Leaking valve cover...the 4th try!

[LaGrasta]

What the heck is the deal here? I replaced my valve cover with an internet special $25 chrome one and put on a new cork gasket (no sealant) and it leaked.
I put another new cork one on (with sealant) and torqued too hard and it crumbled as I found out when I removed the cover again to see why it was leaking.
I replaced it yet again, but with a rubber one (with sealant) and it still leaked.
I took it off, coated it on BOTH sides with sealant and tried it again. It still leaks. I have done extensive work on this car and this easy task is going to be the end to me. Is it the cheap cover? What's the torque supposed to be? Rubber or cork? Suggestions?

 

[FastRonald]

8) We are in the same bost.the factory cover leaked on the intake side, the new chrome one does in the same spot. I suspect the cast iron head may have been warped over the years, or had sub standard surface milling when new.

 

[Anonymous]

I allways use cork with sealant on both sides and never had a leak

 

[Anonymous]

have you tryed cleaning the surface realy good before putting a new one on. I recomend using like a wire wheel or ruff buffer pad on a dremal tool to remove them, you want it to be pritty smooth. Over all in the long run a Rubber gasket's are the best way to go, a bit more expensive but better.. What type of sealer are you using. I use Permatex high temp Rtv silicone 26b.. Just a little bit to hold the gasket in place. Also when you put the cover on you want to be sure part of the gasket goes into the little cut out holes on the valve cover itself. What type of oil are you using. Dont use the synthitic oil on a motor that is old, as that type is designed for newer motors. hope this info helps



wes

 

[Anonymous]

You may have a tiny hole in the valve cover next to the hole. I glued the rubber to the cover and it worked great until the last time I had it off. I found I had popped a hole in the cover by tightning it too much.

 

[Falcon62]

Factory torque is 3 - 5 ft lbs, (36 - 60 inch lbs) that's screwdriver range! FWIW, I always use cork, glued to the valve cover only. Problem could be your new valve cover, especially if it didn't leak before.

 

[strat1960s]

The next time you take your valve cover, oil pan or trans pan off look at the bolt holes in your pan. When the bolts are tightend over and over again or if the bolts have been over tightened, the bolts holes become mishaped (bent inwards). When this happens, it creates a an uneven surface and no matter how much you tighten the cover/pan bolts you won't get a good seal. Using a straight edge ruller, you can actually see light through these gaps. To correct this, I used a hamer and a socket to beat it back into shape, so to say.
Now with the valve cover, if this is not the case, look at your fuel runners. If you are running an OZ head, the fuel runners are larger and will make contact with the lip of the valve cover, pushing it up and causing a gap between the gasket and head, this is your oil leak. You may need to modify your valve cover (do some cutting and grinding) in order to get it to work. Another thought would be to find thicker gaskets or double up your gaskets. I went with the cut and grind method and it seems to be hold oil inside much better than before. I hope this helps you guys.
Ted

 

[LaGrasta]

I'm going out now to try again. I'm going ot try another cork, but with sealant on both sides, this is one combo I haven't tried yet. My surfaces are clean before moutning everything up as suggested. I was also over torquing it appears. I was shooting for 9ftlbs. At 5, I can't even use my torque wrench. I guess I'll snug it up and hope for the best once again. BTW, with the old cover it did have a very small leak, very small.

 

[AzCoupe]

LaGrasta, did you catch what Ted said about the gasket retainer lip? With the OZ head, you need to cut/grind away part of the lip as the OZ intake runners will hold the cover up and prevent it from sealing, even tho you think it is tight. Here's a pic of my cover, you can see where the lip is partially removed over the intake runner.

 

[gtm1086]

Most new cars today don't even use valve cover gaskets. Just RTV. So go get some good RTV apply a good bead install the cover. Torque the bolts to 60 to 80 inch lbs. Then let it set up over night.

 

[LaGrasta]

AZCoupe, I'm not running the Aussie head yet. I was going to wait to use it when I build a 200 to replace my 170. I might install it on the 170 though if I get the remaining items needed to make it happen. Knowing me and my impatients, that's more than likely what will happen.

gtm1086, You might have something there about just using a bead of silcone. Although 60-80ftlbs, I think you meant 6-8 ftlbs.

A neighbor (mechanic) saw me tinkering out there today and stopped by as usual to say hey. His theory on this leaking is my EGR valve isn't working. I have one in my cover running to the intake manifold. Where the Crankcase Ventilation System used to be is an air filter used on Harleys to vent their cases, thus running the venting backwards from how FoMoCo did. He thinks I'm building up too much pressure in the vavle cover and it's pushing it out the path of least resistance.
Remember when stock, air would get sucked in through the vavle cover cap/filter and pushed out through the CVS and into the intake manifold. I thought running it my way wouldn't make a difference in function, looks better and vents even hotter air since heat rises. If you have a clear understanding of what I'm describing, please give me your thoughts. Sorry this is so long.

 

[BIGREDRASA]

PCV (Positive Crankcase Ventilation) valve could be a problem. EGR (Exhaust Gas Recirculation) wouldn't.
Which PCV valve do you have?

 

[Anonymous]

I thought running it my way wouldn't make a difference in function, looks better and vents even hotter air since heat rises. If you have a clear understanding of what I'm describing, please give me your thoughts.

I was looking at some very old threads and i saw a picture of what u ust described, with the filter in the pcv hole, so there shouldnt be a problem with that setup, especially when the one i saw was used for racing. Im not too familiar with this setup, did u find it ran any different, did u just plug up the hole to where the hose that went to the pcv is? looks cool.

 

[Falcon62]

Tony's right, you don't have EGR on your 170, you must have been referring to PCV. I seem to vaguely remember you eliminating the road draft tube right? Maybe you could refresh our memories (mine anyway) on how you did this. Your neighbor may have hit right on the problem if your crankcase isn't vented properly.

 

[LaGrasta]

Stock PCV is removed entirely. In it's place is a crankcase breather from a Harley. Basically it's a small K&N filter about 2" diameter.
PCV used to "exhale" air from the block. Now it "inhales". The intake manifold runs to the valve cover via a PCV (not EGR, duh!). The valve cover port used to "inhale" fresh air. Now it "exhales" air into the intake manifold.
I probably could plug the hole in the block all together and remove the K&N, huh?

 

[Anonymous]

ust a thought but what if u drilled a hole in the middle of the valve cover and then insrt a rubber gommit and put the pcv there? that way u could still keep your K&N ari filter where it is.

 

[MustangSix]

Some of those chrome covers are made of thinner stuff than stock. Makes it hard to tighten without distortion. If you go to the MrGasket section at the parts store, you should see some valve cover wide washer thingies for a small block Chevy. You can fit about 4 or 5 of those to help spread the clamping force.

 

[LaGrasta]

TrueSlayer, that's how it's set up already. Came with the hole and grommet in place as well as an oil cap hole on the other end of the cover. I'll get out there and see if this last effort sealed it or not... once it's stops raining.

 

[Anonymous]

Some of the aftermarket chrome valve covers and oil pans tend to be thin, and do not torque down evenly. One thing I done with them is glue the cork gasket to the valve cover using super weatherstrip adhesive. Hold it in place with some bolts, so it stays aligned. This will prevent the cork form moving when tightening. When tighting the bolts, watch or feel the gasket to where it just starts to sqeeze out and then stop, run the engine. If it leaks, tighten again just when it stops to leak.


David 8)

 

[60FALCON]

Hi,
In my opinion I would go back to the rubber gasket no sealant the sealant will make a rubber gasket slide when torqe is applied. To hold the gasket in place you can use gasket tack or something similar. I personally would use string to tie gasket to cover in four places then after starting bolts cut string and pull it out. You must as others have said make sure your flanges are straight.

Good Luck

Chris