Block and heads are new. Heads were shaved and block decked, so surfaces should be pristine.

I know this had been debated endlessly, but most threads are older on this subject, and it was my understanding that Cometic had done something with their HG's to prevent the weeping issues?

Thanks

 

just read an article , Both Cometic and Felpro say to use NOTHING. YES! they both did something, it's called multi layer steel or MLS gaskets

 

only prob I have seen with these is the coating will come off in places after the first use. I have reused them without issue anyway. Should I use copper spray for better multiple use on these mls gaskets? The steel layers shift with heat and cooldown. So there's constant movement across the surfaces. Would using copper spray help or be worse reusing this kind of gasket.

 

If the mfrs. say to use nothing, that's what I would do. Why second guess them??

 

 

Dry first use, they have a coating on them already. Copper when you reuse.

 

Dry first use, use acetone to make sure there are no oils on the block or head surface. A light copper coat when reusing.

 

 

This. Dry the first time.
I copper spray my LS9 gaskets before putting them back on any of my cars. All boosted making decent numbers, no issues even after the 3rd re-use.
I usually won't reuse the stock gen 4 5.3 gaskets since they are cheap to replace and I can get them from most local parts stores at a moments notice.
LS9 gaskets are $100+ and are online order only for me. They're also true MLS unlike the 5.3 gaskets which have a thick graphite middle layer.

 

Dry..

 

 

I've ran a MLS dry and then re-used it dry and had no issues with it sealing but the engine didn't stay together long due to a non related issue. I wasn't going to run them for a third time but I probably could have gotten away with it but it's been my understanding that you shouldn't re-use them because they've already been compressed. I was going to run the new set dry but figured why the hell not spray a light coat on them. It's certainly not going to hurt anything.

 

Nope. I was on about the 15th use on my last set of cometics before I tossed them.

 

Dodge/Shitsubishi was plagued with head gasket leaks years ago when they went to MLS gaskets. While the initial failure was due to gasket design, the field repairs soon failed because of poor surface finish. They published a TSB for the use of copper spray on their MLS gaskets to combat the issue.

The gasket manufacturers recommendation is based upon an ideal sealing surface. IF you have a freshly machined block and head install dry per gasket manufacturer instructions. If installing the gaskets on a typical in-car head swap the copper spray is recommended to help seal voids and imperfections.

 

I remember that, we had a rash of neons come through. Still the only gasket I've used copper spray on

 

For what its worth, I have changed the cam on my GTO 4 times and still use the OE HGs. There's nothing wrong with them. No copper spray.

 

I've got a question for you guys ballsy enough to reuse head gaskets: How are you cleaning them before you reinstall them?

 

Wire brush and sometimes brake cleaner if something is stuck to them.

 

I've never attempted to reuse a GM MLS head gasket like rednari2, but I've reused my Cometics a few times. Just drill out the rivets (keep the layers in order), clean with Brakleen and a quality shop rag, manually wipe the surface clean with more Brakleen using latex gloves, spray the layers and reassemble.

Don't worry about drilling the rivets as the dowel pins will keep the gaskets aligned properly.

 

Small shallow drip tray about the size of the gasket and just barely enough acetone to soak them (8 oz or so).
Shake them around enough to loosen dirt, remove and dry with air compressor.

Ready to go.