Re: [AMC-list] First year for AMC bridged rockers?

[Ken Ames <ameskg@xxxxxxxxx>]

...and the 75-80 rockers pivots are the high-wear aluminum rather than steel.

Ken


Quoting Frank Swygert <farna@xxxxxxxxxxx>:

> Date: Sun, 27 Jan 2013 14:30:30 -0600
> From: "Eddie Stakes"<eddiestakes@xxxxxxxxxxxxxxxxxxxx>
> 
> A customer asked me what year did AMC start using bridged rockers. I could
> not give him a window. Always though 74 but know that these first appeared
> in 1973, just not sure how early. A 401V8 I have out of a 73 AMX has a valve
> cover tag of 612Z05 which is December 5th, 1973 401. The heads are casting
> 3220602 E and have bridged rockers, the flexplate is dated 7 73 (July 1973)
> and engine never been apart. Waterpump 3215719 1 never replaced so as I look
> at this, I am trying to establish a timeline, or window as to when AMC first
> started using bridged rockers on AMC heads. This is earlier than I thought.
> Ideas?
> ================================================
> 
> 1973 model year it is! All the 1973 model year engines should have bridged
> rockers, which means they should have started engine production around August
> 1972.
> 
> In 1974 the six at least went back to shaft rockers for most of the model
> year. There was a patent dispute filed by Buick over the bridged rockers. The
> 74 TSM shows shaft rockers for the six, but still shows bridged for the V-8.
> Might be a slight difference in the bridge design, might just be an editing
> error in the TSM. I don't know for sure if early 74 V-8s went back to single
> stud rockers or not, maybe one of the V-8 guys will know. I can tell you that
> the shaft rockers were dropped late in the 74 model year and they went back
> to bridged before the model year was up, but I don't know for sure when. For
> 1975 everything was back to bridged rockers as the patent dispute was
> resolved. I have no idea how -- can't say if AMC just won, paid Buick, or
> there was some other agreement (maybe a patent license swap -- that's
> happened before -- Buick may have got permission to use something AMC had
> patented in exchange).
> 
> -- 
> Frank Swygert
> Editor - American Motors Cars Magazine
> www.amc-mag.com
> 
> 
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