UPDATE

It is not possible to completely rotate the engine by hand. You can rotate the engine normally and it will get to a point where it stops and does not rotate anymore. It will rotate back but again to the same point. (It's the point where the pistons are in alignment with each other)

Looking at the crank pulley - it looked like it had a slight wobble. I've heard about the short nose crank problems but this is a long nose with the eight hole pulley. Took the pulley off (did not have to lock engine - what ever is not letting the engine turn over by hand is enough to undo the pulley bolt!!) the key guide is slightly worn but not too bad.

Knocking noise continues. Plus, with the load taken off from the waterpump, alternator and PAS, the sound is even more aggressive.

Again - turning the engine over on the starter = no noise.

Cam belt fine. Cam shafts fine. Valves clear of pistons.

The last part to be 'connected' is the starter motor and thought this could be jamming on the fly wheel. Taken this off too but no, engine still 'locked'.

Any ideas what could be causing the engine to stop in one position when turning by hand?

 

Are you sure the horrednous knocking wasn't just HLA noise?

 

If a cylinder is filling up with fluid, fluid does not compress like gas, i say fluid because it could be petrol or coolant, i`d check your injector, pull the one you`ve messed with and another on at the same time, spin the engine and observe the spray pattern`s, two handed and messy job.

 

Ok came back to this today..

Managed to rotate the engine with more force (longer braker bar), it would take a lot of effort, as if something was sticking then let go and complete the revolution.

Took the timing belt off to rule out anything in the head. The result, crank still 'sticks'.

Took the head off and da da - No.2 piston is 5mm lower than No.3 at TDC.

Bent rod? Or bearing damage?

Anyway whatever it is it's an engine out job. Will probably try and source a 2nd hand engine and strip this one when I have time..

 

That's a pisser but at least you know now.

My money is on a bent rod.

I'd mark up #2 injector so it doesn't get mixed up, then get those injectors flow tested and cleaned.
Seems like #2 injector stuck open hydro-locking thee motor.

 

Good call, unfortunately.

 

1 x bent rod..

Contact point:

Wear on cylinder:

Before:

After:

Could this level of damage really be caused by a stuck open injector flooding the chamber??

I've not really done any major internal engine work before so looking for a few pointers.

Theoretically if the rest of the crank is unaffected (engine rotates cleanly and smoothly now bent rod has been removed) could I just fit another con rod and bolt it all back together? Are there any procedures I should be carrying out on refit? (I'm going to get hold of another set of injectors)

Also, anything I should be replacing as a matter of course during reassembly?

 

Wow! Detailed pics, hydraulic forces on a running engine are about as extreme as you could get and I'd say you've been lucky!! Assuming symetry of bores / no scoring / symetrical crank / float tolerances...I'd rebuild the one you have.

I'm amazed it didn't self destruct!!

Edit:- I missed the wear on bore pic!! Bin Job!

 

how on earth did that happen. amazing.

 

Amazing that's the only damage.

Why would only one rod bend? Cylinder full of fuel from the leaky injector?

 

Difficult to say from pics and impossible to say without pics of the valves and piston top.

But because the cars not FI'd or been faffed with i'd bet good money the injector stuck open and hydro-locked the cylinder.

Personally i wouldn't bother faffing about with the motor.
Replacements are cheap and plentiful so i'd just buy a replacement motor and stick it in.

I'd get the injectors flow tested so it hopefully proves without a doubt the injector stuck open, but i wouldn't use that injector again though.

Just out of curiosity has any previous owner faffed about with the wiring?

 

Pete (Skir67) has a complete, very low mileage, Mk2.5 1.6 motor going for a song that he really needs to shift ATM........it's in Wrexham & I know that's some distance from you but if you have means of transporting I'd say it's well worth the effort.

Send him a PM if you're interested.

BTW, hydraulicking is actually less likely with an early 1.6 motor (not with the auto) due to the longer cam overlap duration which is around 20 deg IIRC - you've just been very unlucky I guess.

 

Update

Ok a couple of weeks ago I replaced the bent con rod (thanks Skuzzle for supplying) and bolted everything back together. I also had the injectors tested (thanks Stigatronix

) They were all given intensive testing paying particular attention to the suspect injector. The result; all injectors were healthy, no problems whatsoever.

So, it was not the injector..

I wired in the injectors out of the block to test that they were flowing correctly and to determine if it could be a wiring issue. All good so bolted them in. Final checks, turn the key.. fires straight up and no knocking. WOOOOOP!

I have now run the car for over 1000 miles without issue. However, the cause is still a complete mystery but happy to be driving it again.