Lotus Elan

nut torque specs, especially cam cover bolts

PostPost by: chicagojeff » Fri Mar 27, 2009 1:24 pm

I searched the archives...is there a place where the common bolt torque specs are listed? In particular, I am trying to determine how tight the cam cover bolts should be. Thanks all. Jeff It's Finally Not Snowing in Chicago
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PostPost by: ElliottN » Fri Mar 27, 2009 1:39 pm

All torque settings are in the "Technical Data" section of the Workshop Manual (from page 25 in X036T032TZ).

In this case I'm assuming you mean Camshaft Cover nuts - which are spec'd at 7 lbs/ft or .96 kg.m.
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PostPost by: peterako » Fri Mar 27, 2009 2:20 pm

Or to be more precise....

"Not too tight, but tight enough to stop the oil seeping out" :)

Make sure they are evenly tightened too....

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PostPost by: Frank Howard » Fri Mar 27, 2009 3:18 pm

Someone on this list came up with a sure fire way to prevent leakage around the cam cover nuts. I tried it and it works. Cut short pieces (about 1/2" long) of rubber fuel hose and jam them over the studs that the nuts go on before you install the cam cover. Cut the hose so it compresses when the cover is installed. Once you install the nuts and in turn compress the hose against the inside of the cam cover, the oil will not be able to escape.

I also have a sure fire method to eliminate leaks around the cam cover gasket. If there's an interest, I'll be happy to share it.
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PostPost by: andyhodg » Fri Mar 27, 2009 3:29 pm

Frank

Don't leave us in suspense please share your secrets.

Regards

Andy
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PostPost by: collins_dan » Fri Mar 27, 2009 4:08 pm

Please share, I am about the replace the gasket due to multiple leaks down the front, sides and center. I've torqued as much as I can. Thanks. Dan
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PostPost by: prezoom » Fri Mar 27, 2009 5:43 pm

OK, this isn't original or factory or possibly approved by purists, but the way I solved my "leakage" problem around the studs fixing the cam cover, was to make my own sealing washers. I had tried Keith's method of using tubing on the inside of the cover and was not sucessful in getting a good tight seal. So, I used Viton 1/8" "O" rings, 3/8" in diameter The 1/4"inner diameter that worked out to being just a hair smaller than the stud diameter. They slide onto the stud with a little resistance. I then machined up some cups out of 1/2" aluminum rod, which were bored deep enough to contain the "O" ring, but leave about 1/4 to 1/3" of the ring proud of the cup. I used a 3/8" end mill to counter bore the aluminum rod to the correct depth. The cup captivates the "O" ring and applies downward and inward pressure on the ring when tightened. When torqued to the correct setting, since installing them last year, I have no seepage what so ever from around the studs. When it comes to computers, on a scale of 1-10, I'm 8 below plant life. I've tried and failed to figure out how to post a picture on the board, so I'll send the pictures to Gary, who has been so gracious in covering for my inadequices.

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PostPost by: paddy » Fri Mar 27, 2009 6:02 pm

Back on the question of torque, I found that 7lbs is too tight and will just compress the gasket down too much. If you tighten the nuts and then leave it a few days, you'll find that they are loose again and you'll tighten them a little bit more. This just goes on indefinitely until your gasket is squashed to nothing. No matter how squashed the gasket is, it doesn't seal any better - in fact it gets worse.

What I ended up doiing the last 2 times was use the tiniest amount of silicone on both surfaces of the gasket (spread evenly rather than a bead), and fit the cam cover with the nuts not much more than finger tight to make it seal. Then tighten once more just a bit after it has set. The nuts only have to be tight enough that they don't come loose by themselves - any more is counterproductive.

Anyway, that's what worked for me. It means that you destroy the gasket when you lift the cover next time, but there are no leaks. I'm sure many here have much more experience and may advise differently.

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PostPost by: mikealdren » Fri Mar 27, 2009 6:09 pm

Paddy,
I agree with your comments on the torque being too much, it splays out the soft washers and they leak as well as the gasket. Are you using Nyloc nuts? If so, I'm surprised that they are loosening.

Mike
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PostPost by: stuartgb100 » Fri Mar 27, 2009 7:13 pm

With regard to the cam cover / head interface:

on rare engines I have had problems, which have been solved as follows:

1. all surfaces scrupuously clean and dry ( and cam cover / head faces "true" )
2. a very thin bead of silicon on the head face
3. a light smear of clean engine oil (only a smidget) on both sides of the cork gasket
4. a very thin bead of silicon on the cam cover face

Then nip up new nylocks evenly until cam cover is pinched (just)
Start engine and check for heat rising from block, transferring across headgasket to cyl head and then finally to cam cover
Turn off engine and tighten each nylock one flat.

(assumes no oil leaking at engine turnover !) - never has for me.

You will find the gasket can be reused.

Regards,
Stuart.
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PostPost by: pamitchell » Fri Mar 27, 2009 7:19 pm

I used copper washers with a dab of white hylomar under the nylocs. The copper deforms enough with the Hylomar to seal well. Follow the 7 ft/lb and follow an even torque pattern.
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PostPost by: garyeanderson » Fri Mar 27, 2009 9:26 pm

Here are a couple of photos that Rob Walker sent. they look like a nice solution to one of those iritating issue with the Twin Cam. The rain cleared out early thios morning and the sun came out at 1:30, the roads were dry and Beau and I just got back from a short ride so you get two additional pictures.

Image

Image


Image

Image
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PostPost by: Frank Howard » Fri Mar 27, 2009 10:23 pm

I gave up on the cork/aluminum/cork cam cover gasket long ago. For starters, the three layers aren't bonded together properly when they are new and they come apart within minutes of the first heat cycle.

Here's what I do. First, I make sure that both mating surfaces are clean and dry. Then, I smear a small amount of engine oil over the head mounting surface to act as a release agent. I then take clear common household silicone, that's right, the kind that's used in bathrooms, and using my caulk gun, I apply an even 3/16" bead to the cover-mating surface. Then I place the cover on the head and tighten it down just enough to eliminate any air gaps. I don't compress the silicone very much at all or I'll be left with very little for sealing plus some of it could find it's way into the oil galleries. I just compress it enough to make the silicone form to the two surfaces perfectly, hardly any compression at all. Next, I wipe off any excess and then I wait for the silicone to cure, usually overnight. The next morning, I'm looking at a perfectly formed silicone gasket that has been custom made to fill in any imperfections that may be in the mating surfaces. I then tighten down the nyloc nuts, compressing the silicone maybe 1/16" to get a good seal. If I have to remove it in the future, the silicone will not stick to the head because I smeared the engine oil on that surface when I started. It can even be reused.

I've done this to both of my Lotuses and the cam covers have been oil tight ever since. I even took the Elan on a 600-mile road trip and the cam cover and head remained dry. For those of you who are concerned that the silicone could get into the oil galleries, I can tell you that I have inspected the inside afer many hours of running and while any excess silicone may squeeze into the inside, it remains part of the rest of the cured silicone and doesn't break off. Oh yes, and one more added benefit. Each silicone gasket probably costs no more than .50 but I would do it this way even if it cost $50 because it works!

P.S. Can I interest anyone in a brand new cork cam cover gasket?
Frank Howard
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PostPost by: robcall » Sat Mar 28, 2009 1:12 am

Have not tried this myself-but these guys sell a synthetic/reusable cam cover gasket-p8 in the catalogue http://www.cometic.com/catalogs/sportcompact.pdf
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PostPost by: herrherr » Thu Aug 15, 2019 8:16 am

garyeanderson wrote:Here are a couple of photos that Rob Walker sent. they look like a nice solution to one of those iritating issue with the Twin Cam. The rain cleared out early thios morning and the sun came out at 1:30, the roads were dry and Beau and I just got back from a short ride so you get two additional pictures.

Image

Image


Does anyone know where those can be sourced or how they are named? I hadn't have much luck yet.
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