Grommets popping under boost

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99Super
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Grommets popping under boost

Postby 99Super » Sun Feb 25, 2018 9:06 pm

What do you do about manifold grommets popping out under high boost?

Mine start pushing out when I get near 20 psi boost, and always at the worst time!
I've made an aluminum bracket that holds the two uppers I place and held down w/ a zip tie around the plenum. I'm doing similar w/ the Brake booster nipple.

What are others out there doing? (yes, I've used new grommets and nipples!)

John
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Krizzie
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Re: Grommets popping under boost

Postby Krizzie » Mon Feb 26, 2018 2:45 am

I've seen people weld nipples in, or screw them in when running high boost levels.

I had the same problem a few years ago. You need to clean the holes, put the grommet in and then the nipple (Also clean that). Maybe use a little vaseline if it doesn't want to pop in. Don't use oils or anything cause that makes things too slippery and you blow them out again.
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Crazyswede
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Re: Grommets popping under boost

Postby Crazyswede » Mon Feb 26, 2018 2:42 pm

Tap the ports to the appropriate size and replace the rubber grommets with threaded inserts and then hose clamp the hoses onto the barbed fitting.
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DrewP
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Re: Grommets popping under boost

Postby DrewP » Mon Feb 26, 2018 6:02 pm

I think I always just used zip ties and didn't mind that it was ugly. But you may mind if yours is ugly. ;-)
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99Super
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Re: Grommets popping under boost

Postby 99Super » Mon Feb 26, 2018 7:24 pm

Leave it to Seth to go with the full engineering response...not that it's a bad thing...

I've been using the Zip-tie method, but was looking for something better.

I've come up w/ this...

Gromet_retainer.jpg


A similar one for the brake booster.

John
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Crazyswede
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Re: Grommets popping under boost

Postby Crazyswede » Tue Feb 27, 2018 12:20 pm

one of my cars with a 16v had a 90 degree plumbing fitting epoxied into the manifold for the brake booster hose. That worked well and eliminated the grommet. I like the idea of tapping the ports and fitting threaded fittings just because its a really clean result and works well too.
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DrewP
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Re: Grommets popping under boost

Postby DrewP » Tue Feb 27, 2018 1:22 pm

I like the hold down plate, that looks pretty clean. I have a 90* brass barbed fitting on one of mine too, I think I just JB welded it in place rather than tapping it (probably 15 years ago) and it's still there.
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99Super
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Re: Grommets popping under boost

Postby 99Super » Tue Feb 27, 2018 8:03 pm

DrewP wrote:I like the hold down plate, that looks pretty clean. I have a 90* brass barbed fitting on one of mine too, I think I just JB welded it in place rather than tapping it (probably 15 years ago) and it's still there.


The plate is light, too, probably lighter than 1 brass fitting.

I do like the idea of a threaded/epoxied fitting for the brake booster nipple, as I can justify a more permanent solution, but my MAP sensor also comes off that port, so I may have to relocate it if I can't find/make a similar dual-port nipple.

Off to the garage...

John
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