Soiled Plugs / Power Down

Post by **Dubstar** » 24 Nov 2007, 00:16

I took my van in for it's MOT and the only thing it failed on was the emissions. The CO was ok, but the hydrocarbons were at 3000. Apparently a pass is 1200, but it really should be at about 200-300, according to the garage. I put new plugs, rotor arm and cap on 2 weeks ago. The garage reckons it's only running on 3 cylinders, so I checked all the plugs to see what condition they were in, and on the right hand bank they were nice and grey/brown like they should be. The rear one nearest the hatch on the left hand bank though was really oily, and it's neighbour was a little oily. I've noticed recently it's been down on power and the autobox hasn't been changing like it should. Any ideas, other than a melted piston / burnt valve and me needing a new engine?
It's a 2ltr Aircooled Westy running on LPG. And whilst it's faster on petrol it still seems down on power.
Thanks
Shane

Post by **jason k** » 24 Nov 2007, 11:48

do a compression check.
oily plugs is prob buggered rings on the cylinders on that bank
prob some new pistons and barrels reqd.

Post by **kevtherev** » 24 Nov 2007, 16:41

Agree with jason ...piston rings broken, stuck or worn

is it a smoker (blue on acceleration)

Post by **Dubstar** » 24 Nov 2007, 17:05

Not really. A bit smoky sometimes in the morning, but not when it's warm and driving. I thought it was one of the plug leads at first cos I wrecked one by pulling the end off it when I tried to pull it off the plug. I re-crimped it all back together and it seemd to work. When I checked the plugs though, the wrecked lead one was really clean, it was one of the others that was oily. I know it needs the air leak on the spindles sorting out, which is what I thought it was in the first place.

Post by **kevtherev** » 24 Nov 2007, 18:02

By all means pursue all the avenues that are cheaper than removing the head and barrels.

when the engines warm get someone to rev it hard three or four times...you stand behind and observe.

black smoke = weak spark..or rich

sooty exhaust pipe too I'll bet

bluish is oil

Post by **Dubstar** » 24 Nov 2007, 21:04

No worries, I'll have a look tomorrow. As a matter of interest, is it possible to change the pistons and barrels - like the ones JK do for instance - in situ, or is it an engine out job?

Post by **..lee..** » 24 Nov 2007, 23:40

high hc on the emmision test is unburnt or partially burnt fuel and oiled plugs would cause this.

fitting new plugs (possibly colder plugs) should cure this(short term) and it should then pass the emmision test, only this would not cure the oil burning fault it might buy you some time and get you a mot pass for now.

you could also run the fuelling very,very lean this may cause the van to pass, although you`d have to richen it up soon after as it `d run like "pooh" on the road.

there`s a lot of wangles you can use to get it through the gas test for mot. not a proper fix but it may help you out atm(short term).

lee.

Post by **lloyd** » 25 Nov 2007, 08:53

If plugs are being fouled, r hotter plugs (hotter plug fires a hotter spark and hotter combustion chamber makes it harder to foul) If you lean out carb to pass, don't run far before richening it back up or you take a chance of damaging engine more.

Post by **Dubstar** » 25 Nov 2007, 10:08

It's only the rear left plug that's really fouled. The one in front of it is lightly fouled but the 2 on the right bank were clean as you like. The plugs were also new only 2 weeks ago. Got them from GSF, just asked for plugs for mine, along with the rest of the servicing gear I got. I think they are Bosch W8CC, but I can't be sure as I threw away the packing.
I know when I had the gas conversion done, Steve - Gasure - told me the left hand carb had a bad air leak on the spindle, so he had to turn up the gas to the max so it wouldn't run too lean. It still doesn't explain the soiling though, unless it's the same on gas as petrol when it's running rich - ie, wet plugs? I think to get it through the MOT I may have to clamp up the left hand rubber gas pipe to the carb. Not block it off completly, just enough to get me to the gas analyser and back out.

Post by **lloyd** » 25 Nov 2007, 10:16

check linkage and make sure both carbs are opening same. Maybe they are out of sink causing right side to do the work while left side is being lazy.

Seriously, if carbs are not synchronized properly things won't work like they should. On a old engine this can cause fouling of one bank because it's pumping same on both sides, but one side has to pull harder to get same amount.. and will suck oil past rings/valve guides. Also one side (fouled side) isn't working as hard so runs cooler then other side.. or runs hotter because fuel mixture is too lean.. in other words, make sure carbs are balanced out properly.

Post by **Dubstar** » 25 Nov 2007, 10:30

I have a look at that. I'll have to sort out the spindles with the air leak problem too. Steve told me how to do it. But I forgot some of the measurements, so I'll just have to make an educated guess for now.

Post by **mgm** » 28 Nov 2007, 22:21

Dubstar wrote:I took my van in for it's MOT and the only thing it failed on was the emissions. The CO was ok, but the hydrocarbons were at 3000. Apparently a pass is 1200, but it really should be at about 200-300, according to the garage. I put new plugs, rotor arm and cap on 2 weeks ago. The garage reckons it's only running on 3 cylinders, so I checked all the plugs to see what condition they were in, and on the right hand bank they were nice and grey/brown like they should be. The rear one nearest the hatch on the left hand bank though was really oily, and it's neighbour was a little oily. I've noticed recently it's been down on power and the autobox hasn't been changing like it should. Any ideas, other than a melted piston / burnt valve and me needing a new engine?
It's a 2ltr Aircooled Westy running on LPG. And whilst it's faster on petrol it still seems down on power.
Thanks
Shane

Why not use silicon sealant to seal up the spindles for the MOT? I also heard (don't quote me someone else MUST know the FACTS) that you need to inform MOT station that van is an AIR-COOLED? Also if it does HC fail they need to rev to 1500-2000 rpm and re-assess if the HC and CO drop when revs drop then the system is OK...???
Had I known this before the expense of replacing my SOLEX carbs then I might have had pleasure chastising MOT station and not being big-time out of pocket!!!!!!

Also, wouldn't the CO be low if the HC was high due to an air leak??

Post by **ELVIS** » 28 Nov 2007, 22:41

simple 'fix' until you got time to sort engine - get em to MOT it on LPG !

Post by **ELVIS** » 28 Nov 2007, 22:48

"Vehicles which run on more than fuel (eg petrol and LPG) should be tested on the fuel they are running on when presented."

gives ya a bit of breathing space to fix carbies AND a new MOT

Post by **Dubstar** » 29 Nov 2007, 10:05

It was on the gas when I took it in! I'm taking it back in tomorrow and we're gonna have a play around with it ojn the gas machine, me and the MOT guys, and hopefully get it through. I had it on petrol for a few days and it seemed to get some power back and be missing less, so I've put some mega expensive BP Ultimate in, and I'll give it a run before it goes back, although it's my daily driver anway. I'm gonna try grease on the ends of the spindles too to try and stop the air leak temporarily. My cousin works in a machine shop, so he sorted out some spare spindles I had-but left them at work 'till friday evening as he's now away on a course. Doh! But he did them for free so mustn't grumble. Fingers crossed.
On a positive not though, seeing as it's my daily driver, I'm fairly happy that it only failed it's MOT on one thing. I'd just rather it was a bulb or something.

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Soiled Plugs / Power Down

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