TheSamba.com :: View topic - Valve cover gasket gets sucked in towards the engine

Sun Sep 15, 2013 4:07 pm

This is a single port, I have adjusted valves twice in 90 miles.. checked compression, which was about 120 on all cylinders. I have what feels like no power, and this valve cover gasket keeps getting sucked up into the engine (3&4)

I have had some opinions that the case is not breathing correctly, I have tried to determine if the oil filler vent is clogged, I have a flow of air moving up out of the oil filler spout towards the carb where it is vented to the air filter

I am at a loss... open to your ideas

Thank you for reading

Sun Sep 15, 2013 4:26 pm

im having the same problem on my 1&2 side, the gasket eventually gets sucked in, and even after replacing it i still have a pretty decent oil leak from there. Think i need to vent my valve covers also, i seem to get a nice water vapor cloud puffing from the oil filler breather.

Hopefully thatll stop all my leaks ^.^

Good luck on yours.

Sun Sep 15, 2013 4:37 pm

Check to see if the carb is leaking fuel into the intake. Also check the oil for fuel contamination. Both probems may come from this.
I found the best way to keep the cover gaskets in place is to use a silicone sealer on the cover side. But you have to give the sealent time to harden before use. I even sand the gasket surface of the cover with coarse paper so sealer can grip it.. Make sure to degrease the cover before gluing the gasket on.

Sun Sep 15, 2013 4:45 pm

I had this problem autocrossing with my old 1776. I vented the right valve cover and the problem went away.

brad

Sun Sep 15, 2013 9:33 pm

People used to weld in tabs to the valve covers to keep it from happening.

Sun Sep 15, 2013 9:58 pm

try "gluing" the gasket over night to the head

Mon Sep 16, 2013 12:02 am

This is intriguing as an engine usually creates positive crankcase pressure which would push the gasket out. It would take negative/vacuum pressure to suck a gasket in. Trying to wrap my head around this but humor me for a minute.

Do you have a hose running from your oil fill to your carb air filter?

I am just wondering if the intake air coming in to feed combustion could create enough vacuum in the crank case to overcome the positive pressure, and in turn sucking your gasket in with negative pressure.

Just a thought! Im really swinging for the fence on that one though! haha

The other thing is if your using rubber gaskets with bail closure you might want to switch to cork as they seal better with bails. I have only found the rubber gaskets useful if you have bolt on valve covers. It seems the bails don't have enough pressure to compress the rubber enough to create a seal!

Mon Sep 16, 2013 5:29 am

tncsparky wrote: try "gluing" the gasket over night to the head

Don't do this, you will hate yourself for doing it next time you have to pull a valve cover. Always glue them to the covers, not the heads.

brad

Mon Sep 16, 2013 5:37 am

I can't imagine that kind of vacuum being created in your engine. Venting your valve covers is normally done to evacuate excessive crankcase pressure, not vacuum.
I think you just need to glue the gasket to the valve cover or weld a tab so it can't slide out of position as it is installed. It's a common problem, no need to complicate it.

Mon Sep 16, 2013 6:17 am

slalombuggy wrote: tncsparky wrote: try "gluing" the gasket over night to the head

Don't do this, you will hate yourself for doing it next time you have to pull a valve cover. Always glue them to the covers, not the heads.

brad

Just a little dab will do ya.....

Put a little dot in the four corners and a little in the middle top and bottom.

Use the black silicone gasket sealer and let it dry over night or at least an hour after installing it on the engine.
Make sure you clean the surface area really good.

Mon Sep 16, 2013 6:30 am

Derek Cobb wrote: I can't imagine that kind of vacuum being created in your engine. Venting your valve covers is normally done to evacuate excessive crankcase pressure, not vacuum.
I think you just need to glue the gasket to the valve cover or weld a tab so it can't slide out of position as it is installed. It's a common problem, no need to complicate it.

It's not engine vacuum that pulls them in. IT's excessive crankcase pressure pushing the valve covers out and the gaskets slowly work themselves out of place. As there is a lip around the outside of the covers they can't go out so they start to go into the cover making it appear they are being "sucked" into the valve cover.

brad

Mon Sep 16, 2013 8:12 am

slalombuggy wrote: Derek Cobb wrote: I can't imagine that kind of vacuum being created in your engine. Venting your valve covers is normally done to evacuate excessive crankcase pressure, not vacuum.
I think you just need to glue the gasket to the valve cover or weld a tab so it can't slide out of position as it is installed. It's a common problem, no need to complicate it.

It's not engine vacuum that pulls them in. IT's excessive crankcase pressure pushing the valve covers out and the gaskets slowly work themselves out of place. As there is a lip around the outside of the covers they can't go out so they start to go into the cover making it appear they are being "sucked" into the valve cover.

brad

Beautiful description SB! That's why I love TheSamba. Once you get enough minds working on the same problem, someone will find the answer. Bravo!

Mon Sep 16, 2013 9:50 am

Glue the valve cover side. Also, use cork whenever possible. The rubber ones get to slippery when they get a little oil on them.

Mon Sep 16, 2013 1:40 pm

Actually, they just walk their way in. If you had enough crankcase pressure to significantly enlarge the valve covers I suspect you would have other problems. "Gluing" the seals to the cover was the standard VW method.

Mon Sep 16, 2013 4:13 pm

thanks all..
I will not be gluing the gasket to the cover... this just started this spring, and there is a reason that the gasket is moving.. just have to find out why

so Brad slalombuggy.. have any thoughts on how to reduce the excessive crank case pressure? ah.. the venting someone was referring?

JJozwiak.. yes I have a hose running from oil fill to the air filter.. there is a steady flow of air coming via the oil fill.. nothing hard just a smooth flow

I am using cork gaskets

there is something going on, I posted earlier about lack of power.. hard to get up to 50 mph.. I adjusted valves, does not look llike I dropped one by the naked eye
Thanks all for your thoughts

Mon Sep 16, 2013 4:32 pm

Can you do a leak down test? You might have rings that are going and pressurising the case. IF that's the case no venting in the world will help. A compression test might show it up but a leak down test will show if it's the rings or not.

brad

Mon Sep 16, 2013 5:22 pm

Quokka42 wrote: Actually, they just walk their way in. If you had enough crankcase pressure to significantly enlarge the valve covers I suspect you would have other problems. "Gluing" the seals to the cover was the standard VW method.
Right. I have never tried NOT gluing them.

I have tried the valve cover on the head with no gasket to make sure they are flat. Always a good idea. You'll find some that aren't!

Mon Sep 16, 2013 5:27 pm

I made a plywood form to glue the gaskets to the valve covers. I do this the day before I adjust valves, so I have a set of valve covers are ready to go.

Gaskacinch Has always worked well for me.

The old gaskets usually come off in one piece, and the covers clean up easily with brake cleaner.

Mon Sep 16, 2013 5:51 pm

If you downshift there is a significant crankcase vacuum during deceleration that can suck gaskets, especially if the valve cover bails have lost some of their tension. Many guys that buy new bails are shocked at how stiff they are when new, the way they are supposed to be!

Mon Sep 16, 2013 7:55 pm

tncsparky wrote: try "gluing" the gasket over night to the head

NO... To valve cover....

Also SCAT make a nice stainless valve cover with 5 (I believe) tabs to keep gaskets in place... Love them...

Dale