TR6 Flywheel security above 6000 RPM
From: "kas kastner"
I guess we'll go over this again for the tenth time. The problem
is that the harmonic of the TR-6 engine causes the flywheel to
move back and forth (wobble) and this prys the bolts out of the
crank or STRETCHES the bolts. When this happens the bolts are
found bent over or loose or even out of the threaded crank. Larger
bolts, yes, but the main thing is that the bolts must be of a
type that do not STRETCH.
The only way to solve this on an immediate basis is to lower
the revs below 6000 as the secondary vibration occurs at 5800
and is so strong it moves the flywheel edge back and forth over
a 1/2". Lots of hardware companies sell the type bolt you
need for this crank. Buy the best you can find. REMEMBER hard
not stretching bolts. NOT strong, but hard. Grade eight is not
near good enough for the TR-6.
The GT-6 is a totally different crankshaft and does not have
anywhere near the problem. What fixes the GT-6 will no doubt FAIL
with the TR-6. The only similarity of the engines in this department
is that they are both have 6 cylinders.
In the end you want the lightest flywheel and the lightest clutch
you can come onto. My TR-6 had a total weight of BOTH these components
of 13 pounds. I also had six bolts in the end of the crank and
of an improved diameter and quality. You can fix it, but is takes
some little doing.
----- Original Message -----
Subject: Re: Flywheel woesTo add to the good advice by Russ.
ideally you want a bolt with a large underhead bearing area
& correct grip length. Also make sure that the register in
back of wheel & rear of crank is pefectly clean & flat,
& make sure there are no raised spots around bolt hole chamfer.
Also make sure that the locating dowel is a tight fit in the wheel,
the fasteners clamp the wheel, the dowel takes the shear load.
If the wheel is loose on the dowel the bolts will be subject to
shear load & they WILL fail! Some people add a second
dowel for increased shear strength.
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