EXPERT ! non mb advise please.

[fred_raven]

ok , simply put my gf car ( 2001 vectra 1.8) only 65K mls on clock , pulled up at traffic lights and engine stopped and warning lights came on. when i got there tried to start engine turning over ok but no go! when checked by recovery , oil filler off, no movement at top so obviously cambelt gone! now what are my options? if turning over ok surely no damage to bottom of engine? if top is damaged , valves etc first how can I tell if there is serious damage ? if it is , could i get a replacement head? what are the problems of a direct engine replacement ? and finally as the car , although it has until now been very reliable, is it worth the trouble and expense?

 

[camerafodder]

1st move, take the head off and have a look!

 

[Satch]

If it failed at tickover could get away with nothing more than a cambelt replacement and a few bent valves. But sadly only one way to find out.

(Those engines have a 6 year/60,000 miles cambelt change requirement IIRC....)

 

[Howard]

I had an old Honda Aerodeck cambelt fail on me while going up a hill in Cornwall once . Car just stopped.

Took it to the nearest garage , had new belt fitted , all was right as rain.

Hopefully you might get away with it too.

 

[moonloops]

I had an old corsa GSi company car (yes I know )

Cambelt tensioner went at little over idle, cambelt came off. Engine was wrecked. Took poxhaul 5 months to fix as no spares available.

 

[Stratman]

Mrs. Stratman used to have an Astra. The belt went on the motorway, no noise just a lack of power and the engine light.

Got it home and put a new belt on to carry out a compression test. The first three cylinders were fine, then no.4 returned zero compression. Off with the head, and there was a faint mark where a valve had just made contact with the piston crown. The valve came out OK, and it was only possible to tell it was bent by rolling it. Two new valves (why not?), reassemble and it was fine.

Your engine will have been turning with the broken belt, so a compression test should be your first move. I doubt you will cause any new damage by turning it over on the starter motor.

 

[finisterre]

I agree with stratman; for the compression test you require a pressure testing thingy which costs not a lot, take the spark plugs out, screw in the dial's flexible hose and turn the engine over with the starter motor.

It isn't difficult.

 

[fred_raven]

thanks

thanks for such speedy replies guys!

 

[Bellow]

I agree with stratman; for the compression test you require a pressure testing thingy which costs not a lot, take the spark plugs out, screw in the dial's flexible hose and turn the engine over with the starter motor.

It isn't difficult.

Only to add that prior to that a good look at the plug tips for any metal shards and the suggestion of a bore scope to look at the piston crowns. And I'd turn it over by hand with the plugs out and feel for resistance. It would be a pity to inflict further damage if it is so far retrievable.

 

[dog68]

Unfortunately, the vectra engines are interference engines, so the pistons will have kissed the valves.

 

[jonnyboy]

No point in doing a compression test at all if the cambelt is snapped. Dependednt on the position of the cam when it snapped (which will now not turn in sequence with the crank) there will be valves open which will stay open as you turn it on the starter = no compression anyway.

 

[st13phil]

Unfortunately, the vectra engines are interference engines, so the pistons will have kissed the valves.

There ya go - first question answered. Some (a few) engines are "safe" in that a cambelt failure won't always result in valve damage, but if it's an interference engine you will definitely have bent valves.

As Stratman says, you'll often get away with just a couple of valves if it happened at idle, but the only way to find out for certain is to take the head off. In the meantime, don't turn it over any more!

 

[finisterre]

I thought the compression test was to be carried out after a new cambelt was fitted to check which valves were bent? I was assuming the cambelt would be put on in the right position. I used to turn the engine by hand using the crank bolt on my saab when I was replacing head gaskets but I don't know if your vectra has any accessible pulleys or whatever to turn your engine, Being cautious makes sense as suggested above. I was probably hasty in my description earlier. The advice from Bellow is definitely worth following.

 

[flango]

We do loads of Vectras with this problem, you can virtually write off the top end and pistons unless you have been extremely lucky with it happening at low speed. Head, Valves, cams,pistons usually all need replacing, the cheaper option is just to bin the engine and fit a good second hand unit if you intend keeping it. There are plenty about. Rebuild is possible if only minor damage but as been said only way to tell is head off and asses the damage. On this engine it;s usually the tensioners that fail causing the problem.