Need a suggestion for intake gasket sealant
07-31-2002, 10:30 PM
#1
Racer
Thread Starter
Need a suggestion for intake gasket sealant
Hi all,
The last time I removed my intake manifolds for extrude honing, I replaced the intake gaskets without any sealer as Porsche originally did, and well, that was a bad idea. Eventually they leaked again big time, in fact two of the twelve gaskets were partly sucked into the port, blocking flow and creating a massive vacuum leak. So I took it all apart last week, put in new gaskets, used Curil T sealant at the suggestion of some Porsche owners, decked the plastic insulators with some sandpaper against flat polished granite, put it all back together, and still get vacuum leaks! Ok, so I'm gonna do it again for a third time, with new gaskets and new insulators this time, but am looking for suggestions for a better sealant. What do you guys think?
The last time I removed my intake manifolds for extrude honing, I replaced the intake gaskets without any sealer as Porsche originally did, and well, that was a bad idea. Eventually they leaked again big time, in fact two of the twelve gaskets were partly sucked into the port, blocking flow and creating a massive vacuum leak. So I took it all apart last week, put in new gaskets, used Curil T sealant at the suggestion of some Porsche owners, decked the plastic insulators with some sandpaper against flat polished granite, put it all back together, and still get vacuum leaks! Ok, so I'm gonna do it again for a third time, with new gaskets and new insulators this time, but am looking for suggestions for a better sealant. What do you guys think?
08-01-2002, 07:58 AM
#2
Race Car
Hmmmm, odd - as I NEVER use sealant on intake gaskets. Sealant has a habit of promoting "slip" of the gasket and consequently the vacuum of the intake can suck it in, causing a vacuum leak. <img src="graemlins/cussing.gif" border="0" alt="[grrrrrrr]" />
Another thing to consider is what are you torquing those nuts down at?? I believe they're only supposed to be 16-18lbs, although I'm just taking that off the top of my head - so I may be off.
If you torque the nuts too tight, this is only a two-bolt flange and as you SSI owners may know, the harder you torque them down, the more they leak!
When you torque those nuts/bolts down on a two-bolt flange, it will flex the center of the flanges out, causing a leak.
Something else you can do is take an exacto knife and peel away a bit of the gasket where the hole is...that way the center or "round" area that needs to be sealed can seat better...just an idea...I did that with my B&B header setup as those flanges would leak when you cranked the bolts down.
Hope that helps!
Another thing to consider is what are you torquing those nuts down at?? I believe they're only supposed to be 16-18lbs, although I'm just taking that off the top of my head - so I may be off.
If you torque the nuts too tight, this is only a two-bolt flange and as you SSI owners may know, the harder you torque them down, the more they leak!
When you torque those nuts/bolts down on a two-bolt flange, it will flex the center of the flanges out, causing a leak.
Something else you can do is take an exacto knife and peel away a bit of the gasket where the hole is...that way the center or "round" area that needs to be sealed can seat better...just an idea...I did that with my B&B header setup as those flanges would leak when you cranked the bolts down.
Hope that helps!
08-01-2002, 02:29 PM
#3
RL Technical Advisor
As Jeff said, one should never use sealer on these flanges. It creates more troubles than its supposed to cure,.....
We use the factory gaskets here and do not have any troubles if the flanges are not warped and these are not overtorqued. As these are aluminum, once overtightend, they can warp and must be resurfaced to seal properly, once again.
You can check this by removing the intake manifolds and laying each branch down into a very flat surface (like a small sheet of glass) with a sheet of 400 grit sandpaper. By moving the intake manifold back and forth a few times, you'll instantly see whether the flanges are truly flat or not by observing where the metal is shiny.
If you are patient & careful, you may true these up with this method, IF they are not too badly warped.
We use the factory gaskets here and do not have any troubles if the flanges are not warped and these are not overtorqued. As these are aluminum, once overtightend, they can warp and must be resurfaced to seal properly, once again.
You can check this by removing the intake manifolds and laying each branch down into a very flat surface (like a small sheet of glass) with a sheet of 400 grit sandpaper. By moving the intake manifold back and forth a few times, you'll instantly see whether the flanges are truly flat or not by observing where the metal is shiny.
If you are patient & careful, you may true these up with this method, IF they are not too badly warped.
08-05-2002, 04:24 PM
#4
Racer
Thread Starter
Jeff, Steve, thanks for your advice. Perhaps I have been overtorquing my bolts. I'll also check the decking of my manifolds. This is the second 3.2 I've owned, and it just seems unfortunate that those gaskets always seem to shrink and leak with age.
