Non-SE-R: GM OHV engines (better late than never)

[Bruce.Hearn@cd-tech.com]

Tim Rogers wrote:
>To put it in other words, the OHV engine can't go
>to high RPM's, so you may as well optimize it for
>low RPM's.

Au contraire, OHV **CAN** run fast...with solid lifters.  Neckars run 8000
rpm regularly and can go as high as 9k, but rod life falls drastically. All
the really hot muscle cars had solid lifter engines, though they didn't
spin much faster than those with hydraulic lifters, mainly because Detroit
still used heavy rods and pistons.

Tim again:
>The OHC motor can turn the revs, so you sacrifice
>a little bit of bottom end...

Ayup. Just like our little Sentras.

Steve Obert wrote:
>Any differences between motors has to to with airflow,
>not necessarialy where the cam is located.

Not neccessarily. OHC lends itself to more radical ramp profiles since
there's less mass to accelerate and that mass has higher harmonic
frequency. Still, really radical cams, regardless of location, need solid
lash adjusters.

Bruce in Houston