Engine lovers....best thread.

[pete376403]

Using exisiting designs and tooling meant Chrysler could build the tank motor quickly and cheaply. I'd like to know how quickly it went from concept to production but I'd guess it was pretty fast. It made adequate power (every web site sez 425HP@2850 RPM. Pool gas of the day was low octane, so the main disadvantage of sidies (low compression) wasn't an issue.
Who cares if they are a turd to work on? Worn engines probably just got pulled out and scrapped.

[pete376403]

[QUOTE=Ixion
Woz wrong wiv side valves. Like sidevalves. Nice and simple. Cuts out lotsa stuff what goes up and down and up and down and up and down an....., yeah, well, they're simpler, ain't they.[/QUOTE]
Cycle magazine once did a joke article on a "British World Beater" engine - Widely splayed double overhead cams with bucket followers bearing on pushrods going down to rockers in the crankcase that lifted side valves. The overhead cams for the marketing credo, the pushrods to make it easy for t'lads in assembly and the sidevalves to use up all the stock of prewar parts. The drawing looked fantastic

[Motu]

I like sidevalves I do - had me an M20 for years,really nice motor.In Tuning For Speed Phil Irving talks about a sidevalve 250 JAP that revs to 8,000rpm.The Yanks were the ones to get performance out of flatheads,they had to,and the old Ford V8 was maybe one of the most worked upon motors ever,till the small block Chev.The flattrackers were allowd to have 750 sidevalves competing against 500cc OHV motors...just to keep Harley in the game,and they took the porting,valves and cyl heads to extreme levels,really wierd stuff to look at.

[Ixion]

I like sidevalves I do - had me an M20 for years,really nice motor.In Tuning For Speed Phil Irving talks about a sidevalve 250 JAP that revs to 8,000rpm.The Yanks were the ones to get performance out of flatheads,they had to,and the old Ford V8 was maybe one of the most worked upon motors ever,till the small block Chev.The flattrackers were allowd to have 750 sidevalves competing against 500cc OHV motors...just to keep Harley in the game,and they took the porting,valves and cyl heads to extreme levels,really wierd stuff to look at.

See, the thing is sidevalves became unfashionable because at high revs you can't get the same power. And for competition, it's power at high revs that matters.

But in ordinary riding (not talking sprot bike riders here), one doesn't use high revs.Who is going to go riding around normally revving up to the red line ?I hardly ever use more than half revs - change up at 4000 , down at 2000.
OK, that;s highish for a side valve, but not beyond what they can do. And I only need to rev so high because modern motors have no bottom end torque.
And at low revs side valves are actually better.

It's like multi carbs. Everyone lusted after the Bonnie and the A65 Lightning. But, for ordinary riding (the sort we all do - except sprot bikers) the extra carb doesn't do anything - it's only good at high revs. So for communting and touring the Thunderbolt and Tiger 110 were better.

/me wants a side valve.

Now, if one were to SUPERCHARGE a side valve !

(Still haven't heard anyone explain to me why diesels need overhead cams )

[Motu]

The M20 was like a diesel,it'd rev out to around 4000rpm,but you knew you were doing it - on a hill the revs would drop pretty quickly to where ever max torque was and just stay there,it would ''hang on'' like a diesel.

I hate multi carbs,give me a single carb any day - I was going to fit a twin choke Delorto to the wife's Trident if she kept it,those triple carbs made me wild! I fitted a 1/4 SU to a few Triumphs and even my Norton 600 SS - easy to start,steady idle,100mpg and performance not far off twin Amals.

OHC diesels are an abomination,fit only for crap like Pajeros!

[pete376403]

OHC would make sense in a very large (ie locomotive / marine ) diesel, just on account of the size and weight of the pushrods, rockers, etc. In the small automotive diesels maybe they use OHC because there is parts interchange with similar size petrol engines? Dunno, the last diesels I worked on were Caterpillars about 30 years ago.

And with sidevalves there is a compression limit you can't get past plus you end up with a long thin rotten shaped combustion chamber which is mostly over the top pf the valves, not the piston. The Harley KR dirt tracker had hit this limit, so the rule change allowing OHV/OHC 750s came just in time for them.