Hot Rod Forum banner
1 - 20 of 21 Posts

·
Registered
Joined
·
4,739 Posts
Discussion Starter · #1 ·
Hello guys I am having a problem with my small block chevy valve cover gaskets leaking only in the rear on my dart 377 shp build. I am running dart pro 1 aluminum heads with a set of Summit brand aluminum valve covers and they are of good quality and never leaked on my previous builds using cork gaskets with indian head sealant on the bottom of the gasket.

This build I am using reusable rubber gaskets that leaked in the beginning in the rear so I took them off and put some indian head on the bottom of them to help hold them in place and carefully put my covers back on and torqued them to 2 ftlbs like my torque spec sheet says to put them at. I have a set of cork gaskets I am about to put on as they seem to not have this problem and in the past using the rubber gaskets I have always had problems with them leaking vs the cork.

Now I don't' know if this might be the problem or not but I am using valve cover studs from Moroso that comes with nylock nuts to help keep them tight and I am wondering since I am using nylock nuts that torquing them at 2 ftlbs is not enough since the nylock insert on the nuts are adding resistance and friction but I used them in the past with the cork gaskets and torqued them the same and never had any leaks in the rear.

These are the outer bolt perimeter type valve covers. I am running a correct pcv valve along with the proper breather on the other cover. The type of rubber gaskets I am using I can't remember the name brand but they are just rubber and have not metal crush sleeve or any fancy thing to them.

Any ideas? I am thinking some how I am not getting them to stay in place correctly enough and since the oil will always puddle more in the rear since the engine sits at an angle or maybe with them being stronger vs a cork gasket I need to tighten them more but I have read that anything more then 2 ftlbs is to much and you can strip things. I have a lot of years dealing with small block chevy builds and I have not used those rubber gaskets very often because of this but before I go changing anything does anyone have a better type of gasket recommendation that is better then both of those?

I seen the felpro ones that have a metal crush limiter on them but for over $50 bucks for a set of valve cover gaskets that is a bit pricey.

Sorry if this sounds stupid to ask but figured it would be worth a shot.
 

·
Registered
Joined
·
2,281 Posts
A. You're absolutely sure its the vc gasket & not head to China wall or manifold to China wall or the oil sender ?
B. Never have had any luck with rubber gaskets by themselves. With a bit of silicone , yes
C. the cork gasket weigh the metal sandwiched between the cork have really lasted ,like 15 years with numerous r&r .Paid $15 for 2 pair at a swap meet newly 20 years ago , still on the first set ..
 

·
Registered
Joined
·
4,739 Posts
Discussion Starter · #4 ·
Yes it is my valve cover gaskets. When I rub my finger behind the valve cover under the ridge that sticks out on the valve cover over the gasket. If I wipe my finger along the side on the outer part above my headers I can get a small amount of oil film on my fingers. The rubber gaskets I am currently using I had a heck of a time getting the things just to keep shape and stay square while I put them on.

I stuck some indian head on them to help keep them in place on my head as I have to take a few studs out in order to get my covers on and off as my engine is in a s10 and my valve cover on the driver side is really close to the brake booster and the passenger side is close to the old AC evaperator part and I have to angle the dang things a certain way to get them over a few studs that I can keep in and with the rubber gaskets I had a heck of a time keeping them in place as they would always fall to the side or inside.

I am going to ditch them and just get me some gasket tack and I watched a video and its recommended to put the tacky stuff on the cork gasket and also on the valve cover and leave the head clean and wiped off and then install it on and then re check after a few heat cycles. I did a google search to also see about some tips and I had posted here many years ago and I guess I forgot as I have not messed with anything for quite some time do to health issues.

I saw the felpro ones imsport that you posted and thanks for the info and I will keep them in mind but I will put the cork gaskets on with the tacky sealant and I should be good as I don't need to be taking my covers off all the time as I run a hydraulic roller cam so no need to adjust anything.
 

·
Race it, Don't rice it!
Joined
·
8,828 Posts
Do you have these?

They help a lot. Also, you may need longer studs and I'd go with regular nuts and go 1 turn past finger tight. Normally I use a nut driver instead of a ratchet.
 

·
Registered
Joined
·
4,739 Posts
Discussion Starter · #6 ·
I do have a set of those but I have aluminum valve covers and they have a raised area where the holes are and I can't put them spreaders on them as I always understood they are for the steel type covers but mine have raised areas across the part where you put the bolts at or in my case studs.

As far as my studs goes they have plenty of length and I could install three nuts on top of each other or close to it. The studs stick up pretty high past the covers so those clamps would help but unfortunately they won't work on my covers.
 

·
Race it, Don't rice it!
Joined
·
8,828 Posts
I wasn't thinking aluminum covers even though you did say so. I would make sure the covers sit on the rails properly as I've seen some of the dart heads cover rails are flat but not always exactly right with the covers. There seems to be such a wide variety of covers and heads that slight mismatches seem the norm and it's kind of amazing to me that as prolific as the SBC is, covers and gaskets and heads still vary as much as they do. If they mate up well, I'd glue the gasket to the covers and snug them down to 1 turn past finger tight. A stiffer cover like you have can take more torque. They don't flex/bend and push out the gasket like the cheapie stamped steel ones will do. I've also sanded the covers rails with 400grit paper. Just enough to knock the glaze off of them. That seems to make that particular set hold onto the gasket better. I've also milled and tapped SBC heads with 4 extra. You prolly don't wanna do that but It worked good for me.
 

·
Registered
Joined
·
4,739 Posts
Discussion Starter · #8 ·
Thanks johnsongrass I will look things over with the heads and the covers and see how exactly well they fit over the heads. I will try to rough up the surface as well just for good measure. Thanks everyone and I think I am good with all the suggestions you all gave me and the other gasket options in case my cork ones would leak but I will give them a shot with some gasket sealant. Take care guys
 

·
Registered
Joined
·
813 Posts
Over the last few years I've cleaned both surfaces with brake parts cleaner which, IMHO, is extremely important when dealing with pourous cast iron heads. I've used the rubber/steel Fel-Pro gasket since it came out and Permatex #2 for bonding to the valve cover. I have an old coffee can full of plastic clothes pins which I place all around the rim of the valve cover to hold the gasket in polace until the Permatex dries.I align the gasket by placing the bolts through the gasket and valve cover. When dried I assemble each valve cover stating with the lower left bolt then upper right to lower right ending with upper left. I've never used a torque wrench and go about 1/2 turn past snug. I've used variations of this procedure on Ford, Mopar and GM and have rarely had leaks. If I do It's generally because I didn't get the heads clean enough.
 

·
Registered
Joined
·
8 Posts
Hello guys I am having a problem with my small block chevy valve cover gaskets leaking only in the rear on my dart 377 shp build. I am running dart pro 1 aluminum heads with a set of Summit brand aluminum valve covers and they are of good quality and never leaked on my previous builds using cork gaskets with indian head sealant on the bottom of the gasket.

This build I am using reusable rubber gaskets that leaked in the beginning in the rear so I took them off and put some indian head on the bottom of them to help hold them in place and carefully put my covers back on and torqued them to 2 ftlbs like my torque spec sheet says to put them at. I have a set of cork gaskets I am about to put on as they seem to not have this problem and in the past using the rubber gaskets I have always had problems with them leaking vs the cork.

Now I don't' know if this might be the problem or not but I am using valve cover studs from Moroso that comes with nylock nuts to help keep them tight and I am wondering since I am using nylock nuts that torquing them at 2 ftlbs is not enough since the nylock insert on the nuts are adding resistance and friction but I used them in the past with the cork gaskets and torqued them the same and never had any leaks in the rear.

These are the outer bolt perimeter type valve covers. I am running a correct pcv valve along with the proper breather on the other cover. The type of rubber gaskets I am using I can't remember the name brand but they are just rubber and have not metal crush sleeve or any fancy thing to them.

Any ideas? I am thinking some how I am not getting them to stay in place correctly enough and since the oil will always puddle more in the rear since the engine sits at an angle or maybe with them being stronger vs a cork gasket I need to tighten them more but I have read that anything more then 2 ftlbs is to much and you can strip things. I have a lot of years dealing with small block chevy builds and I have not used those rubber gaskets very often because of this but before I go changing anything does anyone have a better type of gasket recommendation that is better then both of those?

I seen the felpro ones that have a metal crush limiter on them but for over $50 bucks for a set of valve cover gaskets that is a bit pricey.

Sorry if this sounds stupid to ask but figured it would be worth a shot.
I've used Fel-Pro #1628. Last set has been on my Dart heads for 6 years, no leaks and I take them off and on multiple times to adjust the valves.
 

·
Registered
Joined
·
4,739 Posts
Discussion Starter · #12 ·
Ok guys please forgive me as I know this sounds dumb and is over doing things most likely but I got my new gaskets put on last night and I used cork gaskets from felpro and I used permatex form a gasket and coated my valve covers with it and then put a light coat on the gasket to stick it to the valve cover and it held but while trying to install it the dumb things kept falling off and not sticking very well even though I let it set up like it stated and permatex states its for such use.

So I had to reclean everything up as the gaskets were ok and I cleaned the heads with carb cleaner and the valve covers and got the gaskets to stick finally and used my studs as the guides to get my covers back on. I found out that they recommend with bolts with oil to torque to 2 ftlbs which I know they don't need to be tightened down that much to not leak. Before I put the new gaskets on the only spot my covers were leaking were at the rear corner on the outer part area and elsewhere it sealed just fine. I am using aluminum valve covers and they are nice ones and not cheapy ones and I have dart pro 1 aluminum heads. I am using studs by moroso which came with nylock nuts.

I when I first had this motor together I took my covers off as I had to recheck some things with my rockers and had to make my valve lash just a hair tighter. I used the felpro thick rubber black gaskets and were leakers since day one and I checked everything and they gaskets were in the right spot and when I took the covers off I could see where it was not sealing at just a few spots mostly in the rear corners and the rear side. Before I did this I torqued the valve covers down to 3 ftlbs with my small 1/4 inch torque wrench. It did not help but I went ahead and put all things back together and the cork gaskets are set up real nice and held in place real well unlike the rubber the gaskets that kept wanting to fall inside on the longer areas between the bolts even with the studs in place.

Ok to my point since 3 pounds did not work I first do put antiseize on my studs since they are going into aluminum and then I use a flat washer to protect my valve covers and then I guess I had put a set of lock washers on the washers and never thought about it but I put my nylock nuts back on and then I torqued them all down to 4 ftlbs this time and with the gasket tach on the gaskets to keep them stuck on the covers do you think I am safe with 4 ftlbs and not at risk of stripping my threads in the heads? I know this sounds dumb of me asking and I know the lock washer and also using the nylock nuts is overkill and will make more friction but do you think I am safe or should I eliminate the lock washers and buy a set of new nylock nuts as they have been on and off a few times or should I use the lock washers and regular nuts instetad? Or should I just leave it alone and am I worrying to much? I have read torque ranges from 2 ftlbs on average as the most common one mentioned and some saying up to 5 ftlbs which I thinks is overkill there with regular bolts wise but I am using studs.

Sorry for the questions stuff here but I always like to use a torque wrench as much as possible on bolts and fasteners especially on aluminum as I don't want to strip threads as I have not yet ever had to fix a stripped thread before and don't plan on wanting to do so now. All of my studs except three were so tights in the heads that the nylock nuts came all the way off no problem but the other studs as I started to loosen the nylock nuts as they got about half way up the studs the studs just came loose and I did not even have to take the nylock nuts off and was careful the washers and stuff would not fall off anywhere.

The studs have a hex on the top so the other studs I had to use a hex socket to get them out but it did not take to much to loosen them. My question is when I get the nylock and lock washer down on the cover and I am torqueing them are the nylock and lock washer combo actually making it a higher risk of stripping things as it might be actually be the stud turning at that point and no longer the nylock nut as its got to much force against it to turn anymore so the studd will be turning instead?

The reason I am all bent over shape here is I use studs on my mains on the bottom end all the time and also on my cylinder heads and they always state by arp to just install the studs finger tight and no more. That is what I do but the studs still tighten more after I get the other hardware on etc on my covers and do tighten my studs tighter even though I actually finger tight then then back them out just about a 1/4 of turn as I know when putting stuff back on it will end up tightening them up some.

Sorry about the big post folks. Thanks to all who have helped.
 

·
Registered
Joined
·
4,739 Posts
Discussion Starter · #13 ·
Also the covers were sanded and the glaze was taken off of them as they had some very minor spots were there was machined debris left over and some faint flash material but nothing to make anything to leak as it was just a fine hair. The covers did fit good and flat on the heads as best as I could tell and after putting everything on I took a mirror and looked all the way around and the gasket seems to be in all the right spots and is not squishing out and looks even all over on both sides.

Thanks to Johnsongrass for the info and help on that one.
 

·
Registered
Joined
·
657 Posts
Reading here there is lots of good advise given. Here is what I do. First make sure the entire valve cover surface is FLAT & STRAIGHT. Not the formed over edge, that don’t matter. You will need some precise bar stock on a flat plate to verify straight and flat on the mounting surface. To correct have hammer and flat tip punch to dress the surface. This is the most important. Use the hammer and back up with bar stock as you would use a dolly. To be .010“ or .015” off is NG. Next brake clean the valve covers. CLEAN, CLEAN, CLEAN, No paint, can’t stress it enough. Must be total absence of oil. Use what ever Indian glue, Permatex or your favorite to glue the cork gasket to the valve cover. Not RTV it’s useless with cork. I prefer the high density rubber blended cork type. They are cork and black in color. Set the valve cover with the gasket against flat plate with about 10 pounds weight on top of valve cover and let set over night for minimum 12 hours to fully set up. Then you are good to mount them up, no more glue should be required.

I suggest GM aluminum Corvette valve covers because of ridigity and quality as my favorites. But there are aftermarket ones that are good too. If your cylinder head surface is screwed up and not flat and straight you need to rectify it. Trying to mate a nice flat, straight surface to one that is NOT will not seal no matter what gasket and adhesive you use.
 

·
Registered
Joined
·
4,739 Posts
Discussion Starter · #15 ·
I am using aluminum valve covers and not cheap ones as I got them from summit racing and they were about $50 plus bucks at the time but that was years ago and never leaked the very first time I used them but they were on a different engine but I used cork gaskets on it. This is a new engine I had built for me two and half years ago and when I got my gaskets they were a kit and the valve cover gaskets were reusable ones from felpro and they never did seal in the rear corners but everywhere else. And I did not use RTV on valve cover gaskets and never would I know better then that. I used cork gaskets again and used gasket sealant from permatex called aviation form a gasket number 3 which is similar like indian head shellac and said it was good for valve covers. I will see how it works out the next time I get my truck out.

If that does not work then I will get out my straight edge and check all the surfaces as best as I can on my heads and also the valve covers. The exact same covers I am using now never leaked on my old engine that was in my truck with the cork gaskets with the tacky stuff and the gaskets glued to the valve covers like you stated but with the rubber gaskets they leaked all the time no matter what I did and that was with at first steel covers with spreader bars and then I bought the aluminum covers since they don't warp as easy as steel covers and are a lot nicer. I gave up on steel covers a long time ago.

If this does not work and leaks again then I am going to try the rubber and cork black gaskets like you stated and I will get a different tach stuff such as permatex high tack instead and sit them on the covers and let them sit with some weight on them like you said over night then stick them on my engine. That is some great info and thank you for that and to everyone else. I will get this. Thanks guys much appreciated.
 

·
1948 KB-1 International Pickup
Joined
·
191 Posts
I had a leak at the rear of one side of my Summit aluminum valve covers that were on my sbc 327 engine. It leaked down behind the engine where I had limited sight to try to locate it. I finally figured it out after a lot of searching, new gaskets etc. It turned out to be the valve cover had a slightly wider lip on one side and it was hanging up on my intake manifold. It only leaked at the rear on that side. I wanted both of the openings in the covers at the front and that is what created the problem and me not noticing the difference in the lip.
 

·
Registered
Joined
·
4,739 Posts
Discussion Starter · #17 ·
Thanks Captainbob will check that and compare the two if my work does not work. I have yet to need to fire it up to get it out and plan on this weekend since it will be nice out and see how it does.
 

·
Registered
Joined
·
504 Posts
I know this is a month old, but I had a hard time getting mine to seal up also. Chrome "Mr. Gasket" tall valve covers. I ended up using the thicker cork Felpro gasket, glued them down to the covers, hand tightened and then did a crisscross pattern with a 1/2 a turn on each pass until I was 1 1/2 turns passed hand tight. No leak since.
 

·
Registered
Joined
·
4,739 Posts
Discussion Starter · #19 ·
Well bcjones I did like you did and I got the regular cork gaskets and I used permatex aviation form a gasket and tried to keep it stuck to my valve cover but it so tight in my s10 it hard to get at the right angle with out hitting certain things and that is with as much as stuff as possible removed but the gaskets were coated and also my valve covers and I instead of torqueing to 2 ftlbs since I was using nylocks and also lock washers underneath them I knew there was more friction so I just torqued them to 4 ftlbs with a 1/4 inch pound torque wrench and I can say now after a few drives I am leak free and a happy guy. Thanks to all above for your info it has been much helpful.
 

·
Registered
Joined
·
78 Posts
Consider this in the rear of the cylinder heads there are drains to the pan. should these drains be clogged an oil level in the rocker arm area develops. When folks buy quarts sometime they pick at the aluminum foil seal and it winds up in the drain. the oil level that develops overwhelms the gasket and then is assisted by normal blow-by past the gasket . the engine is not level , it is tipped back by design all oil gathers in the rear of the head first till it finds the rest of the drains. Just food for thought !
 
1 - 20 of 21 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top