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

bongo 19-09-2019 22:08

Re: Oil leak from valve cover
 
Quote:

Originally Posted by skipmac (Post 2980156)
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?

Hi Skipmac,
When I talk about fiber impregnated gaskets, I mean longitudinal and horizontal fibers. Much like woven fiberglass roving. With this the elastic material, (e.g. rubber), will not squish out. This type of gasket can be used with a goopy sealant. But yours sounds like a matrix of rubber and cork. (I believe mine is the same). If you use a sealent of any kind, it will extrude; unless, the goop is completely set "before" clamping the valve cover to the cylinder head. Like I said, I waited overnight for it to cure, and in the morning the gasket was firmly in place. . Mine leaked before, but not after. Since only one side, (the valve cover side), is glued on, the valve cover can be easily removed for inspections.
Good Luck

waterman46 19-09-2019 23:21

Re: Oil leak from valve cover
 
Quote:

Originally Posted by skipmac (Post 2979505)
HI RBK,


Thanks for reminding me to mention this. The engine is a Westerbeke W58 which is just a Perkins 4-154 painted red.


The valve cover attaches to four studs coming up from the centerline of the head, not with bolts around the edge.

I have the 4-154 also, but Perkins from 1982. Same problem. Don't use Permatex, it makes a mess, and you need to remove cover to adjust valve pushrod clearances. A new gasket should help, if not see if you can tell if the cover mating surface is flat.

Rod B 20-09-2019 03:45

Re: Oil leak from valve cover
 
Am I right in saying that the old Brit engines that used this type of pressed steel valve cover/gasket arrangement also used 'nylok' type nuts? This allowed you to assemble them with a relatively light pressure on the gaskets and flange without having the the nuts come loose.

skipmac 20-09-2019 04:30

Re: Oil leak from valve cover
 
Quote:

Originally Posted by bongo (Post 2980470)
Hi Skipmac,
When I talk about fiber impregnated gaskets, I mean longitudinal and horizontal fibers. Much like woven fiberglass roving. With this the elastic material, (e.g. rubber), will not squish out. This type of gasket can be used with a goopy sealant. But yours sounds like a matrix of rubber and cork. (I believe mine is the same). If you use a sealent of any kind, it will extrude; unless, the goop is completely set "before" clamping the valve cover to the cylinder head. Like I said, I waited overnight for it to cure, and in the morning the gasket was firmly in place. . Mine leaked before, but not after. Since only one side, (the valve cover side), is glued on, the valve cover can be easily removed for inspections.
Good Luck


Two things, the cover has six, small flanges on the inside that extend just past the bottom lip that help hold the gasket in place and prevent extrusion. And a quick visual around the edge didn't reveal any obvious external extrusion or gaps where the gasket might have been squeezed inward.



I'll get my little inspection mirror and a probe to check more closely on the next trial (see next post) to confirm the gasket is in place.

skipmac 20-09-2019 04:56

Re: Oil leak from valve cover
 
Update.


Went to the boat yesterday with a perfectly clean valve cover and gasket and tubes of Permatex.


First test, a thin layer of Permatex on the mating surface of the cover, mainly to hold the gasket in place during the installation. I think this is going to be necessary no matter what technique I use on this.


First step I finger tightened the nuts to get the cover and gasket in place. Then based on my assumption that the leak was on the low end of the block firmly tightened all the nuts with a little more pressure on the nuts on the low end. No torque wrench on board but using a nut driver with what I would call moderate force, guessing 2-3 ft lbs????

skipmac 20-09-2019 04:59

Re: Oil leak from valve cover
 
Quote:

Originally Posted by Rod B (Post 2980509)
Am I right in saying that the old Brit engines that used this type of pressed steel valve cover/gasket arrangement also used 'nylok' type nuts? This allowed you to assemble them with a relatively light pressure on the gaskets and flange without having the the nuts come loose.


Holding the cover on top is a two part deal. There are rubber seals that insert in the holes to seal around the studs then a nut with a wide bottom like a built in washer that is larger than the gasket and holds it tight around the stud while also holding the cover down.

skipmac 20-09-2019 05:00

Re: Oil leak from valve cover
 
Quote:

Originally Posted by waterman46 (Post 2980477)
I have the 4-154 also, but Perkins from 1982. Same problem. Don't use Permatex, it makes a mess, and you need to remove cover to adjust valve pushrod clearances. A new gasket should help, if not see if you can tell if the cover mating surface is flat.


This is a new gasket and the mating surfaces, cover and head, look flat with a straight edge. Not flat to machine shop standards but see no visible gaps as well as I can tell.

skipmac 20-09-2019 05:10

Re: Oil leak from valve cover
 
Quote:

Originally Posted by Cheechako (Post 2980211)
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?


The cover is vented with a hose to the intake manifold so should have a slight vacuum in the cover. I did check that and it was open and completely clear from cover to the manifold.



Haven't checked the drain holes around the rockers but when I pulled the cover off within a couple of minutes of shutting down the engine there was not any noticeable accumulation of oil in the head so thinking this isn't the problem.


Don't think the rings are bad. Engine starts immediately, no visible smoke and other than leaks, uses very little oil.

Cheechako 20-09-2019 07:25

Re: Oil leak from valve cover
 
Quote:

Originally Posted by skipmac (Post 2980156)
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?

Well, the rubber impregnated cork is good. Plain rubber slips and extrudes from pressure. Here's what I would do:
-Have the mating surfaces clean and dry. Wipe with acetone.
-Use Permatex Aviation Form a Gasket on both sides of the gasket.
-Once in place tighten down just a little on the 4 bolts.
-Let it sit overnight.
-Retighten just snug and evenly.

Warning: that Permatex will be a mess to ever get apart. But I'm the guy that uses 5200 on everything, even installing portlites. Never had one leak. "Do it once, never do it again"
PS: Open the oil filler with engine running. There should be no pressure out the hole...? If you have pressure you have problems.

skipmac 20-09-2019 07:45

Re: Oil leak from valve cover
 
Quote:

Originally Posted by Cheechako (Post 2980584)
Well, the rubber impregnated cork is good. Plain rubber slips and extrudes from pressure. Here's what I would do:
-Have the mating surfaces clean and dry. Wipe with acetone.
-Use Permatex Aviation Form a Gasket on both sides of the gasket.
-Once in place tighten down just a little on the 4 bolts.
-Let it sit overnight.
-Retighten just snug and evenly.

Warning: that Permatex will be a mess to ever get apart. But I'm the guy that uses 5200 on everything, even installing portlites. Never had one leak. "Do it once, never do it again"
PS: Open the oil filler with engine running. There should be no pressure out the hole...? If you have pressure you have problems.


So far nothing else is working and I'm very nervous about tightening too much and possibly warping the cover so I think next step is to Permatex the hell out of everything (with of course cleaning with solvent first).


No pressure under the cover. It's well vented to the intake and the hose is clear. The only thing I see if I remove the oil fill cap when the engine is running is a bit of oil splash and spray.

Cheechako 20-09-2019 07:48

Re: Oil leak from valve cover
 
Quote:

Originally Posted by skipmac (Post 2980595)
So far nothing else is working and I'm very nervous about tightening too much and possibly warping the cover so I think next step is to Permatex the hell out of everything (with of course cleaning with solvent first).


No pressure under the cover. It's well vented to the intake and the hose is clear. The only thing I see if I remove the oil fill cap when the engine is running is a bit of oil splash and spray.

:thumb: Be sure to not use solvent that is NOT oily like Naptha etc. Something that leaves a dry surface like Acetone, MEK, or Lacquer thinner is good. I hope it works for you. :facepalm:

skipmac 20-09-2019 10:24

Re: Oil leak from valve cover
 
Quote:

Originally Posted by Cheechako (Post 2980598)
:thumb: Be sure to not use solvent that is NOT oily like Naptha etc. Something that leaves a dry surface like Acetone, MEK, or Lacquer thinner is good. I hope it works for you. :facepalm:


Thanks, I like acetone in general for this kind of thing. Seems to be a little less toxic than some of the other stuff.



By the way, thanks for warning me that you're a 5200 kind of guy. Will take that into account when reading any of your advise on the forum. :biggrin:

waterman46 20-09-2019 12:55

Re: Oil leak from valve cover
 
Quote:

Originally Posted by skipmac (Post 2979904)

In fact the whole engine looks like carp but it runs like a top, has perfect oil pressure, starts instantly and doesn't smoke at all so I hate to replace it. Then I run into a persnickety little problem like this and consider turning it into a mooring.

Welcome to the wonderful world of old Perkins engines. Your description fits our engine perfectly.
As does the oil leak. Our oil leak seems to come from several places around the seal, not just the rear. It does collect at the rear however. I have taken to stuffing a small rag into the gap between the oil filter holder and the valve cover.

skipmac 20-09-2019 13:45

Re: Oil leak from valve cover
 
Quote:

Originally Posted by waterman46 (Post 2980799)
Welcome to the wonderful world of old Perkins engines. Your description fits our engine perfectly.
As does the oil leak. Our oil leak seems to come from several places around the seal, not just the rear. It does collect at the rear however. I have taken to stuffing a small rag into the gap between the oil filter holder and the valve cover.


Ah yes, the old rag behind the valve cover trick. Know it well.


Problem is, my leak got so big the rag wasn't working. If I could get the leak down to rag level quantities I would be a happy camper.

Cadence 20-09-2019 14:14

Re: Oil leak from valve cover
 
I thought old undestroyable GMs had the title for oil leaks. :-)


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