208 1.2 petrol wont rev over idle

[GiveMeABreak]

Here's the knock sensor:

Item (7) Engine Knock Detector, part: 594631, £27.53

Dismantling

Location

Disconnect the battery following the BSI Reset / Battery Disconnect / Reconnect Procedure

Chock and lift the vehicle on a column lift.

Remove:

• The (2) bolt
• Knock sensor (1)

Disconnect the connector (Press the tab at "a").

Refitting

Connect the connector (at "a").
Refit:

• Knock sensor (1)(Check that the lug is positioned correctly in relation to the notch ) (at "b")
• The (2) bolt

Tighten the Knock detector bolt to 2 daNm.

Reconnect the battery following the reconnection part of the BSI Reset / Battery Disconnect / Reconnect Procedure.

[tmead]

Thanks for the detailed info Marc, very much appreciated. You prompted me to donate. i've had great supprt and hopefully been able to offer a little in updates from my own experience on this forum, it is a fabulous help when I'm so into a project that i can't stand back a bit and think it through.

I'm not ignoring your advice to go for the knock sensor first, but in the limited time I had yesterday I thought i could start with inpsecting the throttle assy first - the plate moves when pushed and spring returns to closed. There's no obvious damage to the connector wiring in that area, and it was securely connected. I didnt have time to probe the pins and see what was going on, but hopefully there will be time tonight to take a look and to scrabble underneath for the knock sensor. (provided it isnt raining!)

[tmead]

Column lift ?

[GiveMeABreak]

Well I've seen it all - or thought I had!

[tmead]

Its not sensor related !

The clean plug in number 2 has niggled away in the back of my mind, so in the little time I had available tonight I ran a quick compression test - 1 & 3 fine, nothing on 2. The piston appears to be there and moving up and down, so I'm assuming a stuck valve.
So now I'm wondering - its probably worth popping the head off and having a look ? Or at least the cam cover and checking that the valves are returning correctly ? Not quite sure how to clean up the valves/stems if I have a stuck one ? I've heard talk of walnut shell blasting, but I'm assuming that's expensive ? It may also require valves to close so that the debris doesnt drop into the cylinder ?

[tmead]

OK, so 'popping the head off' is a right pain on this engine, involving removing the camshafts amongst other stuff. Mentally I'd budgetted time for swapping the engine out, maybe this is the route to go, although I'd probably want to change the cambelt on any engine I put in.

[tmead]

I've been persuaded into fixing significant engine issues rather than just swapping a couple of times, and regretted it each time.
(head gasket on a diesel punto, bores werent really good enough and it never ran well, and a replacement camshaft on a 307 2 litre diesel when the fuel pump drive snapped off. That ran for 20K miles and then dropped a valve into the engine - could have been pump drive debris that I didnt find)

Anybody done a head refurb on a 1.2 EB2 ? theres a photo tutorial online and it doesnt look too crazy. the head set is less than 100 quid too. I'm tempted - third time's a charm and all that !

[tmead]

valve clearances are around 5 thou for inlet and more than 10 for all exhausts. None of the exhaust valve clearances was noticeable more than others.

It looks like the cylinder head bolts have a reverse torx type head, but would need a long thin socket. I think my sockets for these are too bulky, so thats a shame.

The cambelt looks sort of 'woven' on the outer face, which I think indicates it hasn't been changed in the first 80 odd thousand, so that would need doing.

[tmead]

I grabbed some snaps with a cheap usb borescope, down the bores and into the inlets. Piston crown 2 looks a bit cleaner, as expected. Valves look all pretty similar to me.

[tmead]

I'm a little worried that the high oil level may be because the lack of compression in #2 means the fuel has been running past the rings down to the sump. There is little point in doing much with this unless I take a look at the bore I think, that amount of fuel must have washed any oil off long ago ! The diluted oil in the sump will also have been doing a poor job of lubricating big end bearings etc too.

Trouble is even though there must be thousands of these 1.2 engines out there, they dont seem to pop up too often on ebay. The ones on there are crazy expensive (around the grand mark or even more). theres a few breakers with damaged complete cars that I will message to try to get a more sensible price. I'm not limited to a 100 quid clunker, but I'm hoping for around the 500 quid mark.

[tmead]

well I guess this answers the question !
Can you see the problem ?

head view

There doesnt seem to be any marking on the piston, cylinder, valve seat or head, so I cannot figure out where the part of the valve went.

I don't think I will take on replacing the valve, with associated rafting around with setting clearance and lapping it in. Also I have too many concerns about where the piece went, and what the bottom end is like with the possible thinned oil. Time to look for a replacement engine.

[tmead]

Just wondering what people think - I can feel movement in the pistons front to back when i push on the piston crowns, and see them move a little. There doesnt look to be massive wear in the bores, I can almost see the honing marks ?
I was expecting a piston/bore clearance of only a few thou, and the pistons look to move more than that.

I think the engine is going to be swapped out, as I can't take the time to rebuild it.

[ozvtr]

The honing marks are clearly visable in the pictures.
I dont know what the piston to liner clearance would be but most of the compression is contained by the rings.
If you can rock the pistons backwards and forwards then the rings are free and not "gummed up".
Apart from the scoring on the liners, the cylinders and pistons look good. Can you catch a fingernail on the score marks?
The tops of the inlet valves are super clean!!
The bizarre thing I find is that there is no carbon build up on the back of that valve and the valve seat looks very good (well from the photos anyway).
Have you looked on the top of the catalytic converter for any chunks?
How many miles has this engine done?
Does the engine run a chain or belt?

[moizeau]

I can't help you regarding your specific engine but to give you an idea of piston and cylinder wear limits these are from my genuine Kawasaki Zephyr 1100 workshop manual.
Cylinder, standard measurement = 73.5mm, service limit = 73.6mm
Piston, standard = 73.442mm, service limit = 73.29
So with both being on the service limit to piston to cylinder gap would be 0.31mm
Piston ring end gap, standard = 0.2 / 0.3mm, service limit = 0.6mm (Top ring)

On some engines you can remove the pistons with the engine still in by removing the sump and pushing them out the top with the conrod.

[tmead]

Thanks @moizeau, that is comforting ! The only info I saw in a quick web search showed much less clearance, so i was worried about the thinned oil having lead to excessive wear. Looks liike it may be pretty much in line with a 70K engine. I'm still not sure about faffing with a valve and setting up clearance etc. I've a few irons in the fire about a replacement engine, so lets see how that works out.