are you going to try some solvent in the ports...see if the valves seal?

1 hour ago, steveo3002 said:

are you going to try some solvent in the ports...see if the valves seal?

 

Just through the inlet ports? Just this moment popped the manifold back on... Haven't touched the exhaust manifold - don't want to chance breaking any studs

yeah will make it alkward

 

was just thinking sinse theres little sign of trouble could it be a valve seal issue...do you have a compressor /airline?

Unfortunately not - or at least I do have a compressor but its a tiny one used for airbrushing.

 

The inlet gasket was a bit oily on two of the pistons - one more than the other - with oil present in a small quantity inside two of the manifold ports. Does this suggest oil in the combustion chamber and leaky inlet valves? Theres a big part of me that just really doesn't want to know... I feel that a valve job is escalating things a bit!

im thinking a leaky valve resulting in loss of compression would have shown up as a sooty or clean valve ..all yours were same so good 

 

just you know while its off , be a shame if it was a valve??  do you have the equipment to lap them?

I know right? I think I'll chance it though - I feel like gasket changing and cleaning things up is within my remit but wouldn't want to mess up valve seating seeing as it would be the first time I would have done a valve job. I think if I had a mate who had done one before handy I'd feel a lot more comfortable with that. One must be mindful of one's limits eh!

 

Plus while I technically do have paste and a spring compressor I don't have one of those little suction tools to spin the valve from the face end

You don't need a twizzle stick suction cup. Rechargeable battery electric drill chuck on the stem. Did it for all 16 Lupo AHW valves.

Sounds like a good solution!

 

I'm gonna go ahead and put it back together I think - just need it to stop bloody drizzling outside....

Well, the head is back on - frightening part over. Turning those torque angles was...interesting...

wasnt so bad was it?  does it run?

1 hour ago, zob said:

Well, the head is back on - frightening part over. Turning those torque angles was...interesting...

Hi out of interest was do you mean by the way of turning those torque angles ? I understand you torque the new head bolts down.

3 minutes ago, 1vw2many said:

Hi out of interest was do you mean by the way of turning those torque angles ? I understand you torque the new head bolts down.

 

its torque plus angle....torque to x ,then torque to xx ,plus  turn 90 or 180 degrees ...says on the packet when you buy a new gasket

1 hour ago, steveo3002 said:

 

its torque plus angle....torque to x ,then torque to xx ,plus  turn 90 or 180 degrees ...says on the packet when you buy a new gasket

Thanks steveo. 

3 hours ago, steveo3002 said:

wasnt so bad was it?  does it run?

 

Naa wasn't bad, putting it back together was much easier than taking it apart! Triple checked everything and started it up - runs good. Lots of smoke off the exhaust but hopefully that was just the oil from when the head was taken off - can't see any leaks from the new gasket

 

Any advice as to whether I should treat it any different for the first few drives just in case? Is there likely to be any problems down the road if it got all hot just now and revved up fine? Going through the usual stages of paranoia after fixing something (sure there's an extra little squeaking sound underneath the engine note....)

dont need any special treatment , but i tend to keep checking it over often incase theres a leak or something been left loose etc 

Fab, thanks.

 

Out of curiosity if there was any oil that made it onto the top of the gasket when the head went down (errant dribble down an oil channel) would that manifest as a buggered gasket straight away or over time?

imagine it would be ok..

Just now, steveo3002 said:

imagine it would be ok..

 

Thanks for all the help mate - I owe you a beer if we ever bump in to eachother!

no probs..lets hope its fixed

Update after a couple hundred miles of motorway:

 

Runs fine, oil leak above the alternator isn't there but the cold misfire is still present. Chalking it up as a win for the oil leak but not going to worry about the misfire, just going to have to live with it as a mild annoyance. It may even disappear once it gets a bit warmer in the mornings, who knows!

slight bummer but at least the gasket is sound 

 

id still suggest moving that plug and lead to a differant location and see if the misfire follows it 

I'll have a hunt around with the leads and see what I can find, cheers

I have a theory...

 

The cold misfire isn't present from the moment i turn the engine on - it idles perfectly fine for 10 seconds or so before the misfire starts to creep in. My question is - how long would a pretty fouled plug take to foul up totally in a rich mixture? All my plugs are pretty sooty but after a long hard run are closer to how they should be. Could it be down to something like this?:

1) Plugs carbon up a bit from normal driving in an engine that is running, in general, a bit rich

2) Start the car on 4 plugs that have a good spark, everything is well with the world

3) One cylinder has a leaky valve, runs richer than the rest and so starts to foul up its plug

4) Said plug gets so fouled it can't provide a decent spark to ignite the rich mixture

5) Misfire on cylinder

6) Cylinder head temp rises as other 3 cylinders are firing alright

7) Leaky valve stops leaking as everything expands (is this possible? Physically it should be as valve and head are different materials)

8 ) Mixture in dodgy cylinder leans, weak spark ignites it

9) Engine idles as normal and everything warms up

 

Just now the misfire lasted till the end of our road and then was back to a normal ECU-controlled warm-up fuelling schedule. So I guess one question is why are all the plugs so sooty in the first place? The only thing I can think of that wouldn't have any other ramifications is the blue temp sensor (Hella brand) is off and a VW OEM one is needed. That or just its a 25 year old motor and its 2 degrees outside at the moment!

dont think a leaky valve would heal itself up with heat 

 

generally running too rich could be the fault...a lambda controlled engine should have clean plugs all the time , mine look like new after a few miles

 

at first start the lambda doesnt kick in for a while...maybe something to do with that , could it be doing its job and leaning things out

 

has it had a blue temp sender latley....this gives the ecu its temp reading and if wrong the car will thing its very cold or hot when its not  

1 hour ago, steveo3002 said:

has it had a blue temp sender latley....this gives the ecu its temp reading and if wrong the car will thing its very cold or hot when its not  

 

Aye it has - that Hella brand sensor is new in recently. I guess one thing to do would be to look out for an OEM one? Bit loathe to swap out this one now that I've just put in a load of new coolant eh...