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-   -   Oil leak from valve cover (https://www.cruisersforum.com/forums/f54/oil-leak-from-valve-cover-224065.html)

skipmac 19-09-2019 04:04

Re: Oil leak from valve cover
 
Quote:

Originally Posted by Compass790 (Post 2979907)
Hell no! If it runs as good as you say just work on the problem at hand.Trust me, you'll figure it out in the end with the help of the hive. The problem is with the modern engines is they make it more & more difficult to repair yourself. Then they make sure they last for much less time.
Makes for more employment ( tho mostly for 'Bots these days ) & maximises the CEO's bonus. Funny that
Better to use sails where possible IMHO:smile:


Oh I am resisting the impulse but occasionally the frustration builds. I did strip the engine down and replaced everything external: alternator, both water pumps, all hoses and belts, most of the accessory brackets, all coolers (oil, transmission and main heat exchanger), wiring. So hopefully this will be the last of the big/little problems.


And yes I sail it. I learned to sail when I was too broke to buy diesel and sailed everywhere, all the time. The only exception was in and out of slips which most marinas don't allow. Last year I ran the engine less than 50 hours and most of that was three days motoring up the US ICW when it was a bit stormy and I decided to go inside to avoid rounding Cape Hatteras in a blow.


Bottom line, I think I'm smarter than a 35 year old piece of British iron but we shall see.

skipperpete 19-09-2019 04:39

Re: Oil leak from valve cover
 
Quote:

Originally Posted by skipmac (Post 2979911)
Oh I am resisting the impulse but occasionally the frustration builds. I did strip the engine down and replaced everything external: alternator, both water pumps, all hoses and belts, most of the accessory brackets, all coolers (oil, transmission and main heat exchanger), wiring. So hopefully this will be the last of the big/little problems.


And yes I sail it. I learned to sail when I was too broke to buy diesel and sailed everywhere, all the time. The only exception was in and out of slips which most marinas don't allow. Last year I ran the engine less than 50 hours and most of that was three days motoring up the US ICW when it was a bit stormy and I decided to go inside to avoid rounding Cape Hatteras in a blow.


Bottom line, I think I'm smarter than a 35 year old piece of British iron but we shall see.



Provided the oil pressure is good and it has no bad noises or blow by just keep it. Incidentally your 4-154 later became a Mazda XA and was one of the best Perkins models produced.

skipmac 19-09-2019 04:55

Re: Oil leak from valve cover
 
Quote:

Originally Posted by skipperpete (Post 2979932)
Provided the oil pressure is good and it has no bad noises or blow by just keep it. Incidentally your 4-154 later became a Mazda XA and was one of the best Perkins models produced.


Yes forgot to mention that one, oil pressure good and no blowby or weird sounds. Also forgot to say I have a new starter as well.


Glad to hear it has such a good reputation. Makes me feel better about all the effort I put into keeping it.

a64pilot 19-09-2019 05:39

Re: Oil leak from valve cover
 
I was speaking about a cover that has the holes in the perimeter.
They few ones that I have had leaks on with center line bolts, ended up having old pieces of glue or even a piece of gasket under the new one that held the new one ďproudĒ of the surface.
Very often the center line bolted covers do use the better black rubber gaskets as opposed to the cork and rubber mixed ones,that do work, just not as good as the black rubber.
Of you can find a mechanic shop around that has a bench grinder with a wire wheel to clean gaskets off I heavily recommend asking them to clean the cover or let you.
I donít care of you spend a week scraping you canít get one as clean as that grinder with a wire brush can in a minute.
Unlikely itís warped, theses covers are usually pretty strong, but check, see if the edges are bent up,if they are an adjustable wrench can be used or gently bend the edges back down.
You are smarter than a 35 yr old piece of iron.
However I think on especially some older Brit designs that oil weeps were acceptable and an absolute clean engine may be tough.
I had my old MG leak free, but you really had to pay attention on reassembly to get there.

skipmac 19-09-2019 07:02

Re: Oil leak from valve cover
 
Quote:

Originally Posted by a64pilot (Post 2979958)
I was speaking about a cover that has the holes in the perimeter.
They few ones that I have had leaks on with center line bolts, ended up having old pieces of glue or even a piece of gasket under the new one that held the new one ďproudĒ of the surface.
Very often the center line bolted covers do use the better black rubber gaskets as opposed to the cork and rubber mixed ones,that do work, just not as good as the black rubber.
Of you can find a mechanic shop around that has a bench grinder with a wire wheel to clean gaskets off I heavily recommend asking them to clean the cover or let you.
I donít care of you spend a week scraping you canít get one as clean as that grinder with a wire brush can in a minute.
Unlikely itís warped, theses covers are usually pretty strong, but check, see if the edges are bent up,if they are an adjustable wrench can be used or gently bend the edges back down.
You are smarter than a 35 yr old piece of iron.
However I think on especially some older Brit designs that oil weeps were acceptable and an absolute clean engine may be tough.
I had my old MG leak free, but you really had to pay attention on reassembly to get there.


Well the more I think about it the more certain I am that I'm smarter than the engine. However, it can be difficult for smart to overcome stubborn and these old diesels can be quite stubborn.



I have closely inspected the cover and cleaned it carefully and the mounting flange is perfectly clean and was actually very clean with no visible chunks on it when I took it off. Also got a bright light in a dark room and verified no pinholes. So eliminated two possible sources of the problem, I think.


So what do you (or anyone else in the group) think about my plans A and B.


A. Selective tightening of the retainer nuts on the cover to minimize the chance of warping the end.


B. Building up the leaky end of the cover to make the gasket a little more proud on that end to enhance the seal.


Or any suggestions for a plan C or a better plan A?

rbk 19-09-2019 08:17

Re: Oil leak from valve cover
 
Start with tightening then tighten again and if that fails try and build it up. The built up gasket may leak more as they tend to leak out the joints as youíre adding more layers/joints and if high enough they may rock or distort under pressure. If doing this, start with brand new gaskets, laminate them on a bench with a nice even layer of rtv or similar, clean up the joints and let fully cure before installing.

skipmac 19-09-2019 09:46

Re: Oil leak from valve cover
 
Will definitely try careful tightening of the cover before going crazy with other stuff.



But a question. To avoid running the engine and looking for oil to pour out into my bilge (again and I'm starting to run low on oil absorbent towels) I'm wondering if sticking a feeler gauge into the joint would be test enough to determine if the leak is fixed or at least decreased.

bongo 19-09-2019 10:22

Re: Oil leak from valve cover
 
As a marine engineer with over decades of engine room experience, I agree with others here that clean and square and snug are all important. What I want to add is that many gaskets have no fiber reinforcement. If it does not have this reinforcement, then using any sort of goop allows the gasket to deform, (extrude), from its designed dimensions, and they usually leak. If you need to set the gasket in place on the valve cover, apply a very thin layer of the proper silicon, (or contact cement, or Permatex #2), to the clean, dry surface on the valve cover, set the gasket carefully in place, and let it set overnight. After it has set it will not push out when tightening the cover to the cylinder head. make sure the mating surface on the head is absolutely clean and dry with no oily film. Denatured alcohol works good here. Worked great on my Westerbeke 40/Perkins 4-108.

Now I've got to figure out how to get to the rear engine crankshaft seal?

skipmac 19-09-2019 10:36

Re: Oil leak from valve cover
 
Quote:

Originally Posted by bongo (Post 2980144)
As a marine engineer with over decades of engine room experience, I agree with others here that clean and square and snug are all important. What I want to add is that many gaskets have no fiber reinforcement. If it does not have this reinforcement, then using any sort of goop allows the gasket to deform, (extrude), from its designed dimensions, and they usually leak. If you need to set the gasket in place on the valve cover, apply a very thin layer of the proper silicon, (or contact cement, or Permatex #2), to the clean, dry surface on the valve cover, set the gasket carefully in place, and let it set overnight. After it has set it will not push out when tightening the cover to the cylinder head. make sure the mating surface on the head is absolutely clean and dry with no oily film. Denatured alcohol works good here. Worked great on my Westerbeke 40/Perkins 4-108.

Now I've got to figure out how to get to the rear engine crankshaft seal?


Thanks bongo. I had earlier checked the gasket and thought it was nitrile or some kind of rubber but this morning in bright light I see it looks like a rubber impregnated cork or some similar material. The cork (or whatever) is in very fine particles with no visible texture and the overall gasket is flexible like rubber but firm so would not extrude under pressure.


Head surface is very clean and in good condition but have not wiped it with any kind of solvent or degreaser to remove the fine oil film.


So based on this info what's your suggestion?

Cadence 19-09-2019 11:24

Re: Oil leak from valve cover
 
Just maybe a stupid suggestion. Be sure the four bolts a tightened about the same.

skipmac 19-09-2019 11:27

Re: Oil leak from valve cover
 
Quote:

Originally Posted by Cadence (Post 2980192)
Just maybe a stupid suggestion. Be sure the four bolts a tightened about the same.


Actually I was going to try intentionally tightening them differently. Leak is at one end so will try tightening that end slightly more to seal the gasket where it's leaking but tighten the other nuts slightly less to insure no warping of the cover. Since they are higher due to the tilt of the engine installation not likely the leak is there.

Cadence 19-09-2019 11:35

Re: Oil leak from valve cover
 
Quote:

Originally Posted by skipmac (Post 2980194)
Actually I was going to try intentionally tightening them differently. Leak is at one end so will try tightening that end slightly more to seal the gasket where it's leaking but tighten the other nuts slightly less to insure no warping of the cover. Since they are higher due to the tilt of the engine installation not likely the leak is there.

They don't need to be wrenched down tight, snug is enough.

rbk 19-09-2019 11:45

Re: Oil leak from valve cover
 
Quote:

Originally Posted by Cadence (Post 2980198)
They don't need to be wrenched down tight, snug is enough.

Bolts hold cover down via soft rubber inserts. They need to be compressed quit a bit in order to tighten the cover down sufficiently.

Cheechako 19-09-2019 12:00

Re: Oil leak from valve cover
 
That red silicone gasket sealer is good. The only thing I can figure is: is there back pressure inside the cover? Are the pathways that drain the oil back to the sump blocked somehow?
Center tightening covers can be bad for that. But short of making "bridges" that press on the outer flange from the center studs, not sure. But a new gasket with that red goop, or any good goop should work fine if you dont have other issues. If you goop both sides of it and it still leaks you have pressure inside there. It won't leak without that if the surfaces are flat. Blowby, Bad rings?

Cadence 19-09-2019 12:01

Re: Oil leak from valve cover
 
Quote:

Originally Posted by rbk (Post 2980203)
Bolts hold cover down via soft rubber inserts. They need to be compressed quit a bit in order to tighten the cover down sufficiently.

As I said, it could be a dumb post and maybe not relevant. People tend to believe tighter is better which is not necessarily true. JMHO


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