Why do I bother? I should know better by now.
Marc Sayer wrote:
> Thomas - Sweden wrote:
>
> > Long stroke 5, 6, 8, 10, 12 cylinder engines
> > dont have the same vibration problems.
>
> No, but we weren't talking vibrations issues. The issue was rev limits.
> And a straight 4 is often better off in that respect because of internal
> component weights, and crank strength. The Nissan L6s almost all came
> with harmonic dampers, the L4s almost never did. When guys build L6 race
> motors they frequently use a damper, and the L28 turbos had to have one
> or the cranks would break. The L4 guys almost never run them. Nissan
> never made an inline 6 with the sort of long strokes they did in the
> inline 4s, because they couldn't keep the cranks together (even the L6
> diesel, the monster of L6 strokes, only has an 83mm (3.268") stroke).
> Look at the redlines for various 4, 6, and 8 cylinder engines and you'll
> find there is little correlation between a higher redline and having
> more cylinders. As an example, an L18 can be made to turn 8000 with ease
> (and stock parts), and I know of at least one engine builder who has
> gone *well* past the 10k reline barrier with the L18s. These engines
> have a 78mm stroke (3.071"). A Chevy 283 has only a 3.00" stroke and yet
> can't match the L18s for revability. Despite the fact that they have a
> shorter stroke and (as you contend is important) are V8s. The Nissan Z22
> had a 92mm (3.622") stroke and lots of 510 guys are using that motor to
> build a hybrid L22. These guys are easily getting 6000 out of those
> motors and they are screamers with a ton of power. And the Z24 engine
> you mentioned had a 96mm stroke (3.78"). While not the smoothest engine
> in the world, it also can be made to rev well and be a potent sports car
> engine. Of course the H25 is no overhead cam, so it will be limited by
> the valve train, which is why I picked the two examples (Chevy V8 and
> TR6) that I did. My point being that if they could make a decent sports
> car engine out of the TR6 long stroke, long crank motor, then an engine
> with the H25's specs ought to be a fine motor for a Roadster. Again
> assuming the forklift parts will, or can be made to, or can be replaced
> with parts that can, withstand the stresses. As for smoothness, a really
> good balance job, a well designed modern set of mounts, and you probably
> keep trying to start the thing while it's running :-) Okay maybe not,
> but it should certainly be acceptable, especially for an older sports car.
>
> --
> Marc Sayer
> Journalist, Photographer, Dog Trainer (APDT member #062956)
>
> Passions -
> Great Danes, auto racing and fast cars, my wife
>
> Dogs -
> Gracie, Tank, Delilah, PJ, & the rescue dogs
>
> Cars -
> 82 280ZX Turbo, 71 510 Trans Am vintage racer, 93 Ford E150 Tow/dog van
>
> My Homepage - http://gracieland.org
>
> Deaf Dane Rescue Homepge - http://gracieland.org/DaneRescue/
>
> Any Dane at the races is a Great Dane!
>
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