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Join Date: May 2002
Location: Battle Creek, MI
Posts: 519
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Too shim or shorten?
My motor came with 911 swivel foot adjusters, does everyone shim the rockers or shorten the pushrods. If you shim, whats the max recommended. I've always shimmed and shortened on my Type I's. This is on a stock cam, the PO had .060 shims (washers) under the rocker assemblies.
 I hate shoddy engine builders!Thanks, Randy
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2011 Chevy Silverado (The Hauler) 1984 911 Carrera summer daily driver |
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03-27-2003, 01:54 PM
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Take 0.060" off the face of the rocker arms where they are closest to the valve tips.
Shim the rocker stands. Shorten the pushrods. That's how you get the 911 swivel feet to work. It might be a good idea to set up the valve train geometry (yeah it's a pain) so that the adjuster is parallel to the valve stem at half valve lift. This should help the valves live a longer, happier life. --DD
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Pelican Parts 914 Tech Support A few pics of my car: http://www.pelicanparts.com/gallery/Dave_Darling |
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03-27-2003, 02:01 PM
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Join Date: Nov 2002
Location: gatlinburg tn
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i have always tried to get the geometry set correct at mid lift. i would see what is going to work the best on your motor.
it's really a judgement call. was the stock cam base circle cut down? heads shaved? other than the swivel feet, do you know why the geometry was off? i would put stock adjusters in and never look back. prices are not to bad on '74's , but '73's are almost 30 a pop.
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72 911t grey/black mine 74 914 2.0 black/ tan hers 02 g500 black/black womanproof 01 f250 psd dirty the mule 60 correct craft starflite cool 69 correct craft torino hauls butt 72 correct craft ski nautique fun 66 vw 1500s will finish someday |
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03-27-2003, 02:13 PM
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Location: Battle Creek, MI
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It is a brand new stock cam! The heads were mildly surfaced by RIMCO. I have access to a lot of stock motors, will any adjuster fit? My motor started life as a stock 73 2.0 but is currently a 2056.
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2011 Chevy Silverado (The Hauler) 1984 911 Carrera summer daily driver |
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03-27-2003, 02:36 PM
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You can make a swivel foot adjuster fit by relieving the rocker face alone, but you will run out of thread engagement. You can gain back some thread engagement by shimming the rocker stands, which will render the pushrod too short for proper geometry at 50% lift. Either get longer pushrods, or compromise on the geometry by setting it at 60 or 70% lift instead of 50%. The shim thickness and the final rocker geometry will depend on cam lift. (I used Webcam #73 with 0.030" shims and ended up with perfect geometry at 60% lift.)
I did this on my 2.0L engine 35K miles ago, and valve lash stability has been superb. Having gone through this delicate exercise, I still can't figure out this talk about needing shorter pushrods! One of the guys at RIMCO insisted on this as well, but a pencil and a piece of paper, to draw on, is all that is needed to see that it is actually the other way around. |
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03-27-2003, 03:48 PM
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Join Date: Feb 2001
Location: Aircooled Heaven
Posts: 1,054
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EVERY engine is different....
am base circles, Lobe lift, cylinder shimmage, cylinder head flycut and etc make this a per application job......
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Jake Raby Owner, Raby's Aircooled Technology www.aircooledtechnology.com www.massivetype4.com |
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03-27-2003, 06:23 PM
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74 Porsche 914 2.0 
