Lotus Elan

Dipstick Blues

PostPost by: type26owner » Sun Mar 20, 2005 7:44 pm

I've highly modified the original dipstick which was madeout of a D-shaped low-carbon steel wire. The wire broke at the point right above the bulge to keep it from slipping down too far into the female tube of the front cover. That's a clue. Cut it apart and replaced that section with a stainless steel rod that has grooves for three o-rings and silver-soldered the handle and measuring wire back on. It still pukes oil out the damn dipstick. Hey, there's something special happening here which is causing this. Suspect the dipstick is just the right weight along with the right lever arm moment so the vibrations from the engine make it resonate like a tuningfork. No amount of o-rings have a chance to seal up something rattling around like that. It also explains why the dipstick would break apart where it does do to fatigue.

I have two choices that come to mind. Replace it with a short aluminum o-ring sealed plug or add a bracket to the handle loop of the dipstick and secure it so it can't vibrate around violently and allow the o-rings to do their job. Velcro would do nicely to make the dampening connection to the bracket.
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PostPost by: steveww » Mon Mar 21, 2005 10:02 am

I have a spring from the dipstick handle to the alternator bracket. This ensures the dipstick can not come out and may damp out any vibration. Just a thought.
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PostPost by: type26owner » Mon Mar 21, 2005 3:02 pm

Hi Steve,
I made up a short brass plug with an o-ring seal that has too much interference for the o-ring to work long term. Hoping the brass plug does the trick. Have this ritual of kneeling to peer under the car now when it's parked looking for the fresh pools. Hopefully it will end this week.

Have the leakrate down to just two drops of oil when the car is parked now. They drip off the aluminum cooling air deflector plate I added underneath the alternator to direct air up to the backside of the alternator. Finding the leak is going to be just trial and error guesswork. There are many places for the leak to occur. If it's not the dipstick then I suspect the weight of the generator/alternator hanging off of it is causing the engine block to deflect ever so slightly and the pan gasket or the front timing chain cover leaks as a result. Have no foolproof solution on how to fix that particular problem if that's the case. Probably the flange on the pan would have to reinforced and extra 1/4" pan bolts in that local area would be required. Maybe the stiffness of the alternator mount could be changed to dampen better but highly unlikely since it's somewhat compliant already. The only other place to add a stiffening brace would be from the flange for the engine mount in lieu of the aluminum spacers. It depends on the direction of the DOF that needs to stiffened. You may laugh at this suggestion but have a closer look at a bare engine block and consider the forces. This isn't as farfetched as it seems because one would be instantantly be prone to laugh at such a suggestion just like I reacted when the thought popped into my head. Now I wonder.... what kinda is a clue is our BRM race engine has never leaked oil there but then again it does not have charging system either or a dipstick since it's dry-sumped.

I do have a miniature Nippon Denso alternator to mount in place of the huge Bosch one though. Wonder how much less the ND one weighs compared to the Bosch if any?
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PostPost by: steveww » Mon Mar 21, 2005 4:37 pm

Hey the engine design is well over 30 years old. They are know to have a few little leaks, personally I would not worry about a couple of drips. The engine will be burning more than that ;)
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PostPost by: Frank Howard » Mon Mar 21, 2005 4:43 pm

I have heard that a spark plug boot, slid down the stick and over the tube can take care of this problem. I don't see how it can seal completely, but I have heard it works. May be worth a try.

Also, you cannot refer to your oil leak as your last leak. Think of it as your most recent leak.

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PostPost by: type26owner » Mon Mar 21, 2005 5:48 pm

Steve,
I find it's quite embarassing to soil someone elses driveway. My driveway has a greasy slick patch which is dangerous for pedestrians to tread across. My engine has teflon valve stem seals and does not expell any visible oil smoke.

Frank,
I have heard that a spark plug boot, slid down the stick and over the tube can take care of this problem.

I tried that along time ago. IMHO, it's only a cruel hoax. There's no reason I can see why ALL the leaks can't be fixed permanently. Just because no one has done it before is no cause not to give it a shot. I'm close now to having it totally sealed.

I'm just endeavoring to fix all the shortcomings of this engine like the lame flow of heat through the oil and water. Achieving what no one else has done before is what I consider to be fun.

Lotus did it once again on the Elise BTW. An oil to water intercooler is required to deal with the oil temp getting out of bounds IIRC.
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PostPost by: storrar54 » Tue Mar 22, 2005 12:11 am

This sounds rather like that apocryphal bird that flies in ever decreasing circles until it finally ...........
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PostPost by: elan_fan » Tue Mar 22, 2005 10:18 am

Well you obviously love a challenge keith :P I do believe that with the use of good sealents and clean surfaces you can make an oil tight engine, I just don't think it will stay that way. I found that you need to make friends with the owner of a T type MG and you can park over the lake of oil on their driveway ;)

my dipstick is not supported but I do use a rubber boot (erm does that sound kinky)

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PostPost by: type26owner » Tue Mar 22, 2005 1:33 pm

Hi Mark,
Luckily 3M makes a rattlecan with a spray-on sealer that can be applied on the outside of the engine to seal up oil leaks. I can apply that to any suspected areas and see if the leaking stops. In order to fix a leak, first I must be able to find it. That's the tough part with the air blowing around from alternator fan and exhausting the radiator it spreads the oil all over the place.

I had a very similiar experience with the Maserati Biturbo I drove for years. With any marque that puts out a very low volume of cars they tend to minimize the extent of engineering refinements. Major flaws go unfixed and it's up to the customer to resolve those issues. I'm just doing that same thing on the Elan just a bit farther on down the road is all. The Elan is just easier to work on. When I drop a tool from above the Elan's engine it usually hits the ground. On the Biturbo that never ever happened.

Mike Ostrov do you happen to own a smoke machine too? I wonder if one can rent one of those? Suppose I can pay to have the smoke test done at a shop.
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PostPost by: mikefromengland » Mon Mar 28, 2005 7:20 pm

carry a piece of cardboard in the boot.then when you go on someones posh new drive put the cardboard under the car saves any arguing lol regards mike
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PostPost by: type26owner » Tue Mar 29, 2005 1:36 pm

Hi Mike,
Good plan which won't work unfortunately. It always drips before I can scramble out of the car and slip the diaper in place. It's a quick little bugger! :(

It's definitely not leaking from the dipstick I can say positively now. Where, oh where though?
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PostPost by: type26owner » Sat Apr 09, 2005 1:38 am

Been doing a little investigating on how-to chase down hard-to-find oil leaks. Looks like the way to go is use an additive for leak detection that is a fluorescent dye to be mixed in the engine oil. Bought a fluorescent type blacklight fixture to illuminate the trace of oil. It's the UV wavelengths at about 235nm that the bulb emits which actually does the fluorescing so apparently it's important to purchase a bulb which has a quartz tube so the UV portion is not absorbed. We'll see if that does the trick. It is a modest expense at $35 for the light and the dye to give it a try. Really looking forward to having an oil-tight 4-bolt twincam for first time ever.
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PostPost by: type26owner » Sat Apr 09, 2005 3:03 pm

Been having a rash of small oil leaks from the camcover studs lately. My solution to seal the leaking by using a piece of rubber hose slipped over the stud so it seals on the inside of the cover is not totally foolproof. About 10% of the time the damn thing leaks with a slight bit of weeping anyways. Going to design a better way to do this which works 100% of the time.
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PostPost by: types26/36 » Sat Apr 09, 2005 3:30 pm

Keith,
Thread tape round the stud where it protrudes through the cam cover, fibre washer, metal washer and ni-lock nut works for me.
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PostPost by: type26owner » Sat Apr 09, 2005 4:03 pm

Hi Brian,
That works but is too much fuss and bother for me tolerate. Dowty washers have to be specially ordered, replaced everytime and therefore are easily lost. BTDT. Thinking along the lines of perhaps making up my own bronze Acorn type nuts that have a half-dovetail groove to fit a face-sealing o-ring. The best solution though would be one which lives inside the camcover and it not visible at all.

Kinda puzzled why the simple piece of rubber hose does not do the trick. I even spotfaced the inside surfaces of the camcover around the studs. On our BRM I left the cover raw which means it's the as cast surface which is uneven and slopes with respect to the stud hole because the cross-sectional shape is an arc. That damn thing has not leaked even once. It however only gets run about 10 hours per year total. Got the feeling there is not enough stored clamping energy in the hose and it relaxes completely after being loaded and heat cycled many times. This kinda poor compression set problem seems really simple but can be a real bugger solve actually. Suspect the fuel hose I've been using is a nitrile type compound. Whatever it is it's now hard and crushed into a set shape and it does not recover any of it's former length. Perhaps a fluorocarbon hose if it's even available would be the trick solution.
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