Snapped camshaft.

DavidRutherford · Post by **DavidRutherford** » Tue Apr 28, 2009 6:54 pm

Got a call from my Landlord today, as his BX (the Triton green Ex-MrB and Ex-Marty car) had broken down big-stylee. Apparently the pump end of the camshaft has sheared off. The pulley that drives the HP pump and about 3" of camshaft have come off, and hence the car is now un-driveable.

I'm suspicious, as the HP pump belt was slipping badly recently and hence knackered, so I changed it for a new one. I can't see how changing the HP belt could have caused this, but it's a bit of a co-incidence to say the least. The belt wasn't over-tight (you could do the standard 1/2" deflection under thumb pressure), and the HP pump seemed fine.

Anyone heard of this happening before? I've certainly never heard of a camshaft breaking for no apparent reason like this.

Irritatingly, the car has done this when he's some 160 miles away from home, and without breakdown cover, so the Landlord has had to leave the car at a garage and get the train home. He was considering just cutting his losses and scrapping the car there and then, but I've probably been able to sort something to be able to go and collect it with a flatbed trailer. Would be a big shame to scrap the car as other than the sheared camshaft, it's in very good order.

Any thoughts?

350ci muppet · Post by **350ci muppet** » Tue Apr 28, 2009 7:08 pm

in my time ive broke 3 1900d snapping camshafts like you mention 3 inches up the cam but from the belt end not the pump end none for no apparent reason

DavidRutherford · Post by **DavidRutherford** » Tue Apr 28, 2009 8:16 pm

Well, the Landlord has just got back, and presented me with the pump drive pulley and 3" of camshaft. It appears that the failure was along the edge of the bearing surface (no surprise there as it's a stress riser)... but what is slightly surprising is that the failure is brittle fracture, not fatigue.

I suspect the HP pump has siezed solid, and with a nice new belt on it has managed to transmit enough torque to the camshaft to shear it. I'll be willing to bet there's no other damage to the car at all.

This is doubly annoying, as I changed the HP pump about 4 months ago as the old one was leaking from it's shaft seal. The one I fitted had been out of use for some time, but I saw no reason to think it was anything but fine, and indeed it worked fine for these 4 months.

Very annoying.

Post by **mat_fenwick** » Tue Apr 28, 2009 9:29 pm

Do you have a spare cam any more?

I do have a N/A cam from a 205, which has kind of been earmarked for someone else, but I can find out whether they still want it. I believe that some machining of the HP pump end, or the pump pulley will be needed to get it all to line up, but you'd probably know more than me whether that is the case.

DavidRutherford · Post by **DavidRutherford** » Tue Apr 28, 2009 9:32 pm

I do have a spare camshaft, so that aspect isn't so much of a problem.

The question in my mind is whether I can be bothered to repair it. The Landlord has said he's not interested in the car anymore (although might well like another BX TD) so if I want it, it's mine.

Do I repair and sell it, or just strip it for the tyres/suspension/interior/engine/aircon etc.

hmm.

Philip Chidlow · Post by **Philip Chidlow** » Tue Apr 28, 2009 9:37 pm

Well I guess it would sell once repaired, for more than it would cost you to pick it up and drive back. With your time and the hassle though... you might break even. Why not find out if there's anyone we know on here who can fix it nearer to it?

Aerodynamica · Post by **Aerodynamica** » Tue Apr 28, 2009 10:59 pm

Just a thought - could either the PRV or FDV have a jammed slide valve that's caused the pressure from the pump to climb with out dumping at a set pressure to result in something giving? It has been known that on DSs a stuck PRV can occur but the accumulator sphere explodes instead.

- Just incase you write off the HP pump as the cause when it's still sound.

DavidRutherford · Post by **DavidRutherford** » Tue Apr 28, 2009 11:18 pm

It's an interesting thought, but if that had been the case I would have expected the HP pump to stall the engine, or something else to give, and maybe in a more ductile manner. The fail of the camshaft looks like the loading was sudden.

When I recover the car, I plan to change the camshaft and then run the engine with the HP pump belt loose enough that it should slip rather than snap the camshaft, and see what happens.

Post by **docchevron** » Wed Apr 29, 2009 2:14 am

It was a well known problem years back, but aint heard of it happening for a very long time.
It usually occured when starting the engine, especially if the suspension had settled putting immediate load on the pump.

But like I said, I aint heard of it happening for a very long time indeed.
Until now.
Unlucky.

Triton green aint it?
If you want shut of it, I *may* know someone that might take it on.

DavidRutherford · Post by **DavidRutherford** » Wed Apr 29, 2009 7:18 am

It is indeed triton green. It also has speedlines with nearly-new 195's, working Air-con, Le-Mans (I think) interior, centre cubby box, temperature gauge dashboard, etc.etc.etc. It's a rather nice BX.

If you do find someone who wants it, would it be in its current state, or repaired? I'm off to go and recover it this weekend, and am taking a camshaft with me in the hope that I get get it running.

DLM · Post by **DLM** » Wed Apr 29, 2009 1:21 pm

Maybe a silly thought, this, but could it have had A/c compressor startup and HP pump load acting simultaneously? Sounds like a car worth fixing...

Post by **mat_fenwick** » Wed Apr 29, 2009 1:41 pm

The A/C compressor is driven from the crankshaft...

Post by **docchevron** » Wed Apr 29, 2009 1:48 pm

DavidRutherford wrote: If you do find someone who wants it, would it be in its current state, or repaired? I'm off to go and recover it this weekend, and am taking a camshaft with me in the hope that I get get it running.

Either really mate.
It wouldn't be a vast issue for me to stuff a cam in it TBH.
That said, I cant actually get holf of Graham right now..

How much are we looking at?

DLM · Post by **DLM** » Wed Apr 29, 2009 3:42 pm

The A/C compressor is driven from the crankshaft...

my only excuse is that I couldn't be bothered to go down 10 floors to my airconned BX and check, as I couldn't remember offhand... shows how often I've changed a timing belt, though that alternator/compressor belt seemed to go come off and go on more often than a whore's drawers towards the end of last year when playing alternator swapsies.

Vanny · Post by **Vanny** » Wed Apr 29, 2009 6:07 pm

obvious question, but i can't see it having been answered. Where is the car? Surely you could nip up there with a 10mm spanner and 10mm socket, and 2x 10mm drill bits, a shaft and two belts and fix it there and then. For a quick and easy job, it sounds like a doddle!