----- Original Message -----
From: "Greg Solow" <gregmogdoc@surfnetusa.com>
To: "Jerry Van Vlack" <jerryvv@roadrunner.com>
Sent: Wednesday, July 21, 2010 1:11 AM
Subject: Re: [Fot] Flywheel Bolt Locking Plates
> Lock tabs are made of soft material. The steel of the lock tab can and
> sometimes will compress where it is squeezed between the bolt head and the
> fly wheel. The clamping tension of the bolt on the flywheel is then
> reduced. The effect is as if the bolt had loosened, without it having done
> so. This occurred on my own Morgan, with a TR-4 engine, when the car was
> about 16,000 miles from new. It manifested itself as a rattle when the
> engine was gently revved from idle. The noise sounded like it was coming
> from within the timing cover, but it was noise transferring down the
> crankshaft from the rear of the engine. The bolt were found to be "loose".
> They were not stretched and the lock tabs were still bent over and locking
> the bolt heads. Since then, (1966) I have used high strength loctite and
> no washer on an iron flywheel or metric "wave washer" style lock washers,
> which are hardened steel, on alloy flywheels. On high performance engines
> we use bolts that are harder and higher strength than the original "auto"
> bolts. The best standard bolts were labled "BEES" on the head. We have
> only had one "tractor motor" flywheel ever come loose since, and it was
> full race engine. The driver had been revinig the engine to near 8,000
> rpm coming down the switchbacks on the backside of the Pittsburg Vintage
> GP where he had not wanted to upshift and then immediately down shift into
> 1'st gear for the next hairpin corner.. The failure did not occur that
> weekend, but the next race weekend where we found the front generator end
> frame lower ear broken off, then shortly thereafter all 4 ARP flywheel
> bolts sheared and the flywheel lost its attachment to the flywheel
> completely. The dowel pin also was sheared off.. There is obviously a
> resonant frequency somewhere north of 7600 rpm that was inducing these
> failures. We normally insist that drivers keep the revs on a full race
> engine with steel rods, crank, alloy flywheel, light pistons, etc.below
> 7200 rpm which has been safe and reliable in a engine properly assembled
> with all of the correct necessary parts.
>
> Regards,
>
> Greg Solow
>
> The Engine Room
>
> Santa Cruz, Ca. 95060
>
> 831 429-1800
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