Ehaust rocker cover leakage???

[porschetub]

Fitted left side cover after valve reset,nice clean surface and new gasket,torqued correctly and it leaks without the engine even running,is it mandatory to resurface these magnesium covers because they warp?
Have read this is an issue with them,the PO had very thick gaskets and sealer on them

[Dpmulvan]

Time for new ones

[Aurel]

Replace with turbo valve covers. The ribs prevent wrapping. Well documented upgrade.

[porschetub]

Originally Posted by Aurel

Replace with turbo valve covers. The ribs prevent wrapping. Well documented upgrade.

.

Not what I was asking really

[Driver_X]

You could do that, but a better option is to fit turbo lower valve covers.

[timmy2]

A piece of glass made for flattening and sandpaper will square up the cover.

[Targalid]

Or you can do what I did. Get the thick silicone valve cover gaskets from Pelican. No leaks.

[joefrantz]

Magnesium covers often need to be flattened. The best method is judicious sanding on a fixed base belt sander with a very fine grit belt. Depending on severity you can also sand them by hand against a reliably flat surface. Plate glass is often suggested -- hopefully a nice thick piece. I used a sheet of 3/4 inch Melamine surfaced shelf board.

Gaskets are also important. The most popular type seem to be the ones with a silicon bead around the sealing surfaces. Another option is the red solid silicone type that are re-useable, but also somewhat fragile when hot.

Torque and tightening pattern are probably the most important variable. I think that most problems with magnesium covers have come from over tightening and/or not using the correct center-out, upper-lower alternating pattern.

I use the red silicone gaskets, and they will take very little torque. I put my finger on the edge of the gasket at each stud. I tighten until I feel the gasket bulge about 1/16 inch and stop. I would estimate it at no more the 2 ft. lbs. I’ve never had a leak or even any seepage.

Wayne’s engine book recommends 6 ft. lbs. pounds for the standard type gaskets, and I’m pretty sure that would include the silicon bead type.

As for the Turbo type valve covers – yes they're the popular solution, but I think they're a trade-off. They’re less fussy than the mag covers, but a full set of aluminum covers will add 3+ pounds to your engine weight. In my case, I knocked three pounds off of my 3.0 liter by replacing the turbo type covers with magnesium.

[porschetub]

Originally Posted by joefrantz

Magnesium covers often need to be flattened. The best method is judicious sanding on a fixed base belt sander with a very fine grit belt. Depending on severity you can also sand them by hand against a reliably flat surface. Plate glass is often suggested -- hopefully a nice thick piece. I used a sheet of 3/4 inch Melamine surfaced shelf board.

Gaskets are also important. The most popular type seem to be the ones with a silicon bead around the sealing surfaces. Another option is the red solid silicone type that are re-useable, but also somewhat fragile when hot.

Torque and tightening pattern are probably the most important variable. I think that most problems with magnesium covers have come from over tightening and/or not using the correct center-out, upper-lower alternating pattern.

I use the red silicone gaskets, and they will take very little torque. I put my finger on the edge of the gasket at each stud. I tighten until I feel the gasket bulge about 1/16 inch and stop. I would estimate it at no more the 2 ft. lbs. I’ve never had a leak or even any seepage.

Wayne’s engine book recommends 6 ft. lbs. pounds for the standard type gaskets, and I’m pretty sure that would include the silicon bead type.

As for the Turbo type valve covers – yes they're the popular solution, but I think they're a trade-off. They’re less fussy than the mag covers, but a full set of aluminum covers will add 3+ pounds to your engine weight. In my case, I knocked three pounds off of my 3.0 liter by replacing the turbo type covers with magnesium.

Thank you ,thats an answer in detail pretty much what I was after,pulled that cover today and found there was a chip of paint on the sealing surface around where the leak was,makes sense as the gaskets aren't really that thick,have an old mirror so will glue some sandpaper on there and see how I go,will report back,cheers.