[alfa] Re: T-chains and belts

[George Graves <gmgraves@xxxxxxxxxxx>]

You might be right about the gmmt pushing this. It's just the type of 
meddling I've come to expect from the DOT and it's henchmen the EPA and 
Customs.
(We're just asking each citizen to do his/her part and shoot ONE 
Customs official <G>).


As far as gear-driven Cams are concerned, the straight-six Maserati 
engine of the '60's went that route, and apparently, it's a maintenance 
nightmare (if any I-6 Maserati owners or ex-Maserati  owners know 
different, please let me know.). While the gear driven cams will never 
jump time, for the same reason, It's a nightmare to CHANGE the timing 
when you want to as well. Also, the gears were prone to high bearing 
wear and jamming. That six sure sounded nice though. I've been tempted 
more than once to buy a Frua-bodied Sebring (my favorite production 
Maser)

The only thing really wrong with the belt on the GTV-6, is that the 
left (viewed from the front) bank camshaft pulley only comes in contact 
with the belt from approximately 9:00 to approximately 12:00, while the 
right side wraps from approximately 12:00 to about 5:30. This makes it 
awful easy for the left-side cam to jump time -especially if the engine 
gets to turn backwards (NEVER let it happen!). I don't find that the 
short longevity of the belt is any problem as long as the water pumps 
have to be changed at 30K anyway. Belts are cheap, can be swapped 
without affecting timing, and since the beast has to come off to get at 
the water pump anyway, replacing it at the same time is a no-brainer.





On Sep 22, 2004, at 7:22 AM, alfa-digest wrote:


> Date: Wed, 22 Sep 2004 04:08:13 -0700 (PDT)
> From: Sam Wacht <sam_vfr@domain.elided>
> Subject: [alfa] T-chains and belts
>
> I believe there is a gov't push to go back to timing
> chains (in the US), I believe that is one of the
> reasons Lotus used the Toyota engine in the Elise
> instead of the Rover engine (in the US), it either has
> a chain or is being developed to have a chain.  There
> has been discussion about whether this is due to noise
> or emissions (harder for a chain to slip a tooth and
> screw up emissions), but I think in the next few years
> it will be hard to find a belt driven cam engine.
>
> The problem with the V6 belt is the amount of contact
> it has with the cam by the distributor/oil pump drive,
> that and oil leaking on it from the original tensioner
> or water/antifreeze from the 30k water pump.  A
> "friend" with a honda had 122k on the original T-belt
> when he popped the counter-balance shaft seal and
> dumped all the oil, the head was the first thing to
> suffer from loss of oil and froze the cam in the head
> and instead of belt breaking, the gear bolted to the
> cam broke, this made me realize a properly designed
> cam belt is as strong as I could want, plus regular
> replacement ensures proper cam timing.  Chains will
> stretch over time and mess up timing, I have heard of
> chain links being removed on Old Benz's to keep them
> tight.
>
> How about Gear driven cams, no stretch, no break, just
> lots of whining!
>
> Sam
>
> '86 GTV6
> '88 Verde "Rusty"
> '88 Verde "Donor"
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