Aluminum valve covers.

[tmk]

Has anyone used the bolt on aluminum valve covers from CB Performance?

[mike mueller]

I just got a set of the aluminum covers from Brad at all914.com. The only real negitive thing I've heard about them is that oil tends to want to leak where the studs pass thru the cover. I plan on milling in some holes in the top of the covers to help relieve the pressure inside the valve train area.

------------------
Mike Mueller
Antioch, CA
1970 1.8
http://www.pelicanparts.com/MotorCity/mmueller/personal.html

[bowlsby]

I've heard of other potential problems with those Mike...

...they sometimes break off the rocker shaft mounting bolts, or misalign the valve setting because the nuts are torqued too tight...be careful

...becasue of their higher acoustical mass, they are quieter...a good thing

...the seals still don't always seal well...check the archives...this was discussed a year ago or so...convinced me not to get 'em

[Jim Osborn]

I second the stud breaking off problem, been there done that! Also they don't seal at all.

[scriabin]

I'm satisfied with mine, they reputedly aid cooling somewhat also, due to the sturdy finned aluminum stock and increased surface area. But here are several warnings anyway.
Most important first: I would advise prep-ing the cover bolts and the receiving rocker-stud-collet-nuts with a tap and die. I had a cover bolt stick in the collet during removal once, and the collet nut (or the stud it was on, can't remember) was backed-out enough to leave slack between the rocker assembly and head--SEEING this was impossible, even if looking for it--and as a result one pushrod was dropped and bent. I discovered the problem only when testing the tightness of the collet with a wrench. I ended up replacing my cover bolts with shorter ones, much less turns of the wrench now, easy removal.
These covers add 'width' to the engine overall dimension, meaning that with their installation, the cramped space beside the suspenision consoles down there just gets tighter, and engine reinstallations require just that little bit more of clearance and careful jockeying on the jack.
I've had no problem with the bolts leaking, although I usually replace the rubber grommet on the bolts after a few service removals. I use an ordinary dome-faced grommet, sliced in half, one half on each bolt.
The standard factory cork gasket seals mine perfectly, with a little copper-swab sealant on the cover side, and removal is clean. The special neoprene gasket designed for these covers and sold by cb NEVER sealed for me, no matter what painstaking efforts I employed. They were made in HELL by the DEVIL. They made cover installation infinitely more difficult (they're 'taller' than the cork gasket, meaning even less space to work) and would always buckle somewhere, usually at the top where you are trying to pry the lip of the cover in under the engine tin--they inevitably leaked and made me curse something awful.
You can vent the covers with a fitting, but you will be drilling or cutting a hole in the tin also for the hose to pass through, or utilizing the j-tube holes, if 'no heat' is 'no issue' with you.
That's all I know.

--john lambert

[tmk]

Thanks to all. Looks like I will stay with the stock covers. The bolt on ones look like they may have some draw backs to them. This came about after having the # 3/4 cover start leaking at a PCA T/T @ Thunderhill raceway park. It was 104F in the shade and I think it warped from the heat. I was thinking that a aluminum valve cover would expand and contract with the head better then the stock steel ones. CB has aluminum valve covers that use the stock clip. Any thoughts on them?


TMK
73 914S 2.1L

[Dave at Pelican Parts]

TMK, a more-common problem than warping the cover is simply sucking the gasket in. When you run hard at high RPMs for extended periods of time, you can develop a good vaccuum in the rocker box. This can sometimes be more than the vents can handle, and if that happens then the gasket can get sucked in.

The solution to that is gluing the valve gasket to the valve cover. I have heard of people using everything from RTV (in small amounts, please!) to carpet glue, to engine case sealer. But it seems to work.

--DD

[tmk]

The gasket was glued and still in place. I moved the cover from the #3/4 side to #1/2 side and put a new gasket on it. It still leaked from the same place. I now have new stock steal covers and no more leak. I have never had this happen in four time trials and a lot of auto X. I think it warped from the heat as the track temp was over 200F and the engine was running hot. Oil temp was almost 300F with oil cooler and fan and head temp was around 375F.

TMK
73 914S 2.1L