Discussion in 'The Garage' started by barneybasher1010, Apr 8, 2006.
Which valve cover gaskets are better rubber or cork? How about thickness?
I have never had any good luck with the rubber gaskets, seem to leak all the time.
I if i remember, there are like two ot three differences in thickness, i just use the stock type thinner ones, light coating of RTV on the valve cover to help it stick, and a VERY, VERY clean surface on the heads.
I have had problems with chrome covers leaking,,,bad, i think on those you have to use the thin gaskets,,,and have alot of luck.
I bought the economy line cork felpro's the other day, I'll let ya know how they work once I put them back on...in the mean time I've got some slight issues to address under those valves covers
Felpro makes a rubber/metal anodized(sp?) set that I use. They have never leaked and unlike cork and/or rubber, you can re-use them and re-torque them if the do leak. The are spendy but are the last ones you'll ever need.
I have cork gaskets on there and a light bead of RTV and the suckers haven't leaked in the least.
That is what I used on my last valve cover job I did on my 1985 K30 Duallie. I was able to get a set of them pretty cheap from Summit.com for about $21 with shipping and everything.
If I have the dough,I opt for Fel-Pro rubber ones,and glue them to the valve cover with RTV or 3M Weatherstrip Adhesive (the yellow snot)..then put a layer of wheel bearing grease on the other side that touches the head,so it wont stick..you can pull the covers many times and not have to replace the gaskets that way..
But I've used cork cheapies with good results too,just use some RTV black on both sides..the main reason the valve covers leak is because they get overtightened and the covers flanges get warped all to hell..I hammer them flat on a block of wood,paying special attention to the bolt hole areas..those "load spreaders" work wonders too,the stock GM ones aren't long enough..
Not sure where I stand on this one. Right bank is cork fel-pro. Left bank is Red RTV only. Oh and a set of fel-pro rubber gaskets sitting on tool box.
So I would say " User Prefrence ". Any type done right will work.
Cork are far superior to rubber, the rubber will harden over time and then crack and leak like hell. I always use cork and never have an issue. The later engines with the center bolt valve covers use a RTV type rubber gasket that seem to be pretty good but you can't use them on the earlier perimeter bolt heads.
BTW, you have failed to follow the CK5 poll/post rules here buddy,,,there is no NEKKID option
I've had good satisfaction with Cork 5/16th thick. Just don't tighten them down more than snug. Make sure the valve covers are not warped also. I really like the cork rubber combo ones though, they seem to hold up to heat better than cork, or rubber.
I thought SBCs were supposed to leak oil...
Ive never had good luck with rubber or cork. Maybe I just dont know how to use them. Now I just use RTV and have a mess to clean up everytime I have to take off the valve covers but no leaks.
I'm glad I'm not the only one who can't seem to seal them...I will try with "The Right stuff" next time. Last year I went through 5 sets of gaskets, cork, rubber, rubber with steel...all leaked within a month or so. I changed to cast aluminum covers and they lasted about 6 months.
Now the engines apart for a cam change....maybe I can get them to stop leaking.
I never have a problem sealing either of them and never have a leak.
Dump the RTV and use Permatex High Tack. Even if you use it on the rubber ones, you can still remove them, clean them and respray.
I hate leaks, that's why I avoid them (leaks) all together.
I hate leaks too, and finally got em beat on my old smallblock by swapping on a set of cast aluminum valve covers. They're rigid and they're flat...and that is easily half the battle IMO. Because they're rigid you can torque the bolts down a little more and put some good clamping pressure on the gaskets.
I changed to cast aluminum a year ago too...still got leaks. I think its coming through the bolt holes.
I just pulled my valve covers a few days ago to find 2 brand new looking rubber gaskets. The only problem I found is that one is slightly torn. So I will be buying a new set anyway. Now I've gotta just pay attention to what kind wins this debate and base what kind I buy on that
True that. I'll second your motion.
It's when they stop leaking that you should worry. That means you have no more oil!!
But in all seriousness, I'll second what Rene said. Cast aluminum covers help alot. Especially since I think a lot of us have a tendancy to over-torque fasteners.
The first 350 I ever rebuilt, I snapped a head off a valve cover bolt. I think I may have been applying too much torque.
I agree, my 350 is only happy when it can mark its territory!
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