[alfa] Timing belts, chains, fwd, and the Feds

[C M Smith <cmsmith@xxxxxxxxxxxxxxx>]

I understand the wizards working for the US Federal Government think cars 
require too much maintenance. I believe the push to timing chains 
originates with a potential requirement that engines should require no 
emissions related servicing for the first 100,000 miles. Rubber belts 
cannot be made to last that long. Timing chains routinely last twice or 
three times that long, despite what others might suggest. I don't know 
anybody that had to replace a timing chain. I know one person who got a 
defective tensioner in his SAAB engine which required a new tensioner, but 
the original chain remained in place (some SAAB 99 engines used British 
Leyland tensioners from the TR7 which used a related engine, SAAB had no 
trouble after they went to their own spec tensioner). My current SAAB 9000 
T with a twin cam 16 valve head and single row chain has 280,000 km on the 
original timing chain components. It is expected to outlast the body on the 
car, just beginning to show surface rust around the wheel arches. Why 
routine servicing of an engine is deemed to be unacceptable is beyond my 
understanding since oil changes will still have to be made. Except, it 
seems that the Feds think the average US car owner knows nothing about 
maintenance requirements. Ironic considering that very few US car owners 
keep their new cars for much more than 2 or 3 years.....

Timing belts have been used for a long time with great success. FIAT 
managed to convert an iron head ohv engine into a pretty fine aluminum head 
twin cam by using a belt drive, for not a lot of money and those belts were 
not known for breaking. The sweet little 128 engine was a delight, rubber 
timing belt.

When Audi tried to shoe horn a V8 into the latest A4 bodyshell to create 
the new S4 they switched to a chain for packaging reasons. I believe the 
other versions of this engine still use a belt. Audi also shifted the 
timing drives to the rear of the engine so it would fit.

Finally, fwd is inherently safer and more efficient for most drivers. For 
any passenger car under 200 hp fwd is demonstrably superior. It is 
definitely not cheaper to build. It does allow a lighter vehicle to be 
built with the same performance. And most cars are dropped onto their 
drivetrains these days, the drivetrain is fitted from underneath, often 
fully mounted on the subframe with suspension and steering. For most cars 
you probably need to separate the drivetrain to pull parts out from above.

Cheers


Michael Smith
White 1991 164L
Original owner
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