Timing belt or chain?

[redpoint5]

Originally Posted by some_other_dave

Belts are quieter, and I think may actually take less power from the engine than a well-lubricated chain?

Chains tend to be more efficient at transferring power than a belt; one of the main reasons they are more popular on motorcycles.

Take a belt and try to bend it around a radius, and then take a chain and do the same. It takes less effort to bend the chain than the belt.

[cRiPpLe_rOoStEr]

Originally Posted by redpoint5

Chains tend to be more efficient at transferring power than a belt; one of the main reasons they are more popular on motorcycles.

I can't even remember right now a motorcycle with belt-driven cams. Anyway, I'd rather get one with a 2-stroke engine, no valve at all

[Miller88]

Originally Posted by cbaber

My timing belt with only about 60k miles snapped on the freeway and left me stranded in 10 degree weather waiting on a tow truck for 45 mins. (I hate timing belts)

They aren't that bad, but when things go wrong, things go wrong. Luckily I didn't suffer engine damage, but most people need their heads rebuilt after something like that. I think Honda recommends timing belts every 90k? They aren't hard to change out yourself, but it's still a pain if you drive 30-40k miles a year and you have to worry about the belt. Actually for me the tensioner was the culprit that lead to the belt breaking, so that's a common problem between chains and belts.

On the Chevrolaewoozuki products of the mid-late 00s, the timing belts were recommended to change at 60K. They either snapped or lost idler pulleys , religiously, at 40K miles.

Interference engine, too

[user removed]

Originally Posted by cRiPpLe_rOoStEr

I can't even remember right now a motorcycle with belt-driven cams. Anyway, I'd rather get one with a 2-stroke engine, no valve at all

Ducati.

regards
Mech

[theicecreamman]

Originally Posted by cRiPpLe_rOoStEr

I can't even remember right now a motorcycle with belt-driven cams. Anyway, I'd rather get one with a 2-stroke engine, no valve at all

Honda Goldwing, flat 4 and flat 6s. By the way, belts are 2-3 percent more efficient than a chain BUT a pain in the butt especially in engines you have horrid access to the front section of the engine. Ferrari even had to concede that belt cam drives were a bad idea ( witness the 355; a cambelt change was an engine out job that costs $5000.00 minimum. I believe that the V8 powered cars from the 430 on were converted to chain drive because even people who can afford these things don't like high maintenance bills. )

[user removed]

Seen an L24 diesel chain go 864k miles. Thats 14 60k timing belts.

regards
Mech

[cRiPpLe_rOoStEr]

Originally Posted by Old Mechanic

Ducati.

I knew that but I couldn't remember. Anyway, its desmondromic cams are nice because they totally avoid valve floating.

[serialk11r]

Originally Posted by niky

You can implement VVT with gear-driven cams. The mechanism for variable timing is in the gear on the camshaft, anyway, and doesn't care whether it's belt, chain or gear driven.

But those systems are complex and noisy. Almost completely maintenance free, though.

I think Porsche, at least on the M96/97 engines, used variable chain tensioners to adjust timing instead of the usual on-camshaft actuator. However the chains wear grooves into the tensioners and I imagine that's not good for the engine's performance.

[KrautBurner]

timing belts save the manufacturer a little when building the car (figure $25 per engine, over 500,000 engines/year)
and,
they give the dealers a steady flow of maintenance income ($500-2,000 every 50-100K miles)


many car manufacturers have gone away from timing belts recently
(its hard to offer a warrenty / maintenance on a failure item)

Originally Posted by theicecreamman

I'll take a chain over a belt anyday in a light duty engine, hate changing timing belts, but Gates has really stepped up their offerings with higher strength belts.

Originally Posted by Miller88

I have posted this before (maybe not here) but I strongly dislike belts. They are a completely unacceptable cost cutting measure. The manufacturer saves $20 making the vehicle, only to cost the owners multiple thousands of dollars in maintenance over the course of the car's lifetime. If the maintenance is not performed, it's a few thousand for a replacement engine (assuming interference).

I will not own a car with a belt.

[cRiPpLe_rOoStEr]

Originally Posted by serialk11r

I think Porsche, at least on the M96/97 engines, used variable chain tensioners to adjust timing instead of the usual on-camshaft actuator.

Like tensioners weren't enought PITA...