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  #1  
Old December 14th, 2008, 21:20
HawkZero's Avatar
HawkZero HawkZero is offline
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Valve Cover Leak

I replaced my valve cover gasket this afternoon. Torque'd to spec and used a good gasket (felpro metal/rubber with new grommets).

However it appears to still be leaking.

Any other good ideas out there?
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  #2  
Old December 14th, 2008, 22:20
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Re: Valve Cover Leak

Did you put a strait edge on the valve cover sealing surface, and verify it was flat?
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  #3  
Old December 14th, 2008, 22:58
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Re: Valve Cover Leak

Quote:
Originally Posted by Russ Pottenger View Post
Did you put a strait edge on the valve cover sealing surface, and verify it was flat?
x2

Ghetto fix:

Wait for engine to cool.
Clean all oily surfaces with carb cleaner.
Smear a nice bead of RTV along the bottom of the valve cover where it meets the head.
Let dry.
Enjoy leak free valve cover.


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Old December 15th, 2008, 04:47
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Re: Valve Cover Leak

alot of the problems with these can also be if you torque them to spec you have to go back to each bolt like a zillion times because the torques is so light that as soon as you tighten more bolts the others are only hand tight when you go back to them - and always use loctite on them because they will back right out
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  #5  
Old December 20th, 2008, 19:49
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Re: Valve Cover Leak

Quote:
Originally Posted by Russ Pottenger View Post
Did you put a strait edge on the valve cover sealing surface, and verify it was flat?
I pulled the valve cover and found a small dent in flat part of the back. Its almost imperceptible to the eye, but you can feel it with your finger. Its about the width of a pencil.

Anyway - what course of action to take? I figured hammering the other side risks more harm than good. Would using extra RTV to seal that particular spot be ok or should I just pony up the dough for one of those fancy valve covers from Crown?

Last edited by HawkZero; December 20th, 2008 at 19:53.
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Old December 20th, 2008, 20:26
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Re: Valve Cover Leak

boneyard - thats why I like my cast valve covers - they CAN crack but they arent going to dent like the steel ones or bend really - and you'd have to be tightening the bolts like 10 times the specs to crack them too
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Old December 20th, 2008, 20:43
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Re: Valve Cover Leak

I know I've gone over this before - but it's been a while, so here's a freebie:

Materials:
1 Valve Cover Gasket (I prefer cork - in use, it will swell with oil and help seal.)
1 set SBC Valve Cover studs (cast length for cast covers, stamped length for stamped covers.)
1 tube LocTite #518 Gasket Eliminator
1 torque wrench (for reassembly.)
1 7/16" or 11m/m "flex" socket (shorty socket with inbuilt universal joint.)

Instructions:
Disassemble, clean, and inspect. Note any minor flaws (small gouges and the like,) and correct any major flaws (fill and grind, usually.) Don't change your oil yet - you're going to be dropping stuff into it, and you want to get rid of it.

After cleaning, flush all particles down thoroughly with carburettor cleaner.

Insert studs in four holes about the perimeter - I don't put them right in the ends, but I'll do something like second hole from each end. Make sure both of the mating surfaces are free of the solvent you used to flush particles down with.

Coat both sides of the gasket with LocTite #518.

Lay gasket in place.

Lay valve cover in place, overtop gasket, using studs to locate.

Install nuts finger tight.

Go have lunch. Or read the paper. Just do something else for about a half-hour.

Come back, put the socket and extension on your torque wrench, and set to spec (I believe it's 84 pound-inches/7 pound-feet, but you can verify on my site. Specs there are taken from FSMs.)

Install all remaining screws finger tight. Once all screws are in place, torque in "criss-cross" pattern to spec, working gently.

Change oil and filter. This will get more crud out of the engine assembly than draining it before you start. I make oil changes the last step of any job that requires "breaking the oil seal," save anything that involves removing the oil sump directly.

NB: I consider a torque wrench mandatory for this job - whether you're using a rubber gasket or a cork gasket. Either way, it's entirely too easy to crush the gasket beyond utility, and you'll be tearing it down and starting over rather shortly...

NB: If you forget and drain the oil first, do not put the plug back in. Make sure it's out, and flush the particles straight down the sump and into a drain pan. You'll get more out that way.

After doing the job, change the oil filter (and top up the engine oil) after about one week of operation - just to finish getting the crud out that you loosened up.

NB: While you've got the valve cover off, clean the CCV ports and baffles - you're there anyhow. Carburettor cleaner and pipe cleaners will usually do this job quite well. (You don't have pipe cleaners in your toolbox? Why not?)
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  #8  
Old December 20th, 2008, 21:26
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Re: Valve Cover Leak

Quote:
Originally Posted by 5-90 View Post
I know I've gone over this before - but it's been a while, so here's a freebie:

Materials:
1 Valve Cover Gasket (I prefer cork - in use, it will swell with oil and help seal.)
1 set SBC Valve Cover studs (cast length for cast covers, stamped length for stamped covers.)
1 tube LocTite #518 Gasket Eliminator
1 torque wrench (for reassembly.)
1 7/16" or 11m/m "flex" socket (shorty socket with inbuilt universal joint.)

Instructions:
Disassemble, clean, and inspect. Note any minor flaws (small gouges and the like,) and correct any major flaws (fill and grind, usually.) Don't change your oil yet - you're going to be dropping stuff into it, and you want to get rid of it.

After cleaning, flush all particles down thoroughly with carburettor cleaner.

Insert studs in four holes about the perimeter - I don't put them right in the ends, but I'll do something like second hole from each end. Make sure both of the mating surfaces are free of the solvent you used to flush particles down with.

Coat both sides of the gasket with LocTite #518.

Lay gasket in place.

Lay valve cover in place, overtop gasket, using studs to locate.

Install nuts finger tight.

Go have lunch. Or read the paper. Just do something else for about a half-hour.

Come back, put the socket and extension on your torque wrench, and set to spec (I believe it's 84 pound-inches/7 pound-feet, but you can verify on my site. Specs there are taken from FSMs.)

Install all remaining screws finger tight. Once all screws are in place, torque in "criss-cross" pattern to spec, working gently.

Change oil and filter. This will get more crud out of the engine assembly than draining it before you start. I make oil changes the last step of any job that requires "breaking the oil seal," save anything that involves removing the oil sump directly.

NB: I consider a torque wrench mandatory for this job - whether you're using a rubber gasket or a cork gasket. Either way, it's entirely too easy to crush the gasket beyond utility, and you'll be tearing it down and starting over rather shortly...

NB: If you forget and drain the oil first, do not put the plug back in. Make sure it's out, and flush the particles straight down the sump and into a drain pan. You'll get more out that way.

After doing the job, change the oil filter (and top up the engine oil) after about one week of operation - just to finish getting the crud out that you loosened up.

NB: While you've got the valve cover off, clean the CCV ports and baffles - you're there anyhow. Carburettor cleaner and pipe cleaners will usually do this job quite well. (You don't have pipe cleaners in your toolbox? Why not?)
5-90,
Good stuff - I've read your posts before but I was just curious about the part where you discuss repairing major flaws - how would you suggest filling and grinding or otherwise fixing a dented valve cover? Even if I used your technique, eventually the gasket will fail at the same point if I don't do something.
Any thoughts - that seems like an aweful lot of work when I can just sacrifice a couple of extra lunches out and a case of beer or two and get the fancy valve cover.
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  #9  
Old December 20th, 2008, 21:52
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Re: Valve Cover Leak

Quote:
Originally Posted by HawkZero View Post
5-90,
Good stuff - I've read your posts before but I was just curious about the part where you discuss repairing major flaws - how would you suggest filling and grinding or otherwise fixing a dented valve cover? Even if I used your technique, eventually the gasket will fail at the same point if I don't do something.
Any thoughts - that seems like an aweful lot of work when I can just sacrifice a couple of extra lunches out and a case of beer or two and get the fancy valve cover.
I've not had to "repair a major flaw" of late, but I've had good luck building it up with epoxy and sanding it down after it's cured (yes, that's a good 24 hours later...) Filling in with RTV is a temporary repair. Fortunately, there's no real pressure involved, so epoxy works well.

If it's a sheetmetal valve cover, I'll use a flat metal plate (I've got a couple bolted to the workbench - as well as a small anvil somewhere) and use a drift to flatten the dent. Tap gently - you're better off tapping something six or eight times to restore it than smacking it once and having to flip it over and reverse the job (cf: "repousse")

Cast aluminum? Eposy will work as well. Either way, rough up the surface before you apply the epoxy - 60 grit will work well for that. After it's cured, shape with 180 grit (150 if you have to do a lot!) and finish with 240 grit or so.

But, I've even got a couple of spare aluminum valve covers around, just in case I crack one (got a spare timing cover as well - and an oil sump - just on the off chance.)

For sheetmetal parts, a little gentle massaging with a hammer and a brass or steel drift works wonders!
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