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A14NET - Camshaft not "perfectly" aligned

4.9K views 20 replies 3 participants last post by  JLL  
#1 ·
Hi Guys,

I'm replacing timing chain by occassion of taking off the chain cover as it was leaking.
What I've noticed during disassembly and now when assembling is the camshafts that didn't "perfectly" align on TDC.

At first during disassembly I think the difference was a little bit bigger and it was harder to put the locking tool for camshaft.
Now during assembly there is still a difficulty but not that big like before.

All the locking stuff are set up, the only problem is with camshaft.

Looks like the exhaust one (closer to front bumper) is a little bit too far, and I need to rotate it JUST A LITTLE BIT to the side of bumper (while all other locking tools are used).
Only then I can put that the locking tool.

Do you have any idea what can be the reason? and if this should be somehow corrected or it's acceptable?

Thank you very much for any answers, my car is currently in grage waiting for me to be confident with the setup :)
 
#20 ·
So the day came :) My car finally started today. I'am still surprised but... it looks fine so far! :) Works pretty stable, no fault codes, driving acceptable, I would even say it's better than before.
It took longer than I expected, I suppose to start it last week Thursday but when filling coolant, oil cooler started to leak... :) So I had to wait for additional o-ring between thermostat and oil cooler.

Again, big thank you @JLL, you saved me.
All the best for u! :)
 
#18 ·
I've did that during alignment process and for internal test afterwards, indeed didn't do that on video.
I hope this engine will ever start... :)

Thank you very much @JLL for your advises, explanation and time.
I'll come back here to confirm whether it started or not, probably I'll do it in 2-3 days.
 
#19 ·
I've did that during alignment process and for internal test afterwards, indeed didn't do that on video.
I hope this engine will ever start... :)

Thank you very much @JLL for your advises, explanation and time.
I'll come back here to confirm whether it started or not, probably I'll do it in 2-3 days.
You're welcome.
 
#14 ·
As a side note, You did leave the timing tools installed and hold each camshaft still with a wrench while tightening the phaser bolt, right?

Yes, correct.

They do need to be replaced since they are TTY

That's painfull as the price is insane just for two bolts, but seems I've got no choice.

I'll try first with old bolts just to get proof that this is the case and it can be set up correctly, and only then I'll use new bolts.

Thank you very much, I'll come back tomorrow with update - I hope good update.
 
#13 ·
Yes. What you are describing is the exhaust camshaft moving slightly. If that happened you're going to have to take all the tools out, loosen and replace the phaser bolts, retime, and then tighten the new bolts. If you are loosening the cam phaser bolts once they are already torqued they will never tighten correctly due to the large torque that's involved. They do need to be replaced since they are TTY. There could also be is a small defect in the timing tool set. That could be the issue too.

The chain can move if there's too much slack in it before it tightens. If you were paying attention and you KNOW it didn't skip a tooth on the crankshaft than it didn't skip a tooth. But I've seen a lot people get into trouble when they don't pay fully attention.

As a side note, You did leave the timing tools installed and hold each camshaft still with a wrench while tightening the phaser bolt, right?
 
#12 ·
Hey @JLL,

first of all I really appreciate your time spent on those explanations.
And sorry but this is still not clear to me.

I fully agree with the part of exciter rings, crankshaft, and camshafts.
But the first part I still do not understand.

"You can put the chain on in any way BUT, you have to make sure the chain doesn't shift a tooth when you put tensioner on it. If you have any slack after the tensioner has been released and the upper guide is in place, the chain slipped a tooth, most likely on the crankshaft spocket."

In my case for sure it didn't shift after I've released tensioner, the only way is that I've put it incorrectly from beginning, but we already agreed that it doesn't really matter.
Somehow I believe that during tightening the bolt for exhaust crankshaft I've used too much power to counter tightening and accidentally I've pushed it too far, and in result the locker do not fit just by a milimiter.

Do you think that such scenario is possible? or you are still fully convinced that the chain isn't correctly set up?
Tomorrow I'll try to re-do tightening of the exhaust cranshaft.
 
#10 ·
Hey @JLL,

such a great explanation, thanks for that.
However I still don't fully understand how chain can be off by a tooth.

In documentation, guides, references there is nothing about any specific way of putting the chain.
Isn't it that the chain can be putted in any way, BUT we need to make sure that the camshaft is properly aligned with lockers on it proper position before torquing?

If not, then how can we put the chain correctly on? Even that guide I've posted above doesn't say a word about it.
 
#11 ·
You can put the chain on in any way BUT, you have to make sure the chain doesn't shift a tooth when you put tensioner on it. If you have any slack after the tensioner has been released and the upper guide is in place, the chain slipped a tooth, most likely on the crankshaft spocket.

The cam phasers can go on in any direction too.

You just have to make sure when you tighten the cam phaser bolts that the camshafts, exciter rings, and crankshaft are in alignment AND don’t move when you tighten that cam phaser bolts. The camshaft position sensors read the position of the exciter rings to determine what positions camshafts are. If any of those are off there will likely be issues.

The first time I timed a LUV/LUJ I went through 3 sets (6) camshaft phaser bolts at USD $25 EACH before I got it right.
 
#8 ·
Hi Guys,

thank you very much for response, appreciate.
From what I've understood this engine is builded the way that if you use all the tools, and follow replacement steps it cannot be off by a tooth.

Why? It doesn't matter how you put the chain because we are loosen the camshafts bolts and they are freely to align (independently to the chain which at this point is already set up).
It's explained here: How-To: Cruze/Sonic 1.4L Turbo LUV/LUJ Timing Adjustment

I think I need to loosen the camshafts again and try to tighten them one more time. Maybe during tightening them and holding the camshaft with second wrench to not let it move I've just used too much power in holding them and accidentally moved it by milimiter.

I'm afraid to unscrew them for the second time, but seems I've no choice.
 
#9 ·
Hi Guys,

thank you very much for response, appreciate.
From what I've understood this engine is builded the way that if you use all the tools, and follow replacement steps it cannot be off by a tooth.

Why? It doesn't matter how you put the chain because we are loosen the camshafts bolts and they are freely to align (independently to the chain which at this point is already set up).
It's explained here: How-To: Cruze/Sonic 1.4L Turbo LUV/LUJ Timing Adjustment

I think I need to loosen the camshafts again and try to tighten them one more time. Maybe during tightening them and holding the camshaft with second wrench to not let it move I've just used too much power in holding them and accidentally moved it by milimiter.

I'm afraid to unscrew them for the second time, but seems I've no choice.
If you loosen the cam phaser bolts after they have been torque you will need to replace them. But yes, you will need to do that.

You actually can put the chain on incorrectly. There is enough slack in the chain to skip a tooth. In your video when you try to move only 1 camshaft, you can see that the chain bunches up. That's an indication that the chain is off a tooth.

If the chain is physically off a tooth, the mechanical timing or base timing is off. The variable value timing (VVT) system uses the base timing as a reference point.

To clarify here is an example.
Let's say ECM commands the VVT system to add 20 degrees of timing when the base timing is correct at TDC or 0 degrees. For this example let's say there are 72 teeth on the cam phaser gear. Than means each tooth represents 5 degrees of cam timing. 360/75 = 5.

Actually timing = 0 +20 = 20

But if the base timing is off by a tooth that we said represents 5 degrees, the ECM and the VVT system don't know that. So,

Actually timing = 5 + 20 = 25.

But the ECM is only commending spark advance at 20 degrees because it doesn’t know any better. That can cause partial combustion, which can cause incorrect fuel trims. Then the engine runs rough.
 
#3 ·
Hello @JLL,

Thank you for response.
Well, I'm using dedicated box for this engine, hard to estimate whether they are good quality or not.

As for me - yes. Let's say I've partialy tested the tool.
I've put the locker only from the exhaust side, and tried to move it forward slowly to side of intake crankshaft. It's blocking on middle of the head (which actually prove that the exhaust camshaft is not perfectly aligned). This is not happening on the intake side.

I'll record video today how it looks so maybe it will be easier to understand.

Meanwhile, can those camshafts position be fixed somehow?
I've unlocked the camshaft on the left side for both, set up all the tools, then I've screw both of them while aligned, but still there is a minimum requirement to push the exhaust camshaft to side of front bumper to put the tool.

To be honest, I've found few videos and guides where people say to minimally rotate the camshafts if it's needed to put the tool, but in most of videos they says it should easily go on it position.
 
#4 ·
Make sure the cams aren't out of phase with each other.

Other than that, It's pretty much trial and error. You just have to keep removing all the timing tools. Rotating the engine, 720 degrees, lining the crankshaft up to TDC, installing the timing tools.

Also make sure you replace the phaser bolts if you torque them and then have to loosen them.