Cleaning Sparkplugs

[rupertw]

As per the title, is there a straightforward way to clean oily spark plugs so that they're basically as good as new?
One of my cars is very prone to oiling up plugs if left to idle for more than a couple of minutes, which isn't usually much of an issue as it is mostly used for racing purposes and not for road use.
However, having decided to take it for a more leisurely and lengthy road run at the weekend I managed to get through two sets of plugs which isn't ideal and starting to get a bit costly. Obviously there is an underlying issue causing the plugs to oil, but there is a limited amount I can do to the car setup without causing other issues!

Would soaking them in white spirit make any difference?
My dad mentioned that you used to be able to get some sort of mini sandblasting kit or something like that, but I can't find anything along those lines on the internet

[welshpug]

if they're getting oiled up surely theres a problem with the engine not the plugs?

fouling from running rich i could understand, which you can get around by either leaning out the mixture or using a hotter plug though you'll not be able to wind in as much advance

[rupertw]

I think it's more them being fouled by the engine running rich rather than oil from the engine - its had new pistons etc. fairly recently so shouldn't be that. Changing the mixture involves making a new main jet, and it is running very well with the current mixture which took a huge amount of fettling to get right, so I'd rather not touch the mixture.

It's a very quick job to change the plugs before each event, but it'd be nice not to put in a new set each time!

[andyborris]

This is want you're looking for, not sure how well they work though.

If you do buy one, can I have a consumers report please!

[rupertw]

Superb, thanks for that link, it's a little bit more expensive than I'd like although I've found it cheaper elsewhere and it would theoretically pay for itself with the first use so I may well investigate it and report back!

[slater]

Hang on a second. Do you actually mean oiled up? I mean unless it's a two stroke there's got to be something majorly wrong with the engine to oil them.

If you mean black carbon fouling then what's wrong with a wire brush? Or a wire wheel?

I assume this is happening at idle? Your idle mixture must be way off. Nothing to do with the main jet. What carb and engine is it? Have you got the right grade of plugs in there too? They might be running way to cool.

I know I'm not answering the question but theres got to be a way to solve the actual problem.

[deaddave72]

have you any pictures of the plugs in their oiled up state? You mention that the engine has had new pistons recently, it may be that the gaps in the rings are in the wrong position or in the wrong way around thus allowing oil blow by them. FWIW i use a gas torch to burn residue off and when cooled a wire brush to remove the dried up filth.

[rupertw]

It's an Austin 7 engine running a Solex MOV30 which I think was originally fitted to Alvis engines twice the size - hence the car taking quite a bit of setting up to get running right. The engine is definitely running rich as it barely requires choke even when cold, but adjusting the jets is not all that straightforward since they're not exactly off the shelf items! The car is running very well at speed, and plug fouling has always been a common issue with vintage racing engines, so I'm not overly worried about that aspect.

The wire wheel works to extent, but ideally I'd like to be getting right down into the plug which is hard to clean unless you spend ages messing around with sand paper.

[ferny]

May 24, 2016 6:27:45 GMT andyborris said:

This is want you're looking for, not sure how well they work though.

If you do buy one, can I have a consumers report please!

They're fairly useless to be honest.

[taurus]

I usually just use a wire brush - seems to work for me.

[93fxdl]

Have used one of the sandblast kits to clean plugs, it makes the insides rough, so they foul up very quickly after. Options for setting tickover mixture could be a colour tune or a lambda set up with a multimeter, the lambda option means you can check mixture, while driving,
Ttfn Glenn

[Rich]

It sounds like you need to adjust the idle mixture via the idle mixture bypass screw. Nothing to do with the main jets. You'll damage your engine leaving it running horrendously rich.

[stonyray]

May 25, 2016 7:38:21 GMT Rich said:

It sounds like you need to adjust the idle mixture via the idle mixture bypass screw. Nothing to do with the main jets. You'll damage your engine leaving it running horrendously rich.

Nothing wrong with some epic borewash, keeps the block clean!

[stonyray]

[Rich]

May 28, 2016 9:57:47 GMT stonyray said:

May 25, 2016 7:38:21 GMT Rich said:

It sounds like you need to adjust the idle mixture via the idle mixture bypass screw. Nothing to do with the main jets. You'll damage your engine leaving it running horrendously rich.

Nothing wrong with some epic borewash, keeps the block clean!

Free oversize rebore for moar power, amirite?

[stonyray]

This guys bimmer was in the process of increasing its displacement for FREE! when the silly sausage pulled it apart.

[skylinedave]

Come on lads , he is talking about a vintage engine used for events , its kind of different to a modern tuned engine don't you think ? One aspect may be a offset to gaining something in another area for instance .

You might have some success with sticking them under a map gas torch which will clean the ceramic end .

Others recommend leaving them in any strong bathroom/toilet cleaner with hydrogen chloride in , then rinsing off and spraying with carb cleaner to dislodge anything .

Might be worth experimenting with those methods .

[vitesseefi]

Maybe use a hotter plug? Gas torch should do the cleaning.

I have found that current NGK plugs cannot handle being fuel soaked and do not recover even with blow lamp treatment. I have read that the Japanese made ones are OK and European ones not but cannot confirm.

Nick

[rupertw]

Thanks for the suggestions on cleaning - it's looking like the good old fashioned wire brush might be the most effective way.

As for the mixture issues it is certainly something I'll be looking into in due course, but I'm not overly worried as the plugs are only fouling when left at idle, and the car doesn't generally sit around idling often. It's used for hillclimbs and sprints, so hardly a daily driver!

[composimmonite]

There used to be numerous little 12v sandblasters which were basically a motor that blew fine sand onto the electrode. Worked OK but nowhere near as effective as a new plug as quickly fouled again - probably due to the micro pitting sandblasting causes.
Sorry but I agree with everybody else - cure the cause and not the problem it creates. How long does it take to bolt on a standard carb and then swop back to the oversized item just for race meetings ? From what I can see it's just two studs that hold carb on !
Solex mov30 -