Hi guys. New to site. I have a 2008 HHR SS fully built motor, full bolt on which includes a 5557 precision turbo and waste gate, tial bov, header, intercooler, 5th injector and much more.


I recently replaced the my timing chains at 50k because the first one stretched then broke. I used all factory parts. I replaced both chains, tensioners, all guides and lower crank gear. after 6k miles I broke the chain again.


Does anybody know of a stronger chain or fix for this?

 

What the hell are you doing haha. Ive never heard of chain failures and tons of people have built motors using the stock chain. Are you the one doing the work?

 

Yes, I did the work. I am ASE certified 22 years. Don't forget I am pushing over 22psi. I Haven't torn it completely apart, but it seems it might be the chain oil squirter. but the fact that I had to replace the chain at 50k miles and now it broke again at 60k makes me wonder if its the power or something else. In all manners I'm trying to bullet proof it as much as possible.

 

Maybe zzp

 

I remember a while back i wanna say it was fmsr that was working on a better chain but we all know theyre a flop. You could ask zzp and see what they have to say. But people run more boost and more power without issues, i dont think its the chain.

 

How high are you reving it?

 

^^^ even at work ive never had a chain just break, it always jumps time and dies before breaking. although ive had quite a few balance shaft chains break, but everyone knows about those. I did one time have a 250k hhr break the chain, but it wasn't the chain, the guide was worn down into two pieces and had caught the chain.

I would check your oil squirters too. Ive never seen one clog up but I suppose its possible.

 

^^^My chain got stretched because of a failing guide, Yes we caught it before it failed but When I was fixing mine with john powell he told me all sorts of failures he has seen so anything is possible.

Anyways in a nut shell I upgraded my timing bolts which fixed my problem, I had a stretched chain and it was very strange tick, It would only tick if it sat longer than six hours, Any shorter period of time it wouldn't, It Also would tick underload from 2-3 rpms and would not do it in neutral with no load at any rpm, Lastly the tick went away when I hit 54c on my coolant display.

It was a strange issue and it got me very paranoid and I felt like I was going crazy.

I am not sure if you have done that or not but I just thought I would throw that out there, Since I never made a post about it.

Also have you opened it up to see if anything else has failed with it ? Have you inspected the parts to see if they have scoring to indicate oil starvation?

Hope this helps, Keep us posted

 

I finally tore it down. the oil squirter was damaged from previous time. So this is partial of the problem. the right side guide, which is brand new, broke at the top bolt. so the chain was riding on the bolt, which is why the chain broke I believe. Still makes me wonder why the guide broke. Thanx for the website info. I looked on ZZP, didn't find chain. going to call tomorrow. Did find some bigger injectors for the direct injection, which I ordered. Getting ready to dyno tune hopefully within the next week.


Only reving it to 7k

 

Nice glad you figured it out, ZZP is a great site. Ecotec Timing Chain & Guide Set - Camshafts & Valvetrain

On a side note- Since you are in the timing anyways, I don't know if you have heard about these parts/issues. I will link the pages below for you.

https://www.cobaltss.net/forums/2-0l...pgrade-298146/

https://www.cobaltss.net/forums/how-...sioner-276244/

 

i believe that is the bolt that mongo makes and sells its a beefed up version that wont break.
(if its the one that goes through the side of the head)

 

Mongos is a repair bolt for if yours breaks off in the head.

If its not already broken get the arp kit. I believe CED has them

 

I run 35psi on an s256 stock timing set to 8500rpm. never had a problem. some people have the guide bolt break but that's all I"ve seen on our builds.
also depending on how much you head and block were decked, you may need an solid tensioner to take up more slack then the stock one does.

 

What did you torque the bolts to. Also how are you setting the tensioner?

 

the bolt mongo makes is a stronger one than oem, why wait until it breaks to fix it ?

the arp bolts are 3 other bolts inside the front cover, the one mongo makes is not one that arp makes.

 

you know you cant use that solid tensioner on a dd

 

Youre talking about the one in the head correct? His 'repair bolt' isnt even really a bolt. It just presses the guide against the head. I wouldnt use that in a high hp application, its simply a repair.

 

Arp makes the bolts for him...

 

How much damage are we talking if the timing chain breaks? I currently have no compression in 1,2, and 4.

 

your probably bent valves...

it really depends WHEN it breaks. ive seen cars where it snaps at idle and nothing happens. Other cars that happen at speed it bends valves which can also lead to other issues.

 

It happened as I was backing out of my driveway to go to work. The engine just slowly slowed down and stalled over the course of 2 or 3 seconds and wouldnt start again. Engine was at idle when it happened.

 

Hey Slowbalt2000, What is CED?


Yellow, I'm using the stock hydraulic tensioner


Omiotek, I torqued the guide bolts to 12Nm, None have broken yet


I bought new guide bolts from dealer just to be safe. Now that I have it back together, it seems as if the timing chain is to tight. Its making a whining noise. I've put all new timing parts including Cam adjuster/gears. And when I say all new parts, I mean ALL


On the timing tensioner, I just popped it with a big extension to release before starting it

 

CED is crate engine depot. Crate Engine Depot - Chevrolet Performance Parts and Engines

 

Did you make sure the recess was positioned properly with the guide? If its not then it will hold the timing chain tight and eventually break it or the tensioner.

Also was the tensioner in the packaged position? The piston should wiggle without pressure if it is. If you have to force by hand then it was already set and hitting it again could of broke the tensioner and locked it. Or some guys like to put the tensioner in set rather then hitting is nd if your not careful you can break it as well

 

Oh the fun I've had with this thing!


Omiotek- I think I found out the whine. You were definitely right on the tensioner. It did not sit down in the recess position. pulled it out and reset it and instantly gave me the hair slack I wanted. But the damage was already done. Some how the chain was crooked on the guide for the tensioner. The chain ate a nasty groove into the guide. So now we wait for another guide. All the others are still good.


I just added the new ZZP bigger injectors, and high pressure fuel pump along with the Cam follower. When I tried to pull the cam follower out, found it was stuck almost. Which is probably what was causing my lean codes. After much deliberation, I found the Valve cover bolt above the follower was to long and pressing down on it. keeping it from pumping proper fuel pressure. Then when we would start it, it would pop a code for the FRP sensor immediately. (Just cause its new, doesn't mean it's a good part) Swap it with the old one and fixed that problem. Some where in the midst of things, the oil ran low and my timing jumped. But this is how I found the bad guide. So I guess things happen for a reason. Hoping to Tune it next week.


Thanks for the help everyone!!