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Nov 11, 2009 | 11:41 AM

Vette73

Thread Starter

LS/MFT

Joined: Jun 2000

Posts: 5,874

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From: Cary IL

St. Jude Donor '09-'10-'11-'12

What's your trick...

for sealing the rear of the L98 intake?

This month's Corvette Fever (Jan 2010) had two questions related to this problem in the "Wear & Tear" Q and A section. As anyone with an L98 knows, getting a good oil-proof seal on the rear of the intake can be a challenge and many tricks and techniques have been tried. I once had someone suggest that the block should be dimpled with a punch at 1/4" intervals to ensure a good seal.

So how 'bout it: what method have you used that you've found works over the long term?

Nov 11, 2009 | 01:09 PM

Inlove

Instructor

Joined: Mar 2003

Posts: 110

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I googled that yesterday as I am tracing an oil leak of my own. The dimpling method was mentioned, thanks for explaining what it was. The main consensus was the use of Felpro gaskets and Permatex's The Right Stuff. Dimpling sounds too extreme for me so I may just rough the surfaces. Also mentioned several times was to give the sealant the proper time to cure.
http://www.permatex.com/products/Aut...sket_Maker.htm

Nov 11, 2009 | 02:24 PM

Aardwolf

Race Director

Joined: Jun 2004

Posts: 13,966

Likes: 709

From: WI

I've had mine apart several times and had no trouble just using RTV and nothing else special. I've found the single biggest thing to be placing the intake on straight and not shifting it around. It's easy to disturb the bead.

Edit, normal RTV has always sealed fine for me and the right stuff product is very high priced so I haven't tried it.

Last edited by Aardwolf; Nov 11, 2009 at 08:32 PM.

Nov 11, 2009 | 04:28 PM

Churchkey

Melting Slicks

Joined: Sep 2008

Posts: 2,376

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From: Cherokee National Forest TN

Never had a leak in 600+ hp oval track engines.

Dimple the block rail & the intake manifold where it sits on the rail with a punch & hammer.

Use cork end seals. If the gasket set does not come wiith them make them from a sheet of cork. Check the fit & trim the cork as needed to fit the rail & intake gaskets.

Clean all surfaces with a good solvent.

Install the port gaskets & use manifold bolts to hold the location. This assuming you are using Felcro blue gaskets without gasket sealer.

Apply a bead of 3M yellow super weather strip adhesive (Gorilla Snot) to the end rails & immediately install the cork seals. Monitor the corners or place a weight on the corners to hold them in place. Allow 20 minutes set time.

Next install a bead of RTV silicone on the cork. Use extra RTV at the corners. Let the RTV set up about 10 minutes.

Install the manifold.

Nov 11, 2009 | 05:22 PM

engle1147

Le Mans Master

Joined: Jul 2007

Posts: 5,043

Likes: 8

From: Tampa Florida

Clean the surfaces then use Permatex's "The Right Stuff"

Nov 11, 2009 | 07:29 PM

John A. Marker

Le Mans Master

Joined: Mar 2004

Posts: 5,107

Likes: 171

From: Dublin CA

Dimple the "china walls" with a center punch, dimple the rear and front of the intake manifold also, clean several times with lacquer thinner and then use 3/8" bead of THE RIGHT STUFF.

Nov 11, 2009 | 07:53 PM

jmrl98

Drifting

Joined: May 2002

Posts: 1,509

Likes: 3

From: Hazel Park MI

I'm a dimpler also - and I used the right stuff too. Very sound advice, as even with the dimples, regular black permatex didn't do it (leak at rear), so I used the right stuff and that did the trick. I'm going to find out soon how hard it is to remove the manifold after the right stuff, and it doesn't thrill me...