tn, He used the Felpro gasket set to rebuild the engine the head gaskets were not the race ones. I believe they are the no retorque ones perma. Is that really true? Dont all head gaskets need to be retorque after they get hot then cold? Here are a few pics, you can see its near every bolt. I do not have anti freeze in my oil, the egine never 0ver heated. Will the retorquing the head bolts do the trick? Please any comments would be appriciated. I have $5,000 in the engine and its leaking anti freeze. The shop charged me $1,800 to do the break down and reassemble, I bought all the parts rods TRW Pistons cam lifters so forth,They did the start up and break in on a stand. Heads have been milled to clean them up. Runs great no smoke coming out tail pipe. Passenger side looks worse than driver side.

You should retorque the heads after a few heat cycles.

I agree, re-torque as is and my bet is that all will be fine with the details provided above (never over heated, milled surfaces), etc... I always add anti seeze under the heads of bolts, washers, etc... for a more accurate torque to eliminate any un-necessary friction between the two surfaces.

Tim john---

its always a good idea to re torque the hardware.

also a good ides to run a block sealing formula through the block until everything stabalise's.

a competent machine shop will know what industrial standard of roughness resurfaced heads and decked block should have. anything else will cause head gasket problems

I've had to use bars leak on a sbc build before. Not the warm fuzzy feeling we look for after dropping 5 large...... I am with the others, re torque and add sealer....

Did you ever wonder why we don't re-torque bolts on new cars? They don't even use sealer on the head gaskets--and very seldom develop leaks.

The block was checked with straight edge not decked, they said it didnt need it. I will retorque the heads. back off 1/4 than go to 100 lbs.

Do NOT back the head bolts off prior to torquing. That will disturb the preload already on the system and make things move around. Torque to spec and leave it.

could it be something else, maybe an intake leak, or freeze plug on the head???

I would re torque it and see what it does. Do it cold and don't loosen and re-torque. Just torque it from where it is.

Torque to 100 ft/lbs cold.

If it still leaks you have a problem with level somewhere or gaskets and heads need to be pulled. Period.

Thank all you guys for your input I really do appriciate your comments to help. So do I back off a 1/4 turn then retorque? or just retorque where the bolt is at? I here different opinions back off? or dont?

I,ve never re-torqued any of my head bolts ever, on pontiac, ford , chevy, mopar. notta.

Contrary to what others have posted, you must back off the bolt to properly re-torque them. What you have to do is one at a time. Back it off a 1/2 turn and then torque to 100 ft lbs in one motion. If you just try to torque them when they are tight, the breakaway torque is much more than the actual torque value. It wont be accurate.

Those are leaking pretty heavily. Not sure a re-torque will fix it. I wonder if the head bolts are bottomed out and keeping the gaskets from sealing. I'd have to agree with an earlier post. Heads need to come off and see what the issue is.

Serious damage will occur if a cylinder fills with coolant and you try to start the engine. Broken pistons and bent rods. Not worth the risk in my opinion to just torque the head bolts again.

These pictures are recent from a cold week or two sitting. I noticed anti freeze on the ground. The cold temp seem to really make it leak.

Like Bruce said.

I deck all blocks we build. Even though they check flat with a straight edge, you would be amazed at how much they are off. I have seen Pontiac blocks with a factory deck job that sloped off at one corner and took .015 to clean it up all the way across. You can't pick these things up with a straight edge, only low spots. If it's a gradual slope, especially off to one corner, they will check pretty flat. I have many pictures of messed up decks that the customer thought was good. Hopefully re-torquing and stop leak will fix it. Otherwise, you'll need to tear it down.

Here are pics of a Pontiac deck that checked pretty flat. This block took about .010" to clean it up. This is a typical factory deck job, and this is exactly why we deck anything we are going to build. If it leaks, we have to take it apart to fix it. It's just not worth it.

also, there is a specific roughness to the finish after decking the block that you need for the head gasket to seal....also, i think the finish is different for aluminum blocks/heads as well due the expansion. a good machine shop knows what those surface finishes should be.

I'm in this camp. Why build an engine and go without decking the block? Not only is it a chance, but as previously stated, the finish is also an issue. Makes me wonder what other areas/tasks were skipped/short-cutted.

IMO, if it's leaked, the gasket needs to be replaced, at minimum. Once a leak-path has developed, you need to take appropriate steps to ensure it doesn't leak further.

You might be able to get away with replacing the head gasket and cleaning up the surfaces, if amount of work is a concern, you can try that first.

And yes, any and every head gasket needs to be re-torqued after a few heat cycles.

.

This is correct, for the most part.

Any more, with all gaskets, smoother is better. Especially so with aluminum heads and cast iron block. The heads will expand more than the block so it is very important to have a very smooth surface with aluminum. The head needs to be able to slide across the gasket as it expands. Otherwise, if the surface is rough, when the head expands, it pulls on the head gasket and after time, tears the coating on the head gasket. Other times, it rips the sealing ring around the cylinder, apart. Smooth works best for MLS as well as fiber gaskets. MLS has to have a smooth surface. Fiber can get away with a little rougher if cast iron heads are used.

As for us, we deck smooth for any gasket. We don't have head gasket issues either. The old wife's tale of "you need a rough surface to BITE the gasket" has been invalid for many years now, though some shops still follow this philosophy.

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.

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.

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....

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.

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.

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.

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.

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.

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.

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.

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.

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.....

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.

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.

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.

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

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.

I agree, back them off and then re torque

Actually I torque initially to the low end of the range run it up to brake in the cam and check every thing, once I feel its all good I loosen up the head bolts , then retorque to the top end of the range.

run it up again and check for everything

then I do the block seal routine

Some light reading material:

Flatout Gasket Tips

Felpro Tech Tips

Dragracing On Line Forum

Yellow Bullet Forum

Wiki Answers

You'll notice the first two links are gasket manufacturer's tech tips - and one would suspect that they will have at least a partial handle on what works.

At least you and Bruce and a couple others get it. When I torque head bolts, I leave at least 25 Lbs. to the last torque setting. If I try to do it with just 10-15 lbs. It won't move the bolt at all before the wrench clicks off. The only thing the OP will find out by just setting the wrench to 100 lbs. and checking them is if some of them were never torqued to 100 in the first place. Then, that would be the fault of whoever put the heads on.

When I torque head bolts, I leave at least 25 Lbs. to the last torque setting. If I try to do it with just 10-15 lbs. It won't move the bolt at all before the wrench clicks off.

Very true. This is due to the coefficient of static friction being greater than the coefficient of sliding friction. After all, bolt threads are merely a glorified incline plane in the form of a helix/spiral. Slide just about anything across a surface (e.g. furniture across the floor) and you will note it typically takes a measurable additional amount of effort to get it moving initially...once it is in motion, it takes less force to keep it moving.

The only thing the OP will find out by just setting the wrench to 100 lbs. and checking them is if some of them were never torqued to 100 in the first place.

Not necessarily true. If you just torque it to 100 ft/ lbs. from the get-go (and are sure it is 100 ft/lbs.) torquing of the rest of the bolts may pull the head in more, effectively lowering the actual finished torque of that first-tightened bolt(s), even though it WAS 100 ft. lbs. to start with. The latter bolts will be at, or near the 100 ft/lbs., the but the earlier one(s) may not be anymore. The more "give" in the head and the more bolts the head had engineered to provide the needed clamping force for the application, the more this is true.

Always torque the heads in proper sequence and in proper increments as Paul has described above.

That being said and the proper torque sequence performed (assuming the threads were clean and not galled), I vote for the bolts being too long. I would verify that they are not too long before putting additional twist on "bottomed out" bolts" for fear of damaging the threads. More often than not, additional tightening will stop the leak. However you must ask yourself, "Are you feeling lucky, punk?"

Tony

A little late, but here are pics of the black Felpro gaskets that wouldn't seal up because of the extra thick compression ring. Knew I had them somewhere. The gasket had been torqued down and installed properly and we had coolant leaking out on the floor. The pics are of the compressed gasket after it was removed from the engine. Even the composite part of the gasket was thicker than normal.

Did FASTGOAT66 ever mention if he's using stock or ARP head bolts, and to what spec either was torqued?

I recall seeing something similar occur with ARP head bolts if lubed with 30W oil and 95 to 100ft/lbs. Simply not enough clamping force to keep the engine sealed up tight while the components expand and contract from ambient temperature changes.

The machine shop used my stock head bolts with oil. what ever stock specs were is what they did. It makes sence after a few heat cycles to retorque the head bolts. I just never did. Im going to get a torque wrench on each bolt and get back with my findings. Thank all you guys for taking the time to help me.

I think the answers regarding the differences in friction coefficients are correct. think of sliding a piece of furniture across the floor - hard to get started, easy to keep it moving.

Hope for the best expect the worst good Ruck.

My 1966 Motors Repair Manual says head bolt torque is 95 ft-lbs for '59-66 engines.
I've always had good luck with Felpro 1016 gaskets, even on engines with stock or pitted deck surfaces.