-> > I have often considered using a V-8 automotive engine with much
-> > altered cam and ignition timing running at 540 RPM (PTO speed)
-> > to run a generator.  By careful selection of components, it
-> > would probably be made to be quite efficient at that speed.
-> > Maybe even run it off piped-in natural gas for co-generation.
->
-> Craig,
-> I doubt that this lashup would be "quite efficient" compared to an
-> engine more closely sized to the load. There's lots of friction loss
-> in such engines, and it would be quite significant at low RPM and
-> load.
Was thinking that the rings could be changed to a different type.  Maybe
even put in lightweight valves with very light springs for "atmospheric"
intake much like a hit-and-miss.  With zero-gap rings such as some
racing engines use, it may not be bad.  I suspect it would be crucial
in ring selection.  Those zero-gap rings actually use an overlapping
end to approximate that...
-> Think about engines like a Geo Metro or other mini-car. Run it at a
-> reasonable speed, and belt the alternator to also run at a
-> reasonable speed. I'd define "reasonable" to be the RPM that it runs
-> when the donor auto is doing maybe 45 MPH. Slower would get it way
-> off the torque curve, and faster just wouldn't be necessary for this
-> application.
It's more a matter of vibration.  I had a diesel Rabbit engine a few
years ago from a totalled car and was considering it for stationary
use.  Didn't seem the right one for it.  I want to get some fairly
large engine running very slowly.  Build the thing specifically for
the application.
-> FWIW: I jacked up my VW Jetta Diesel and had a friend run it at 45
-> MPG in high gear while I checked the engine speed with an electronic
-> tach. It was about 2200-2400 RPM, or about 50 RPM/MPH. Running the
-> car at 67 MPH would turn the engine at 3600 RPM; it sounds like it's
-> really cranking at that speed, but could easily operate like that
-> for extended periods.
Soundproofing would be a major trouble.  Making flexible hoses for the
fluids and exhaust, a spring-mounted subframe...  Ton of work there.
At slower speeds those problems drop dramatically.
-> Running that Geo engine on natural gas and using the cooling water
-> for heat is eminently practical. Putting it into practice will "keep
-> you out of the bars and arms of loose women" for quite a while. (to
-> coin a phrase)
-> Good luck!!
Heh!  Have never had any problem keeping on the straight-and-narrow.
My wife would certainly help in that .
Will do a "paper build" using a Chevy 350 to see if this could be done.
If a part isn't made for the 350, you don't need it. .
Thanks!
-c-
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