Don,
I run a 3 liter Chevy II 4 banger with a Fontana head. I have had good
luck (2 Speedweeks and 8 El Mirage meets) by following the instructions for
my 10,000 RPM 2 disc clutch. That is to use stock genuine Chevrolet flex
plate bolts with no washers and red locktite. I have no locating dowel in
the crank flange and am amazed that it works. Understand that this is with a
super light aluminum flywheel not a heavy steel dyno wheel. I also have a
flat crank, if you are using a V-8 crank your mileage may vary.
I agree that a four can have strange harmonics. I have noticed some
fretting between the camshaft OD and the inside of it's keyed drive flange
and the timing pointer seems to be touching the crank hub in two places on
the OD. This is with about 1/16" static clearance on the pointer. I could
not find a harmonic damper that would clear the Fontana gear drive and cover
so I have not been running one.
Another problem I had was starter drive sprags, I destroyed a heavy
duty Summit starter the first time I tried to start it. Tilton told me to
use their pro stock starter and a 16 volt battery. A four with 14/1
compression and 31 degrees in the mag is hard on the starter. Against Don
Zig's advice I also put a mechanical start retard in the mag base (he
doesn't like them), it worked but I suspect it made the timing scatter a
little. We have switched to an MSD ignition with start retard (and a rev
limiter), next month at El Mirage I will find out if it helps. I hope this
helps you.
Jim Dincau
> Anyone silly enough to cut an engine in half should probably expect to
> encounter some "unusual" problems along the way. During a recent dyno
> pull, our half Windsor (3 liter inline four) sheared off all six Locktite
> secured 7/16" ARP flywheel bolts, and almost welded the flywheel to the
> crank. Seems that we have a harmonic vibration problem that has created
> more force than our system can tolerate. So.......... we probably need to
> strengthen the parts and reduce the "bad vibes".
>
> The most obvious action would be to strengthen the parts by increasing
> the bolt diameter, adding some dowels, and making sure that everything
> fits. Reducing the the force could be a little more difficult. The
> balancer (cheapo fluid type) is clearly not up to the task and should to
> be upgraded to something more in tune with this engine's harmonic
> characteristics. I really don't have any experience in this area and
> would greatly appreciate any thoughts that list members would care to
> share.
>
> Thanks, Don
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