Valve cover gasket keeps blowing......HELP

[buickgeoff]

I just got done with my last project. It started with fixing exhaust leaks then into upgrading valve springs to finding I need a valve job to finding I had a cracked head. So after putting everything back together and driving around town for awhile I finally decided to get into the boost. the car gets about 14 lbs and then starts making a shuttering sound. kinda like the sound when you slower let off the throttle on a normal gn. As soon as this starts happening the knock gauge starts climbing. I return home to check under the hood and find i also have a blown valve cover gasket at the bottom center on the passenger side under the pressure relief port. I changed out the gasket and took the car for a ride. The car did the same thing except the gasket was fine until I throttled up in park in the garage. At 2,000 RPM the gasket blow again.

Any help, thoughts and/ or ideas would be helpful.

 

[novaderrik]

you need to find out why you have that much pressure in the crankcase- rings, pistons, head gaskets, etc. need to be checked..
what kind of crankcase ventilation setup do you have?

 

[buickgeoff]

Ventilation system?

It's a stock Block with breathers on both valve covers. I bought the racing PVC valve from RJC but haven't put it on yet cuz of this problem.

 

[mikestertwo]

What valve covers are you using?

 

[buickgeoff]

http://www.cottonsperformance.com/proddetail.asp?prod=HE-VCB6&cat=88

 

[mikestertwo]

I had the same problem with those valve covers....leaks. I had to mill the rail flat where the gasket rides. If you look at the casting along the rail it is pretty rough and not very flat. While I was at it I milled down the posts where the bolts go so I could use the stock length retainers.

 

[MeanBuicks]

Make sure that the breather grommets are not restricted. Back in the '90s had a set that barely let any gases through and it would push the oil dipstick out of the tube and put oil on the header. Opened them up a bit with an X-acto knife and all was good.

 

[buickgeoff]

I'll try both tonight and report back. Thanks for the info. I'm was hoping its not the head and have to tear it back apart.

 

[GerrywithaG]

Make sure that the breather grommets are not restricted. Back in the '90s had a set that barely let any gases through and it would push the oil dipstick out of the tube and put oil on the header. Opened them up a bit with an X-acto knife and all was good.

^^^

The grommets supplied are restrictive and do create a noticable amount of crank case pressure and should have the bottom section of them removed with a razor blade or knife.

 

[buickgeoff]

The bottom section? How much we talking, just enough for the rubber grommet to stay in the valve cover?

Took the cover off and its not warped. still need to get a machine shop to mil the cover down though.

 

[novaderrik]

forget about the valve cover and figure out what's actually wrong with the engine that's causing it to build up that much crankcase pressure.. the way you describe how it runs, i'd look at a head gasket.
start by checking the compression on all 6 cylinders.

 

[buickgeoff]

Compression check is good accross the board

 

[Phoneguy]

What head gaskets are you using? What heads? Studs or bolts?

Bryan

 

[buickgeoff]

Bolts, stock heads w/ 445 last three casting, heads gaskets I don't know off hand. There from o' Reilly's. I checked them as they went on and matched up with all water jackets etc. I know I got the part number off here or gn/t-type.

 

[Phoneguy]

If you are hearing a flutter under boost at 14psi it sounds like you are lifting the heads. I have done it with Cometic head gaskets and aluminum heads but havent heard of it with a stock style gasket. Do you have a cracked header?

Bryan

 

[buickgeoff]

No I just replaced my headers. The head gaskets are felpro I believe. Ceramic Coated the headers. One thing my dad said was maybe I don't have my rjc boost controller set right. Since that's new and suggested to put the y back on and see if it still happens.

 

[buickgeoff]

Well adjusted the waste gate and tried again. same results except the valve cover held. So one problem down one to go.

 

[buickgeoff]

I changed back to the factory y and went away. The only thing now is I'm getting knock starting at 15 lbs of boost and keeps going til red. I can hold 10 lbs with no knock. Any ideas??

 

[Phoneguy]

You need to list all of your mods in your signature so we can see what you have. If you are not using ALKY you better watch what you are doing with that boost on pump gas without some kind of tuning aid.

Bryan

 

[fleebag]

dont mean to hijack but i just did a cam&intake change and i used the rubber valve cover gaskets... they suck.use cork .... as does the allen head bolt on pass side lower rear.. omg what a pain... had to use a 3/16 bit and then use a 1/4 open end..