Well, I just finished up a build that has been plagued by head gasket failures, even though I've used the methods outlined by Cometic which has worked for countless builds, so I've spent the last few weeks researching different methods others have used to keep the gaskets sealed under more extreme cylinder pressures. I've read different schools of thought and consequently some strange methods used with varying degrees of success, but I thought I'd ask here to see what "secrets" you guys have tried.

For this one, we used the Cometic head gaskets with Permatex copper spray, and torqued the 11mm ARP head studs to the recommended torque value of 80ft-lbs in three even increments. This is the same process that was used last time, but still failed as the engine injested a 200 shot of nitrous in fifth gear at over 190MPH (Texas Mile) This time, however, I used a heat gun in the water passages to bring the heads up to 180 degrees and retorqued the head studs to 80ft-lbs. The damn things took another half turn to get back to 80ft-lbs! We'll see if it holds up in about a week...

 

These cause your problem. Cometics don't use Permatex to seal. It actually makes that worse.

Let the heat cycle naturally as the engine warms up, don't use outside "accelerators". Drive for a bit without going nuts, then check again.

There are not "tricks" if you follow proper procedure and don't invent quick work-arounds to get it to work properly. Stick with K.I.S.S. and you're good.

 

I normally take them out of the package, put them on my block, and then put the head on top, and torque them down.

 

lol x a million^^^

not very complicated, but in all seriousness, having head gasket problems and youve tried everything, ensuring flat surfaces? If so id talk to your tuner.

 

There are no tricks. Perfectly flat surfaces finished to the proper RA. Tighten fasteners to manufactures specifications.

 

Adding a 200hp shot of nitrous in 5th gear is going to be a little tricky to tune for. What engine is it, and what other power adders is it using? how much total output? I would think you'd have to run quite a bit less ignition timing at that high load and heat soak by the time you are in 5th gear on top of adding 200hp on top of those situtations. Gear based timing retard by chance? Just spitballing is all, in no way am I saying it's tuned wrong.

 

INB4 "Cometic sucks!"

If your studs took a half a turn to retorque to spec then that tells me your studs are loosening in the block which is probably the issue. I torque studs into the block to 15ft-lbs and Ive never had to retorque head studs since.

 

Actually know how to use a torque wrench

 

The copper spray actually has shown to help. I've used Cometics with and without the copper spray, and on the big power stuff I've never had a head gasket problem. This is really a different animal though as it's full 1 mile passes at WOT, plus the nitrous.

The KISS method just isn't working.

Again, been there and done that. Freshly machined head and block and torqued to spec. With all due respect, if you have simply followed the instructions then I don't need your input. There are "tricks" that people have used with success, which I plan to experiment with later when there is more time. I'm looking for those who have more extreme applications where one of these "tricks" helped.

It's a V8, makes 600whp without nitrous, 800whp with it. We've pulled a lot of timing out for this and we're not getting into any knock. I don't even want to mention the abuse the diff and trans are going through. The owner of the car does not want to gear it to keep it out of fifth.

 

O ring and oem gasket

 

A trick I use....

I always use oem MLS head gaskets with a little honda-bond around the passages, Endyne also uses this method. I then torque to the spec of the particular head bolt/studs Im using (every manufacture has their own process), I then let the car go through a couple heat cycles and cool down completly and then re-torque.

When you get to the final torque step try to keep the turning of the wrench smooth and in one motion. IE: Don't start and stop in the middle of the process


Where did you experience the head gasket failure on the gasket? Pics of the gasket?

 

I've run cometic on a few motors and OEM w/orings on a few motors, never had an issue.

I've also put head studs in hand tight vs torquing them, never had an issue.

Copper spray? C'mon man....

A 1 mile run with a 200shot is a long time on the squeeze man, my guess is the tuning/timing/ignition needs work. Prolonged 5th gear runs aren't good for any motor.

If you find yourself having to do all these "tricks", ask why so many others have made TONS of power without having to do any tricks.

Not trying to 'hate' on you as it sounds like you're doing a fine job otherwise. Just food for thought that maybe some other demon exists in this engine you may not have uncovered yet.

 

Use High temp paint , its just like copper spray basically but..its a old f1/nascar trick.. and it works..

Your main problem is mostly cometic HG's are just crap, I've personally never had any problems with stuff like OEM , GE, JE, I'd see if another company makes HG's for your v8, which btw are u using?

We all know here you know how to build a motor, and probably its due to the long term stress on a long gear. Do you have anything to retarded timing by gear??

 

It leaked right between the cylinders, where it gets down to a minimum of .215" thick (4.185" bore and 4.40" bore spacing) and it looks like they blew out on top of the gasket while the block looked to still be sealed to the gasket. The first time, the engine was run to get the water temps to about 180-190, then each nut was backed off one at a time just slightly so that it could be retorqued and keep everything sealed.

Trust me, we're on the same page as there are turbo cars making over 1500whp and going over 250MPH, but those are turbocharged. The nitrous is pretty violent in comparison, which I think is the root of the problem in this type of racing. I think the o-ring would do the trick, but it wasn't an option as there simply wasn't time to have it done before this event. At this point, the engine is getting installed and will be run as is.

I've read some interesting stuff from guys making upwards of 2000whp in a small block, which is where the heat gun idea came from. He would use an aircraft sealer on the gaskets and use the heat guns to bring the temps up slowly and without water in the block to keep temperatures from varying too much throughout the engine.

 

I've heard of that before, just never tried it though.

It's an MID sleeve LS engine, so our head gasket choice is limited. I think Cometic is the only company that makes MID specific head gaskets.

The tune is of course another area we're looking at. We pulled a lot out the last time, but it didn't do much good. We're gonna fire this bitch after TDC if we have to lol.

 

Well. Ok. Not much more to say to you after that. I've used about 6-8 MLS Cometic gaskets all without a leak or a damage for over 7 years running.. I didn't say I left the COMETICS plain I said I didn't use copper spray. I use a thin layer of TOYOTA transparent sealant on the MLS gaskets from COMETIC, and Copper spray on the OEM gaskets. But you seem to have it under control however, so its a moot point.

As ALL MOTOR stated, perhaps your tune with the Nitrous may be the center of your issue. Good luck to you. K.I.S.S. Always helps. It's more than a process, its a belief system.

 

EG1834, In your situation, I don't think paints, sealants, and spray on additives are going to be the solution. Under those cylinder head temps and pressure, you'll gonna need some alternate clamping force in between the cylinders. I would try o-ring. Aluminum heads right? Maybe it'd be better to o-ring it rather than spend the time trailering it to test or run setup and blow gaskets again. Maybe Cosworth can do gaskets? But like I was inquiring before about ignition timing, you might have to do a gear based retard. With 5th gear run, the drag at 190mph, and the combustion chamber design maybe that is what you'll have to do. What fuel? If you're not on it already, maybe some ethanol to combat cylinder temps that get heat soaked upon the longer runs. If rules permit. If not, maybe some alcohol injection to help keep temps down, not as a fuel. I'm just tossing ideas, might not be applicable to your situation, but you never know.

 

For extreme applications I use OEM headgaskets and a thin/even layer of Indian Head gasket sealant shellac by Permatex, been using it over 10+ years, good from -65*F - 350*F. Never had a headgasket failure under extreme pressure conditions while using it. I usually only use it on turbocharged setups, but I'm sure it can/will work for anyone in any situation.

 

Good stuff, even though its not necessarily needed on a MLS gasket thats coated with viton. One thing ive found is that the aftermarket viton gaskets dont seem to separate (the material from the steel) as easily as OEM gaskets. I'm not sure what the OEM gaskets use for a sealing material but I have stayed way from them as I find they are less durable.

 

All great ideas, and I appreciate your input as well as everyone else's thus far. I believe it's running C16, or at least a mix with 93 octane and C16. No meth/water injection though, not sure how much cooler it will be on top of the nitrous already being sprayed. I'll update in about a week after its been run.

 

I have had very good experiences with the Indian Head sealant. Granted, you are correct, it is not needed for a Viton sealed MLS gasket, although I only use OEM which is where I was referring my experiences towards.

As far as I know, OEM (HONDA) headgaskets do not use any sealing material, they are standard stamped 3-layer and are held together with rivets. Not sure about other brand gaskets in which the OP decided against using.

 

OEM gaskets are coated, but i dont think they are coated with viton, i find that the aftermarkets, especially mahle (victor reinz) hold up alot better in a situation where OEM tolerances arent exactly there.

 

Here is something I have learned from the Nuclear industry....

When we assemble a nuclear reactor after a refuel we have a cold torque and hot torque value on the reactor head studs. There is a reason for that. Steel expands and contracts (different than aluminum). If we were to run our power plant with just the cold values it would leak, which is not good. When we hit normal operating temperatures and pressures (557 deg F and 2250psia) the studs are torqued again and we have zero leaks.

So, I have adopted this same technique on my drag car. Benson sleeves, no o-rings, GE MLS head gasket, AEBS or GE studs, no copper spray, no Honda bond, nothing. Just a dry clean gasket. I boost the car over 40psi, make well over 1100whp and I don't have any issues. I heat cycle the car 3 times and on the 3rd heat cycle I tear the top end apart as quick as possible (got it down to less than 10min) and retorque the studs. I typically get at least half a turn. I go about 5-8lbs over their recommendation. The difference of expansion will cause things to shift and settle.

Never pushed a head gasket or had failure.

Make sure you use a good torque wrench, know how to use it properly, know how to use it consistently, and use oil (moly lube can cause over torque).

Just sharing some fun stuff I have learned over the years. Enjoy.

 

I have called arp and golden eagle before to ask about a hot torque spec for our application and they allways dont reccomend it because of the friction difference of the threads when hot...I know some V8 guys that swear by it.

As stated above I allways do the cold re torque after a few heat cycles and there usually is atleats 2 out of10 that can go anouther 1/4 to 1/2 turn to reach the original torque spec.

 

Thanks tepid, good stuff to know!