From: George Graves <[email protected]>
Date: February 9, 2010 4:11:44 PM PST
To: Joe Elliott <[email protected]>
Subject: Re: [alfa] GTV-6 engine problem
Most 12-valve Alfa V-6's can survive one or two jumped teeth without
valve damage, but definitely NOT three. Usually it is the off-side
cam that jumps teeth because the belt only engages the cam pulley
from 9:00 to 12:00. The driver's-side Pulley, OTOH, is engaged fro
12:00 to roughly 6:00 and therefore is much less likely to skip.
Practically all Alfa V-6 belt slippage can be put down to two causes
1) Belt failure due to not being changed within the 30,000 miles/3
year interval, or 2) failure of the de-tensioner. The latter is, in
my estimation, the biggest cause of this problem. The Canadian-made
mechanical tensioners are, in my humble opinion, junk. They do fail
and often and many mechanics install them improperly in the first
place. A better solution is to find an old original hydraulic
tensioner (try the Larrys Dickman at APE) with good bearings, and
block off the oil feed (turns out it's not needed anyway) and fit
that. It should end all worries about the belt skipping (as long as
you replace the belt at recommended intervals, that is).
George Graves
'86 GTV-6 3.0 'S'
On Feb 9, 2010, at 3:34 PM, Joe Elliott wrote:
I came home from work on a flatbed, and the timing belt has
definitely jumped a couple teeth. But it couldn't be a simple
matter of the crank pulley having slipped, wherein I could just
lock down the cams and put enough force on it to skip the other
direction. The right cam was retarded one tooth, but the left cam
is retarded at least two, so I guess I'm going to have to totally
re-fit the timing belt before I can determine whether or not
there's been internal engine damage. Which means driving the
Porsche 928 to work tomorrow with a couple inches more snow
predicted; that should be interesting.
Thanks again,
Joe Elliott
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