Dobbs · Nov 14, 2015

Chaps, what does the collective brain reckon to this problem.

I've just replaced the vacuum pump on 12J. But now it's all back together, the engine won't start.

It turns over ok, and there's fuel at the injectors - I bled them as I had to move two pipes to get the vac pump off.

What I have noticed, is there's now a loud popping and smoke coming out of the air intake too.

Any ideas?

Cheers In advance
Dobbs

jamesmartin · Nov 14, 2015

is that all you removed? i can understand it not staring due to disturbing fuel system ie air or weak lift pump that often goes unnoticed till you disturb the system ,did vac pump fit home easily you didnt need tto pull it down with the bolts, might be worth checking valve opening and tappet clearance ,dont run engine with vac pipe nor secured to servo as it will pump air in to engine

Dobbs · Nov 14, 2015

The fuel was my initial thought too, which is why I bled it, but all four injectors are getting a good stream now. The only other thing u changed was the seal on the mushroom, so that now fits well rather than rattles about.

Vac pump went on fine, no probs. All sealed up new gaskets etc, new pipe to servo, nothing to suspect there I don't think.

It's the loud popping and smoke in the inlet manifold that's bothering me now.

jamesmartin · Nov 14, 2015

check valves first and then timing belt hasnt jumped a tooth

Dobbs · Nov 14, 2015

Timing belt...

Yes that was my worry too, I can't think the valves would be so far out so quickly, so timing belt was the other suspect. Will that be a new belt if it looks ok, or best to replace the belt regardless?

Thanks JM.

jamesmartin · Nov 14, 2015

if youve gone as far as removing front cover you may as well change the belt considering its about a tenner , you could check exhaust peak no been 108 degress btdc without removing the cover if you have the means, see how tight cam is to turn and valves

Dobbs · Nov 14, 2015

Not sure how I could check exhaust peak. I don't have TDC markers on flywheel sadly.

jamesmartin · Nov 14, 2015

start with valves and push rods then remove front cover to be certain

Dobbs · Nov 14, 2015

What should I look for with the valves and pushrods?

Cheers

Dobbs · Nov 14, 2015

Hmmm.. Looks to me like pushrods 2 & 7 are bent. I'll whip the rocker off tomorrow and take a better look. They at a different angle to all the rest, but I can't be sure yet.

I did think the vac. pump was quite stiff; some I'm now wondering if it was too stiff, and jammed the camshaft when I turned the engine over, causing the timing belt to slip and throw the timing out. Which has now bu**ered the engine.

If that is the case, the supplier who will be named and shamed, will be getting a right earful on Monday. Vac pump did not arrive in a blue box btw.

flat · Nov 14, 2015

Doubt it's buggered, re-time it and fit a couple new pushrods etcz

Dobbs · Nov 14, 2015

flat said:
Doubt it's buggered, re-time it and fit a couple new pushrods etcz

Cheers mate, that's what I'm hoping. Will have the timing cover off tomorrow to see what the story is under there, and the pushrods out too. Just reading the tappers might need replacing too though.

flat · Nov 14, 2015

Yeah and hopefully it's just the belt that's skipped and none of the key ways are shagged.

Dobbs · Nov 15, 2015

Bu**er. As we suspected. Timing has jumped. 6 of the 8 pushrods are bent.

Could there be other damage too.. to valves, or cylinders?

zeaphod · Nov 15, 2015

The pushrods are pretty easily bent compared to the valves, but it's definitely worth checking them while you have the rocker cover off. Get something to transfer the force down onto the top of the valve stems, push down hard and make sure they are all moving freely. Out of interest, why did you change the vac pump - lack of braking power?

Dobbs · Nov 15, 2015

Thanks. I'll def check out the valves too I think. Will the valve heads be ok, or is there a chance they've collided with the piston tops?

Yes, failed MOT due to lack of servo effect, and it had already had a new Servo and pipe, so vac pump was the next suspect.

jamesmartin · Nov 15, 2015

Dobbs said:
Thanks. I'll def check out the valves too I think. Will the valve heads be ok, or is there a chance they've collided with the piston tops?

Yes, failed MOT due to lack of servo effect, and it had already had a new Servo and pipe, so vac pump was the next suspect.

you can check valves by checking they are all the same height and will push open (you should be able to rig up a lever o do it)fully with pistons at half way, you need to be looking why which my first guess would be the vac pump or the fitting of

Dobbs · Nov 15, 2015

The valves all look ok so far, and seemed to working ok when I was rotating the to check the rocker clearances yesterday.

I'm 100% sure the cause was an overly stiff vac pump. When I fitted it, I noticed the thing wouldn't turn, and assumed that was normal. With the lid off the pump it turns fine, but with the lid on its almost rock solid. It's got score marks on the lid too, from the rotor inside. Obviously made to too tight a tolerance.

jamesmartin · Nov 15, 2015

too tight with lid on when off or fitted?

Dobbs · Nov 15, 2015

jamesmartin said:
too tight with lid on when off or fitted?

In hindsight, both. I just didn't think it was a problem before I fitted it. It's not like you can fit it any other way than correctly is it.

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