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overcompressing the oil pan rubber-cork gasket
Posted by: Saxon ()
Date: May 07, 2022 08:50AM

When I torqued the new rubber-gasket oil pan gasket, these corners did not catch my attention or they slowly split from tension these past few months. 3 of the four corners are that way. May that mean the actual hole around the bolt is also compromised?

I vaguely recall the same split corner condition of the used rubber gasket I removed many months ago.

I used the recommended 60-80 inch lbs, but I should have used less.

Northern CA
66 Monza Coupe 4-spd 140

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Re: overcompressing the oil pan rubber-cork gasket
Posted by: RobertC ()
Date: May 07, 2022 08:58AM

Did you straighten the gasket surface around the pan bolt holes?

People deform this area when overtightening the pan bolts.

Personally, I have used two of the GM paper gaskets glued together - my Corvair mechanic's solution. Also, used 3M 77 Spray Adhesive - as opposed to RTV.

Other people here have different solutions.

Your torque wrench? 60 - 80 inch lbs should not deform the gasket that much?

I torque pan bolts to 11 ft lbs - 120 inch lbs - with the paper gaskets. Again, my solution... Also, torqued Otto Parts pan with thin paper gasket to same specs. Otto Parts pan required re-torqueing a couple times until bolts held torque.

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Re: overcompressing the oil pan rubber-cork gasket
Posted by: Saxon ()
Date: May 07, 2022 09:57AM

Did all the Fred Johnson sealing tips:

-tapping flat the indented hole areas
-used thread sealer on bolts
-Hi Temp RTV on the sealing surfaces

I used a made in usa, Sturtevant Richmont calibrated dial type torque wrench made for work under 100 inch lbs.

When tightening, I did not like how bolt holes were deforming again (not as bad as before). Given the thickness of this gasket and possible metal fatigue around the bolt holes of my pan, I will give your two paper gasket solution some thought.

Northern CA
66 Monza Coupe 4-spd 140

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Re: overcompressing the oil pan rubber-cork gasket
Posted by: cnicol ()
Date: May 07, 2022 10:08AM

Based on the visible and excessive squeeze-out and your report of corner splitting, the oil pan bolts are clearly overtorqued.

You only want to tighten until the gasket "just starts" to pooch out. Published torque values are for the oe type "hard paper" gaskets.

Craig N. Coeur d'Alene ID.
66 Black Monza 4dr, 4.2L V8 49k
61 Seamist Jade Rampside 140 PG
65 Canadian Monza 4dr 110/PG 40k
66 Sprint Corsa convt - First car! Re-purchased 43 years later
2+2 gnatsuM 5691

+17 Tons of parts

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Re: overcompressing the oil pan rubber-cork gasket
Posted by: toms73novass ()
Date: May 07, 2022 10:14AM

If you have to order a new pan gasket, I HIGHLY recommend the one that John Sweet sells, it seals well and is less squishy.

-Tom


63' Monza Spyder Convertable (in process) MY Build Thread
62' Wagon rebuild MY Build Thread
65' Monza MY Build Thread
73' NovaSS 454 Big block (Sold)
86' BMW 325es
67' UltraVan 211 "Violet"
NFCC, UMCC
Grand Island, NY

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Re: overcompressing the oil pan rubber-cork gasket
Posted by: DOUG WARD ()
Date: May 07, 2022 10:42AM

When my Nephew got his '61 Lakewood, he also got some extra parts with it. One item was a new Clarks sheet metal type oil pan. I was impressed at how thick the metal is in their pan. MUCH better than a stock one, as they almost always seem to distort around the bolt holes. I have switched to a Clarks finned aluminum pan for two reasons. 1) it helps some with cooling the oil;2) it's much stiffer than a stock sheet metal one. Oh, and 3) it has provisions for not only an oil temp sender, but it drains from the rear of the pan where it's easier to get to the drain plug. I do not like the rubber / cork gasket as it did the same thing as yours did. With the aluminum pan, I use the thin paper gasket with thread locker on the bolts. I don't need to re-torque the bolts later on.

Doug Ward
Orange, Calif.
65 Corsa 180, 64 Monza convertible, 61 Lakewood, 61 Monza


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Re: overcompressing the oil pan rubber-cork gasket
Posted by: REM654DPG ()
Date: May 07, 2022 01:59PM

Here's some info from an old conversation on the same topic.

[corvaircenter.com]

Regan Metcalf
Portland, OR

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Re: overcompressing the oil pan rubber-cork gasket
Posted by: Saxon ()
Date: May 07, 2022 04:11PM

Thank you for the link, Regan. The search function here is not strong.

After reviewing my situation with a steel pan whose holes I re-flattened again as best as I can, I have decided to go with two paper gaskets, hi tack permatex on engine side and silicone based sealant on the pan side.

My experience thus far has been any moderate tightening below 60 inch lbs results in thick gasket squish and dimpled holes. I can't imagine how the straight edges could seal with that.

Everyone has different methods and I should be able to find a workable solution for me.

Northern CA
66 Monza Coupe 4-spd 140



Edited 1 time(s). Last edit at 05/07/2022 04:11PM by Saxon.

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Re: overcompressing the oil pan rubber-cork gasket
Posted by: doug6423 ()
Date: May 08, 2022 07:23PM

toms73novass Wrote:
-------------------------------------------------------
> If you have to order a new pan gasket, I HIGHLY recommend the one that John Sweet sells, it seals well and is less squishy.

I agree. I tried the cork type and still had leaks. Switched to John Sweet's and problem solved.

Doug
65 Monza
Cincy, OH

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Re: overcompressing the oil pan rubber-cork gasket
Posted by: wittsend ()
Date: May 10, 2022 08:19PM

I recently torqued my cork/rubber pan gasket down. I believe I stopped at about 40 in lb.'s being that the gasket just seemed to be saying "enough." It was recommended that flat washers be used ('61 EM engine with lock washers). The smallest OD washers that I could find still did not sit flat on the pan (see arrow, lower bolt). I spent some time at the bench grinder getting flat edges and then painting them with high-temp engine paint (upper bolt).

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Re: overcompressing the oil pan rubber-cork gasket
Posted by: JerryM ()
Date: May 10, 2022 08:58PM

Haven't tried this on a steel Corvair pan, but a technique I've used successfully on a couple 283 SBC's using cork gaskets on stamped steel timing covers and oil pans is, obviously, ensure the sealing surfaces are very straight and clean, apply a very thin layer of RTV to both sides of the gasket - I use Permatex Ultra Black, a lot of people prefer Permatex Right Stuff for this - tighten the bolts to the point all surfaces have made contact without squeezing the cork. Let it cure. Torque after cure, I torque to 75 in-lb.

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Re: overcompressing the oil pan rubber-cork gasket
Posted by: Saxon ()
Date: May 11, 2022 10:26PM

Thanks, I will adding some curing time and serrated washers to my next go around.

Northern CA
66 Monza Coupe 4-spd 140

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