Date sent: Sat, 7 Oct 2000 23:34:09 -0700
To: triumphs@autox.team.net
From: Bill & Skip Pugh <anabil@caltel.com>
Subject: Dynamic Balance
Send reply to: Bill & Skip Pugh <anabil@caltel.com>
AFTER, I had removed the fan and fan hub extension from my TR-3
(1957), I read in Piggott's book that doing so can cause crankshaft
failure...ARRRGGGGHHH. Now I wonder, is this true? In normal
operation? Racing operation?. Is there such an animal as a bolt-on
dynamic balancer (I know Detroit iron has them).
Please tell me my crankshaft is Not going to disintegrate....
Thanks for your time
--
Bill Pugh
aka Wily
1957 TR-3 aka Casper
TS16765L
Hi Bill,
I think that crankshaft failure was a very nasty habit of some TR3
engines and this already in the sixties, at that time electric fans
were not yet a standard replacement.
In the late sixties a graffic was produced by Triumph Customer
Service after having recorded 156 crankshaft failures. At that time
around 70 000 TRs had been built. Almost all failures 80% occured
between 2200 and 2600 RPM the peak number lying at 2400.
The exact reason for the failures was not given, but the engines
had all their standard fan.The only conclusion could be that the
engine was probably developing a kind of vibration resonance and
as a result of a badly balanced flywheel and clutch unit the
crankshaft broke.
A carefully balanced drive unit (crankshaft-flywheel-clutch) should
not need any balancer on the front side.
Jean from Belgium
60 TR3A
70 TR6 PI
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