URGENT - AFN interference engine???

S4_dan · Mar 27, 2015

Tried to start the car after bleeding it, cracked a few injectors and she was almost starting!

Then one last turn on the key and it didn't sound right. So quickly removed the timing belt cover.......belt snapped! The screw in the centre of the top cover had collapsed and dropped into the belt!!

Is this engine an interference one?

Although it was only just turning when I noticed it snap. I didn't hear any clanging!!!

Really fecked off right now.

Kevinb5 · Mar 27, 2015

Not good mate,they are an interference engine,but surely if it was just turning like that you should ok?woild explain why it wouldn't fire easily aswell I suppose,the injection timing in the pump can be off with a slack belt

jbh · Mar 27, 2015

Ive heard of a few folk being lucky and it not doing damage but ive also heard of it bending valves..
I do have a complete head sitting Dan
it came off a good running engine.
only reason the engine got broke was I got offered good money for the pump so it made sense to break it and bag the head up.

S4_dan · Mar 27, 2015

Oh dear, not good news then!

I'm going to rob the belt off my mates engine tomorrow and fit it to mine to test the engine.

The washer from the middle screw in the top cambelt cover had come off and fallen in, cutting the belt :-(
It's all stripped ready. I just need to somehow time up the cam and crank. I've got the pump near to spot on. Just need to find a suitable tool to lock it.

JBH, what sort of price you looking for it? Postage will be a killer i bet?

Kevinb5 · Mar 27, 2015

5mm drill bit should lock the pump I think

jbh · Mar 27, 2015

postage wouldn't be that bad to be honest. if I get it in a good strong box and get it shipped by paisley freight I reckon £20 at the most.
as for price make me an offer. it will just go towards a belt kit and water pump for mine

jbh · Mar 27, 2015

im sure a bit of plate could be made up to lock the cam

as Kevin says a drill bit could be used to lock the pump.

jbh · Mar 27, 2015

on a side note... make sure when you lock the cam its on the correct cycle
my mate had his skoda engine rebuilt after cracking the sump and running it with no oil.
the garage " mechanic" swore it was lined up correctly but the car wouldn't run..
I told him that the cam was 180 degrees out but I was told not a chance..
so a few hundred quid spent at a diesel specialist plus a recovery charge it turned out the cam was 180 degrees out...

adamss24 · Mar 27, 2015

Take the rocker cover off and check the lifters for spiddering/cracking- it means the pistons have hit the valves hard and some valves might be bent...

S4_dan · Mar 27, 2015

Cheers. I will remove the cam cover tomorrow morning. Are the lifters easy to spot even with the cam in? The tippex timing marks for the crank and cam seem to be about in the right place. So I'm hoping the belt just snapped and no movement on the cam or crank has caused any issues.

I'm really kicking myself as the car was just about the start. I was hoping it would go in for an mot on Monday. Doubtful now though.

S4_dan · Mar 27, 2015

Would it be easier to unbolt the cam and see if the lifters all lift back up? That way I could possibly time it up better too?

S4_dan · Mar 27, 2015

Anyone know the torque/ nm of the cam bolts?

Kevinb5 · Mar 27, 2015

45nm seems to be the going torque for it,have you removed the cam then?

S4_dan · Mar 28, 2015

Not yet. I will first thing though in the morning.

aragorn · Mar 28, 2015

Ouch thats seriously unlucky. Though i guess, better it did it then, than doing it driving to the MOT station, so you've got some chance that its not mashed.

I once rebuilt a 1.4 8v petrol engine in an astra, got it all running and there was a odd whining noise from the timing belt. Took it to a garage mate and he said the belt was far too tight and i needed to reset the tension on it properly. Went home and took it all apart, set the tension and thaught "Ill just fire it up to check"... What i hadnt remembered was i'd removed the bolt that holds the crank pulley on to get the alternator pulley off to get access to the belt, and so the crank pulley was just sitting on its woodruff key. It started, was idling perfect, revved it up to hear the noise all sounded good, left it idling and got out to look at the belt, and the engine stalled. looked in the engine bay to find the belt has come off and the crank pulley is missing

Luckily for me, i put it all back together after retreiving the crank pulley from under the car and it ran fine.

S4_dan · Mar 28, 2015

Tell me about it!

Looking at the belt this morning, I now don't think the loose washer had caused it to snap. There is no rubbing mark at all on the belt. it's a jagged snap. I think it's due to age (nearly 4 years) and been stood for a long time.

I've got the cam up, the lifters seem all to be good, no spidering and cracks. However, they are not all at same height......

The one in the middle of this pic just doesn't sit quite as high as the one next to it.

As for the timing, something isn't right. Or maybe it's just me! lol

Fuel pump locked, matches the tippex;

Crank tippex matched;

The '0' in the fly wheel is half way through the edge on the flywheel (is this correct?!)

Put the camshaft on the tippex mark.....

And then the cam key end for locking isn't level! The keyed part is at 45 degree not horizontal.

So I put the cam in a position i think is correct 180 way (going off a picture JBH posted and got this:

and:

Oversight on my part might the the cam is 180 degree out, as once it's nipped down I think the key will be too low. Thus making the tippex mark sitting at about 2 o'clock. not 12 o'clock.

Have I been unlucky with the lifters not seating at the very same level?

Dan

S4_dan · Mar 28, 2015

This is the cam in the correct position. The first lobe behind cam pulley is also pointing at 2pm.

Do I need to remove the pulley? Or fit a new belt keeping the cam locked, IP locked and crankshaft by keeping the tippex mark lined up and observing the '0' on the flywheel?

Then putting the tensioner back on and making sure everything is still lined up?

jbh · Mar 28, 2015

when the crank is on the mark can you remove number 1 injector and see if you have a long thin screw driver to put down and see if the piston is at TDC
you can turn it slightly to line the mark up in the 0 on the flywheel and see if this raises or lowers the piston.

as for the cam being marked 4 teeth out... ive no ideas there how its ever ran with these marks..
I would lock it up and start again but as you say with the looks of it you have been unlucky and it looks like its bent a valve with the lifter sitting down.

S4_dan · Mar 28, 2015

Think going to whip the head off when I get home then. No point in chucking a belt on and risk bending more valves if that's the case?

jbh · Mar 28, 2015

S4_dan said:
Think going to whip the head off when I get home then. No point in chucking a belt on and risk bending more valves if that's the case?

that's what I would do. then you can put number 1 to TDC and see where the mark is after that.
also once the heads off you can then rotate the cam and check the valves.

S4_dan · Mar 28, 2015

Got the belt on, it's all timed up (the cam tippex is about 4 teeth out!) but locking tool on it shows it right.

Turned it over a few times. No clanging noises.

However, cylinder 1 and 2, the cam lobes lift off the followers where as cylinder 3 and 4 have continuous contact with the lobes.
Is this an indication of bent valves or lack of oil pressure lifting them fully?!

Not sure if I want to risk putting everything else back on and try starting the car.....

S4_dan · Mar 28, 2015

jbh said:
as for the cam being marked 4 teeth out... ive no ideas there how its ever ran with these marks..

Maybe explain the thick black soot/smoke when revving hard? But it sound ok when it did run. Although I only reversed the car I couldn't tell if it was underpowered or not.

S4_dan · Mar 28, 2015

Ok, been doing some thinking about the cam and it being 4 teeth out. My theory is this:

The cam pulley has slipped causing the pistons to clash with the valves thus snapping the belt.

The cam couldn't have move after they've clashed as the belt was snapped at the crank pulley.

However. I know where there is a cylinder head about 2 miles from here. The car is a 1998 AFN Passat. I'm sure the head will be the same?

It has 130k miles on. The owner has said I could have the full engine if I wanted. I think it's easier to fit a head than a full engine? At least it'd have a new head gasket fitted along with new tensioner and pulley.

Worth doing?

jbh · Mar 28, 2015

if you can get the replacement head yea go for it.

Kevinb5 · Mar 28, 2015

S4_dan said:
Ok, been doing some thinking about the cam and it being 4 teeth out. My theory is this:

The cam pulley has slipped causing the pistons to clash with the valves thus snapping the belt.

The cam couldn't have move after they've clashed as the belt was snapped at the crank pulley.

However. I know where there is a cylinder head about 2 miles from here. The car is a 1998 AFN Passat. I'm sure the head will be the same?

It has 130k miles on. The owner has said I could have the full engine if I wanted. I think it's easier to fit a head than a full engine? At least it'd have a new head gasket fitted along with new tensioner and pulley.

Worth doing?

Absolutely 100% go for it

S4_dan · Mar 29, 2015

Anyone know how to get the cam pulley off without the special tool?

There is no hex on the cam to hold it.
Or is it possible to leave the pulley and lift the head with the back plate still attached?

adamss24 · Mar 29, 2015

Get the cam bolt off then knock the pulley off the cam with a punch trough the hole in the metal back plate. It helps to have the bolt on a few threads to stop it from breaking your radiator when it falls ! I would swap the engine if i was you, don't take it the wrong way but whilst fitting a cylinder head is not a difficult job, you don't seem over confident and tipex marks are bad when setting engines at TDC for a timing belt...

There is no way to replicate the way factory fastens the cylinder head bolts (all at once with a special torque wrench) so if the engine is good then i would just swap it whole !

If you decide to do just the head then make sure you blow all the oil and coolant from the bolt holes in the block, fit the head gasket the right way up (!)- i know it's silly but i have seen it before and make sure you use new lifters regardless of how good they look...

S4_dan · Mar 29, 2015

I'm going to make a tool today to hold the cam pulley so I can undo the cam bolt. There is no radiator on the car, it's in service position.
I timed the car up properly yesterday to see the offset against the tippex and see how the lifters were against the cam.

I have done headgaskets before, but only on petrols, the only difference being the IP needs setting up via vcds according to research. I've got all of the tools apart from the cam pulley tool. Cams I've worked with before usually have a hex on the cam after the first lobe to hold the cam whilst undoing the bolt, but on the AFN, this hex isn't there.

My not overly confidence probably stems from a mixture of frustration from the belt snapping in the first place and no means (currently) to removing the cam pulley.

I could swap the full engine over but where is the fun in that? lol. I've got a week off soon, so I will tackle the car then.
Maybe the engine swap isn't a bad idea as I could swap the subframe with the engine out, might make it a bit easier?

jbh · Mar 29, 2015

If youre going to change the subframe and you know the other engine is a good one I would do the engine swap.
you might need to change the engine loom over and a few sensors so try not to damage anything when unplugging it

URGENT - AFN interference engine???

Fire up the Quattro!

Registered User

TDi lover

Fire up the Quattro!

Registered User

TDi lover

TDi lover

TDi lover

Registered User

Fire up the Quattro!

Fire up the Quattro!

Fire up the Quattro!

Registered User

Fire up the Quattro!

"Stick a V8 in it!"

Fire up the Quattro!

Fire up the Quattro!

TDi lover

Fire up the Quattro!

TDi lover

Fire up the Quattro!

Fire up the Quattro!

Fire up the Quattro!

TDi lover

Registered User

Fire up the Quattro!

Registered User

Fire up the Quattro!

TDi lover

Similar threads