Hi all.

 

My first post here although I've browsed the forums before.

 

I think my car may have skipped a tooth or two on the timing chain.

 

I had my Son out on L plates, he stalled at a junction a few times and we were there for a few minutes with cars behind. I think he started panicking so I said to swap seats. I stepped out the passenger side and the rear of the car dipped as if he'd popped the clutch with the handbrake on. I got in and it wouldn't start, also sounds weird. The engine is turning over but no sign of firing.

 

I scanned the ECU with my Carista tool and got P0341 camshaft position sensor fault code. It reset but came back after trying to start again.

 

I towed the car home and started reading online and the timing chain skipping looks like a common fault. The engine may have reversed when he stalled it.

 

Is there any easy way to check if this is the case or any manuals available that describe how to set up the chain/timing, so at least I can get an idea if the timing is off?

 

I'd rather know for sure before I get a huge garage bill.

 

I've been googling and can only find vague references to cylinder 1 being at TDC then checking markings on the cam sprockets but no real information.

 

The car is a 2014 Fabia MkII 1.2 3 cylinder petrol.

 

Cheers in advance.

Need to know if it's a 12-valve or 6-valve engine before I can offer any useful advice. 

12-valve ones have the spark plugs vertically downwards in the middle of the

head, 6-valve engines have them hanging out the front of the head at a steep angle.

 

Engine code is always the best identifier of engine type. On the sticker in the boot.

Edited 18 September, 20214 yr by Wino

Hi Wino,

 

I thinks it's a 12 valve, engine code is CGPA.

 

Cheers

 

I just found this video so I'm off out to check: CGPA timing check

 

If mine is off what would be the process of resetting it? I'm pretty competent when it comes to mechanical work but I've never worked on timing systems.

Yes, that vid looks useful at first glance.

 

The official stance is that you buy the timing locking kit (1 crank lock pin and 2 cam locking pins), remove crank sensor to fit the locking pin in there, then try to fit (and screw in with the M6 screws) the cam locks into the same slots that can be visually inspected; but just observing the relative orientation of the two slots in the cam ends is usually adequate to detect a slip/jump.

 

Bear in mind (managing expectations here, sorry) that not only is it quite a mission to get into the chain to do anything about it, but on the 12-valve engines valve damage is quite likely as a consequence of the mistiming, if found.

Edited 18 September, 20214 yr by Wino

I just watched this video (same chap): Timing chain replacement so a bit too much work for me, it would take me weeks.

 

I pulled the end covers and took these photos. They look aligned. What are the chances both jumped the same number of teeth?

 

I also put both images in to GIMP and aligned them and I can't see any difference in angle.

 

If it's not a jumped timing chain what else would stop the car starting after a few stalls? I don't think the camshaft sensor failing would stop the engine starting ( I may be wrong).

 

 

The chain could have jumped at the crank sprocket, leaving cams in phase with each other but mistimed relative to crank.

So coil and plug out of cylinder 1 and find TDC by poking something long down onto piston crown. Only turn the engine in its running direction, by 12-point socket on crank bolt.

 

When at TDC no.1, both cam slots should be parallel to head gasket. 

 

 

Thanks Wino, that makes sense.

 

I'll have a go tomorrow although I don't think I have a 12 point socket, luckily I have another car.

 

Is cylinder 1 closest to the timing chain?

Yep, cylinder 1 at timing chain end.

If you take all three spark plugs out, you may well be able to turn the engine by just pulling on the auxiliary belt.

It's not looking good.

 

I've just inspected the cylinders (with a cheap USB inspection camera) and I can see debris. 

 

The timing is also off with cylinder 1 at TDC.

 

Pictures say it all. I'll add more later from my laptop of the cylinder.

A view of inside the cylinders:

 

The flakes are small, must be the coating on the valves. I managed to pick up a few with a magnet. The second photos looks like impact damage?

 

I'm awaiting a quote from my local garage.

 

Thanks for your help Wino. Much appreciated.

 

Not knowing what's faulty is sometimes worse than finding the fault.

There are designed-in valve reliefs on the pistons for the inlet valves from memory. Confirmed in third photo here: VOLKSWAGEN POLO 6R Piston W/ Connection Rod 1.2 Petrol 51kw CGPA 2016 | eBay

Just an update on my predicament which might help others in future.

 

My local garage couldn't take my car in as it would take them too long and they have a backlog, I don't know any other garages around that I'd trust so I had no option but to strip the engine myself. Unfortunately all the intake valves are bent and sitting in the same plane as the piston top.

 

This is my first time doing an advanced job like this so I have more questions to get this thing back on the road.

 

- Do I have to lap the new valves?

- What should I replace other than the valves? Stem seals? I can't see much else on this diagram (4cylinder, I can't find the 3 cyl version) which would need replacing.

     I'm awaiting delivery of a spring compressor tool to remove the valves.

- What jobs should I do while I have this thing apart?

List of parts so far:

6 intake valves and seals.

Timing chain kit.

Head gasket

RTV silicon for the timing and rocker covers.

Spark plugs (they're due).

Oil change

Coolant.

 

Cheers

 

 

My photos didn't upload on the last post and I can't edit. Here they are:

I would have taken the head to an engineering shop and got them to do all the work so you could just refit it.

Check for excessive play in the valve guides, both exhaust and inlet; the former as a known wear weakness on earlier versions of this engine, the latter for damage due to recent trauma. My gut feeling/hope is that both will be OK, but worth checking while head is off.

I'd chuck a new exhaust gasket at it for the sake of a few more £s.

Consider hoovering out the exhaust manifold to try to remove any metallic debris that may be blocking the pre-cat to some degree.

I don't know any places around me that offer that service. Garages in and around Aberdeen are extortionate price wise at the best of times, they mostly just want quick jobs. I'd probably have to travel to find someone offering a rebuild service.

 

Now I have it apart it's not too daunting (putting it back together and getting it running may be another story 😬).

6 minutes ago, Wino said:

Check for excessive play in the valve guides, both exhaust and inlet; the former as a known wear weakness on earlier versions of this engine, the latter for damage due to recent trauma. My gut feeling/hope is that both will be OK, but worth checking while head is off.

I'd chuck a new exhaust gasket at it for the sake of a few more £s.

Consider hoovering out the exhaust manifold to try to remove any metallic debris that may be blocking the pre-cat to some degree.

Thanks Wino, I'll do that when my removal tool arrives.

 

My last post was for sepulchrave, I still can't edit posts to quote 🤔

Have you got the locking tools for crank/cams? Can be found pretty cheaply these days. 

Lapping the new valves in sounds like a good idea to me. 

1 minute ago, Wino said:

Have you got the locking tools for crank/cams? Can be found pretty cheaply these days. 

Not yet but they're in my amazon basket.

 

1 minute ago, Wino said:

Lapping the new valves in sounds like a good idea to me. 

Something else I've never done so will get that tool also. And watch some Youtube videos 😬

Nobody younger than me will have any memory of regular decarbonisation (decoke) and valve grinding, I still have all the tools but reckon that the rubber suckers will be perished by now.

 

Hats off to you for tackling this as your first advanced job, years back it was not o advanced but they were not the days of DOHC 16 valve engines plus all the emissions junk you have to wade through just to get to the oily bits. Back then it was routine maintenance beyond 40 miles.

1 minute ago, J.R. said:

Nobody younger than me will have any memory of regular decarbonisation (decoke) and valve grinding,

 

Oh dear that puts me in the getting on a bit phase of life then!

 

Lapped in quite a few valves in m time. A couple of notes of caution:-

1. Is it an Aluminium head? Carefully does it! - before getting stuck in check how air tight it is - or liquid tight to test. It might not need much doing.
2. After lapping in make sure all trace of the lapping in paste has been thoroughly cleaned away - you don't want it grinding in/wearing out other parts of the engine - esp valve guides! I ONCE made this mistake on a Morris A series head!

No need to be carefull, Aluminium heads use hardened valve seat inserts, even all cast iron heads have done so since the demise of leaded fuel.

Head and block are aluminium alloy.