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[El_Swervo]

Hello All,

As previously posted on the newbie message board, I have a problem with my Omega estate.
It is a 97P plate, 2.5 V6 auto, cd. When leaving work (very slowly), last week it sounded like a diesel dump truck. I shut it off after about 30 seconds and liftd the bonnet to have a look. I re-started it and it sounded even worse with the bonnet open. I turned it off and the car was recovered by the AA to a garage. I went there myself today and had a look to see what exactly had gone wrong. To the untrained eye the cambelt looks fine to me and all in one piece. I didnt want to totaly disable it so couldnt get to the tensioners to see if there is any failure there. The cambelt has done, dare I say it 43 thousand miles, I can here all the sighs and told you so's from here!
I did however, have a look in the front cylinder on the left (from the front of the car), with an endoscope borrowed from work, (like a fibre optic with a light). There was definite damage in the combustion chamber, to the sides and to the top of the piston. I couldnt get to see how badly the valves were damaged as the scope didnt get round that far, but it did confirm( I think), that there has been at least a slipped cam/cambelt.
So what next? I recovered the car back to work so I can get to it at any time. I guess it will be heads off and see what damage has been done.
So will I need a new head(s)? obviously new cam belt and tensioners etc. I am unsure if I can do the work myself, but I do have access to the locking tools and the timing tool for a limited time plus I have a Haynes manual! I cant go wrong! I have seen the post explaining head removal, this will become my bedtime story for the next few nights!
Ok over to the experts, what do I do now? any help greatly appreciated.

Cheers
El Swervo

[Matchless]

It sounds like you might have had the tensioner bearings or one of the idler bearings collapse which can lead to the belt slipping a few teeth.
First step is to remove cambelt cover and check on the cam timing, rotate the crank until the small notch is facing directly down and in-line with a V notch on the alloy caseing beneath the crank sprocket. The marks on the cam sprockets should now line up with notches in the back plate (may need to rotate crank through 360 deg to achieve alignment) Cam sprocket timing marks are numbered 1-4 from left to right.
We think you can get away with 2 teeth out without valve damage but thats all.
Check the belt for missing teeth, a failed tensioner or idler is usually pretty obvious.

If 2 teeth out its worth fitting a new belt kit and seeing if it runs.
If more than 2 teeth its likely to have bent valves so heads have to come off to assess damage....new valves are available on EBay (same for all ecotec engines xcept 3.0).....If valve heads are bent significantly then the valve guides are likely to be cracked which means replacement heads --- dont reuse a head with cracked guides!!!!

If a new belt kit gets it running OK then check the manifold vacuum, anything less than 19" would suggest slightly bent valve heads, I have had to rebuild one recently due to poor performance and high fuel consumption, vacuum was 17" and the valve heads were found to be around 0.006" off the seats but the damage wasnt visible, engineer's blue found it.

[TheBoy]

I agree with Matchless above - first port of call is to strip to cambelt, and see if its slipped.  The cambelt DVD (£3 from user Robin Hood) is worth its weight in gold as well.

Once you know if its slipped, then start to make further decisions....

[ffcgary1]

Sorry to here about you troubles but i think that it is VERY unlikly that you will have got away without bent valves and cracked guides, there are a pair of 2.5 heads on ebay at the mo so i would get those as you WILL need them. timing belt and rollers without a doubt and the job is time consuming but not too hard to do.
 

[El_Swervo]

I agree with Matchless above - first port of call is to strip to cambelt, and see if its slipped.  The cambelt DVD (£3 from user Robin Hood) is worth its weight in gold as well.

Once you know if its slipped, then start to make further decisions....

Hello, matchless,TheBoy and ffcgary1,
Cheers for all the help, I will be stripping it monday or tuesday and will see what has occured. If its slipped will go for a new cam kit and hope for the best. If still no good I will mabee get the heads, depends on the budget really as the car needs a few other jobs done like the front brake discs and pads also the tracking and a new tyre. There is also a lurching uneven idle problem that will need to be fixed as its like being at sea when waiting at the lights!
I have got the DVD from Robin Hood, How good is that! Only payed my £3 yesterday and its here already and I have watched most of it. Very Very good, Gives me a lot more confidence to do the job myself and 100 times better than a Haynes manual, Cheers Robin Hood!
I will continue this thread with the results.
Thanks again!

[TheBoy]

I agree with Matchless above - first port of call is to strip to cambelt, and see if its slipped.  The cambelt DVD (£3 from user Robin Hood) is worth its weight in gold as well.

Once you know if its slipped, then start to make further decisions....

Hello, matchless,TheBoy and ffcgary1,
Cheers for all the help, I will be stripping it monday or tuesday and will see what has occured. If its slipped will go for a new cam kit and hope for the best. If still no good I will mabee get the heads, depends on the budget really as the car needs a few other jobs done like the front brake discs and pads also the tracking and a new tyre. There is also a lurching uneven idle problem that will need to be fixed as its like being at sea when waiting at the lights!
I have got the DVD from Robin Hood, How good is that! Only payed my £3 yesterday and its here already and I have watched most of it. Very Very good, Gives me a lot more confidence to do the job myself and 100 times better than a Haynes manual, Cheers Robin Hood!
I will continue this thread with the results.
Thanks again!

I am sorry to be the bearer of bad news, but if it has slipped 3 or more teeth, and 'sounds like a diesel', it really doesn't bode well

Still, strip to cambelt, then you will have better idea

[El_Swervo]

Its me again.
Well I have stripped the car down to view the cambelt, thanks to that great dvd.
It appears to have slipped on number 3 and 4 cams.( this is with the crank shaft at top dead center and cams 1 & 2 lined up with the timing marks). The belt does not seem damaged at all and the various idlers and tentioners look to be intact, although I realise this is does not mean that they ARE ok. One thing I noticed was that the inside of the plastic cover has witness marks at the top, where the belt has  touched,(and melted), the plastic. The cover is broken in one place but repairable.
The amount of slippage seems to be 2 teeth only on both at the most.
I have checked all but one cylinder inside with an endoscope and looked at the valves and all look like they are free of heavy damage so I am going to proceed with the repair and change the belt and tensioner etc. Hopefully this will be successful. I will then go further on to test the manifold vacuum etc.
The one-way valve mentioned on the dvd seems to be u/s as when sucked it sounds like a trumpet.
Any comments gratefully accepted and noted!

[TheBoy]

the noise still worries me.  may be worth timing it up, and doinf compression test

[El_Swervo]

the noise still worries me.  may be worth timing it up, and doinf compression test

I know what you mean, but this would mean doing the job twice? (The noise was a bit like pinking so it could have been that sort of rattle??) I have thought about this way round it but I have just this last few minutes bought a new cambelt kit to do the job and will have to hope for the best. I can allways take it back off again and use it on another,(compatible), car? I have also bought a cam belt tool kit complete with all the bits on e-bay they have 2 left I think. The kit I was going to borrow is not available until Friday and is only the cam belt locking tools and does not have the timing gauge.
i will have a go as soon as it all arrives, hopefully Thursday latest! :-/

[El_Swervo]

the noise still worries me.  may be worth timing it up, and doinf compression test

what I didnt mention is that I was worried that if a tensioner had collapsed or been damaged, I would further damage the engine by running it again with the old bits?
I did notice the belt "pucker-up" when rotating the crank a couple of times, I dont know if this is normal? I suspect not?

[IrmscherKris]

Theres a 3ltr MV6 engine in the for sale section  

Because the timing has to be spot on, its poss the timing moved only a tad thus causing valve piston contact hence the noise.

[Kevin Wood]

Do the tension marks on the tensioner pulley still line up or has the tension gone?

I'd say it's worth timing it up with new belt and tensioners and see how it runs and what the compression is like. Can't do any harm and you may well have escaped with only very light contact with the valves.

If you'd like a second pair of eyes cast over it (and loan of a cam locking kit and compression gauge) I work in Fleet. Not far from you?

Kevin

[El_Swervo]

Do the tension marks on the tensioner pulley still line up or has the tension gone?

I'd say it's worth timing it up with new belt and tensioners and see how it runs and what the compression is like. Can't do any harm and you may well have escaped with only very light contact with the valves.

If you'd like a second pair of eyes cast over it (and loan of a cam locking kit and compression gauge) I work in Fleet. Not far from you?

Kevin

Kevin,
I wouldnt turn down any expert help, the car is at work in Pyestock, just down the road from Fleet, so if you are around later this week let me know!
The tensioner didnt look as if the marks lined up at all, but couldnt be sure.
 I was only going 5mph when it occured very low revs. would be nice if it is only light damage!
Cheers!
Dave

[Marks DTM Calib]

You may be lucky, you often get away with two teeth and the rattle might well be a noisey idler or tensioner which would be the route cause.

Fit the new belt and tensioner/idler and see how it goes....

[El_Swervo]

Well, I have got the locking kit and new belt kit waiting to go. However I have encountered a problem with the crankshaft locking tool from the kit I have bought. The tool does not lock the crank in the correct place. I line up the timing just before t.d.c and attatch the tool. I then keep going until the tool locks onto the water pump,( just like in Robin Hoods DVD), It seems to over shoot. When I remove the tool it has gone past t.d.c on the crankshaft pully marks.  The tool does not line up in either way, niether with t.d.c or in line with the w. pump pully. It actually misses it as if its too far foward, towards the front of the car. If I move it about it will lock up, although not very well. I could bend it back a little to line it up but as its new I dont want to break it so if its no good, I can send it back. The set is from lazer tools and is the right kit, any ideas? As I said though, even if the tool was in line with the pump pulley it will still allow the crank to go beyond T.d.c,(according to the marks on the crank pulley).
comments very welcome!