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Discussion Starter · #21 ·
Hi all

I started the car today and it idled pretty smoothly a little light tapping from valves but I think that’s normal. Let it idle for a while then took it for a drive … about a mile down the road the car died in me .. no warning and now it turns over but won’t start. Any ideas to start trouble shooting?
 

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As a rule of thumb. There's always one valve open in 2 cylinders.

They're never all closed.

Does the motor crank over or does it free spin? When cranking.
Hopefully the belt didn't mess up.
 

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Discussion Starter · #24 ·
Hi guys

wow I think I’ve screwed this one up. I started trouble shooting yesterday after the car shut off and would not start. Fuel was getting to the fuel rail fine and I don’t think air or spark is a problem since plugs/distributor are new. So I’m sure it was the timing.
So I took it all back apart and lined up the timing marks on my cam sprockets only to find that the timing channel in the back of the exhaust cam was roughly 1/4 turn off (channel was almost vertical when it needed to be horizontal). This puzzles me as I had both channels aligned horizontally when I reinstalled the cam sprockets with the timing marks in the correct spot. I can’t figure out how it could be so far off when everything was aligned when I reinstalled the can sprockets. To make matters worse a friend of mine helping me do this work broke a tooth off the exhaust cam at the end near the timing channel. 😑 Guys I really need help figuring this out .. I have not sent my old head back yet so is it worth pulling my old cam out and replacing the broken cam in my new head? The damage to the new cam is on the very end here is a pic to show which piece has broken off the circle within the circle shows the piece that broke clean
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Also just to clarify because I have never gotten an answer on this. When reinstalling the cam sprockets the only tool I have to decide cam orientation is the metal bar that slides in the back of the cams. Is that all I need to do to get the cams in the correct position so I can reinstall the cam sprockets? That’s the way I did it the first time and I ended up way out of time so I’m not understanding where I went wrong.
 

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The Nuclear Option
2015 Chevrolet Cruze LT 1.4L Turbo
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The 1.8L is an interference engine....

Is that exciter ring pressed onto the cam like in the picture you posted? The exciter ring is the part you circled. I believe you said it was broken? That's what the camshaft sensor reads.
 

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Discussion Starter · #27 ·
The little tab that I circled is broken off completely the other tab’s timing channel are intact. I’m assuming I would need to replace the cam? No point in moving forward if internals are bent so is it worth it at this point?
 

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The Nuclear Option
2015 Chevrolet Cruze LT 1.4L Turbo
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The valve(s) could be bent. You won't know unless you, do a compression test, take the head back off, or look with an endoscope. I would get the timing set correctly and start with a compression test since the engine is mostly assembled.

If the exciter ring is broken it will need to be replaced.

As for is it worth it, it depends on if your willing to spend the time and/or money to do the job correctly. That includes educating yourself.
 

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Discussion Starter · #29 ·
Fair enough I did follow the procedure in the manual here so I’m not sure where it went wrong. Everything was torqued correctly… I’ll try the compression test and see where we are at
 

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Discussion Starter · #30 ·
Can you explain how the timing works on the top end of the motor? I had all timing marks lined up when I installed everything per the manual. I can of course repeat that process but will probably get the same result. How can I be sure the valves are in the correct position as well as the cams when I reinstall the cam actuators? That’s the missing piece here I can line up the timing marks all day but if the actuators aren’t installed correctly I’ll never get the timing right. I’ve researched this many hours and I’m sure the answer is out there but I haven’t found it, that’s why I turned to this site but I cant seem to get an answer to that question.
 

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The Nuclear Option
2015 Chevrolet Cruze LT 1.4L Turbo
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Can you explain how the timing works on the top end of the motor? I had all timing marks lined up when I installed everything per the manual. I can of course repeat that process but will probably get the same result. How can I be sure the valves are in the correct position as well as the cams when I reinstall the cam actuators? That’s the missing piece here I can line up the timing marks all day but if the actuators aren’t installed correctly I’ll never get the timing right. I’ve researched this many hours and I’m sure the answer is out there but I haven’t found it, that’s why I turned to this site but I cant seem to get an answer to that question.
So the question shouldn't be: How does the timing work at the top end of the engine. The question should be: How does engine timing work in general?
What is your understanding of that?
 

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Discussion Starter · #32 ·
I understand what timing is the timing belt ties the crank gear to the cam gears. There are timing marks on all 3. The cam gears time the cams so that the lobes are in the correct position & therefore valves in the correct position at the correct time in correlation to position of the position in each cylinder. There is a cam for intake valves and a cam for exhaust valves that is why there are 2 cams. The crank drives the pistons and that is why they are all tied together so that internals are synchronized. There are 2 strokes I believe exhaust and intake so it takes 2 full revolutions to go through one filling timing cycle in this motor where the pistions will be at TDC twice. Once for combustion (intake stroke) and once to remove exhaust (exhaust stroke). Valves must be open / closed at the right time in order for this to happen. BTW I totally destroyed the refurbished cylinder head. On the fense about ordering another one. I can time a motor when the timing marks on the sprockets are accurate but removing the sprockets and reinstalling then without understanding the cam orientation is where I got confused. If I give this another shot I will need to understand that before I can successfully compete this
 

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The Nuclear Option
2015 Chevrolet Cruze LT 1.4L Turbo
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I understand what timing is the timing belt ties the crank gear to the cam gears. There are timing marks on all 3. The cam gears time the cams so that the lobes are in the correct position & therefore valves in the correct position at the correct time in correlation to position of the position in each cylinder. There is a cam for intake valves and a cam for exhaust valves that is why there are 2 cams. The crank drives the pistons and that is why they are all tied together so that internals are synchronized. There are 2 strokes I believe exhaust and intake so it takes 2 full revolutions to go through one filling timing cycle in this motor where the pistions will be at TDC twice. Once for combustion (intake stroke) and once to remove exhaust (exhaust stroke). Valves must be open / closed at the right time in order for this to happen. BTW I totally destroyed the refurbished cylinder head. On the fense about ordering another one. I can time a motor when the timing marks on the sprockets are accurate but removing the sprockets and reinstalling then without understanding the cam orientation is where I got confused. If I give this another shot I will need to understand that before I can successfully compete this
That's mostly correct. There are 4 strokes.

Each stroke is 180 degrees of the crankshaft and 90 degrees of the camshafts.

The intake stroke, where the piston goes down and the intake valve opens drawing air and fuel into the cylinder through the motion of the stroke and then closes at the bottom.

The compression stroke, where the piston goes up and all valves are closed in that cylinder. The air fuel mixture is compressed during this stroke.

The power stroke, where the spark plug fires and ignites the air fuel mixture causing the piston to go down. This stroke is what give all of the pistons motion when the starter is not in use. All the valves in the cylinder are still closed in this stroke.

The exhaust stroke, where the exhaust valve opens and the piston moves up pushing the exhaust out of the cylinder. The exhaust valve closes at the end of this stroke.

And then the entire process is repeated to complete the cycle.

The cam gears do not determine the position of the cams. From the picture you displayed, The bar that you put in the back of the cams do. There is only one combination that the bar will fit correctly into the cams without resistance. That position is the correct positioning at TDC. Then you put the cam gears on and line them up with the marks without moving the cams. If the cams move at all while you are tightening down the cam gears the timing will be off.

Does that make sense? If not there are videos on YouTube that you can watch.
 

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Discussion Starter · #34 ·
Thanks for explaining, it does make sense. However, I used the timing bar tool to line up the channels on the cams before I installed the sprockets and timing belt. I can’t understand how I ended up out of time if the cams were in the correct spot. Like you said the tool only goes in one way. IDK but I’m gonna pull the head off again today and take a look at the bottom end to seek if pistons are damaged… I’m certain the valves are bent & bearing for cylinder 2 exhaust cam is chewed up. I’ll post pics of the damage so everyone can see what failure looks like 😬.

This Cruze is my second car I use for commuting so I don’t rack up unnecessary miles on my other car. Would be nice to have both again as work is a 170 mile commute round trip. Hoping the bottom end is okay and I can take another shot.
 

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Discussion Starter · #35 ·
Here are pics of the damage, bottom end looks fine and valves look okay they all close and seat would that rule out that they are bent? Is the damage to the cylinder head repairable? This is where the cam bearing sits for cylinder #2, I can order a new cam but if the head can’t be repaired then I’ll need a whole new head.
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The Nuclear Option
2015 Chevrolet Cruze LT 1.4L Turbo
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Did you assemble that cylinder head yourself?

It almost looks like the cam bearing tolerance was too tight or there wasn't enough assembly lube/oil on that cam bearing and it spun dry?

I don't think that's from the timing being off. It could be but normally if the timing is off the valves bend from contacting the piston crown.
 

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Discussion Starter · #37 ·
Yea that’s what I was thinking it does look like it was not lubricated enough. No I did not assemble this head it was ordered from a cylinder head shop through eBay. Also it was only that one bearing that had damage the others are normal I would think that if bad timing caused the damage it would be across the whole cam and not just one cylinder.

I can sand the bore smooth but it’s pitted pretty bad in the spot you can see in the picture. I also have another cam and bearing cap that are undamaged with exciter intact 🙄…… so the only surface that needs repairing is the bore on the cylinder head.
 

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The Nuclear Option
2015 Chevrolet Cruze LT 1.4L Turbo
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No I did not assemble this head it was ordered from a cylinder head shop on ebay.
That's what I did too. However, I disassembled the head and rebuilt it with performance parts along with new GM lash adjusters, rocker arms, and valves. I was very disappointed at the some of parts I found in a "fully rebuilt" remanufactured cylinder head. Half the rocker arms were flat spotted and rusted, most of the lash adjusters were seized. And there was NO assembly lube or oil on anything.
 

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Discussion Starter · #39 ·
You have the 1.4 turbo right? Not sure if it’s worth building a 1.8 I thought I’d be safe with a rebuild head but I guess it could be low quality work the head was a little under $500 on eBay. My other car is a Subaru sti factory at the moment but it’s halfway paid off and powertrain warranty expires in about 1,500 miles so I may start modding that soon, will probably keep the Cruze factory unless you could suggest som easy upgrades while it’s torn apart.
 

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The Nuclear Option
2015 Chevrolet Cruze LT 1.4L Turbo
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You have the 1.4 turbo right? Not sure if it’s worth building a 1.8 I thought I’d be safe with a rebuild head but I guess it could be low quality work the head was a little under $500 on eBay. My other car is a Subaru sti factory at the moment but it’s halfway paid off and powertrain warranty expires in about 1,500 miles so I may start modding that soon, will probably keep the Cruze factory unless you could suggest som easy upgrades while it’s torn apart.
Yes, I have the 1.4L LUJ.

I don't know of many engine modifications that are worth it on a small displacement naturally aspirated engine other that a tune and forced induction. Before my Cruze, I drove a Cobalt. I put a couple thousand dollars into it. Rims, tires, suspension and around $1,000 in engine and drive train modifications and I only gained around 20 HP.
 
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