>Date: Wed, 23 Sep 1998 15:10:31 -0700
>From: William G Abbott <william.g.abbott#064#boeing.com@mail.mdc.com>
>Subject: harmonic ballancer
>
>Does anyone have a used harmonic ballancer for a 77B,
>My spare engine (77)has a large chip missing harmonic ballancer.
>I may have to use this short block a while when I rebuild the 74 B
operational
>engine
>Presently I have slight bearing noises coming out if the lower end engine
>during cold starts of my 74B motor.
>Does anyone know if the 74B and the 77B harmonic ballancers are
>interchangeable?
>I bet the timing marks are different?
>
William,
The ballancer/pulleys are interchangable, read (will fit the
crankshaft)
but the diameters are different. TDC (top dead center) will still be in the
same place and I believe the timing marks are in the same place on the
timing covers. But you can check that for yourself. You could interchange
them temporarily. You will need a different fan belt to accomodate the
change in pulley diameter. The water pump and alternator will run at
increased speed though, but that should not hurt anything. The 77B ran
hotter because of the catalytic converter. I think the larger pulley was
used to speed up the water pump and push more water through the engine to
try to improve cooling.
The 77B also had the electric fans in place of the mechanical fan on the
water pump, also another attempt at better cooling in stop and go traffic.
Good luck John.
-------------------------------------
E-mail jdb70@juts.ccc.amdahl.com
John Bartholomew Amdahl San Jose CA.
408-746-6361 07:00-16:00 PST.
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