CAM BELT FAILURE! V6

[AeroNut]

I need some educated advice ....
There I was running along the M25, in the road works 50mph on Tues 6:20am when ......... silence befell me. The steering became suddenly very stiff.... I managed to make it to the coned off area between the live lanes... and there I sat.

.. long story short, today I have been informed the cam belt has failed.... The engine (crank) turns over but the cams don't go round....

.. not sure of the valve clearances and timing of the V6 engine but am I looking at bent valves and the like or does this have a happy ending?

Any advice would be appreciated ...

Otherwise this could be the end of my Bongo experience....

Regards

Terry D

[Bob]

You may be lucky but Bongy is an 'Interference Engine' ie the valves will contact the pistons if the cam belt fails.

Possibly if you were going slowly and stopped quickly enough it might be ok, but sounds bad.

Sorry to hear of your bad luck.

[mikeWalsall]

Maybe some one will confirm as there seems to be conflicting info .. some Mazda V6 engines are not interference engine ... but no specific mention of the 2.5 quad cam RF-V V6 engines ..

[AeroNut]

....I never heard any loud noises, though I did have the radio quite loud..

Start planning a rebuild ?...

[mikeWalsall]

If it's .. not .. an interference engine then the valves will not have hit the pistons and a new cam belt kit should get you mobile ..

Simon Jones as posted a cut away drawing of the V6 .. this should illustrate the pistons TDC in relation to the maximum valve (lift) opening ..

[Simon Jones]

I've got this diagram, but unfortunately it's not really detailed enough. Not sure if it's an interference engine or not. I've got a spare cylinder head in the garage although I can't recall how deep the valves are recessed. Do you know when the cambelt was last changed? I'm not 100% sure what the recommend schedule is, but I'm guessing it's not dissimilar to the diesel: 50,000 miles / 5 years.

[AeroNut]

Hi all,
Thanks for your replies so far....
I bought the car in Feb 2011 and it's prob' covered about 25-30K kilometers since then. Where I got the bongo from I asked them to have the cambelt changed. It had only arrived from Japan the day before I first saw it. And on that day I returned home to wait 4-5 days for them to do the work and have the tyres changed and paperwork done. I have a stiker inside the door shut that says it was done .... though ?

Like has been suggested, if the likelyhood is they may not be damaged then I'll invest in belt kit, cam crank seals poss' a waterpump whilst i'm there etc
If it's likely the valves have been hit then I'll invest in head gaskets and bolts and a belt kit etc. I've seen the head gaskets and bolts for around £250 (but if I don't need them....)

If anyone has any experience with working on the V6 ...

Regards
Terry D

[Simon Jones]

Might be worth contacting the original dealer to ask them if they or the belt manufacturer offer any form of warranty on the work. It's also possible that the tensioner has failed which has allowed the belt to slip.

Has the cambelt cover been removed to confirm the exact nature of the problem?

I've found there are not that many garages that like working on the V6 but two that are recommended are Allan's in Plymouth (where I had mine done) or Discount Trucks in Newbury which would be the closer for you.

[mikeWalsall]

After the Saga with your auto box ... you do seem to be having a run of bad luck with your V6 ..!!

[mantaJim]

To the best of my knowledge the V6 is not an interference engine. My cam belt failed around 2 years ago and after searching the net convinced myself it wasnt an interference engine. As it happened the van suffered another failure a few days after it had been repaired apparently due to a dodgy tensioner bolt which came with the replacement kit. On neither occasion was I advised that any valves had been bent which would either suggest I have been exceptionally luck or the engine is indeed a non-interference engine.

[AeroNut]

Mike ... I honestly try to forget but well remembered

Jim .. thats what I want to hear.. not that you had issue ofcourse.. I mean that the issues you had never resulted in valve damage..

I think I'll prep for a belt change (Belt, seals, waterpump, etc) and see how we go...

If it turns out to be more then I don't think its wasted effort?

Regards

Terry D

[mikeWalsall]

My lads and me mess about with motor bikes / scooters .. using the removed one as a pattern .. we tend to source new seals from a local engineering / bearing business .. they tend to be cheaper and a better quality than some of the (Chinese) pattern parts ..

You will find that you can hook / pull them out quite easily with a 'spring puller' .. (easy to make one) ..

http://www.ebay.co.uk/itm/like/30132486 ... 108&ff19=0

[AeroNut]

Nice tool...
.... sure Ive got something like that laying around....

Thanks for your thoughts...

Regards

Terry D

[Simon Jones]

Pulled the spare head out the garage and looking at it, the valves do appear to be quite deep set. Unfortunately, the are no hydraulic lifters so I can't see how far the valves travel.

[AeroNut]

Have ordered an amount of parts to replace the belt and most parts that are worth doing whilst I'm there...
Parts should arrive tomorrow ...
This weekend could be busy...

What I'm looking for now is guidance on setting it all up... are there notes some where on timing a V6. I understand I have to remove the distributor and pull cam pulleys and the crank pulley off. I'm assuming there set with a key on the shafts but the shaft to shaft setting has timing marks.... I in general know how to set an engine (ford pinto's and the like..).... but not this one!

any help, suggestions greatly received

Regards
Terry D