Suspected cam chain slipped

gsi2000

Hey All:
Purchased vectra c back in january and eml was on, code pointed to missfire on cylinder 1. set of new plugs (which looked shorter in length than ones fitted) sorted the missfire.
Car idled fine and revved to redline smoothly without hesitation or lumpyness.
however when driving it ran pretty rough and serious loss of power until revs reached 3.5k then it took off.
2-3 second rattle at start up when left stood still for a few hours or on cold mornings but no other chain noise after that.
priced up new chains and was gonna get them replaced (timing+balancing) until last saturday when i started car up in morning (same 2-3 second rattle) drove to nearest petrol station just over 1/4 mile away to put some juice in, went to start car again and wouldnt fire up, engine turned over really fast and only way to explain it is the sound you get when the starter motor is spinning but not latching on to turn engine over.
Called RAC out and he performed a compression test on cylinders 1 & 2 which showed a reading of 40 on both cylinders. resulting in his diagnosis of a snapped chain, towed me back home and sunday i stripped it down a bit as far as getting rocker cover off. the attached pictures show how the car is at the moment, chain not snapped but really loose.

My question is, where do i go from here? do i align the cams and crank up and fit a new chain kit, or do i go further and take the cylinder head off?
Any advice you can offer would be greatly appreciated as id like to keep it running rather than sending it off to scrap yard.

Many Thanks to @[deleted] for his help so far with this issue

KevinH

If you shine a torch down the front opening near the inlet cam you should be able to see if the front guide is still intact or if it has broken up. Similarly, towards the rear opening you may be able to see if the chain tensioner is still in contact with the rear guide.

Obviously tension has been lost and it's very likely that the chain has slipped one or two teeth causing compression loss.

Worth checking that all the cam followers are still in place but it is possible that you may have some valve damage in which case the cylinder head would have to be removed.
Were there any noises apart from the starter motor when you last turned it over ?

Looks like it may need a strip down to check everything and if a guide has broken up it is possible some of the bits might have ended up in the sump, which would require removal and a clean up.

gsi2000

When i started the car after putting petrol in there was no noises apart from engine turning over, and seemed to be turning over fast.
on the 1/4 mile drive to the petrol station again no noises out of the ordinary. just the same 2-3 second chain rattle at start up.
Apart from the slack chain, nothing seems to be loose, broken etc, ive tried to have a look down to check tensioner and guide rail but cant really see much, just an oily chain. ive tried wiggling the cams and everything connected under the rocker cover but there is very little or no play with any components.

KevinH

If everything is still intact then that is a very stretched chain which requires renewal.
I guess once the timing/oil pump cover is removed it will reveal if any guides have broken.

Out of interest, how many miles has the car done ?

gsi2000

Its done 151000
No service history with it so no idea if chain has been done before, im guessing not. hence why i wanted to get the chains done as a matter of precaution.

IDI_AMIN

I would say it is very likely the timing chain tensioner has failed.

As Kevin said what is mileage. This info will help
You would notice one of the valves sitting higher if there was any damage i.e. a bent valve or one of the rockers out of position like sitting sideways and jammed under the cam lobes

You could be lucky and just need to put a new chain set on. I have had the problem of low compression just from having a slack chain without any internal damage

But you need to investigate a little further and see if any of the guides are damaged. But if you take out the tensioner you will probably find it is not functioning properly. You will need to do this anyway because the timing will need reset when new chains are fitted which you will need to do because it will be part of the process of rectifying the problem

The chain guide at the top looks a little old and worn It also looks like the plastic guide part underneath this is missing, so it is probably at the age to renew the chains. What is year of car?

gsi2000

My apologies its a vectra c 2004 with 151000 on the clock.
That plastic guide must have been loose because when i took the rocker cover off it fell and bounced down by the chassis onto the floor.
is it just me or does the exhaust cam between 2 & 3 look odd from the rest of the cam or is that normal (colour wise)

KevinH

At 151k miles with no service history it's definitely time to install new timing/balance chain kits.
If you have the budget go with genuine GM kits, you won't regret it !

gsi2000

Thanks guys for your help,
so to sum up:

remove old chain kit
align crankshaft to tdc piston 1
align both cams with cylinder 4 at 10 and 2
put new chain kit on
turn crank about 10 times to make sure valves and pistons dont smash together
reassemble everything
turn the engine over with the key and see if it fires up

Would i be right in assuming thats how to go about it or am i going to be doing something wrong?
not sure im going to have time to look at it during this week so weekend is more likely, once ive done the checks you mention in previous posts and all turns out clear im hoping to get the new chain on

IDI_AMIN

All above is correct but 2 full rotations of the crankshaft is enough to let you know if everything is ok.

Probably a new balance chain kit also it would be wise to do both chain sets rather than just one. There is plenty of info on the website to help with aligning chains if you are not too sure.

So the problems you have are likely age related rather than down to any serious damage

It's a good experience to fit the chains yourself and not really that hard.

KevinH

When you align the crankshaft to the TDC mark, do it to No 4 cyl (gearbox end) so that the lobes are at 10 (inlet) and 2 (exhaust). If the chain has jumped some teeth on the sprockets you may find that the camshafts lobes are slightly out from this position.

Have a look at the link below, this is a pretty good guide.
https://z22se.co.uk/threads/how-2-fit-cam-chains.10042/

As Idi says, it is prudent to change the balance chain at the same time.

gsi2000

Thanks, i'll get on to it this weekend and follow your advice regarding both chains. personally im used to vauxhall cavalier single overhead cams, this vectra will be a learning curve into newer engines lol

evocarlos

to add you want al 4 pistons half way down before moving the cams with the head on to avoid valve to piston contact
turn in the crank on its own with the cams not connected with a chain could lead to damage

gsi2000

Cheers for that.
Dont think my budget is gonna stretch to a genuine gm kit. Can you recommend any alternatives even if its to run it for a few months until i can get it sorted with a genuine kit

figo126

there are a few out there, but like everyone keep saying use gm genuine , genuine kits on ebay that's where I got mine from ,,,

gsi2000

UPDATE
Been out today working on car and thought id upload some pics, only problem i encountered really was the crank pulley bolt.

A lot of oil spray from somewhere:

Looking filthy so gonna give it a good clean before it goes back on:

Nothing looks obviously wrong, but hey im no expert lol. (i took chain off one top sprocket hence it hanging down)

And here is the broken top guide: (there is still a third piece that is on the chassis leg)

Still got the tensioner to remove and take chain completely off, as for the balancing chain, theres about half a centimetre slack in it, maybe a tad more, is that normal?

KevinH

The bottom photo is the front guide which has broken up.:eek: Some pieces may have fallen into the sump.

The balance chain may be OK, but certainly not worth leaving it on, be sure to renew it with a new kit.
From the photos, it looks as if regular oil changes have been neglected by previous owner(s).

gsi2000

guess next step is get the sump off then and check/clean it up. i will be renewing everything in next couple of weeks (monthly pay sucks lol)
With regards to cleaning all the oil and carbon build up whats best stuff to use, at the moment i have the bottom timing cover soaked in swarfega jizer degreaser.
carb cleaner would work wonders on the grime but unsure if it would be safe to use.

figure while its all apart i may as well clean as much as i can.

Dave_Gilbert

Soke anything you want to reuse in petrol or turps

front guid snapping isnt good but u may get away with just fitting new chain kits (both)

All the oil round the crank pulley will be the crank oil seal. @[deleted] will give more advice on if there could be more damage

evocarlos

looks like the lower front guide bolt hole is cabbaged to