Marc Sayer wrote:
> Well come on now Dennis, tell them why. :-)
>
> Dennis' aluminum flywheel was on old style flywheel that had a solid aluminum
> hub. The crank bolt holes on most new aluminum flywheels are sleeved with
> thick-walled steel sleeves to prevent exactly what was starting to happen to
> Dennis'. The washers on the crank bolts start to bed themselves into the
> aluminum of the hub of the flywheel. This results in a reduction in clamping
> force between the flywheel and the crank and allows the flywheel to start
>moving
> a little bit on the crank. The first signs are pockets around the washers and
> chatter marks in the register where the crank boss sits. This is a synergistic
> situation where the more it moves the more it can move, and usually goes from
> barely noticeable to total failure pretty quickly. Dennis' was just showing
>the
> first faint signs of this and I told him to swap it out for an iron flywheel
> before it failed and took out other components along with perhaps his
>feet.... I
> have seen this happen several times and it is always ugly. You can address
>this
> by using a solid disk of steel with bolt holes in a circle that match the
>crank
> bolt holes (in 510s and Zs you can get just this sort of piece from and
> automatic car but with a Roadster you'd probably have to make it) and using
>this
> instead of individual washers on each crank bolt. Or you can do what Tilton
>and
> others have done and put thick-walled steel sleeves in the bolt holes. But for
> the street a lightened iron (if done right) or steel flywheel is probably
>still
> better. The clutch bolt holes are also weaker in an aluminum flywheel and
>there
> is an increased possibility of failure there too. On a race car, that is torn
> down every few races or at least once a race season (i.e. no more than say
>every
> 10 to 15 hours) this is not a problem as the flywheel can be regularly
>inspected
> and bolts retorqued if needed. But in a street car where you expect to go
> hundred of hours or more between inspections, it is just not the best
>material.
> Some have gotten away with it, others haven't. I'd just rather be a bit more
> sure about the flywheel's longevity on my street ride.
>
> Dennis Currington wrote:
>
> >
> > I heard that some of "you" guys drive your cars pretty hard. Now me, I
> > have been running an alum. flywheel for 7-8 yrs and never noticed a problem
> > with street driving. Recently, during a tranny change, Mr, Sayer convinced
> > me to go back to a stock one. The jury's still out on that one.....
> >
> > Dennis
> --
> Marc Sayer
> 82 280ZXT
> 71 510 2.5 Trans Am vintage racer
Oh. I knew there was some reason :-) And after only 60,000 easy miles too?
BTW, Victor, maybe we need to talk about that "deal" I offered you :-)?
Dennis
"showing the first faint signs of ,,,,,,,,,"
--
Dennis Currington
1967.5 2000
1970 510
1971 240Z
San Diego
http://www.Datsuns.net
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