Author Topic: TCS: Sealing approach - atop the pulley cam shaft seal and half-moon plugs  (Read 334 times)

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Offline FourLoti

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Hi:

I've done a lot of reading on this and am about to put the valve cover back on my '74 for (my) first time. I decided to adopt the "sealant + grease" approach and have glued the gasket to my cover. But what I haven't seen explained in this approach, is what to do about the top of the cam seal and the tops of the rubber plugs (which are slightly recessed on my engine.) It seems like I should hit those with a thin coating RTV or similar, but don't have clear picture of how to best do this while also applying grease to the adjacent gasket.

Any tips would be appreciated!

Ron
« Last Edit: Tuesday,July 25, 2023, 08:08:00 AM by FourLoti »
1974 TVR 2500M
1996 Porsche 993 Carrera Coupe
2005 Mitsubishi Montero Limited
1974 Europa Twin Cam Special 5-Speed (gone)
1987 Esprit Turbo (gone)
1980 Eclat (gone)
1963 Elan S1 (gone)
1970 Europa S2 (gone)

Offline Pfreen

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Re: TCS: Sealing approach - atop the pulley cam shaft seal and half-moon plugs
« Reply #1 on: Tuesday,July 25, 2023, 09:16:02 AM »
If you glue the gasket to the head that solves the half moon issue.  You will need sealant over the top of the cam seal.  I use ultra black.  The intersection of the cork gasket and the seal needs sealant.

Offline Bryan Boyle

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Re: TCS: Sealing approach - atop the pulley cam shaft seal and half-moon plugs
« Reply #2 on: Tuesday,July 25, 2023, 11:35:03 AM »
If you glue the gasket to the head that solves the half moon issue.  You will need sealant over the top of the cam seal.  I use ultra black.  The intersection of the cork gasket and the seal needs sealant.


Exactly...it's better to seal the cork to the head first, which lets you get all the crannies, d-plugs, and cam seal joints all worked out and tight, then put the cover on.  It's not a case of 'if a little goop is good, a lottle is better'...the THICKEST the rtv should be is less than 1/8" bead.

Sealing the 8 through bolts on the top is another issue.  I've gone over to using dowty washers instead of the rubber faced washers the usual suspects sell.  I smear a light coat of ultra black on the mating side, put in place, torque down.  They seem to be working better so far than the other method.  YMMV
Bryan Boyle
Morrisville PA
Commercial Pilot/CFII/FAA Safety Team
Amateur Extra Class Operator & FCC Volunteer Examiner
Currently working on 3291R, ex 444R, 693R, 65/2163, 004R, 65/2678
http://www.lotuseuropa.us for mirror of lotus-europa.com manual site.

Offline Lotuswins

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Re: TCS: Sealing approach - atop the pulley cam shaft seal and half-moon plugs
« Reply #3 on: Tuesday,July 25, 2023, 07:50:34 PM »
Hello Ron,

I disagree about gluing the gasket to the head.  When adjusting the cam shims, which requires removing the cam, that gasket will get torn and you'll be replacing it.  Also, those D rubbers should be flush with the gasket surface of the head.  If they are not, they may have shrunk from age, and perhaps new are in order.  I glue all my valve cover gaskets to the valve cover, using silicone type sealant.  Then on the surface to the head use hylomar which remains soft such that you can remove the cover and the gasket is unhurt.  I do use silicone around the cam seal though, but be sparing with it since I've been warned that lose silicone in the motor isn't a good thing, and when removing the cover for a cam check, it will release fairly easily.   As for the washers on the hold down bolts, I just use what Bean and other sell, they seem to work fine but keep a new set on hand as they seem to work only once.  The cork gasket seems more compliant than the fiber one they now sell so if you can find one, get it as long as it isn't too old since the cork seems to shrink if it isn't restrained.

I wish you well.....

Jerry Rude
4005R

Offline FourLoti

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Re: TCS: Sealing approach - atop the pulley cam shaft seal and half-moon plugs
« Reply #4 on: Wednesday,July 26, 2023, 06:45:42 AM »
Thanks to all for the helpful input. It's all buttoned up now so we'll see if what I did works. In retrospect, I should have replaced the half-plugs as they were 1/32 shy of the head surface. I glued in some thin gasket material shims. Will do it all up more properly next time, but I'm not going to be running the engine for very long any time soon. Assuming it actually starts after 20 years, I still need to go through the cooling and fuel systems - not to mention some way to make the car stop!

Ron
1974 TVR 2500M
1996 Porsche 993 Carrera Coupe
2005 Mitsubishi Montero Limited
1974 Europa Twin Cam Special 5-Speed (gone)
1987 Esprit Turbo (gone)
1980 Eclat (gone)
1963 Elan S1 (gone)
1970 Europa S2 (gone)