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Decoking?

I've Googled this for ages now, and I'm just getting too many conflicting opinions appearing. So, since there are people here who clearly know what they're talking about, I thought this is probably the best place to ask.

Having stuck my new eBay endoscope down the plug holes of my old 2003 Fiesta, it reveals, as expected, black, cruddy piston crowns. It wouldn't normally bother me, but since I have a suspicion that it is pinking (which could, of course, just be a rattle), I thought it might help to clean them up a bit.

I'd rather not take the head off, but I will, if absolutely necessary, but first...

Is it even worth doing? Might it make things worse?

Does leaving Redex in the chamber overnight really work?

Does spraying water into the air intake really work?

Will using premium fuel work over a long period of time? Maybe using some other additive?

Has anyone here tried any of these?

I know this could easily fall into the category of idiotic questions, but I believe it does no harm to ask.

Reply to
Etaoin Shrdlu
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Our 1997 1.3 endura (ohv) Ka used to pink at high speed, and eventually I found that reducing the spark plug gap by 0.15mm cured this.

HTH

David

Reply to
David

Interesting. Costs nothing to try, too. Thanks.

Reply to
Etaoin Shrdlu

Done that, works lovely. Easiest way is get the engine hot, stick a hose from the brake vacuum connection in into a jar of water & open the clamp on the hose carefully. Obviously apply some common sense as hydraulically locking it will only make life worse.

Reply to
Duncan Wood

That's very interesting. I'd be a bit worried about locking it up, and since we have a fairly useless steam cleaner (like a kettle with a long tube), I was considering using that somehow. Maybe take one of the inlet ducts off near the throttle body, and let it blow steam in there.

Thanks.

Reply to
Etaoin Shrdlu

small clamp (or if you've ever done it just bending the rubber pipe) makes it very controllable.

Reply to
Duncan Wood

Okay, thanks - I'll find something. Is there a visible difference afterwards?

Reply to
Etaoin Shrdlu

Yup, you can see it on a borescope. You do need to suck it in fairly quickly.

Reply to
Duncan Wood

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