bis smokes on tick over then stalls

[poxxxy]

Compression test is ok... 9.5 and 8.5 bar but had 9.5 bar on the one reading 8.5 yesterday and 9.5 on one that was reading 5-6 bar yesterday... do I carry on whipping apart?

[poxxxy]

Just drained the oil and got some on my hand to notice it smells a little petrolly,  anything that could be causing it or anything linked that could cause problems? Might not be, could just be mineral oil as I've never really used it before lol

[Gadge]

Do you remember what the very top of the block surface was like? Perhaps there's damage and it's not sealing very well?

[poxxxy]

Block surface is all good... stripping it down at the minute. Stuck trying to remove the sump!

[Mics126]

Mineral oil does not normally smell like petrol.

[poxxxy]

I don't think the fuel pump is leaking... had the sump off today and pushed the pistons out... found some nasty looking rough surface on the cylinder 1  wall (unsure whats its been caused by, perhaps water/rust damage when the head previously died and overheated way before I bought it if water was sat in there? the head did warp on that side so might make sense?)... also the top edge of the piston may be slightly worn where it has been rubbing against... unsure if the piston rings are at blame to be honest, they seem ok unless they weren't span around the correct way to not allow blowby...

I'm wondering what the next steps are now! . New block? Or can I get liners? Perhaps just honing it out... I don't know... . If I could find suitable pistons i'd have it bored out a little for some more displacement. Perhaps someone can help (and maybe might have an explanation)! .

Attached pictures after another day of laboring away .

Cylinder 1 Wall





Cylinder 2 wall:


Pistons (Cylinder 1 piston on the right):

[Pete126]

Looks like it has been stood for along time with water in number 1 cylinder,
If it was mine i would use a [glaze buster] to clean and crosshatch the cylinder walls and buy a new set of piston rings unless you can find a good secondhand engine

[poxxxy]

Looks like that might be the way forward... never seen that tool though, doesn't look like the normal honer! Will have to see if I can see some documented crosshatcing with the tool. A new block with installed liners is kind of tempting at 150 euro though .

Guess I can balance the con rods and pistons on some cooking scales while I wait for the new rings to arrive if I find they differ! I can't really run new piston rings in though once installed as its not road legal lol. Also not sure the carb is up to it and seemed to be struggling to give me full throttle and not opening the secondary butterfly as it should be, when done manually the engine just bogged down! Need to figure out the adjustment on the POS 30 S2HR but its seen better days really! .

I need some con rod bearing shells and was tempted by the new pistons and ring set... but looking at them they should be OK really!? I've seen worse from peoples experiences with engines that run without this much smoke lol.

EDIT: Seems the glaze breaker might be the option as it removed less metal than the hone tools i've seen . Wonder if I can get a 45 degree cross hatch at all! lol.

[Pete126]

As long as the liner isn't badly pitted it should do the trick,

[Gadge]

I had very similar damage on one of my bores but it was quite as bad as that but not far off. I too used a drill powered deglazzer which cleaned a lot of it up. Also one of your pistons seems a lot blacker than the other so that does seem to be the problem bore/cylinder. I must admit I'm baffled at your problem as everything seems normal from your photos other than some pitting and dis-colouring on a piston.

[poxxxy]

Yup, bit of a pain in the arse! The cylinder wall is a little pitted it seems to be honest... guess i'll only know by attempting to deglaze it a little and get a crosshatch on there. But seems like i'm gonna be spending money for no reason and more hours labor... really didn't want to put it back together without finding something solid to go on . Can't take any more disappointment lol.

[Gadge]

Have you looked into buying a second hand engine. It may well end up costing the same but without all the hastel of sourcing pistons and rings and going though more heart ache of it not working again

[poxxxy]

I've looked... but where they're hiding I don't know! Lupo TDI over on vwvortex had a brand new engine from somewhere a few years back . lol.

Thinking about going all out at the minute...

Today I removed the block from the bell housing, found some damage to both the bell housing and the starter where the bottom right stud from the block goes through... totally missing. Is the starter meant to be like that?

Also the rear crank bearing sounds a little noisy to me.

So parts list so far:

Piston Rings
Con Rod Bearing Shells
Crankshaft Bearing

Tempted by:

Bigger lighter pistons (if I could find some suitable without going custom!)
Hot cam
Forged crank















Most of the engine and ancillaries in a box (where they may stay!? hopefully not .):


If rebuilding the engine, best to do it in style while its in pieces... but could be an expensive lump of useless metal at the end of it lol. smallcox offered his time/balancing services if I manage to come up with something to take to him! No replacement for displacement though and sounds so tempting to go down that route if possible!

[poxxxy]

I've been advised to look at the fire trap somewhere near the oil breather pipe? I did see something resembling a spring in the bottom of the crankcase/block sitting there... maybe thats off this firetrap? or is it just an aircooled thing?

[Gadge]

The damage you pointed out on the starter area most deffinatly shouldn't been there (I've certainly not seen it before) it looks like a bolt has been cut from it in desperation at some point however it still looks like you can pass a new bolt though it ok enough. Unfortunately hot cams aren't available off the shelf for the BIS - and no the air cooled one won't fit.

The fire trap is a square(ish) piece of metal and 1 inch by 2 inches with a few holes in that swings on a little hinge. It sits just under the oil filler neck inside the front cam chain cover. Not sure how affective it is.