RPM limits

["REUBEN ERICKSON" <HEYRUBE@xxxxxxxxxxxxxxxx>]

I have not idea what makes for an rpm limit, but I bet it is a lot of stuff
besides just valve springs. 

But for years I have had an unanswered question about whatever happened to
the 2500 fpm piston travel limit that Road and Track (Rodent Rack, an
advertising publication) used to put in their road test specs in the 50's
and early 60's. At the time I understood it to be an index of maximum
cruise limit, not a max limit. My 57 MG could barely go the 50's speed
limit before exceeding  the fpm limit (about 60 mph). A VW at that time
could go 112 mph, if it could, before hitting the cruise limit. No wonder
VW's lasted so long. Had to do with short stroke and gearing. I think my 74
2000 is about 4200 rpm, which is pretty fast in mph. 

I bet good old Fred D. knows something about this.

By way, why don't more of you AD subscriber's join the AROC? Their monthly
publication, religiously read, would answer maybe 50% of the questions I
see in the AD. Maybe even mine.

Rube Erickson

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