Author Topic: V6 Engine Cambelt  (Read 1096 times)

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Offline cphill

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V6 Engine Cambelt
« on: December 15, 2020, 17:04:35 PM »
Does anyone know if the later (post 1997) cambelt tensioner pulley (with outer flange), idler pulley and bracket (code 'E') can be fitted to a 1993 V6 engine, which came with the earlier bracket and non-flanged tensioner pulley (code 'D') ?
I ask because, although I specified a cambelt kit for my 1993 V6, the supplier has sent the kit with the later bracket and tensioner pully.
I'm aware that with the flanged tensioner you have to fit the cambelt clockwise, instead of anti-clockwise as you do with the unflanged tensioner.

Offline agw9262

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Re: V6 Engine Cambelt
« Reply #1 on: December 15, 2020, 18:32:42 PM »
I’ve never tried to, and therefore I don’t know if it might work. But from a personal perspective, I wouldn’t chance it.


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Offline cphill

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Re: V6 Engine Cambelt
« Reply #2 on: December 15, 2020, 20:44:41 PM »
Thanks for the reply. The cambelt kit is from Gates and I've now noted from their website that they supply the same kit part number for pre and post 1997 V6 engines. So it does look as though they're expecting that pre-1997 engines can be fitted with the later flanged adjuster. I'll try to get advice from them via their website (but I don't hold out a lot of hope!).
One other thing I've noticed: the cambelt comes with two sets of markings to line up with the timing marks - one set in white, the other in beige. Gates's fitting instructions don't mention these at all. I suspect that one set is for fitting the cambelt clockwise (as is required for the flanged tensioner pulley) and the other set is for fitting the cambelt anti-clockwise - when the unflanged tensioner pulley is used.
But which is which? Can canyone help?

Offline agw9262

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Re: V6 Engine Cambelt
« Reply #3 on: December 15, 2020, 21:03:13 PM »
Are they both single line markings?

Is this some help? Doesn’t mention the line colours but might help you with replacing.

http://cloud.tapatalk.com/s/5fd9167ee8893/How%20to%20replace%20timing%20belt%20on%20Vauxhall%3AOpel%20Calibra%202.5i%20V6%201993-1996.pdf


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Offline cphill

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Re: V6 Engine Cambelt
« Reply #4 on: December 15, 2020, 22:10:59 PM »
There are 2 sets of double line markings (white & beige) for the crankshaft sprocket, and two sets of single line markings (white & beige) for cam sprockets 3 and 4 (at the front of the engine). However, there is only one set of (white) markings for cam sprockets 1 and 2

Offline cphill

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Re: V6 Engine Cambelt
« Reply #5 on: December 15, 2020, 22:17:09 PM »
Correction! The two sets of single lines are for cam sprockets 3 & 4. The single set of white lines is for cam sprockets 1 & 2

Offline cphill

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Re: V6 Engine Cambelt
« Reply #6 on: December 15, 2020, 22:19:32 PM »
Sorry - got that wrong. tThe 2 sets of single lines are for cam sprockets 1 & 2. the single set of white lines is for cam sprockets 3 & 4 at the front of the engine

Offline cphill

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Re: V6 Engine Cambelt
« Reply #7 on: December 18, 2020, 13:39:56 PM »
I've, disappointingly, received no reply from Gates on the two sets of markings on their cambelt for the V6 engine.
So I've done some more researching online and turned up a US Youtube video showing the fitment of a cambelt to the same V6 engine that is used there in the Cadillac CTS (which is really a Vauxhall Omega in disguise). www.youtube.com/watch?v=DFWtovLxE4Y
This indicates that the white markings are used on the pre-1997(1999 in the US) engines with the flangeless tensioner pulley where the cambelt can be fitted in an anticlockwise direction. The beige (or yellow as they're called) markings are used in the later engines with the flanged tensioner pulley where the cambelt has to be fitted in a clockwise direction. The beige markings are for the crankshaft and for cam sprockets 1 & 2 (rear of the engine for Calibras and Cavaliers). The white markings are for cam sprockets 3 & 4 irrespective of the year of the engine.
I then compared the tensioner bracket casting on my 1993 engine with the new one supplied in the Gates kit - and they are not identical. The tensioner pully in the Gates kit is mounted further "out" than in my older version. I think this explains the need to use the beige markings - because the cambelt has further to 'travel' between crankshaft and tensioner pulley as you fit it. This also applies to cam sprockets 1 & 2 of course, but not to sprockets 3 & 4 because the idler pulley between the two sets of camshafts can be adjusted accordingly.
This still doesn't explain whether you can fit the later bracket, flanged tensioner pulley and idler pulley to the earlier engines. The fact that the Gates kit part number is the apparently the same for all V6 engines would suggest that you can, but I am still cautious about this. I think I'll swap the idler pulley from the new bracket to my older one, and leave the flangeless tensioner pulley in place, Luckily, the bearing on this still feels smooth in operation.
It really would have been helpful if the Gates kit had this information packed with it - or online - but unfortunately it does not, the online instructions are very generic.

Offline agw9262

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Re: V6 Engine Cambelt
« Reply #8 on: December 18, 2020, 15:37:47 PM »
Sad to hear that but I think your cautious approach and apprehension is very sensible.

Do keep us posted, interesting to hear how you get on.


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Offline cphill

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Re: V6 Engine Cambelt
« Reply #9 on: December 21, 2020, 13:15:03 PM »
Well I’ve now received a reply from Gates to my query about the white and yellow timing markings on the timing belt supplied in their kit no. K015453XS:

“For models till ’99 (with idler just above crankshaft),
•   Use the TM’s on each side of the direction of rotation arrows to line up the left camshaft sprockets.
•   Use the 3 remaining WHITE TM’s to line up crank- and right camshaft sprockets.
For models from ’99 onwards (with idler in the middle between left camshaft and crankshaft),
•   Use the TM’s on each side of the direction of rotation arrows to line up the left camshaft sprockets.
•   Use the 3 remaining YELLOW TM’s to line up crank- and right camshaft sprockets.”

The belt supplied in my kit has only white TMs around the direction arrows so this advice effectively means that only the white TMs should be used on pre-1999 models, while a mix of white and yellow TMs should be used on post 1999 models.

However, the reply is confusing in two areas:
1.   The reference to LH and RH camshaft sprockets does not define whether this is as you look directly at the timing belt from the side of the car (or from the front on a Vauxhall Omega), or whether it refers to an Omega, sitting in the driver’s seat looking forward. I suspect the latter because of the way the white and yellow TMs are arranged on the belt, and because this is the way LH and RH are conventionally used.
2.   The reference to an idler just above the crankshaft for pre 1999 models, and between the left camshaft and crankshaft for post 1999 models is very confusing. As far as I’m aware ALL V6 engines have two idlers – one just above the crankshaft and the other between the two camshaft pairs.

I’ve replied to Gates asking for some clarification, but I’m getting a bit pessimistic about getting it!

Offline cphill

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Re: V6 Engine Cambelt
« Reply #10 on: December 22, 2020, 18:20:49 PM »
Gates, who supplied the kit K015453XS for replacement of the timing belt and pulleys on my 1993 Cavalier V6 have, despite my initial pessimism, been very helpful in sorting out the use of the white and yellow timing marks on the belt and the issue of flangeless and flanged tensioner pulleys.
The changeover from a tensioner pulley with no front flange to one with flanges at both front and back occurred in 1997, so my 1993 V6 engine came with the flangeless pulley. Gates has confirmed that the flanged tensioner pulley, together with its mounting backplate and top idler pulley, as supplied in their kit, is a direct replacement for my flangeless version, and that this change has nothing to do with the use of the white or yellow timing marks on the belt. Since the flangeless pulley has been associated with the belt riding forward and scuffing the plastic cover, changing over to the flanged design is a good move (though I’ve never had a problem with my flangeless design in 114,000 miles).
The white and yellow timing marks relate to a later change which occurred in 1999 and is illustrated in the diagram. The left hand diagram shows the pre 1999 arrangement, while the right hand diagram shows the post 1999 arrangement. The only difference is that the idler pulley up from the crankshaft in an anti-clockwise direction in the diagram has been moved higher up. For the pre 1999 engines, solely the white timing markings on the belt are used. For post 1999 engines the yellow marks are used for the crankshaft and cam sprockets 1 & 2 (the pair on the left in the diagram), while the white marks are used for cam sprockets 3 & 4 (the pair on the right in the diagram), there being no yellow marks for these two positions.
So, with Cavalier Mk3 manufacture ending in 1995, and Calibra manufacture ending in 1997, the yellow timing marks only apply to later Omegas – and of course subsequent Vectras and other GM cars that used the V6 engine.
This has taken significant effort to sort out – I wish the timing belt kits would come with a simple printed sheet with this explanation and diagram.
And yes, I know that people have successfully changed timing belts without using the timing marks on the belt. I have done this several times also, and without a locking tool kit either, but now I have a locking kit I want to do the job “by the book”.

Offline agw9262

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Re: V6 Engine Cambelt
« Reply #11 on: December 22, 2020, 18:24:45 PM »
Gates, who supplied the kit K015453XS for replacement of the timing belt and pulleys on my 1993 Cavalier V6 have, despite my initial pessimism, been very helpful in sorting out the use of the white and yellow timing marks on the belt and the issue of flangeless and flanged tensioner pulleys.
The changeover from a tensioner pulley with no front flange to one with flanges at both front and back occurred in 1997, so my 1993 V6 engine came with the flangeless pulley. Gates has confirmed that the flanged tensioner pulley, together with its mounting backplate and top idler pulley, as supplied in their kit, is a direct replacement for my flangeless version, and that this change has nothing to do with the use of the white or yellow timing marks on the belt. Since the flangeless pulley has been associated with the belt riding forward and scuffing the plastic cover, changing over to the flanged design is a good move (though I’ve never had a problem with my flangeless design in 114,000 miles).
The white and yellow timing marks relate to a later change which occurred in 1999 and is illustrated in the diagram. The left hand diagram shows the pre 1999 arrangement, while the right hand diagram shows the post 1999 arrangement. The only difference is that the idler pulley up from the crankshaft in an anti-clockwise direction in the diagram has been moved higher up. For the pre 1999 engines, solely the white timing markings on the belt are used. For post 1999 engines the yellow marks are used for the crankshaft and cam sprockets 1 & 2 (the pair on the left in the diagram), while the white marks are used for cam sprockets 3 & 4 (the pair on the right in the diagram), there being no yellow marks for these two positions.
So, with Cavalier Mk3 manufacture ending in 1995, and Calibra manufacture ending in 1997, the yellow timing marks only apply to later Omegas – and of course subsequent Vectras and other GM cars that used the V6 engine.
This has taken significant effort to sort out – I wish the timing belt kits would come with a simple printed sheet with this explanation and diagram.
And yes, I know that people have successfully changed timing belts without using the timing marks on the belt. I have done this several times also, and without a locking tool kit either, but now I have a locking kit I want to do the job “by the book”.

Fantastic update, thank you!


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Offline cphill

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Re: V6 Engine Cambelt - Addendum
« Reply #12 on: December 23, 2020, 12:57:12 PM »
Addendum: I’ve just been able to look at the excellent DVD from the Omega Owners Forum showing V6 timing belt replacement. This states that the different backplates for the tensioner and upper idler pulleys are NOT interchangeable. This is in opposition to Gates’s advice that the later backplate is a direct replacement for the earlier one and, having taken another look at my original backplate and the new one in the Gates kit, I can see that they do differ significantly in the position of the tensioner pulley. So I think the best advice is, if the kit supplies a different backplate to the one on your vehicle, just swap the older tensioner and upper idler pulleys for the new ones in the kit and keep the original backplate. It appears that you can still swap a flangeless tensioner for the newer flanged type when doing this. The advice on which colour timing marks to use is unaffected by this new information.  Ho hum – why is this so complicated?

Offline agw9262

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Re: V6 Engine Cambelt
« Reply #13 on: December 23, 2020, 14:25:57 PM »
God only knows but it sounds troubling... I was lucky - the kit was an identical and straight swap - but I have the 1997 v6 model.


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Offline cphill

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Re: V6 Engine Cambelt - addendum 2
« Reply #14 on: December 23, 2020, 16:25:28 PM »
New information that I have just received via the Omega Owners Forum is that the Gates advice is correct and the new design backplate, tensioner pulley and upper idler pulley assembly in their kit is indeed a bolt-on replacement for the older design in my engine. In fact it is NOT recommended that I move the newer tensioner and upper idler pulley from the new backplate to my older one. So.....you pay your money and take your choice!