Dizzy

as per question? surely they wouldn't break as much... is it purely down to cost?

RON

Noise is a big factor, plus the fact that chains tend to stretch!

AJbaseBloke

So the EZ30 is released...

Chain drive it is then

Pete Croney

AJ

I think it has a chain for the same reason as the H6, engine bay space. The chain takes up quite a bit less room on the front of the block.

It's cheaper for the manufacturer to fit a belt and get the customer to pay for its replacement every 3 years. As John said, they are also quieter.

jhd

belts are also more efficient than chains - less frictional losses blah blah blah.
im for chains - at least they rattle before leaving go

jhd

BugEyed

John, Pete, and jhd have it correct.

A belt is superior in terms of noise, and not needing lubrication. However, they occupy more space and have greater inertia and require more space due to the width of them. In particular they also suffer from overheating unless supplied with plenty of airflow and can suffer from jumping if stones get into them.

Chains suffer from the need to be lubricated and create noise, even when correctly tensioned. This is particularly the case where one chain is used to drive twin overhead cams per bank as the torsional vibrations between the cams can result in the chain being constantly switched been drive and overun between the cams. This not a problem in the single cam per bank engines such as the H6.

Duncan

Pete - how could you be so cynical to suggest that Subaru would pass the cost onto the customer - it would be so unlike them.

MorayMackenzie

BMW use duplex camchains in a number of their 4 cylinder engines... its odd looking through a service schedule book and not finding a cambelt interval! Apparently, the BMW chains are designed to last the life of the engine. Having seen one in an open S14 I dont doub't this. A BMW main dealer told me that its the tensioner that you need to watch... if you start hearing more noise from the camchain as the tensioner starts to fail, that's the time to change the tensioner. Apparently, the E34 models tensioner is a bit more rugged, and can be retro fitted to the E30 cars if and when a tensioner change is necessary.

Mind you, the chain in the H6 looks a little less substantial than the BMW duplex one.

Leigh

Who says chains are more reliable? My wife's Astra coupe 2.2 snapped its cam chain at 21k miles/14 months!!
Thank **** for warranties... The explanation from the dealer was that it was "Just one of those things!"

Vauxhall = Quality

milkytadpole

Most cars will revert back to camchains in the near future as ultra-long service intervals become standard. J

MorayMackenzie

I guess that means we will be losing the turbochargers too, to extend oil service intervals as well ?

MorayMackenzie

personally, I think they should make camchains and pulleys out of tungsten carbide... and rear cambelts should be welded on or cast into the block... but thats just me. ho hum.

JohnD

iTrader: (5)

Cheaper, quieter, do not need lubricating. As for chain stretch - It would be taken up by the tensioner but could result in a small change in valve timing. Belts stretch a little but not much.
JohnD

[Edited by JohnD - 2/12/2003 8:45:06 PM]