More timing chain bs - look inside

[3400beretta]

So, I've got a strange noise coming from my timing cover area, sounds like a metallic buzzing sound which can only be heard as the engine speed approaches about 2700rpm.

Since I have LS6 yellow springs, and am pushing nearly double the power output of a stock 3500, I can only assume that my crappy 2000+ timing chain has stretched and is causing this racket.

I have my old 3400 sitting in the garage, which just happens to be a 99, so I tore the front cover off to have a look at the timing set. Well, there is a little more slop in the chain then I'd hoped for. Definately more than 1/4", probably around 3/8". Now this is a GM timing set, and this engine has around 50,000 kms on it since total rebuild, with a completely stock valvetrain.

So after doing some digging around, I have discovered something. The gen 2 3.1 has the same part number for the crank gear, which can mean only one thing - the chain must be interchangeable between the gen 2 and the early gen 3 timing sets. However, the chain has a different part number. So what I'm wondering is if the older chain is better, or worse? Perhaps they switched manufacturers, and or cheaped out on the newer chains? Given the fact that the new chains/gears are definately weaker than the pre 99 stuff, one can only hope..

Anyone with a 2.8/3.1 kicking around care to investigate?

[Rootie524]

when i did my cam shaft on my 2002 3100 malibu with 103k miles the POS timing chaing was stretched pretty bad. it was really skinny and weak looking. i had bought a timing chain for a "3100 engine" from a member on another forum not even knowing there were two different versions. When i got it it looked much larger/stronger than the 2002 one and it turned out to be a pre 99 one. as u already stated they were larger and stronger looking. so i decided..well i got it now and its new and better than what just came off..so i put it on and it works great. IMHO, pre 99 chains/sprockets are much more dependable and better built than the 2000+ chains. go pre 99..it goes right on no mods needed. and if you really feel like going all out. get the double roller chain from WOT tech..modification is needed for it to work though.

[Azrael]

To be on the safe side, buy one from GM. Cloyes sells the older ones for less than the newer ones which has me suspicious.

[86FieroSEv6]

To be on the safe side, buy one from GM. Cloyes sells the older ones for less than the newer ones which has me suspicious.

I don't know how suspicious you should be, but I am certain that the volume of sales over the age of the design is probably a major price factor.

[3400beretta]

Well well well, looky what I found.
Specs for 3.1 timing chain: http://info.rockauto.com/SealedPower...tml?222372.jpg
Specs for early 3x00 chain: http://info.rockauto.com/SealedPower...tml?222385.jpg

0.44" wide vs 0.625" wide for the 3.1 chain!! Now, the question is will it fit under the 3x00 timing cover, or with little modification. I think yes.

Who has a 3.1 timing chain kicking around that they can test fit under a 3x00 timing cover?

[robertisaar]

well, ain't that something...

it's only an extra ~.18" wide i imagine it would... are the sprockets wider as well?

[3400beretta]

Nope, like I said they share a common crank gear. The chain is just beefier, the metal that makes up the links must be thicker.

[3400beretta]

Also found these on ebay.

http://item.ebay.com/280304623058

Looks to be a real gm timing set.

[Rootie524]

like i previously said i used a pre 99 timing chain set from coyles on my 2002 3100 and it was bigger. everything..the chain and sprockets..and it fit in fine with no modifications... looked like the one linked above..and it is no doubt larger than the one i took off..

[3400beretta]

I am quite aware about the pre 99 timing set, have you even read this thread?

[pocket-rocket]

Pre 99> 00 as we already know. Also GM > Cloyes. I've seen a GM vs a Cloyes side by side and the GM is much better.

[Guest]

These 660 timing sets seem to stretch a lot the instant the engine is fired for the first time...

I had around 50,000 Kms on my Franken60, and the timing chain appeared to be strecth the same amount as some 300,000 or so Km chains.

[86FieroSEv6]

I'd like to know why we don't have a gear drive set for the 60 degree v6 yet?

[robertisaar]

I'd like to know why we don't have a gear drive set for the 60 degree v6 yet?

from what i understand, they're a bit "noisy" and interfere with the knock sensors on the SBCs... i imagine it would effect us just as badly.

[Guest]

I'd like to know why we don't have a gear drive set for the 60 degree v6 yet?

Because gear drives suck?