Donut Gasket

[Econoline]

Which donut gasket do you prefer, the blue on or the silver sintered one? I keep getting a leak at the donut, I've been using the blue ones.

 

[chad]

"Pic's wortha..."
I know U, U re-tq after a few heat/cool cycles, no?
I aint seen mine since the '80s so don't be mambah...
Use the other this time?

 

[Econoline]

I'm wondering if people have had better success with one or the other. I don't know why I'm having this problem other than maybe my flange on the pipe side isn't formed right. I added a bracket/strap welded to the head pipe that bolts the head pipe to the block when I redid my exhaust last year. I'm going to add a 4" long flex section in after the o2 bung when I pull it apart next time to have the head milled.

 

[chad]

U have the cast oe exh mani, correct?
Is there any distortion where the donut goes?

 

[Econoline]

Yes and the seal area is good.

I think I have found my answer, according to felpro support the silver ones are better.

https://www.felpro-only.com/break_room_forum/showthread.php?tid=2268

 

[rbohm]

i have had failures with the silver gaskets as well, but then my manifold is cracked all to heck so i need to replace it. when that time comes i will probably also use a high temp sealer with the donut gasket.

 

[Econoline]

I'm going to try the silver sintered metal one. I can tell by looking at the head pipe flange it isn't "perfect" but it looks like it should seal and it does for 500-1000 miles with the blue ones. I'll let you know. I'm going to dbl check the geometry at the mating surface. When I welded on the block strap I had it torqued up with an old gasket, maybe it's not quite congruent. It's going to be a while but I'll let y'all know how it goes.

 

[bubba22349]

How's the exhaust pipe flange of the head pipe is it still in good shape? The donut needs to have support on the inside part of it going into the exhaust manifold. Good luck

 

[Econoline]

It was newly formed when I put it in a couple thousand miles ago. It's a little off but it has the inner portion. It's the right flange, like a dbl flare formed with a bit of pipe left on the end to support the inner portion of the seal. I wasn't clear about that, it's not just a flare or dbl flare.

 

[bubba22349]

ok that's good then, I have had old head pipes that the inside part was missing a section of it and couldn't make the donut last very long until I replaced the end with a new section. The donut should fit fairly snug onto the inter section of the head pipe. Good luck

 

[Econoline]

Thanks. I'm on my 3rd donut since I changed the exhaust out and it's recently started leaking again...

 

[bubba22349]

:wow: that's not great having to change them out so often hope it's lasts this time!

 

[drag-200stang]

I think that a torque strap would help by keeping the motor from moving around a lot , stressing the joint.

 

[chad]

Gene just made up one for the Mav...

 

[drag-200stang]

Gene just made up one for the Mav...

And a fine one at that.

 

[wsa111]

There should be a bracket on the headpipe that bolts to the lower part of the block & that will prevent movement at the donut ring.