Why does Subaru still use a timing belt. Eventhe newcheapo suzuki sx4 has a chain
- posted
16 years ago
Why does Subaru still use a timing belt. Eventhe newcheapo suzuki sx4 has a chain
Troll
Hmmm, It is lighter, costs less.
One moving part vs hundreds!
;^)
Carl
Which also has a service interval.
-- Todd H.
2001 Legacy Outback Wagon, 2.5L H-4 Chicago, Illinois USA
if you want transportation that never requires you to service it ride the bus (please).
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I am with jim on this one, I think belts are a big business and a lousy alternative, the owner ends up putting out the money the manufacturer saved, but:
Chains: Normally last the life of the engine, are noisy, sprockets and idlers are lubricated by the engine, you hardly ever hear of catastrophic chain failure.
Belts: Quieter, low cost, idlers have bearings which will require replacing at least every other belt change, belts are guaranteed to fail, and sometimes even ahead of time, (think Audi)
Gears: Expensive, wont allow for flexible engine designs.
Hurray for rotary engines with no valves.
snipped-for-privacy@gmail.com wrote:
So if you're going to make statements like that, back it up.
How many engines out there are fitted with timing belts, how many with chains, how many with gears ?
Why is Subaru better/worse than any others?
For the same reason that Honda and Toyota still do - cost, quietness compared to a chain, lightness, etc.
Dan D '99 Impreza 2.5 RS (son's) Central NJ USA
A more intriguing question is "why are so many engines interference designs where a belt failure is catastrophic?"
I believe the answer on that has to do with efficiency of the cylinder design, et al, but it's never been explained to me in sufficient detail for me to fully get on board with that.
-- Todd H.
2001 Legacy Outback Wagon, 2.5L H-4 Chicago, Illinois USA
A belt probably gives a more consistent valve timing over the life of the belt, and doesn't require an oil bath. Useable at higher RPMs too.
Perhaps a better question would be:
"Why do manufacturers insist on putting interference engines into consumer vehicles?"
A broken timing belt or chain is merely an inconvenience in an NI motor, but is often a disaster of the highest degree (read "new motor") on an interference engine.
And I fully understand that an interference type head/piston arrangement means higher flow, more power, possibly even slightly better efficiency, but it _also_ means that you'd better watch that timing belt, buddy! Or else!
Just as an aside, last summer I acquired for cheap a '99 Forester with under 100K that had what sounded like a bad rod bearing in it's 2.5L SOHC motor. Turned out to be a failed idler bearing. (Bonus!)
When I performed the 105K service on my wife's '02 Forry (also with the SOHC motor) a couple months ago, the belt looked OK, but several idlers were going, particularly the same cogged idler that had failed on mine.
What this means is that simply replacing the belt does not guarantee that you're good to go for another 100K; you absolutely _must_ check all of the idlers that the belt rides on (including the waterpump), and replace any that aren't perfect. Or, do as I do, and simply replace everything while it's apart. $igh.
And just one final note; I have heard it said that the EJ22 (as found on early Legacys/Imprezas) is an NI engine. Don't count on it; I've seen at least two with bent valves resulting from timing belt failures . . .
ByeBye! S.
Steve Jernigan KG0MB Laboratory Manager Microelectronics Research University of Colorado (719) 262-3101
I don't like interference engines, and wonder who they can't cut reliefs for the valves in the piston tops. I have heard of ones that had Tripple chains.
I had wondered why I have seen timing belts sold with the idlers. I should have realized they can go bad, but never owned a car with a belt. I had a friend who was upset because a mechanic told him his VW needed a new motor, since the motor had a knock. When the friend told me his Oil Light was on, and he had been driving it for THREE Mos like that. I Had to check it out. The knock was coming from the front of the motor, near the TB cover, and didn't sound like a valve, rod, or anything I had heard before. I pulled the cover and the idler was moving with metal shavings on a flange. I told him That was his knock.
Figured the oil light sending unit was bad or something. Told him to pick up the parts and I would fix it. Changed the idler and sending unit, and the oil light was still on. Took it out and poked in the hole, and the oil light went off, so sludge was blocking it. My friend was pissed that the mechanic was going to charge him 1600$ for a new motor. Having a knock and no oil pressure did sound bad, but Not being able to drive it for very far.
VF
I thought it was because they are quieter, but wish they were NI.
I read that the SOHC will have less damage if a belt breaks. Something about the DOHC free wheeling and bending all the valves.
VF
c'mon buddy - it was a joke!
The flat six 3.0s (like my wife's OBW) have a chain.
I once had a '51 Chevy that stripped a timing gear!
Carl
And if you want to see a mess, take one of those apart.
Oh, come on, two long-ass chains with tensioners under a cover with about 300 little bolts, what's not to like? With the water-pump chain driven, I think.
(03 H6 owner)
Dave
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