Can anyone give me a bit of technical knowlege on the Vauxhall V6 engine (2.5 belt cam).
A colleagues 1997 Vectra V6 broke its belt, and the vauhall garage started to strip the engine. After romoving the heads he was told they would have to remove the pistons to check for piston ring damage. I thought this a bit over the top and suggested he go alobg to look at the car him self.
On looking, there is no evedence of valves hitting the pistons, and he has told them to just rebuild the top end with new valves where needed. They told him that the reason both heads needed removing is that the cambelt drives one camsharft, and a 2nd belt links the 2 cam shafts together. I wasn't aware the Vauhall V6 had this arangment, I thought it was one belt....
Any ideas?? Does cambelt breakage on this engine normally cause bend valves.... or is the dealer trying a sneaky one?
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Neil T
Mondeo Ghia TDCi 130 Estate, SEAT Toledo 20VT Sport, Various Montegos...
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I don't know the answer to your main question, but..
>>just rebuild the top end with new valves where needed
And why would new valves be needed if the old ones hadn't hit the piston ?
I would have thought that any damage to the valves indicated a collision and that any bits missing may well have impacted the rings. Although if it is possible to turn the engine over I would also expect that most damage would show almost immediately on the bore, especially if some marker was used to show up any uneven scratching.
In the end I guess it depends how long he intends to keep the car and how much he cares about it compared to the cost of doing the whole job.
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>>>And why would new valves be needed if the old ones hadn't hit the piston ?
I did state "just rebuild the top end with new valves 'where needed"
I know from experience on a Citroen AX that just becuase there is no sign of impact with the piston that the valves can be bent, I had to replace all 8.... some only had the slightest of damage.
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Neil T
Mondeo Ghia TDCi 130 Estate, SEAT Toledo 20VT Sport, Various Montegos...
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I have a photo of the the Vectra V6 cam belt run: It is indeed one belt, that takes a very typical routing for a V6 engine: Having passed over the top of both cam drives for the rearmost bank of cylinders, it then drops down, passes under a tensioner between the two banks, and rises up again to pass over the top of the two cam drives for the front cylinders.
Cambelt breakage often damages valves on this 'interference' (i.e. things hit when a belt breaks) engine, and your colleague is lucky not have damaged pistons too.
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If the valves didn't hit the pistons then just put it back together, reset the position of the camshafts, add a cambelt, and off you go...
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Hard luck on your colleague. There will certainly be damage to some of the valves. The stems are incredibly thin which seems to confine the damage as on other engines I have come across with sturdier stems the resulting contact of a belt breakage can cause the top of the piston to distort and pinch the top ring. Never seen this on a late Vauxhall though unless bits of broken guide have added to the fun. Go ahead and have the heads rebuilt by an independent reconditioner and make sure the guides are inspected and replaced if necc.
Andrew
ps it is only one belt btw.
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Simplicate and add lightness!!
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