Hello Barney,
I had read a description of this kind but the loudest noise at idle is from
the fan, whose rubber mounting bushes are absent. Revving at anything up to
3,000rpm, the engine is knock-free and all nasty noises disappear at any rpm
above 800 or so. On that evidence, I think (for which read hope), that the
crank isn't broken. Otherwise, the engine is very sweet.
I noted from the archive that two listers had experienced the same problem.
One was Bob Allen, who wrote...
"On investigation, the crank pulley would rotate several degrees without
having the crankshaft come with it. The bolt holding the crank pulley
was still in place and tight. The pulley is indexed with a woodruff key
and a slot on the crank snout. Apparantly the woodruff key was getting
tired."
There appears to be no follow up, although I have mailed Bob off list.
The other lister, whose name I forget, simply tightened the pulley nut after
adding Loctite to the keyway.
Thanks,
David Hill
> At 03:58 PM 4/8/02 +0100, David Hill wrote:
> >Playing with my '72 GT donor yesterday, I spotted that the crank pulley
> >can be moved by hand, in relation to the crankshaft. The free rotation is
> >about 10 degrees and when the pulley moved, the centre bolt moves with
it.
> >It is definitely not the outer rim that's moving - the damper appears to
be OK.
> >....
>
> This could (maybe) be even worse that anything suggested yet. If the
> center bolt is tight, and the pulley hub is indeed snug on the crankshaft,
> and the nose of the crankshaft is turning slightly with the pulley, then
it
> may have a broken crankshaft. Done that once on my MGA 3-main-bearing
> engine. The crank broke at an angle across the web just behind the front
> main bearing. The engine continued to run, made gentle knocking noises at
> idle, but made LOTS of very loud knocking noise with just slight
> throttle. The rest of the story is interresting but long, culminating in
> changing the crankshaft in a motel parking lot.
>
> Barney Gaylord
> 1958 MGA with an attitude
> http://www.ntsource.com/~barneymg
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