Moroso blue valve cover gaskets are leaking, please help

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kiss

kiss

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Okay guys, this sucks. Quick rundown, the 360 LA in my 71 Dart was rebuilt a couple months ago. Stock rebuild 4bbl intake, Edelbrock carb, pretty standard. It runs great. The engine was assembled by a friend who used the cheap valve cover gaskets that came in the engine gasket set and they leak a little bit. After searching around on here I bought the Moroso 93050 gaskets (the blue ones) to replace them.

It just has a cast head surface and I use stock valve covers. They aren't interfering with the intake manifold, I'm 100% sure of that. What I did was take the valve covers off and cleaned both the head surface and the valve cover surface very well. The old gaskets didn't stick to anything so that went fairly smooth. I also took the stock valve covers and flattened the holes against a wooden board as best I could, they're in pretty good shape, no reason why they wouldn't seal. I also bought triangle valve cover washers to spread the load a little.

With the surfaces clean I put the blue gaskets on, and snugged the valve covers down by hand with a nut driver (screwdriver with a 7/16 socket on the end). I got them pretty tight with just the nut driver which is the tightness i've always used for stock valve covers. I drove the car and they leak like crazy. I grabbed a ratchet with extension and snugged them down more, pretty snug with the ratchet gripping it close, and they still leak a bit. I'm not sure what to do. I let it heat cycle and checked to make sure they were all snug and they still leak.

I have no idea if I should try tightening them down more or not. Honestly I think they are probably too tight already, I've never snugged down valve covers with a ratchet so im not sure.

Honestly guys the only idea I have is when I took the Moroso 93050 gaskets out of the package I was skeptical right away. It's vulcanized rubber over a steel core. I just couldn't see how that would have enough 'give' to seal all of the casting imperfections. They looked great for machined surfaces, like Magnum valve cover mounting surface, but casting not so much. Does anyone else agree?

I have hydraulic lifters so I shouldn't need to open the valve covers. Should I find some cheaper rubber valve covers and just use RTV on the head and valve cover to glue it shut? If so, which gaskets should I get for that?

Any help is much appreciated.
 
99 percent of the time it's not the heads surface that leaks. It's the imperfection in the valve cover. I use mopars gaskets that are very similar to moroso. Steel shim covered in rubber. I also use mopar cast aluminum valve covers. Silicone the gasket to the cover. Let cure over night before install.
 
Recheck the gasket on the head, and then on the cover, to make dam sure the gasket is covering the corners...
if thats not it.... The cover is bent... or the you must have a interference issue...

I use the MR. Gasket 5876.... Or Just Plain Fel-pros..
 
How tight do you guys tighten down the valve covers?
Also, do anything with the bolt holes or threads on the bolt? Coat threads with RTV??
 
my blue morosos have never leaked, chrome DC valve covers, no sealant, snugged up fairly tight , nothing outrageous. had them off and on at least 10 times in 2 years, just lucky i guess
 
I'm interested in thread as I've got the same problem. Bought the Mopar Performance rubber w. steel core when reinstalling my stock valve covers. Didn't use any sealant the first time and the passenger one leaked a lot near the firewall. Took it off and used Permatex #2 between the valve cover and gasket (nothing on the head side) and now it leaks almost along the entire passenger side (downhill side closest to the spark plugs). I waited 24 hours for the sealant to set before I tightened the bolts. The drivers side also leaks but not nearly as much as the passenger side. Also tightened the bolts after after a few heat cycles but didn't reef on them since that would warp the covers. I'm almost ready to try the old school cork gaskets....
 
I use regular Felpro cork gaskets.
Then I use Edelbrock Gasgacinch to seal the gasket to the valve cover.
Never glue on the head side.
After I glue the gasket to the VC, I lay it on a flat bench with some weight on top of it.
Let the gasket/glue setup, or dry for a few hours.
Pop it on, and tighten the bolts to factory specs.
Do not use rtv on your bolts !!!
Unless you like having rtv on all the threads,when you remove them.
 
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Johnny Dart said:
I use regular Felpro cork gaskets.
Then I use Edelbrock Gasgacinch to seal the gasket to the valve cover.
Never glue on the head side.
After I glue the gasket to the VC, I lay it on a flat bench with some weight on top of it.
Let the gasket/glue setup, or dry for a few hours.
Pop it on, and tighten the bo, ts to factory specs.
Do not use rtv on your bolts !!!
Unless you like having driedrtv particles all over them, when you remove them.
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I don't have Gasgacinch and I've never used it. I have a new tube of Permatex Ultra Black RTV. Can I use that in place of Gasgacinch to glue the cork gasket to the valve cover? I happen to have 2 cork gaskets from the engine gasket set, not sure what brand they are, doesn't say.
 
one of the hardest feats in small block sealing..... getting that poorly cast head flange to seal to a thin easily bent factory cover. IMHO the Moroso and MP gasket were intended for more race engines, aka, wide smooth machined surface on head, wide smooth/thick aftermarket valve cover. With stock stuff I usually had the best luck with a good cork gasket attached to the valve cover via gaskacinch or weather strip adhesive. 72 in lb is the tightening spec.
 
Thanks for the help everyone. Here's an update on what I did this AM, with a couple more questions. I took the valve covers off and double-checked straightness along the raised edge that engages the gasket, very very straight. The holes aren't warped either, I was impressed by how good of shape the valve covers were in. I used to cork gaskets and RTV them (Permatex Ultra Black) to the valve covers very well and used a good amount. I put them on a flat surface with weight on them for like a half hour to stick. I also cleaned the head surface and put a THIN amount on the head as well as the bottom of the gasket just in case. I put the valve covers on the head CAREFULLY and made sure they didn't move, the cork tabs still being held nicely in the valve cover notches. I lightly snugged down the bolts and now it's just sitting.

I figured around 1pm I would snug down the bolts to factory spec, that will give it about 4-5 hours of drying time. Then around 3pm I was going to take it for a test drive. Does that sound like a good plan?

Here's what I'm not sure of, after the test drive should i re-torque the bolts again while engine is hot, or let it cool first then re-torque?
 
Gasgacinch $6.00 pretty much anywhere.
Why should anyone try if you are not going to take their advice ?
 
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Johnny Dart said:
Gasgacinch $6.00 pretty much anywhere.
Why even try if you are not going to take the advice ?
Good luck dude.
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I'm not ignoring advice at all, I even did a +thanks to your very helpful post. You recommended Gasgacinch and another person in this thread said Silicone. RTV Silicone is what I had on hand. I followed the exact steps you recommended though, with cork gaskets even, and I appreciate it very much. I just logged on to report no leaks! I took the car on 2 drives this evening and so far so good!
 
I doubt its the gaskets been using those Morosos's for 6 seasons with no leaks been on and off several times..check to make sure the covers are flat/even..
 
stroked340 said:
I doubt its the gaskets been using those Morosos's for 6 seasons with no leaks been on and off several times..check to make sure the covers are flat/even..
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As I said in post #13, the second time I had them off, I double-checked straightness and they are very straight, and the bolt holes aren't warped. The stock valve covers are in very good condition. The Moroso gasket just didn't have enough give to fill the imperfections in the valve cover or head, as said by @A body in post #1. @H22A4 in post #8 describes the same issue I had.

Not bashing those Moroso gaskets what-so-ever, they just didn't work for me and it looks like a few others. Just something to be aware of in case someone else references this thread in the future for having the same problem with stock manifolds and stock cast surface heads.
 
Silicone based "sealers" are a poor choice for gluing anything to anything else. Use the Gaskacinch or yellow weatherstrip adhesive to glue the cork or rubber gaskets (stock type only for stamped steel valve covers) to the valve covers. Once they are dry, you should be able to install the covers dry on the engine. Torque the bolts gradually/evenly to 40 inch/pounds. You need to remember that the surface of the head that these gaskets touch is not exactly flat, and the steel covers will bend to match it.

The Morosos really only work well with machined heads, and cast or heavy fabricated valve covers.
 
69_340_GTS said:
Silicone based "sealers" are a poor choice for gluing anything to anything else. Use the Gaskacinch or yellow weatherstrip adhesive to glue the cork or rubber gaskets (stock type only for stamped steel valve covers) to the valve covers. Once they are dry, you should be able to install the covers dry on the engine. Torque the bolts gradually/evenly to 40 inch/pounds. You need to remember that the surface of the head that these gaskets touch is not exactly flat, and the steel covers will bend to match it.

The Morosos really only work well with machined heads, and cast or heavy fabricated valve covers.
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^^^^^^^^^^^^^^^^^^THIS^^^^^^^^^^^^^^^^^

Cork gaskets ad gaskacinch and be done with it. Silicone is too slick for rubber.
 
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