Subject: FIAT cam belt design

[RonHorowitz <RonHorowitz@domain.elided>]

>I believe the first mass production use of rubber belt cam drives was on
>the FIAT 124

Sorry, Michael!

The first _production_ over head cam motor to use a cogged rubber belt was
the Glas SOHC as used in the GT. Interestingly, the first DOHC motor to use
a cogged belt was a Panard special built right here in the USA using Norton
"double knocker" DOHC heads and barrels machined and bolted to a Panard
block. (And the manufacturer of the drive belts said it would never work!)

>when they grafted that twin cam head onto the rather

Woops! Sorry, again! The 124 pushrod block and the 124 DOHC block are
significantly different and non-interchangeable. You can't bolt a DOHC 124
head onto a pushrod 124 block and make an engine. Actually, the 124 pushrod
 probably shares as many components with the old 1500 pushrod as it does
with the 124 DOHC, (though they're the smaller components like timing
chains, gears, cam followers, etc.) I don't really know why, but eveyone
confuses the Fiat push-rod / DOHC engine situation with the MGA!

>pedestrian pushrod four to create a sports car engine.

Hey! Wait a second. If I was a pedestrian, why would I need an engine? I
have to say that as pushrod motors of the period went, the 124 pushrod
wasn't bad. If I wanted to pick at nits, I suppose I could suggest that
it's at least as good a basic motor as the pushrods used in the various
Brit cars, and with some work to the top end, it can be made to go nicely.

> The
>main problem with cam belts is they are a consumable and people forget to
>have them serviced periodically.

I'd put it slightly differently, but yes, absolutely true.

>There are lots of advantages to rubber
>belt cam drives.

Low noise and vibration, high mechanical efficiency, and low cost not being
the least.

>Unfortunately, the designers of the 164 V6 (actually the
>Alfa 6 V6) also forgot about serviceability of this component and made the


Could be worse. Could be a Ferrari 308....
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