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[Ricky043]

After having got my dad's old omega back on the road after about 7 years being idle I have enjoyed using it for a few months till my mechanic, whilst working on my P5, enquired when I last did the timing belt. It has a chain I said, confusing it with the previous senator. I don't think so, he said. He was right, of course, On checking thru the service history I found the car had the timing belt kit fitted at 41,000 miles. Now on 88,000, so I breathed a sigh of relief. That is until I looked at when it was done. 2004!!!!
So it's back off the road pending a belt change in the next couple of weeks till my mechanic is free. My big question is about locking the cams. The ABS site says they should always be locked but my mechanic says he never locks them unless the belt is already broken, and he marks the pulleys with white paint for alignment purposes before belt removal. He's done thousands of timing belts but not a v6 Omega.

So my question is this. Is the v6 Omega timing belt so out of the ordinary that the cams simply must be locked before changing the belt or is my mechanics confidence in doing it without a locking tool common and acceptable for a professional mechanic rather than a super cautious home mechanic ( i.e. me)?

[Doctor Gollum]

ALWAYS use the locking kit.

If the belt snaps you're replacing heads, valves and pistons so that's a pretty stupid thing for him to say.

In short if he's prepared to cover the cost of rebuilding it then don't use a locking kit. Otherwise...

[Migv6 le Frog Fan]

Use a different mechanic. Anyone who says the belt / tensioners on a V6 Omega and be done without the proper locking kit is to be avoided at all costs !

[Nick W]

I'm not quite so dogmatic but it's extremely unlikely he'll get the timing better than close, and that will require considerable experience of this exact job. My car was clearly done the same way, with several extra marks. Unfortunately for whoever did the job, the timing tools showed that all four cams were a tooth out. Correcting that made the car run and perform better and added 3mpg to the fuel economy.


The cam locks are not the really important  part of the tools, as they only save you having to grow six more hands to feed the belt into place. What's essential is the crank tool and the gauge which allow you to ensure that all five toothed pulleys remain correctly timed after you adjust the various tensioners. That's probably the error whoever had fitted my belt made, as it can take multiple rounds of adjustments to get the timing exact. Anyone who thinks exact takes too long or is too much work shouldn't be trusted - I managed to do mine, for the first time, correcting the above faults in about two hours.

[Andy B]

I'm not quite so dogmatic but it's extremely unlikely he'll get the timing better than close, and that will require considerable experience of this exact job. My car was clearly done the same way, with several extra marks. Unfortunately for whoever did the job, the timing tools showed that all four cams were a tooth out. Correcting that made the car run and perform better and added 3mpg to the fuel economy.


The cam locks are not the really important  part of the tools, as they only save you having to grow six more hands to feed the belt into place. What's essential is the crank tool and the gauge which allow you to ensure that all five toothed pulleys remain correctly timed after you adjust the various tensioners. That's probably the error whoever had fitted my belt made, as it can take multiple rounds of adjustments to get the timing exact. Anyone who thinks exact takes too long or is too much work shouldn't be trusted - I managed to do mine, for the first time, correcting the above faults in about two hours.

when I did a cam belt on mine, it took me a week end. It's not often I'm ill, but I started the job & then felt unwell ... so I did a bit .... then a bit more the next day!

Dr Omega did the next belt! 

I agree with the fact that you could do a belt something like without a locking kit .... but it'd only be a best guess.

[Jim82]

My big question is about locking the cams. The ABS site says they should always be locked but my mechanic says he never locks them unless the belt is already broken, and he marks the pulleys with white paint for alignment purposes before belt removal. He's done thousands of timing belts but not a v6 Omega.

Are you an ABS member? They will loan you the locking kit for a nominal deposit/cost of postage. Or you can often find them second hand on eBay for about £30. Even if its possible to do the job without them, it's just so much easier with them

[Enceladus]

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So my question is this. Is the v6 Omega timing belt so out of the ordinary that the cams simply must be locked before changing the belt or is my mechanics confidence in doing it without a locking tool common and acceptable for a professional mechanic rather than a super cautious home mechanic ( i.e. me)?

A V6 Omega isn't really out of the ordinary. Since it's a GM 54° V6 and 24 valve there are two sets of camshafts to be timed to the crank pulley, that adds some complexity versus an inline 4 or 6. However nothing else is driven by the timing belt. I would expect that any other make of 24 valve V6 is at least as complex to set-up.

I agree with Nick W below. Even if you find an alternate means to lock the cams you still need the crank tool to lock the crank at TDC and the gauge to check the timing marks on the cam sprockets. Else you risk shifting the crank whilst adjusting the idlers. If it's not right then you risking scrapping the engine.

Also be aware that the adjustment order is the eccentric on the lower idler (should be so on your car), then the eccentric on the upper idler and then the tensioner. You need to rotate the engine using the crank nut through 720°, before checking and readjusting if required.

ContiTech (Continental AG) who were the OEM suppliers have a video here on how to go about replacing the timing components on an X25XE. Shows the use of the crank tool and the timing gauge. And the initial and final positions of the eccentric on the idlers. And also the setting of the tensioner

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The cam locks are not the really important  part of the tools, as they only save you having to grow six more hands to feed the belt into place. What's essential is the crank tool and the gauge which allow you to ensure that all five toothed pulleys remain correctly timed after you adjust the various tensioners. That's probably the error whoever had fitted my belt made, as it can take multiple rounds of adjustments to get the timing exact. Anyone who thinks exact takes too long or is too much work shouldn't be trusted - I managed to do mine, for the first time, correcting the above faults in about two hours.

[Nick W]

A V6 Omega isn't really out of the ordinary. Since it's a GM 54° V6 and 24 valve there are two sets of camshafts to be timed to the crank pulley, that adds some complexity versus an inline 4 or 6. However nothing else is driven by the timing belt. I would expect that any other make of 24 valve V6 is at least as complex to set-up.

It's not that the procedure is complex, but that the thinking behind the tools is so German. Hondas 24v Vtec NSX engine has a hole in each cam sprocket, and a corresponding one in the cylinder head. There's a special set available, but any appropriately sized rod will work - my friend uses the shanks of 6mm drill bits to lock, tension and align his using a similar procedure to the GM engine. The Renault 24v V6 isn't much different, once you realise that despite Renault's procedure it's perfectly possible to do it without removing the engine from the car...