Trying to replace my timing chain and components. I'm getting mixed answers for the correct part #'s for the VVT sprokets. I made the mistake of ordering the Cloyes Kit without the sprockets (4201SAWP). All the part sites (including Cloyes) only show the VC107 (exhaust sprocket) for the LE8. The other brands mention the sprocket being the same. However, I called Cloyes and was told I needed the VC106 for the intake side. When I searched this part it only refers to being used in the 2.0 and 2.4. Does someone know the correct answer?

Also, could I get away with not changing them for now (I do have new bolts) and come back and change them at a later date without any negative effects? My only issue is I'm having some performance and gas mileage issues, and although I don't have any CELs that relate to the cam, the symptoms match the phasers possibility being bad ( could also just be that the chain is stretched, I haven't torn it apart yet).

Thanks in advance!

What is wrong with the sprockets? They don't normally wear out. I think they are integral with the VVT actuators/ phasers. I would not bother with them unless there is visible wear.

Say "no CEL:S that relate to the cam" makes me think there are CELs; there are a lot that don't seem to relate to cams that do.

You don’t need to replace the VVT sprockets unless they are damaged. ZZP frequently has VVT sprockets available, take offs from LNF engines, same for the 2.2 LE8

I’ve never had to replace VVT sprockets, I suggest you go ahead and change your timing chain, balance shaft chain and water pump. Cloyes is the go to kit for this application, I don’t change the balance shaft sprockets either, very rarely do they get damaged unless the chain breaks.

I strongly recommend installing this front guide
https://zzperformance.com/products/z...ng-chain-guide
And one of these replacement bolts
https://zzperformance.com/products/e...ain-guide-bolt

I've done at least 10 timing chain replacements and never replaced the VVT sprockets.

As donbrew said, they are part of the VVT actuator system (oil flow into them controls the actuator angle change).

Look at them, and unless you see visible damage or unusual wear, don't replace them.

Steve

Thanks for all the great feedback. Saved me a little money! Will knock out tmw and report back if I have any issues 😆😅😁

I don’t recommend using the black plastic front guide or the original upper guide bolt

I have some emissions related codes. 2 have been there for ages as the rear o2 grounded out and took probably a diode in PCM out (codes related to heater). A new one is from low tank pressure (think it's from the cheap evap solenoid and canister valve I threw in once upon a time, swapping them back out and got a new gas cap to try to narrow it down). My concern with the sprockets is I get the traction lights and whatever else come on from time to time, I've already replaced the solenoids in the past.

The car has 255k miles, and I only need to squeeze maybe 30k more. Think it will hold for now? In the market for a salvage ss to swap drivetrain into this one, so I'd rather dump money into that engine overhaul.

Most likely a stretched timing chain or broken front guide

In my 96K 2.0 I changed zero sprockets. Only did the job because the front guIde broke. Except for that, there was zero evidence of guide wear, sprocket wear, or chain stretch. Had I not order parts ahead of time and knowing what I know now, would have replaced the just the front guide, the two tensioners with OEM, the shaft seal, and the engine cover gasket, in that particular case. Today, now the the ZZP improved front guide is available, I would have used that.

Next change job, I will inspect the system before ordering parts. If it's a VVT, I will pay particular attention to the phasers. The first time, I considered only sprocket wear. But they can get damaged internally, and noisy, especially due to solenoid problems, I suspect.

As long as there is a CEL The computers are running in open loop; which will reduce MPG and performance as well as mask some other codes. I suggest you take care of the codes first then worry about the chain. Ignoring the CEL is a very bad idea.

I found this on the RA site for the VC106 sprocket

https://www.rockauto.com/en/parts/cl...sprocket,18586

And the VC107 sprocket

https://www.rockauto.com/en/parts/cl...sprocket,18586

Both are for Ecotec 2.0, 2.2 and 2.4

Is related to pre-heating on 02, if my memory serves me correctly, after it heats up it closes loop. I've literally driven the car over 100k with the codes, avg 30mpg many times. The evap code is another story.

Swapped everything out and shes running like a champ. Chain was stretched, lots of play, and front guide was loose. Shifts a whole lot better now too.

Run it into the ground if you want to. Those computers are just trying to take over, not help us. Kill Skynet.
Why not just buy a new sensor and borrow the tool? That is a lot cheaper than buying a new cat when it dies because you ignored the warnings.
Both codes might be as easy as a fuse; the heated O2 sensors are on fuse #33 same as the EVAP purge valve and MAF/IAT. The EVAP vent is on fuse #64.

The issue is within the pcm (the grounding circuit for heater circuit b1s2). I've already diagnosed it and thrown plenty of parts at it, i even built an entire engine harness for it from scratch (for other issues). The secondary 02 sensor isn't even needed, it's strictly for emissions. In fact, I don't even think the Standalone ecotec setups even have it, could be wrong though. Still have original cat at 255k...

So, 1 transistor out of thousands up and burned out with for no reason. Internal computer faults cause codes. Did you check the wires for continuity?
BTW, the sensor does no use ground, it uses low ref. If the fault was in the ECM other circuits would have problems.
There are 3 different codes relating to the #2 O2 sensor heater, P0036 is the control circuit and P0054 is heater resistance. P0141 is either the heater is drawing too much or too little amps., less than .25 or more than 2.5 amps

The heater should be 1-2 amps resistance. It operates with PWM, so looking for ground in the controller is pretty much futile. The temperature is calculated using the resistance of the heater.

https://cimg1.ibsrv.net/gimg/www.che...cd3b271d06.png

Don't make me embarrass you, you're an absolute troll. A low reference is a ground, 0 1, high low, these are dc circuits.... it literally shows it being grounded in the diagram you posted (but clearly switched). The heater circut only comes on until it is heated. It doesn't stay on 24/7. If you're such a genius, tell me why fuse 33 is connected to a relay that keeps things on the entire time the engine is running? Explain why bank one sensor 1 works perfectly fine? I can tell you why, the sensor was grounding on the body from a bad flex pipe, and it would generally blow while I didn't have time to diagnose it (driving down the road) so I'd simply change the fuse out. Over time it killed most likely a diode in the pcm. Get off your high horse man, just because you think you have skin on a hhr fourm doesn't make you an expert. If I revealed myself you would be absolutely embarrassed...

You would be arrested for public indecency, and I would giggle.
Actually low ref is some voltage between 3.5 volts and 0 volts that stays exactly the same at all times, usually exactly 0 volts whereas ground is a negative value. Similar, not the same.
A diode is a type of transistor. Digital high in the HHR is mostly exactly 5 volts, digital low can be anything below 3.5 volts usually 0 volts., not ground. The switch is a PWM circuit so looking for ground is not right you would look for a frequency.
I don't know how grounding the + side of a circuit would send enough back current to blow a diode. Possible if the Low side was shorting to voltage.
#33 powers the ECM, the car would not run without it.

Go to Facebook if you want high horses. I ride a wheelchair. No insults thrown at you.

Sorry, once again my attempt to help is met with anger.

Dude, look at the diagram that YOU posted. See that upside down fork? That is ground/earth.... and it is clearly switched... the heater circut is not a sensor, it is either on or off.. it is a 12v circut....you're not entirely wrong about low reference, but in this case you are. It is not pwm. The other part of the 02 sensor is definitely a pwm signal. The o2 senor has 2 circuts....

A diode can be many things, they come in many forms, but in this case it's certainly a junction diode that protects the ground circuit in the rest of the pcm from the heater circut. Quit acting like you're a genius...

From Mitchell OnDemand:"

https://cimg5.ibsrv.net/gimg/www.che...9f3fec8379.png

Perfect!Now actually read what it says. Clearly outlines the heater circut being 12v, and the SWITCH to turn it off and on (a transistor), is controlled by pwm. Again, my issue is the diode to ground, ask me how I know...

OK, fine.