[Fot] Fw: Flywheel Bolt Locking Plates

[Greg Solow]

----- Original Message ----- 
From: "Greg Solow" <gregmogdoc at surfnetusa.com>
To: "Jerry Van Vlack" <jerryvv at 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