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Posted by: Mueller Sep 25 2016, 10:24 PM

I thought I bought a 1.7 from a member and it looks like it is really a 1.8 that had 1.7 D-Jet installed on it.

So the rockers have the larger 10mm holes instead of the 8mm 1.7 rockers so my 911 swivel feet adjusters won't work as is.

Would there be any benefit to ensure the valve tip to adjuster foot is perfectly aligned or should it be offset a tad more one way or another?

Posted by: jcd914 Sep 26 2016, 12:16 AM

They are offset from the centerline of the valve so the the wiping action causes the valve to rotate slightly, this helps keep the contact surfaces of the valve to valve seat clean of carbon and reduces hot spots on the valve and valve seat.
There was a member here that had shimmed or machined the rockers to line up dead center but I don't remember who. How much difference it would make, I don't know and it could be years before any difference was noticed.


Jim

Posted by: porschetub Sep 26 2016, 02:28 AM

Correct and well explained, but shimming is a bandage machining the rocker the arms is the cure,do not change the rocker arm offset to the top of the valve stem.
I'am running the original CB performance ones in my speedster plastic copy with an 1.8 euro carb motor ,I machined the arms and it works fine with arms from an 1.7.
Appears these kits are now poorly made (samba info) and to go to 911 ones is very expensive.
You can still maybe buy the original adjustment screws but I don't know of a source.