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Gm Head Gaskets

Someone should inform the manufacturures of this thread perhaps. Often time companies do want to improve the products, but lack real world information, especially with guys like you pushing them to the absolute weak link, and having the urge, time and money to do it repeatedly!!

Especially when it doesn't cost them a penny R&D.

Maybe they'll give you free gaskets just to abuse and test.
 
That would be sweet, but it sounds to easy, I should call Felpro first,since they have some solid steel core gaskets for small block chevys,so they should be able to make one for the 6.5.
 
Since Cometic makes the to custom order, and they already charge a premium for that service they may be able to make it however you like.

Companies might not care to improve things if youre running 60psi in a system designed for less than 20psi.
 
buddy said:
Since Cometic makes the to custom order, and they already charge a premium for that service they may be able to make it however you like.

Companies might not care to improve things if youre running 60psi in a system designed for less than 20psi.
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Thought would be to really stress test them. For example, a tire rated for 60psi is tested to 120psi. Maybe a pipe dream, but its worth a shot. Can't fail if you don't try, but you can't succeed either. (more volume with less psi)
 
I talked to a local shop today that has a water jet,he thinks he could make me some copper gaskets,but I need to give him an old one for a template,probably the center piece from my Cometics should work. Plus I need to decide what thickness to go with. I got a Harbor Brake dial indicator to measure how far the pistons stick out of the hole.
 
Got my Isky Groov o Matic oring groove tool today,it came with .040 copper wire. Not sure if I'll use the copper wire or stainless steel wire. I might try oringing the 6.2 using the Corteco gaskets,just to see if it is possible.
 
SmithvilleD said:
I've worked around an engine builder that was a firm believer that the stud threads/block threads needed to be under their normal strain load while the loctite cures.
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chevyinlinesix said:
That is one hell of a good idea :thumbsup:
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ARP makes this point very clear in their literature also. I'm not sure how long the various grades of loctite take to set up, but this approach sounds problematic to me.

Seems like a soft or semi soft slow-setting sealant on the threads would be best.

I wonder how to test exactly what the leak mode is... iow, is the coolant forcing it's way past the thread sealant? And if so, is that any different for bolts? Or is the leakage occurring under the shoulder of the bolt/nut, where the TTY bolts have the ring of orange silicone pre-applied? If this last bit is the culprit, seems like installing the studs, then carefully applying a ring of RTV at the stud:washer:nut joint might do the trick.

How often do TTY bolts leak coolant into the valve covers? Don't think I've read any reports of this, but maybe it would be difficult to notice? Just as reported with the studs... not sure I'd have caught a slightly overfull dipstick reading if not forewarned. (THANK YOU chevydiesel !!) I'd be watching for milky oil and thinking everything was fine.

So for thread sealing:

TFE sounds like it would ideal, but the results aren't consistent given the different reports I've read about here.

RTV sounds like the consensus best compromise solution, but I wonder... what's it like trying to chase the threads next time the heads come off? Sounds near-impossible to get it all out.... maybe using a chasing tap, then very stiff round wire brushes similar to those used for engine oil galley cleaning? Seems like you'd push a fair amount of RTV scraps into the block. Maybe flushing with the rad hoses disconnected would prevent sending all that debris into the core tubes.

For a simple problem, this sure gets complicated.

We need an accelerated test routine. I'm willing to conduct some testing, as I'm going to use studs in this next motor. Anyone have suggestions about how to structure the testing to really nail this down?
 
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I made some test grooves on my old 6.5 block. First one I went with the cooper wire about .013 protrusion and a used Felpro and torqued it down, and then took the head back off, the wire got off the edge of the fire ring a little . Next try I removed the copper wire and used .040 regular steel wire and a used Victor Reinze gasket, this looked better but were the oring landed on the wire that is inside the fire ring it didn't compress. The head gasket fire rings are not exactly centered on the cyl. Next try I grooved another cyl a little wider this landed the oring to far out in the fire ring at some spots,so I removed the fire ring and flipped it around,the top is a lot wider,this made a nice groove after I torqued it down ,pretty much dead center of the fire ring,but totaly missing the wire that is inside the fire ring,so the tension on the fire ring won't be that huge,but it will have a pretty good bump that the fire ring will have to slide over to actually move enough to leak. I am thinking of getting some Victor gaskets and flipping all the fire rings,guess the steel piece for the prechamber won't matter if its on the bottom ?
 
Yea it was,but I did use a $20 Summit coupon so I saved a little. The more I think about it the worse it looks if I would use stock gaskets,any tips on how to cut copper, jig saw dremel,drill,or utility knife,the center Cometics will make a nice template. Besides that it would have to be water jet.
 
Are you trying to cut the rings? Out of a Copper $heet?

I would have to think some type of circle cutter on it with either a sharp knife type blade or a really really sharp point would do it. You wouldn't have to worry about the center attachment point which is a huge plus. (screw) should be able to mount the sheet and the circle cutter's pivot together, and just scribe the circles until it cuts through I would think.

Could use just that, draw the circles to spec, attach a screw in the middle, and a loop on the string to your cutting tool of choice should follow your drawing, then follow the scribe lines pretty good until it cuts through. Find a fixed hard object to replace the string for easier accuracy.

Or are you cutting gaskets?
 
Water-jet should be pretty cheap as they shouldn't need to use any abrasive with it (main cost factor) but you could also get them laser cut. I know of a place that does nothing but water and laser cutting, but not sure if they deal with the public as they are not listed anywhere. I'd advise you to call any and every shop around getting quotes, you will find prices vary a lot likely.
 
I was thinking of cutting my own copper gasket, machine shops say a laser will glare and possibly ruin the eye. I'm sure water jet is the best way,but I might try it myself, thought of bolting the sheet to an old block a long with a Cometic center piece ,so I would have a good pattern,and what ever cutting tool I use can go through the copper. Another idea is to screw it onto a piece of wood,that would work good for drilling all the bolt holes and the water holes.
 
Yeah, I actually forgot about the reflectiveness of the copper sheet, laser wouldn't work. I know you could drill out the bolt holes etc. fine, but I'm not sure about the cylinder bores. Copper is soft, but is it soft enough to cut with a good blade? If it is then I think that would be the most cost effective way to go for sure.
 
Just throwing cutting ideas out, you could sandwich it between 2 1x8's and then cut it with a fine tooth jigsaw would leave that copper perfect for sure. Hell even a good circular sawblade would cut the sandwich with great results. It would basically turn it into a piece of wood, and when all is said and done, unscrew the 2 1x8 sandwich and you'll have a gasket as perfect as your cuts for sure.

You could lay the template gasket on the sandwich and then spray paint over it to leave a template maybe.

3/8ths plywood sandwich may be easier less meat to cut, but more expensive. Have the home depot or wherever rip it down to 8" or whatever size rips to make it easier for you.
 
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