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[JamesV6CDX]

Back in September I bought an extremely tidy low mileage CDX with a few issues, including (very) early oil cooler failure and a couple of engine management issues which I traced to the cam sensor

Because it was a project on the drive I've taken my time over it, stripped the top end completely, removed the heads etc to properly clean everything up and sort out a slight manifold blow.

I've slowly and carefully rebuild it, doing just a couple of hours at a time. It's been done meticulously, everything clean and assembled correctly.

Timing belt kit new, cam cover gaskets new, all seals, stat, water pump, hbv, all genuine parts too

Absolutely everything has been torqued correctly and fitted as it should be (hell I've done enough V6 engines) with no corners cut

Today I fired her up having finally finished her.

She ran fine at idle for about 10/15 minutes, there was a loud lifter or two, but I figured they'll need to recharge after major surgery, so just let it run to settle

I gave her a rev once she was fully up to temperature, and, as the rev counter went up, there was an absolutely stomach wrenching noise and the engine died instantly.

Upon examination, I can see that the crank is spinning freely, but the cams appear to be locked in place. The crank has obviously continued to spin at some force with the cams stood still, because it's shredded the teeth off the timing belt at the lower pulley.

Basicaly something has seized up here, it appears to be at the top end, and, it's let go at the higher end of the rev range. I think it's safe to say that the engine is likely to be well and truly goosed, with valve/piston contact at that engine speed.

I don't buy into the fact this is a freak accident. Apart from it's idle issues it ran fine before, and it's not likely to be a co-incidence that it's died after having work done.

But, I'm confused as to what has caused it. Timing belt pulleys are all intact and where they should be. It was all double and triple checked and fitted/torqued with the right tools.

I've yet to do a full post mortem. I had to walk away from it as it was soul destroying after all the money and work!

The only thing I can think is that, during the work, I've fitted 3.0 cams as an upgrade. But - as I understand, the camshaft caps are line bored to the head? I retained the 2.6's caps, and fitted them in the correct positions and rotations, to the correct torque, so no issues there that I'm aware of? I naturally checked that the cams all span freely by hand too before fitting the belt and running it.

I'd welcome any constructive opinions. I just can't stress how meticulously and thoroughly the work was done, this is the main thing that's confusing me, I've done so many of these and it didn't even cross my mind anything would go wrong !

For now I'm going for a beer.

[JamesV6CDX]

I should add. I have my 3.0 also on the drive. The body of this car has seen better days, which is why I've been stripping it - but the block / heads are all 100 percent intact, and the engine was in bloody good order.

I might just have to fit all the new bits onto the 3.0 engine, and transplant it in to the 2.6, using the 2.6 manifolds and engine management system, effectively making a 3.0 litre Drive-By-Wire engine. Different I suppose, but I don't see why it wouldn't work!

[05omegav6]

That idea will work provided you use all the 2.6 sensors, and I mean ALL of them would certainly put all the new bits to good use...

Had you dropped the oil? If so did you refill it?

[Kevin Wood]

Most likely cause IMHO is that one of the cam bearings have seized. Not sure it it's possible to fit the head gasket upside down or back to front, but on some engines that can starve the heads of oil pressure. Failing that, foreign object under the cam cover?

Bummer.

Can't see why the 3.0 wouldn't work  as long as it's new enough to have the threads for the DBW coil packs. Exactly what Daz did a couple of years back, in fact.

[05omegav6]

Most likely cause IMHO is that one of the cam bearings have seized. Not sure it it's possible to fit the head gasket upside down or back to front, but on some engines that can starve the heads of oil pressure. Failing that, foreign object under the cam cover?

Bummer.

Can't see why the 3.0 wouldn't work  as long as it's new enough to have the threads for the DBW coil packs. Exactly what Daz did a couple of years back, in fact.

That was his silver 2.6ish MV6 iirc can't for the life of me remember what he called it

As for the dead engine, once removed, strip it down and the cause should be obvious

[JamesV6CDX]

The head gaskets were definitely fitted correctly, I triple checked they were correct prior to fitting

I will whip the cam covers off tomorrow to see if any clues exist

[JamesV6CDX]

And yep 3.0 has threads for coil packs in the heads

[VXL V6]

Most likely cause IMHO is that one of the cam bearings have seized. Not sure it it's possible to fit the head gasket upside down or back to front, but on some engines that can starve the heads of oil pressure. Failing that, foreign object under the cam cover?

Bummer.

Can't see why the 3.0 wouldn't work  as long as it's new enough to have the threads for the DBW coil packs. Exactly what Daz did a couple of years back, in fact.

That was his silver 2.6ish MV6 iirc can't for the life of me remember what he called it

As for the dead engine, once removed, strip it down and the cause should be obvious

Was called OBI, the combination of Diff and Manual Box with a 3.0 block upfront made it a fabulous car to drive, pull away in second, put it in third and never bother to change gear again!
 

[05omegav6]

See, who said manuals were difficult to drive

[4x4]

You did notice he only used 2nd and 3rd because he couldnt get the other gears 

[omegod]

Some years ago I bought a 2.6 from a scrap yard,low miles and absolutely mint but had failed it's MOT due to a misfire/MOT emissions fail. It was literally a one Dr owned car with full VX history and low miles. I replaced coil packs, sorted breathers,cam covers, cam belt/serviced it fully and it ended up in Roger Budden condition. I used it for several hundred miles without issue but could I buggery sell it for decent money. I ended up selling it to a decent chap locally and just covered my costs but literally 15 miles later it had the clatter of death and he phoned me to come and have a look.

On inspection it had a terrible rattle at the back of the left cylinder bank and knowing it was now a breaker asked him to drive it back home but eventually the crank seized near my house, I'm convinced it was the oil pick up blocked due to poor VX servicing schedules. I know of several 2.6's having the same issue since and will forever swerve them or will strip off the sump if it's worth bothering with as a keeper.

[Sir Tigger KC]

Having just completed my first V6 strip down (HG's) and rebuild, you have experienced what I was dreading! 

Can't add anything constructive, other than I'm feeling your pain....    Bastard!!!     

[JamesV6CDX]

I am going to get the cam covers off shortly just to look in the cams for any obvious signs

That's all I'm doing aside of wrapping presents, eating, dog walking and beer drinking, this side of January though

In the new year I shall set about it with fresh enthusiasm and drop the 3.0 in there.

If there is one thing I will not be, it is beaten!

[Webby the Bear]

Feel your pain bro.

[TheBoy]

OBI was pretty rapid, although I only had a shortish spin, as DLK said I drove like a man possessed.