I talked to Leigh last night.
He agrees that trouble such as the below examples would be a problem
with the serpentine belt system. However, he did express that he would
hope that owners would have their alternator, A/C compressor and power
steering components in good repair and the fact that vehicle
manufactures have gone to the single belt almost universally in order to
have an engine capable of running up to 100,000 miles maintenance free.
Some of the benefits he sees with the single belt system are the pickup
of up to 5 additional horsepower, one vs. three belts to stock and
because the water pump runs backwards, water is pumped from the top vs.
the bottom hose of the radiator into the engine. He says GM's testing
showed that the water is cooler at the top of the radiator. In the past
it was apparently accepted that since heat rises, the top of the
radiator would be hotter.
Anyhow, the benefit of cooler water is a slight lowering and more
consistent temperature throughout of the interior of the engine. GM
supposedly found out that the compression ratio could then be increased
by up to one point while still using regular gasoline without suffering
pre-ignition (pinging) problems.
Leigh's system utilizes the original type pulleys (A/c compressor,
alternator, crankshaft and power steering) with their belt flanges
machined off. Serpentine pulleys, having the same diameter as the
original individual belt ones do, are machined the opposite (i. e. the
center portion) way. The resulting two components are then TIG welded
together.
His kit, priced at $695.00, provides the belt of course, three tension
pulleys with associated mounting brackets (one mounts to the front of
the A/C compressor housing and another to the left front engine cylinder
head and I don't recall where the third one goes), new bearings for the
A/C compressor pulley, new fan clutch and new fan blade (remember that
the serpentine system turns the water pump backwards) that has the tips
turned up (resulting in increased air flow and supposedly practically
noise free).
Now you know the rest of the story!
Paul Bartz
> From: Bartz, Paul
> Sent: Wednesday, April 22, 1998 4:57 PM
> Subject: RE: GMC: GMC Motorhome Digest V1 #149
>
> Jim:
>
> I experienced what you list in Reason #1 (the A/C compressor clutch
> bearing went out and locked up the compressor). Had to cut the belt
> also.
>
> I'll contact Leigh Harrison and get his response and let all know.
>
> Paul Bartz
>
> From: James Bolick [SMTP:jbolick]
> Sent: Wednesday, April 22, 1998 4:05 PM
> Subject: Re: GMC: GMC Motorhome Digest V1 #149
>
> I must have missed what the good reasons are for changing to a
> serpentine belt. I personally would not:
>
> Reason #1: when my dash A/C compressor burnt up and was smoking
> and making all kinds of growling and crunching noises, I just cut the
> belt and continued on my trip. You can't do that with a serpentine
> belt.
>
> Reason #2: when my power steering hose ruptured and the power
> steering unit was again making all kinds of grinding noises, I simply
> cut the belt off and continued on my trip, can't do that with a
> serpentine belt. I drive a 1973 GMC and none of my three belts
> operate more than one mechanical item.
