GBurch1@aol.com wrote:
> I honestly don't know whether these new pushrod engines rev lower than their
> ohc competition, but I'd imagine that one of the things that's made them
> winners again is new materials tech that allows a lower-mass pushrod.
Hmmm now Im more curious than ever. Composites wouldnt be any
good for that purpose and I dont know of any materials breakthrus
in the past several years in metals, unless they are using one of those
new tricky sintering technologies. But I wouldnt think that would be
any good for a part as big as a rocker arm or a pushrod. Curious.
> The benefits of getting rid of a long timing belt or chain, with all the lash
> problems and tension-maintenance issues they give rise to, may offset the
> reciprocating mass cost of the pushrods.
Ja, but I would think the answer to timing chain lash is a direct shaft
drive with bevel gears for the overhead cam shafts. That system is
still reasonably light, reliable and very durable under high revs.
I notice the motorcycle world going back to push rods, which shocks
me, but I assumed the reason was to imitate Harley Davidson. Have
you seen the Japanese Harley clones? Yamaha is building one that is
so Harley-like you need to be right next to it to tell the difference:
pushrod, fat bob tank, softtail-like back-end, air cooled 98 CI Vtwin,
even a belt final drive. They must stopped. I want one. {8^D spike
This archive was generated by hypermail 2b29 : Thu Jul 27 2000 - 14:13:40 MDT