OT: timing belts

[Chad Fernandez]

Gordon JC Pearce wrote:

> Well, that's just down to stupidity.

That's called an interference engine.

>  A new timing belt costs a tenner 
> at the most and even on an absolutely evil b*st*rd of an engine to work 
> on (step forward, Citroen XM 2.5TD, not nearly as nice an engine as the 
> CX 25DTR) it takes at worst a couple of hours to fit.  I can do Volvo 2- 
> and 3-series belts in about half-an-hour...

Do these engines sit transversely in a front wheel drive (fwd) car? 
Most cars here are fwd, and have the engines positioned transversely.  A 
lot of times you will have to disconnect at least one of the engine 
mounts and lift the engine up.  Also, since it's bound to be an overhead 
cam engine, the accessorys will have to come off.

> As to why we use timing belts, well...  The problem with timing chain 
> designs is that the chains wear and go slack.

I don't know too much about chains used with overhead cams, but on push 
rod engines this doesn't happen until many miles are on the vehicle.

The only problem I've had with a chain, actually was the top timing 
gear, not the chain itself.  It was on my 69 Buick LeSabre.  The top 
gear was aluminum with nylon or plastic teeth.  They stripped off, while 
on the highway.  This happened in 1995, so the car was about 26 years 
old, with 100K miles on it.  I thought the gear design was dumb, but I 
assume it was done for sound or vibration purposes.  I know GM may not 
rank very high with the Europeans on the list, but it's one of my 
favorite cars that I've owned.

I did have belt problems once on my 1982 Dodge with a 2.2L engine.  I 
got it wet in the snow, since I plowed into a snowbank, with the plastic 
cover off.  I had a heck of a time getting it back into position, after 
it skipped.  I didn't really know how to get the belt around the 
tensioner, cam pulley, and crank pulley with out throwing the timing 
off.  I was probably sick and tired of working on the car, in the cold, 
and ran out of patience.

Chad Fernandez
Michigan, USA