I posted this in LT1 tech yesterday, but it didn't get a single response.

"Just a simple question...

I've got copper head gaskets on my o-ringed 357 and I have a small oil leak coming from the deck/head area. I'm assuming the copper gasket has developed a leak. I was told I could reuse these copper units, but I'd like to verify that here. Also, when I reassemble, should I use any sort of coating (copper coat or otherwise) on the surface of the gasket?

thanks all"

 

Hi Jesse,
I have a high compression copper head gasket SBC myself. My machine shop guys told me to us Hylomar (available thru Summit or Jegs). Just clean your old gaskets a spray liberally. So far they're doing fine on mine.
Kevin

 

as stated about.

It is also pretty common for them to leak till they have been heat cycled a time or two.

 

these have been cycled many times, but they still leak. I'm going to pull them and give it another whirl this weekend.

Also, checking on this Hylomar stuff.

it was never stated blatently, but I can in fact reuse these, right?

 

One of the selling point for Cu gaskets is that there reuseable.
Most of them advertise that there reuseable up to 5 times.
I was told to make sure that the block, head and gasket are very clean and to put a super thin layer of silicone around the water jacket.
At work we have air cooled diesel engines that have copper head gaskets, If they blow out I all ways clean the head, block and gasket off with denatured alcohol.
None of the ones I fix come back. I also retorque the head studs after it has run, the tech manual that we have to use dosen't say to, but I know better.

 

When you say Heat cycle, you are retorquing while warm at least once...correct?
Then when cooled also?

 

well, damnit, I am now

 

You definitly need to retourqe those head bolts after your first heat cycle. I have copper head gaskets and o rings on my TA and have never got them to completly seal they have aleays spewed some coolant under boost but I have never leaked oil. If this is a street car you are going to have to live with leaks, if its just a race car then you should be fine. I know I'll never use copper again on a street strip car.

Jeff
96 SS BLOWN
96 TA 396 D1

 

As far as I am concerned, copper head gaskets should be used only on race cars, where a little seepage is not an issue. It is unusual for them not to seep. If your heads and deck are absolutlely flat and you are using head studs you may not see seepage, but they just don't seal as sell as other gasket types, thoguh they are very resistant to blowing out.

Rich

 

no head studs .

I'm going to pull the head, clean the surface, and heat cycle them a few times. If that won't seal them, I'm going to switch to something else.

 

if your pulling the heads anyway you would be crazy not to install studs get studs in their now.

Jeff
96 SS BLOWN
96 TA 396 D1

 

haven't bought them yet . Do they use the standard SBC head studs? If so, I might be able to find a set.

Can you get the heads over the studs without pulling dropping the motor? I wasn't aware you could...

 

I get them off the studs in the car but I have no heaterbox in the way , if it is even in the way on that side.

good luck bro!

 

I would suggest replacing the gaskets with fel-pro or cometic.

I've never seen a copper gasket that doesn't leak 'some' coolant.

 

Gotta make sure the deck and head surface have a smooth enough surface finish on them to run Cometics. If so they seal like a champ if not it's like running a copper head gasket that leaks.

Bret