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Comments on shimming under rocker arms

Hi, I'm back!

I replaced the pistons and head on my beetlemex engine. Replaced with: Mahle pistons ( stock) and stock (VW heads which turned out to be made in Brazil - felt cheap and the inlets were very rough - almost gouged) With either my stock or EMPi steel pushrods, I have about 2 mm of valve lash with adjusting screws being backed all the way out. One valve cap is against the rocker arm.

I noticed with these heads that the valve spring stem is above the height of the top of the spring - in my old heads, they are not.

What is the consequence of putting a shim under the rocker arms to give me an adequate valve gap? - I know I'll loose some "pushrod throw"

I don't understand why I'm having this problem, I'm guessing the heads are seating deeper into the piston sleeves than what they should be. I'm guessing my compression would then be too high(?)

No I did not cc my heads, - I'll kill myself later over that fact. and I'm assuming that the Mahle piston sleeves are not shorter than stock.

Thanks again for your comments

Matt S

Reply to
Matt S
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Matt, if you are comfortable assuming things are "okay" and hoping for the best then go ahead and shim the rocker bases...i would be more concerned about the situation than you seem to be, but im OCD that way....can i assume that you haven't checked for proper rocker geometry?

Reply to
Joey Tribiani

Thajks Joey, I am pretty concerned about this problem, I guess I'm going to admit to myself that I will pull the engine again and cc the heads to see what is going on. As for rocker arm geometry, to me that means whether ther rocker arms should be shifted slightly to the left or right from their current position to properly hit the valves tops off cener- and if this is correct, I don't know how that would change my lack of valve lash problem. Am I missing something ?

Thanks, I really apprectiate it

Matt S

Reply to
Matt S

rocker geometry isn't how the rocker contacts the valve stem, but at what angle...the ideal rocker geometry would be that the rocker and valve stem will be perpendicular at exactly half lift.....this is what would be affected by just adding shims...but being a stock engine(i think?) it is a very good possibility that the rocker geometry was never set properly in the first place... check these out..:

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Reply to
Joey Tribiani

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