This may be useful for someone in the future during a build but I measured my 74000 mile chain and folded in half straight links parallel its 23 1/4 inches. Found someone with a new chain and they measured it at 23 1/8. That would mean there is only a 1/8 diff in the whole chain or 1/16 when the chain is routed around the gears. Would anyone care to add their measurement to the thread or tell me what you all did with your build. Replacing it anyway due to the enitre engine being rebuilt just wondered about the discrepancies or does it even matter?

 

id say a 1/8 inch over that length is nothin to worry about

 

Right and that is with the chain in parallel. Its only 1/16 when seperated and ran around the timing and crank.

 

i'd say that's very good info to know, especially for people worried about just their timing chain tensioner and if they'll have to replace their chain.....

 

this isn't my picture but here it looks as if the guy that measured it may have been off a bit since it was on a bed. I measured mine on the bench.

 

I have inspected the chains link by link. Thinkining if you sre around these measurements you should be good. The tensioner should be replaced if its an older style. I have an 07 lsj. I believe 07 and up have the newer p/n.

 

good info

 

the tensioner has 2 purposes
1 is to keep the chain at a specific tension
2 to act as a shock absorber

one more thing worth considering is this
oil pressure
1 if the pressure isent sufficant the chain will not be tight enough to control the mechanical timing
2 the tensioner will not be able to control the shock load and that can cause premature chain wear and excessive chain slap which is what leads to broken sliders and bolts

the farther out the tensioner gets the harder it is to control the chain so is an 1/8 of an inch enough to worry about that is up to you
if you decide to replace the chain all 3 gears should be replaced with the chain and the sliders should be replaced

 

Thanks. Another thing is that the service manual doent have service intervals for anything timing related. Chain is specifically mentioned as a non servicable item. Think its in my GM build book. Gotta go look.

 

Oops it was my Chilton manual page 2A-8. It states per inspection for wear, replace any component that is in questionable condition.
My service intervals read nothing for timing chain...

 

I gotta do my timing set i think. I just replaced the tensioner nothing else a while back but ive read that can actually screw things up. Not sure how to know if my timings off lol

 

my factory service manual sayes its a non serviceable parts...but replace if there r signs of wear

 

Not sure how that would mess anything up. I wouldnt worry about it. My build book says replace as needed. Not all at once. Listen for problems. We have a loud valve train but if its a non normal sound. Pull the timing cover. Check it

 

if its throwing a cam correlation code that is a sign of it being out of time

it should all be replaced at once
if the valve train is noisy you have a problem and the people who write the Haynes and Chilton books don't mess with the platform

 

Waste of money to replace all at once or at all if the components show no wear. I have a garage full of used and new parts. Everything from bearings to bolts to timing, to tranny, etc. Most of them don't need replaced, the general consensus is that if you are in there replace it but that is such a dumb rule of thumb.

Do a search for noisy valve train, its standard on these cars. Surprised you don't agree on that one but agree to disagree. My car was noisy stock, the guy that lent me his engine stand has a cobalt ss, its noisy, and both my neighbors have ecotecs in their saturn and cavalier; all noisy.

Edit, totally agree with the chilton and Haynes books. They are bland for info but they did help me track down electrical bugs in my hvac and they have all the toque specs for the ecotec motors. there is also 20 pages of pics on the engine. Its not the best but if you need a quick reference they did at least tear into an ecotec...

 

mrb, is the machine guy gonna let you pick up the block tomorrow? edited above

 

its not a waste of money to replace it all at once considering they are considered wear sets if you replace the chain and not the gears the wear pattern on the gears will cause an accelerated rate of wear on the chain and the same if you replace the gears and not the chains now the sliders as they wear they allow slack into the chain that the tensioner has to take up for and not to mention the tension slider is prone to failure so it may be a dumb rule of thumb for some but those in the know know better

 

^^^ this. When the build book was written the GM guy took information from our shop and many of the pictures of the Grand Am builds were ours. The great guru of Ecotecs at GM Russ Oblenz was consulted a lot on the build book information. Russ was a drag racer. It is not written in the build book, but Russ had a habit of replacing chains gears the whole shebang constantly on his drag racing builds. Like often.

I have been bitten on a cheap rebuild for a cheap customer, by not changing the timing chain on a detonated LNF.

wont happen to me again.

its up to you...

 

thats what i was going to ask, the dealerships replacing my head tomorrow, and i dont think a chain would come with the assembly, but since its apart i owuld like to do it, ill c how it looks once they rip it down, i think ill hang out the day there

 

this is very true, if a component is wearing another replace them both.

 

the dealership will do only what it takes to get by while putting the most they can in their pockets

anytime you replace something in the valve train you should rotate the engine over by hand first to endure the valves aren't going to hit

 

i think there goin all out now lol, 2 weeks ago they replaced all the lifters and the front cam shaft, and motor still ticks, now they got me a complete head assembly supposly, ill c it tommorw since i want some pics of it

 

it would be funny if it was the water pump chain circuit...iirc there is a tsb out for that on suv ecotecs.

 

ehh i hope it doesnt fit it, ill be like whats next now, the second time lol