timing "belt".. or is it a chain? when replace?

[brokendown]

I'm not clear enough on this point but i know all other cars in the modern era have timing belts they want you to replace every 60-100k. Noninterference engines just break down if it breaks, interference engines destroy themselves. I had in notes I took for my own use awhile ago that I believed the 99 saturn SOHC SL0 i had was noninterference and had a timing chain for the life of the engine, I don't remember where I got the info but maybe someone can tell me definitively. :P I read elsewhere that I may have been wrong on both parts.

I have 200k on the engine, is a timing belt or chain replacement something I need to get done ASAP or be worried about?

[billtag454]

Definitely a chain. Should last the life of the engine.

[anmasher]

Timing chain, and it makes significant noise long before total failure. Never supposed to need replacement but YMMV. It is an interference engine.

[SL19302]

Originally Posted by brokendown

I'm not clear enough on this point but i know all other cars in the modern era have timing belts they want you to replace every 60-100k. Noninterference engines just break down if it breaks, interference engines destroy themselves. I had in notes I took for my own use awhile ago that I believed the 99 saturn SOHC SL0 i had was noninterference and had a timing chain for the life of the engine, I don't remember where I got the info but maybe someone can tell me definitively. :P I read elsewhere that I may have been wrong on both parts.

I have 200k on the engine, is a timing belt or chain replacement something I need to get done ASAP or be worried about?

Its a Chain driven engine, just make sure your engine oil stays CLEAN and FULL and your chain should last a long time, as stated if the chain starts having issues it will make alot of noise and warn you its in need of replacement.

[700+SL2]

Any desciption of the noise. I don't know the true mileage of mine and I've been a bit concerned about how noisy the engine is. I was thinking about the chain.

[alordofchaos]

Originally Posted by SL19302

just make sure your engine oil stays CLEAN and FULL and your chain should last a long time,

Can't be emphasized enough. I try to check my oil at least once a week, and try to keep the oil a little above the FULL line - will add a few ounces at a time so that it never drops below the FULL line (owner's manual says 3/16" above or below the line is proper level)

There are many Saturns with over 500k miles on the original chain, but the owners stay on top of the oil level

Originally Posted by 700+SL2

Any desciption of the noise. I don't know the true mileage of mine and I've been a bit concerned about how noisy the engine is. I was thinking about the chain.

There are several videos and MP3 links on this forum - here's a video by PaulClawson3 - listen for the clattering - increases with rpm
http://www.youtube.com/watch?v=QOoUJpq6dFI

[satlite440]

as a dealer tec yes the chain is supposed to last the life of the engine..however all parts are mass produced and from the lowest bider..i have taken newer 2010 2.4L with 30k on them and found them streched beyond reuse...as a rule i would recomend 100-120k a chain replacement especialy if it is a man trans and the owner downshifts useing engine brakeing.. if you hear rattling from the cover area and your oil level is full.. there is 1 of 2 issues 1st is the chain tensoner failing to mecanicly lock and hold during engine shut down... 2nd the chain is streched.. there is a lot of load on the chain..imho after 120k you are gambling..

[OldNuc]

Originally Posted by satlite440

... especialy if it is a man trans and the owner downshifts useing engine brakeing...

This the key to chain life, if you do not use the engine for a brake then chain life will be sufficiently long that it will be the next owners problem. Along with that oil level must be maintained at the FULL mark and not allowed to run down to a quart low before additions.

[anmasher]

How is engine braking going to hurt the chain? I stay in the current gear down to 1500 then shift to neutral and continue braking from there. Is that harmful?

[OldNuc]

No, what stresses the timing system is shifting from 5th @80mph into 4th and letting the clutch out on a closed throttle, or 3rd if you are exceptionally creative.

[satlite440]

notice i DID NOT say it would hurt the chain.. i said it will help strech the chain...way more than an automatic.. a mun trans is coupled directly throuth the cluch to the flywheel.. as you start from idle the crankshaft bogs abit when letting the cluch out..the cranck pulls the cams along for the ride..as you get up to cruse the load on the chain is some what reduced as it is the moter creating power to drive the chain.. now when you down shift flareing the rpms into the 3500 or more range as a certian someone she who will not be named or higher to slow down puts a lot of strain on the chain.. like the whole weight of the inertia of the vehical as you let the cluch out yes the trans absorbes some of the load by gearclash(clearence between the gears) you are still putting the weight and momentum of the car on the chain&crank and cam gears.. now a t-bellt is basicly a rubber band and can absorb some of this shock better.. a chain is not so springy also when you are climbing the power band the crank is being power driven by the pistons.. when gear breaking you are esentaly over-running the crankshaft and useing the compression in the cyclinders to slow you down...adding ring wear to chin wear... now.. wear is going to happen all thing mechanical have a lifespan and cyclinder wear and timming chain wear will ocure.. im just saying that the wear happens faster in a 5spd vs and automatic..you would never think to subject you auto trans to the downshifting you do in a 5spd...for rear of hurting the trans.. but nobody stops to think what it is doing to the timming chain

[sallydriver]

Originally Posted by OldNuc

No, what stresses the timing system is shifting from 5th @80mph into 4th and letting the clutch out on a closed throttle, or 3rd if you are exceptionally creative.

What if one is rev-matching, as in they're using the gas pedal to match engine revs to wheel speed, THEN downshift?

[satlite440]

if it's the engine slowing you down , it's doing it..

[anmasher]

Stretch=hurt to us rednecks. Sounds quite reasonable why it is bad though, thanks!

Downshifting doesn't make much sense to me anyway given all the effort and wear of expensive parts. Brakes work just fine.

Originally Posted by sallydriver

What if one is rev-matching, as in they're using the gas pedal to match engine revs to wheel speed, THEN downshift?

That's quite a bit easier on the trans/clutch/etc, but I don't like revving the engine up real high like that while unloaded. Notice the idle rev limiter is 4k rpms. [Speculation]I think stresses on the rods go way up at high rpm when unloaded[/speculation]

[OldNuc]

Operated as designed meaning no down shifting engine braking, maintaining oil at full mark, and no jack rabbit starts the timing chain will not be failing first. It is not a high failure rate part.

If you are concerned then pull the cam cover and while maintaining the chain between the top of the sprockets tight check the intake cam timing when the crank is at TDC. If it is more than a drill bit off(retarded) then plan on a replacement project.

[SL19302]

I dont know of this is good or not but mine are both autos and I usually put it in neutral going down hills as I dont want the engines racing at 3 grand all the way down, I dont know of thats hurting anything or not but the way I look at it is Id rather change brakes then a timing chain or internal engine parts, I personally hate when the Autos shift into 3rd going down hills....

[OldNuc]

Why I am not a fan of autotragic transmissions.

[SL19302]

Originally Posted by OldNuc

Why I am not a fan of autotragic transmissions.

I know, They have alot of issues, but I have to say one thing about them when they work CORRECTLY they actually shift very smooth, Got to love the TC lockup its almost like a whole other gear

[Signmaster]

Unless a person is banging down through the gears at high revs, engine braking changes RPM slower than normal acceleration does, and way slower than when a person hits the gas when the clutch is in.

The load on the chain is the same pulling the cams regardless of how or why the engine changes speed. It happens more or less constantly, it's just a matter of how fast it happens.

Every launch on a manual, every shift on an auto, every rapid braking, etc, etc... they all accelerate or decelerate the engine and put different loads on the chain.


People that are scared of engine braking must drive like old ladies and get crappy gas mileage because they don't enter DCFO mode.

[adventureoflink]

Originally Posted by SL19302

I personally hate when the Autos shift into 3rd going down hills....

isn't that an intentional feature of the TAAT?