Another Chain Failure (z22yh)

5ignum

Looks like my chain has jumped as car will turn over but not fire. I have striped down the cam cover and the timing marks appear to be out by 1 tooth on each sprocket, will this be likely to have caused any damage?

Anyone an expert on chains on these and would fancy a trip to Crawley to help?

vocky

it really is 50/50 whether the valves have been damaged (n)

5ignum

vocky said:
it really is 50/50 whether the valves have been damaged (n)

Is just a matter of new chain kit and see what happens or are there other tell tale signs I should be looking for, hoping not to need to take the head off.
Hopefully getting the loan of an inspection camera to look inside cylinders, will the pistons show obvious signs of contact with valves?

IDI_AMIN

I think it is a bit of a gamble to just put a new chain on . If the current chain has jumped a tooth it is highly probable that there is some bent valves
Unfortunate but your best option may be to take the cylinder head off but before you do that i think people would recommend a compression test. no compression would mean bent valves.
You could be very lucky and not have bent valves

evocarlos

easy to tell if the valves are bent 🙂
take off the rocker cover and see if any of the roller rockers can be removed from under the cams if they can then theres bent valves if not then they're not 🙂

IDI_AMIN

what would it mean then if it will not start, timing seems ok ,no evidence of bent valves from trying to remove roller rockers. What would the next recommended step be?

evocarlos

on z22yh if the timing is out by 2 or more links then it wont start the cam sensor on the exhaust sprocket throws a wobbly

5ignum

Cheers guys for the comments, went out to the car tonight to inspect the roller rockers and to take a look inside at the pistons with a bore scope a mate had brought home from work.
Well it is looking quite promising roller rockers aren't loose and the piston faces don't show anything nasty so may have got away with it.

What do you suggest? New chains, then compression test? is there anything else I should look at replacing whilst I am in there?

evocarlos

has the chain ever been done ?
if it was not rattling before hand and theres no parts of the chain guides missing then get the timing right and go from there

5ignum

To my knowledge it is the original chain, I have only had the car 2 years and it was bought with 38K on the clock has now only just passed 50K. I haven't got inside the chain cover yet but as the engine is turned by hand the tension in the chain is all over the place, so I suspect that something has broke, may just be a tensioner failure but I am thinking that by the time I have shelled out for 1 of them I may as well fit a whole chain kit.
Do I leave the balancer chain well alone if no obvious signs of wear or change as I am in there anyway?

5ignum

I will be hoping to start stripping the car down on Saturday so I will find out what has actually failed then, I hadn't noticed any rattles before it went wrong possibly a slight misfire on start up but that lasted for a second or so.

Just visited the Shop and bought both chain kits, I figured I may as well replace them as I am sure something has failed with the tensioner or guide and with their reputation to fail I am a bit paranoid.
I have seen that there is a cam timing tool "http://www.ap-tech.co.uk/products/details/782.html" is it required to do the chains?

5ignum

right car stripped to view the chains, I haven't removed anything yet as replacements won't be here until 13th hopefully. A quick inspection shows that everything is still intact but both chains have play in them , so this points to both tensioners as you can push the guides against them.
A tip for anyone doing this regarding the crank pulley is to loosen the 3 top bolts on the engine mount slightly to allow the engine to drop enough to get a socket onto the 21mm nut.
Lower the car with the wheels at full lock to the right, place in gear chock the wheels, then using a breaker bar with a couple of extensions place it on the nut with the bar pointing to 1 o'clock pull back against the bar using the tyre as an anchor point, a couple of pulls and it should be free.

evocarlos

5ignum said:

A tip for anyone doing this regarding the crank pulley is to loosen the 3 top bolts on the engine mount slightly to allow the engine to drop enough to get a socket onto the 21mm nut.
Lower the car with the wheels at full lock to the right, place in gear chock the wheels, then using a breaker bar with a couple of extensions place it on the nut with the bar pointing to 1 o'clock pull back against the bar using the tyre as an anchor point, a couple of pulls and it should be free.

that dont always work 🙂

any of the roller rockers loose ?

5ignum

It all looks ok from what I can tell, none of them seem loose and the camera didn't show any signs of contact.

evocarlos

thats good news then so whats your next step ? reset the timing and give it a whirl ?

5ignum

I am not sure, I have ordered both chain sets from Matt, but I have to wait for him to get back from his Hols.
There is slack in both so I think the tensioners are knackered, yet to remove them and check, the main tensioner has a flat nut and suspect it is the original (the car is an 04). My worry would be that if the tensioners are shot could the chain jump again and cause more damage.
what do you think?

evocarlos

it could just be the chain is stretched and the tensioner can no longer reach it

5ignum

so best to wait for the new chains kits?

evocarlos

5ignum said:
so best to wait for the new chains kits?

yes 🙂

5ignum

Chains arrived today (y). So got cracking and got the balance chain fitted before dinner, was then allowed out to fit the main timing chain. Both are now on and in the correct alignment. Just got to fit the tensioners and double check everything, but hopefully may have it running soon.