Gasket(s) installation

[Anonymous]

I installed a Felpro rubber gasket on my valve cover with some RTV silicone (I know, it says not recommended for rubber gaskets) and she leaked from every single bolt hole. I have heard about soaking cork gaskets in water overnight and installing them without any sealant; does this work for valve covers? I also need to change my carb-to-spacer gasket and possibly my spacer-to-instake gasket, how do you recommend I do this?

 

[JackFish]

Wow, is your PCV valve working?
Maybe the flanges on the cover are bent outta shape? from overtighening?

 

[simon]

skip the RTV on a NBR gasket. Instead, check your valve cover flanges for straightness, especially around the bolt holes. Use hold-down clamps to prevent and to spread the load evenly. Straighten as necessary with hammer and dolly. Do not overtorque the bolts - all they need is a tight fit, so stay with 3-5 lb/ft. as stated in the manual. As long as you don´t have the crankcase pressurized (yuck!) neither the cover bolts nor the gasket have to bear any real loads.

unbolt the carburetor and spacer and stuff a clean rag into the manifold to prevent dirt from entering the plenum. Then proceed to scrape off the remains of the old gaskets... depending on earlier attempts at sealing from previous owners, those may have baked on and take some time to remove completely. make sure your carb flange and spacer flanges are even and clean.
New paper gaskets on carburetors neither reqire any additional sealer, nor is it recommended. However, you may spray them with a penetrating oil like WD40 or apply a thin film of grease.

 

[CobraSix]

I installed a rubber gasket ONCE and only once on my valve cover. I removed it 3 weeks later to put a cork one back on. My rubber gasket did nothing but leak and didn't fit very well. I have heard many people complaining about the rubber gasket. I only used the rubber gasket after I remove the head so that I can readjust the valves after 2-3 weeks without wasting a gasket. I still have the rubber one around for the next time I do it.

Make sure to give both surfaces a good cleaning.

I just RTV-blue on the valve cover cork gasket and it hasn't leaked in 2 years at all.

Slade

 

[Asa]

i've got a rubber gasket on mine, haven't had any problems with it

 

[Anonymous]

Simon, it looks like only the carb-to-spacer gasket is leaking, do you recommend I still change the spacer-to-intake gasket anyway? I know one of them is causing a vacuum leak and now a gas leak.

CobraSix, someone told me that RTV silicone allows the gasket to slip during installation when tightening screws/bolts. Use a product specifically meant for gasket installation, like a gasket dressing that allows easy removal of item later if needed.. Do you know of any such product?

jackfish, I'm not absolutely positive, but I'm pretty sure the PCV value is good. Would I get smoke coming from the oil filler cap/breather if it were bad?

 

[MustangSix]

The gasket mounting surface needs to be flat. Overtorquing makes the cover warp around the bolt hole making it impossible to get a good seal with any gasket. Use a ball pean hammer to reflatten the flange.

Then get some small block chevy valve cover washers. They're sold by Mr Gasket, Trans Dapt, and others. They'll help spread the load. Actually, the best ones ar for a Corvair. they're longer and work very nicley. You can fit five or six of them, IIRC.

Then tighten gently. The more you tighten, the more it will leak. I use a hand held nutdriver. You don't need any more than that.

 

[wallaka]

I've never used sealant on valve cover gaskets, water pump gaskets or anything. It just makes them leak. Just tighten in a criscross pattern like you would a wheel. Except not that tightly.

 

[Anonymous]

The trick I learned while wrenching was to spray the gasket to attach it to the valve cover (I used black weatherstrip adhesive sometimes too with success). Never used RTV on a vc gasket and never leaked. MustangSixs' torque idea is perfect (never too tight), and I never thought about the chevy washer idea but that is a good idea too.

 

[Anonymous]

Thank you to some of you who took the extra time to answer some of my questions via private message and email. I pulled the PCV value and as I was looking I noticed the elbow was cracked. I replaced it and it no longer has symptoms of a vacuum leak.

However, the valve cover is still leaking from one bolt hole, where it is obvious the previous owner over-torqued the bolt. It had pushed the bolt hole downward, creating a thin crack. I attempted to straighten the bolt hole out, but it didn’t stop the leak. I am afraid the oil is leaking into the sparkplug hole. Btw here is what my valve cover looks like.

The other thing that I have noticed is that neither the rubber or the cork gasket seems to fit the valve cover or head correctly. I have been told that all "small" inlines (144, 170, 200, 250) have the same gaskets. So I get Felpro gaskets for a '65 200, despite the fact that I have a '78 250 and '80 Head.

 

[CobraSix]

CobraSix, someone told me that RTV silicone allows the gasket to slip during installation when tightening screws/bolts. Use a product specifically meant for gasket installation, like a gasket dressing that allows easy removal of item later if needed.. Do you know of any such product?

Generally use an RTV Gasket maker, forget the type and all my tubes have been thrown out as they dried up on me. Biggest thing, use as little as possible to get a nice coating over the entire gasket. if you use too much, it can slip.

Also, wait until it's slightly tacky and it shouldn't go anywhere.

Del