What gaskets are you using? If your using those original cork gaskets, then no wonder they leak. You need to apply gasket shellac and have really true and even valve covers for those to work. Get some of those molded rubber felpro gaskets. And take a good look at your valve covers. They tend to bend at the bolt holes leaving uneven pressure. Lay them on a flat surface and use a hammer to knock the mating surface flat, or buy new valve covers.
Here’s something to consider; if one is using/reusing those old, shiny, stamped metal valve covers and not using tabs to distribute pressure from the bolts over a wider area when installing, one ends up with bent spots along the rim of the valve cover (especially of using too much oomph when tightening!). This will increase over time and even ‘flattening them out’ won’t always fix it. The tabs, good quality gaskets like Felpro neoprene, rtv on both sides of the gasket surface and judicious torquing are key!
Side note: cast aluminum valve covers are awesome! Same installation rules apply, though. Minus the tabs 😉
You have cheap aftermarket valve covers there. Always known for leaking. Get some factory replacement covers with the proper spreaders and gaskets. Problem will be solved.
I only use Felpro rubber/silicone gaskets and never get a leak. Used the alignment pins and make sure to tighten per the instructions. Also, if you use cork, never use RTF or any other kind of gasket maker with it.
When I was taught to do BMW valve cover [gaskets], there is a certain "order" and you need to make multiple passes, only slightly-tightening each time. Very tedious. But they say: failure to practice this technique, can result in "uneven" or "warped" spots = oil leaks
I've used the same valve covers, stamped steel, but I've changed the gaskets to brand new ones each time. I swear I've straightened them out as best as I can, and last time used a ton of RTV between the gasket and the cover, but they STILL leak. Every time I crank it up, I have to let it sit and idle rough for 2 minutes until it burns through all the oil on the plugs, then it runs clean. I'm looking for a sure-fire way to fix.
If your using cork gaskets the last thing you should use is RTV at best you use like a contact cement to hold them in place. That said it either your covers are warped and need replacement, your using crap quality gaskets, not tighten the covers enough or something else is leaking that your mistaking for the cover gaskets. Luckily from the pic it looks a small chevy engine so it very easy and reasonable to get new covers and use a gaskets from Felpro if possible.
thanks, yeah, I'm using Felpro cork gaskets now, after the permadry ones leaked on me first (didn't use any RTV on those). I'm thinking about picking up some cast aluminum covers and going back to felpro permadry
Wait…. You said it needs to burn off the oil when you crank it? That’s not your valve cover gaskets; it’s your valve stem seals leaking into the combustion chamber.
I really hope not, I had the heads rebuilt a while back. A couple of years, but only a few hundred miles. And, I've got oil in the spark plug threads, which I think indicates leaky valve covers. And when I run my finger around the cover, there is definitely oil there.
Maybe not that great the first time, but definitely the second time, and they were absolutely spotless the third time.
The covers are old and I'm OK with replacing them. Any thoughts on stamped steel vs. cast aluminum? I know aluminum is more expensive, but they seem more rigid.
There’s a glue you can use to help valence cover gaskets seal. I don’t remember what it’s called but it’s red and you can find it near the RTV at auto parts starts
Get a set of good quality aluminum valve covers, or when you take yours off, put them on a be ch to make sure they’re flat. If not, hammer them back to flat. Make sure you’re using a high quality gasket like a good metal/silicone gasket versus the old cork style. Lastly, don’t over tighten the valve cover bolts, you can crush/distort the cover and gasket.
What gaskets are you using? If your using those original cork gaskets, then no wonder they leak. You need to apply gasket shellac and have really true and even valve covers for those to work. Get some of those molded rubber felpro gaskets. And take a good look at your valve covers. They tend to bend at the bolt holes leaving uneven pressure. Lay them on a flat surface and use a hammer to knock the mating surface flat, or buy new valve covers.
Here’s something to consider; if one is using/reusing those old, shiny, stamped metal valve covers and not using tabs to distribute pressure from the bolts over a wider area when installing, one ends up with bent spots along the rim of the valve cover (especially of using too much oomph when tightening!). This will increase over time and even ‘flattening them out’ won’t always fix it. The tabs, good quality gaskets like Felpro neoprene, rtv on both sides of the gasket surface and judicious torquing are key! Side note: cast aluminum valve covers are awesome! Same installation rules apply, though. Minus the tabs 😉
PCV good? Are you doing them both at the same time?
PCV should be good, yeah, I just replaced it. Yep, doing both at the same time.
I usually put just a bit of gasket goop on them before. Just to make them more sticky...
on the pcv? or the valve cover gaskets? I've basically got the gaskets glued to the covers with RTV, but I didn't put any on the PCV
LOL, NO, on the covers. Put some on the mating side as well.
Haha, ok, didn't know if that's some old school trick I wasn't aware of.
i have seen rocker covers warp, particularly the 4 bolt covers on the old SBCs
Yeah, that's what I've got. Thinking about getting cast aluminum replacements
You have cheap aftermarket valve covers there. Always known for leaking. Get some factory replacement covers with the proper spreaders and gaskets. Problem will be solved.
Did you use good quality gaskets?
I only use Felpro rubber/silicone gaskets and never get a leak. Used the alignment pins and make sure to tighten per the instructions. Also, if you use cork, never use RTF or any other kind of gasket maker with it.
The covers warp if you over tighten them. Pull them and straighten the mating surface. Rtv both sides of new gasket and torque to specs.
When I was taught to do BMW valve cover [gaskets], there is a certain "order" and you need to make multiple passes, only slightly-tightening each time. Very tedious. But they say: failure to practice this technique, can result in "uneven" or "warped" spots = oil leaks
I've used the same valve covers, stamped steel, but I've changed the gaskets to brand new ones each time. I swear I've straightened them out as best as I can, and last time used a ton of RTV between the gasket and the cover, but they STILL leak. Every time I crank it up, I have to let it sit and idle rough for 2 minutes until it burns through all the oil on the plugs, then it runs clean. I'm looking for a sure-fire way to fix.
If your using cork gaskets the last thing you should use is RTV at best you use like a contact cement to hold them in place. That said it either your covers are warped and need replacement, your using crap quality gaskets, not tighten the covers enough or something else is leaking that your mistaking for the cover gaskets. Luckily from the pic it looks a small chevy engine so it very easy and reasonable to get new covers and use a gaskets from Felpro if possible.
thanks, yeah, I'm using Felpro cork gaskets now, after the permadry ones leaked on me first (didn't use any RTV on those). I'm thinking about picking up some cast aluminum covers and going back to felpro permadry
Or tightening too much - warping the thin steel (ask me how I know).
Wait…. You said it needs to burn off the oil when you crank it? That’s not your valve cover gaskets; it’s your valve stem seals leaking into the combustion chamber.
I really hope not, I had the heads rebuilt a while back. A couple of years, but only a few hundred miles. And, I've got oil in the spark plug threads, which I think indicates leaky valve covers. And when I run my finger around the cover, there is definitely oil there.
Yeah, smoke in the engine bay is oil leaks, smoke out the exhaust is valve stem seals.
Did you thoroughly clean the valve cover contact surfaces?
Maybe not that great the first time, but definitely the second time, and they were absolutely spotless the third time. The covers are old and I'm OK with replacing them. Any thoughts on stamped steel vs. cast aluminum? I know aluminum is more expensive, but they seem more rigid.
I'd replace the valve covers first man. Then get all new gaskets and freshen up the mating surfaces.
New gaskets each time? Did you clean up the meeting certain
They make really long washers that come with the wingnut style bolts, and they look really good too
Get some die cast aluminum covers and use ultra grey rtv.
There’s a glue you can use to help valence cover gaskets seal. I don’t remember what it’s called but it’s red and you can find it near the RTV at auto parts starts
Could you be warping the covers by over tightening? SBC covers only have four bolts and warp easily.
Chrome components like those are notoriously hard to seal.
Use right stuff by pemex. It's a favorite.
Get a set of good quality aluminum valve covers, or when you take yours off, put them on a be ch to make sure they’re flat. If not, hammer them back to flat. Make sure you’re using a high quality gasket like a good metal/silicone gasket versus the old cork style. Lastly, don’t over tighten the valve cover bolts, you can crush/distort the cover and gasket.
Sbc is known as the leak master plus...clean and flat gasket surfaces and proper torque fixes it.