Another MOT done and a unusual CL55 problem

[Will]

Had the 190E MOT'd again today, no problems as usual :bannana:

Anyway, whilst I was there I noticed a CL55 in a particularly dismantled state engine wise. It turns out that it was in for a rebuild after suffering from a bent con rod. Apparantly an injector was faulty which had filled a cylinder with fuel and caused it to hydraulically lock

I've seen/heard of hydraulic locking when a large amount of fluid enters very quickly (ie slurping a deep puddle of water through the airbox etc) but it seems very unusual for an injector to drop this much fuel into the engine! Anyone seen or heard of this before? Not a nice sight.

Will

 

[television]

If this fault started off slowly, the oil would be diluted with the excess fuel, I wonder what the bottom end is like

 

[miro]

Had the 190E MOT'd again today, no problems as usual :bannana:

Anyway, whilst I was there I noticed a CL55 in a particularly dismantled state engine wise. It turns out that it was in for a rebuild after suffering from a bent con rod. Apparantly an injector was faulty which had filled a cylinder with fuel and caused it to hydraulically lock

I've seen/heard of hydraulic locking when a large amount of fluid enters very quickly (ie slurping a deep puddle of water through the airbox etc) but it seems very unusual for an injector to drop this much fuel into the engine! Anyone seen or heard of this before? Not a nice sight.

Will

The early sign might be a misfire or a shake.

 

[Rory]

The early sign might be a misfire or a shake.

Which presumeably wouldn't be as obvious as in many lesser cylindered cars (especially to someone not mechanically minded)!

Still seems incredible that the injector could dump that much fuel in there (especially with the lower comression ratio of a petrol engine) - can they stick open and just continue to squirt fuel in?

 

[glojo]

The old Triumph engines used to push the stuff out, so this must have been an awful lot of fuel that managed to get into the chamber? Which in turn asks the question how on earth did it happen. Could it have been the excessive fuel igniting and the ensuing explosion? Or could it have sucked in water during the recent floods? I'm just trying to envisage how much fuel would be required to do this damage?

Nice post that makes you think.

Regards
John

 

[Will]

I'm with you John, my initial thoughts were the same as you - ie sucked in water because of the recent weather - I am only going on what I've been told but the garage are very straightforward and honest so I'm pretty much with them here.

I too was trying to picture how that much fuel could get in.

If the engine was running, surely it'd not have enough time to completely 'fill' the cylinder, and if it was switched off, the only pressure (and therefore fuel) that could get into the bore would be what's in the system with the pumps shut off?

Anyway, certainly a big failure and a nervous sight seeing a completely stripped AMG V8!

Will

 

[barryj]

You wouldn't get a replacment down your local engine centre would you......................"Yeah just had one in mate from a low mileage one owned by the local Vicar"

 

[scotth_uk]

I've lost an engine to fluid intake - not pretty. I'd be hesitant to buy anything with an AMG engine that had been cracked open by anyone other than AMG. :-(

 

[DieselE]

If the only damage was a bent con-rod then the fault did not occur with the engine running. Hydraulic lock tends to occur when the cylinder partly fills with fluid while the engine is shut down and the piston then hits the incompressible fluid during start up.