Heat wrapping exhaust to prevent lower valve cover warping?

[PhatRedHead]

So since I've had the car I've had oil leak problems out of the lower valve covers.

I've tried what I think is every possible combination of original lower valve covers, paper gaskets, thicker rubber gaskets, turbo valve covers and even putting a liquid gasket (high temp RTV) type on the lowers. I still get leaks more than I should be out of the lowers. This is the first time I've had all the covers off since the motor was rebuilt and my thought it that something has rattled/shook loose a little bit and the plan is to re-torque everything to spec and button her back up.

But I had the idea this morning if my lower covers are getting so heat soaked that they're warping and then leaking...what if I exhaust wrap my headers (no heat exchangers) to keep some of the heat in.

Did heat exchangers keep that much heat away from the lower covers that this is what I'm missing? I remember the exchangers being closer to the covers when I took them out.

I also don't want to drop $100+ on exhaust wrap to have it leak right on to the headers that are now wrapped up nicely and have them get oil soaked again and make it look like the Batman smoke screen.

Thanks.

Joe

[will hung]

I've heard stories of fires created by oil soaked exhaust wraps. If lowering the temps is a concern, I'd consider ceramic coating them. Should be a performance gain also.

When these cars set for long periods of time, even the best of them will leak. It's due to their air cooled nature. The gaps between mating surfaces are designed to seal themselves when they are hot, so when they set cold for long periods of time, they will seep.

[sc_rufctr]

Just to make things harder... You may also have an oil leak from the rocker shaft ends.
The PO of my car sealed the ends of the rocker shafts with an RTV silicone. It seemed to work OK but I've since sealed them with the RSR Orings.

[PhatRedHead]

Definetly don't need fire...(more heat) :P

It's a car that sits all winter (Minnesota so maybe that's my problem) So am I just doomed to do lower covers every spring? Probably not the worst thing..

A little frustrating, cuz I've run it after a winter of sitting and I can get it to temp and then I see it literally drip out and it will continue to drip and leak after the car shuts off and then on hot start its an oily smoke screen behind the car burning off the headers.

Joe

[PhatRedHead]

Originally Posted by sc_rufctr

Just to make things harder... You may also have an oil leak from the rocker shaft ends.
The PO of my car sealed the ends of the rocker shafts with an RTV silicone. It seemed to work OK but I've since sealed them with the RSR Orings.

I've heard of the rocker shaft issue also and it's my intent to look into those when I get to diving into it. Where do I get the RSR O-Rings? Available on Pelican?

[sc_rufctr]

^^^^ yes they're available here. I only used them on the exhaust side. So you only need 12.

[will hung]

wow. That's a conundrum.

When I adjust my valves, I place aluminum foil over my SSI's to prevent oil dripping all over them. I read it here once as a tip. It was so easy and effective that I planned on making it one of my winter storage steps.

But that sounds like a pretty serious leak. What kind of a/f ratios are you looking at? You might be running extremely lean to be putting off that much heat. Are you spending a lot of time idling?

[porterdog]

Have you decked the covers? I did mine in the garage- wet/dry sandpaper on a big piece of glass. The sealing surfaces were *not* flat...

[skrufy]

I agree with porterdog's suggestion. I have a '77 930 with the original 'non-Turbo" exhaust valve covers. I have NO oil leaks. I am using the red silicone covers now- installed when I last tuned it, but had the normal graphite ones before with no leak issues. IMHO, the Turbo valve covers are nice, but not necessary. They do need to be checked for flatness- it can be corrected using a large flat file at at angle if that is all you have, or as porterdog suggests, the wet/dry paper on glass- maybe 150 grit to start, finishing with 320. The problem I see with using the wet/dry paper, though totally manageable obviously, is that the sheets of wet/dry aren't long enough as the cover is stroked back/forth...... maybe some industrial supply shop has longer ones?.......

The quickest and easiest method is to lightly hold them on a belt sander with a bed large enough to do the whole cover at once. Sand for a few seconds, then check how it's going. I did mine in less than a minute each. Be careful to firmly hold on to the covers, as that sander will want to take them out of your hands and send them flying. I have not had any drip issues. I live in the mountains at 8000ft- so it gets pretty cold here as well, and the car sat for a few years ( kids, remodel the house, kids, move, etc...) while I did some restoration work- still no leaks....

You could always take them to an auto machine shop where they could deck them on their head surfacing machine- that might cost a few $$ because they would have to fit it or make a jig to hold something so small.... No belt sander access? Go with porterdog's method.......

Good luck- it's very easy to do......

Tim

[skrufy]

TYPO! I did proof read it- but just not close enough.....

that should have read "red silicone gaskets" as available from our host. Cost savings- they pay for themselves in about 2 tune-ups, and are the last ones you ever need to buy.

Tim

[kodioneill]

If the upper valve covers are warped they will leak oil down through the voids on the lower cover making it look as though the lower covers are leaking. Also like the previous post say's the rocker shafts could be leaking. If you want to protect the covers from heat buy a set of " Heet Sheets" they work well and look cool to.

[Tippy]

Have you resurfaced the cover themselves? Is the mating surface of the cam towers free of old gasket material?

[PhatRedHead]

Rehashing this with an update. Brought the covers over to my brother's house who's a 100% mechanical engin-nerd. Has a stone that is perfectly flat down to .0001 or something horribly accurately flat. Low and behold one of my lowers is not flat, haven't tested the other one yet because I hadn't gotten it completely clean of old gasket and he didn't want that on the stone...can't blame him...

My other part of this is if I go with the RSR rocker arm inner shaft seals, (exhaust side only) can those be done while the motor is in the car or is this a motor drop project?

Part of me would really like to check all my torques in the motor and button up the covers (resurfaced/etc) and drive it around for the rest of the summer then possibly tear into the motor over the winter (optimistically with first kid due in early September) without doing the rocker seals. I know it'd be dumb/foolish to button it up to tear it down, but man I just want to drive it again, been over a year.

[kodioneill]

I never had a rocker shaft leak when installed correctly and torqued to 21 foot lbs.

Look up in there and see that they are positioned correctly if not reposition them and re-torque. If you have to reposition set the corresponding cylinder on tdc before you try to move them.

[PhatRedHead]

retorquing rocker shafts doable while motor still in car, from looking, i would say yes, but just want to clarify

[kodioneill]

It would be tricky. It depends which direction the 5mm is facing. If it's been taken apart before they could be all different directions. You'd have to use a inch pound wrench. Or just tighten the hell out of them?

[rwest]

Joe,

I used to get leaks too until I realized that even though the nuts are 13mm they use very low torque because the blue plastic insert keeps them from vibrating off. Now I just tighten them until the gasket seats; I use the red reusable gaskets also and hardly ever see drips.

Good luck,
Rutager

[porsche930dude]

Id try and fab up some kind of heat shields before wraping the headers. All you need is one thin layer of metal to reduce temps a few hundred degrees.

[kodioneill]

Originally Posted by porsche930dude

Id try and fab up some kind of heat shields before wraping the headers. All you need is one thin layer of metal to reduce temps a few hundred degrees.

"Heet Sheets" work well as stated before and they look good.

[Flat Six]

Originally Posted by kodioneill

"Heet Sheets" work well as stated before and they look good.

You may not be aware, but Heet Sheets have been NLA/Discontinued for years . . .