On 10/05/2020 16:47, AJH wrote:
On 10/05/2020 15:49, Weatherlawyer wrote:
On Saturday, 9 May 2020 16:22:34 UTC+1, JohnÂ* wrote:
On Sat, 09 May 2020 04:48:43 -0700, Weatherlawyer wrote:

How does the first Ford compare to the latest iteration, that is how
does the 1930's environmentalist compare to the 2020 version?


The original ford V8 engine was a side valve engine.

That's good to know. So how was the side valve replaced by a more
efficient high compression engine?
And why?

Once the block casting was sorted it wasn't a big step to put push rods
where the valve stems were and and OHV head on, this would have given an
immediate increase in compression ratio as the empty space the valves
previously opened into could be eliminated, and the relationship between
thermal conversion to power is a straight line with compression ratio.

What I don't understand isÂ* what, other than higher engine speeds, the
advantage of overhead cams give in relation to thermal efficiency?

Reduction in valve mass and spring tension required, plus improved gas
flow (inlet and outlet) since your manifold design does not need to be
compromised to avoid the pushrods. (its also supposed to be easier with
double overhead cams to implement 4 valves per cylinder)


--
Cheers,

John.

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