Anyone with MAC headers try Percy's aluminum gaskets and have them leak really bad? I put a set on my car this weekend and they leaked so bad I had to pull them off and put some Felpros back in. I just want to know if this is header related or gasket related.

 

well... does it leak now?

 

Well actually it still leaks but only from the #8 port. With the Percy gaskets it leaked from every port.

 

Aren't the percy gaskets supposed to be leak/blow-out proof? I figured if you tightened them down enough they, being made from soft aluminum, surely wouldn't leak. Good heads up though, I was going to use their gaskets when I got headers.
maybe the gaskets aren't lined up well, or the primary doesn't mate up evenly?

 

yeah who else is having problems with these gaskets. I'm already have all the parts i need to do my header install. I bought the percy's gaskets because i heard they were the best. But now i have been hearing that people are haveing a lot of problems with them leaking. Whats the deal with this?

Also RocMephis did you install the flat side toward the header or the head?

 

I installed the flat side toward the head per Percy's instruction which I assume was the shiny side. They look like they would seal good with a solid flange header but with MACs being separated flanges they didnt seal worth a crap.

 

I started out with stock type gasket but when the bolts loosened up they blew out. I then went with the Mr. Gasket soft copper that looks like the percy but is copper and used Breslin split lock bolts. Bolts didn't loosen but gaskets leaked all over the place. Took em out and found they protrude into the port bad design. I now use the Fel-Pro 1406 that was advised by many and with the split locks it seals like a champ with absolutely no bolt loosening. Those bolts are the best!!

 

What do you mean "they protrude into the port"? Are you saying that they were smaller diameter than the Port opening, or are you saying that the bumped out ridge on the gasket went down into the port?

Dan

 

Sorry, I ment that they were too small and the lower part of the gasket was higher than the port and partially blocked the opening. Hope that explains it better. After this happened to me I did a search and found a lot of other people had the same problem.

 

O.k. Thanks. Makes sense.

Glad the new ones worked out for you.

Dan