Looking for recommendations on the best small block valve cover gaskets .
:popcorn:
I think it's felpro that makes a silicone gasket with steel inserts for the bolts to go true, and are re-usable, but i an not sure if they have them for your application. :alan2cents:
Not sure about felpro but moroso makes this one that has a steel core. Pretty thick and will seal some irregularities in on the portion of the head where the gasket seats.
A really good idea, if your heads are ever off is to have the top sealing surface / valve cover seat, machined flat. This will help immensely with leaks at the base of the valve cover.
What are you trying to seal up ?
Factory heads are far from flat unfortunately but steel covers will flex & conform to the surface
Alum covers are the worst & can easily be broken when tightening them onto a factory head as they will not conform , generally a soft thick gasket will work better in this case .
The aftermarket heads usually have milled rails & are easy to to seal with any covers .
I have used the Blue gaskets with steel inserts with godd success in some cases , sometimes & double thick cork will work well also .
My mopar performance chrome valve covers are leaking . My motor was built about 30 years ago . Not sure if I used rubber reusable ones or not .
Covers are on j heads
I onu use and highly recommend the Fel-Pro CORK-LAM SET #1646. These are hj-grade cork rubber with a steel center core... total thickness .313". The cork rubber is conformable to irregularities of the cylinder head's valve cover rails, as well as conformable to the flange of nearly every different kind of valve cover.
I'm a former Fel-Pro engineer... these are the best for our engines.... they are the only valve cover gaskets that I ever use... never leaks and easy to align.... lasts many long years.
Problems with molded silicone with steel center core is that they are not very forgiving to flange/mating surface distortion or irregularities.
Thanks Mitch . I have seen some Fel-Pro gaskets requiring a special sealant do these gaskets require the special sealant ?
The best gaskets I have found are the P5249581, original used on the late 80s cop small blocks.
I stocked up on them years ago, not sure if Mopar is still stocking. Have a look, great gasket, reusable for most of the cars life.
The steel core ones really work well by not squirming around.
Sealants?... best installed dry, especially rubber to be installed dry! The gasket does the sealing... not the chemical.
The steel cored gaskets are stable and align easily.
Non-steel-cored gaskets are a bit flexible and ... for alignment purposes only... can use a quick-drying contact cement to attach it to thew valve cover.
I prefer to use studs in the cylinder heads.. helps with aligning the gaskets.
Some gaskets (non-steel-cored) will have little outside tabs that are intended to fit inside the factory stamped steel covers... for attachment and alignment purposes.
Quote from: MOPAR MITCH on April 27, 2020, 07:20:04 AM
Sealants?... best installed dry, especially rubber to be installed dry! The gasket does the sealing... not the chemical.
The steel cored gaskets are stable and align easily.
Non-steel-cored gaskets are a bit flexible and ... for alignment purposes only... can use a quick-drying contact cement to attach it to thew valve cover.
I prefer to use studs in the cylinder heads.. helps with aligning the gaskets.
Some gaskets (non-steel-cored) will have little outside tabs that are intended to fit inside the factory stamped steel covers... for attachment and alignment purposes.
@MOPAR MITCH (https://forum.e-bodies.org/mlist/mopar-mitch_365) Sorry, just to confirm, you dont have to use a sealant for these covers to seal properly? I have the mopar performance aluminum valve cover and I have read good things based on your tip in this thread to use these felpro 1646 gaskets. I have a small leak on my passenger side near the firewall on my stock 340. Thank you.
Neil
"The best gaskets I have found are the P5249581" I took your advice and called my local Mopar dealer. The part# was B/O'd and I asked him to add me to it. He called the next day and said that Chrysler has cancelled my order and that there were not going to be any more available. This's in Ontario, Canada and he said there were a couple of US dealers who showed a bit of stock, so good luck. :cheers:
Quote from: nsmall on May 03, 2020, 02:41:51 PM
Quote from: MOPAR MITCH on April 27, 2020, 07:20:04 AM
Sealants?... best installed dry, especially rubber to be installed dry! The gasket does the sealing... not the chemical.
The steel cored gaskets are stable and align easily.
Non-steel-cored gaskets are a bit flexible and ... for alignment purposes only... can use a quick-drying contact cement to attach it to thew valve cover.
I prefer to use studs in the cylinder heads.. helps with aligning the gaskets.
Some gaskets (non-steel-cored) will have little outside tabs that are intended to fit inside the factory stamped steel covers... for attachment and alignment purposes.
@MOPAR MITCH (https://forum.e-bodies.org/mlist/mopar-mitch_365) Sorry, just to confirm, you dont have to use a sealant for these covers to seal properly? I have the mopar performance aluminum valve cover and I have read good things based on your tip in this thread to use these felpro 1646 gaskets. I have a small leak on my passenger side near the firewall on my stock 340. Thank you.
Neil
I used these FelPro gaskets on my J-heads and with aluminum covers. Once I had the clearance ground into the VCflange to miss the intake runners, they sealed perfectly with no sealant. I torque them, then come back the next day and do it again because they will take a bit of a set.
Neil -- regarding the small leak on the passenger side valve cover, look to see if the mating surfaces are good. I've seen cylinder head flanges with slight dips and irregular casting surfaces. Same goes for the valve covers.. regardless if stamped steel or cast aluminum. If stamped steel, the flanges could become distorted from over-torquing and making the flange no longer flat. The use of load spreaders (such as commonly found on older GM covers) would help spread the load.
Also, sometimes the threadings in the cylinder heads may not be cleaned well enough... or tapped deep enough... to allow full clamp load. I prefer to use studs instead of small bolts... the studs also help alignment of the gasket... keeping it in its place.
IF all else fails, you could apply a small dab of RTV (red is preferred for better its better heat specs) at that suspected leakage area, allow it to dry about 24-hours, then keep your fingers crossed.... but it may possibly still leak down the road in some time.
Quote from: MOPAR MITCH on May 05, 2020, 09:37:22 PM
The use of load spreaders (such as commonly found on older GM covers) would help spread the load.
Also, sometimes the threadings in the cylinder heads may not be cleaned well enough... or tapped deep enough... to allow full clamp load. I prefer to use studs instead of small bolts... the studs also help alignment of the gasket... keeping it in its place.
IF all else fails, you could apply a small dab of RTV (red is preferred for better its better heat specs) at that suspected leakage area, allow it to dry about 24-hours, then keep your fingers crossed.... but it may possibly still leak down the road in some time.
Sorry to keep asking. Its just that I have already broken one of my cast aluminum mopar valve covers so I am trying to not waste a bunch of money and time.
I have the load spreaders.
I have the new gasket you recommended.
So
@MOPAR MITCH (https://forum.e-bodies.org/mlist/mopar-mitch_365) How do i clean the threading? I dont want to run a tap in there, but I did use silicon a couple of times on the bolt on my past failed attempts to correct this as I hoped that would stop the leak. There could be some silicon in the head threads.
Final questions, I will check the valve covers and the heads to see if they look straight. I was thinking I should use the new gasket you recommended with no RTV for the first try, but you are recommending using some RTV if I notice a leak? As in put a dab on the head where it is not straight if I notice any straighness issues? I dont have a torque wrench, I do have some nice 1.25 ARP bolts to use as my others were only like 3/4 so I dont know how significant that is, I was just going to snug each bolt evenly one by one. Thanks again. Really appreciate everyones help.
NS -- I can say that if you don't prep the threadings.. tapping or wire-brushing the fasteners... it'd be like a doctor not washing his hands before an operation... or a painter not prepping the surface before applying the final coats.
If you've applied RTV (silicone) to the threadings of the fasteners, then you're not getting proper clamp load.... it must be cleaned/removed... RTV silicone is the most mis-used, abused and over-used chemical in the automotive marketplace. It should be used as filler of gap, such as at intersecting corners (intake mfld, oil pan, etc.). IF there is out-of-flat conditions (non-straight), it should be re-surfaced, or replaced... as needed.
I was watching one of those car shows and the mechanic ran a tap and die over new parts to make sure they go together correctly.
Be careful trying to use 1.25" bolts, as they're likely to bottom out and you'll strip the thread and then you've got fun! Rough and dirty, stick a toothpick down the hole and mark where the edge comes to on it and then measure it and the cover and gasket and you'll have a rough idea of how long a bolt you could use. Remember that the gasket'll compress a bit and give yourself a small fudge factor to be safe. :cheers:
Thanks a lot for your help everyone. I really appreciate your time and advice. :bradsthumb: