Yo, engine geeks...

I popped into my dads work to say hello today, and he showed me a piston he extracted from a ford Ka. It was fubar'd, melted through and a right old mess. He's replaced the part and cleaned up the engine, but he couldnt explain why that piston had melted.

So here I am, opening up a discussion for reasons why a piston may melt in a Ford Ka engine. The only thing I know as to why a piston can melt through is a really hot burn from running lean, but it wasnt the case here

sooooo

what could have happened? I'm really interested in this sort of stuff, i find that when you discuss engine faliure, you end up learning alot

I'm gonna see if i can get hold of the piston as a paper-weight

[TSM]

pic

I forgot to take one. the melting-through occured at the edge of the piston, not through the centre

[yorkie_chris]

Yup, pics. Lots of possible causes, too lean, plug too hot, too much ignition advance. A bit of detonation can be survived but if it progresses to preignition then things melt very quickly.
Detonation can sometimes look like a rat has been chewing on the edges of piston.

YC, thats what it looks like. I'll get my dad to take pictures of the piston for me

just seems an odd thing to occur in what is really a reliable car. Goes to show that despite all the modern advances etc etc that drastic things still go wrong

and even though its expensive...its quite awesome, like face-plants

the engine in the KA is about 13 years old now, not what i would call modern......

[yorkie_chris]

But they are a simple design, usually fairly reliable.

Originally Posted by yorkie_chris

But they are a simple design, usually fairly reliable.

I dont hear many tales of car engines failing this way, this is the first one that has seemingly done it of its own accord. The other engine destruction was due to a failed oil pump which wrecked all the big-end bearing surfaces on an audi engine.

Originally Posted by arcdef

the engine in the KA is about 13 years old now, not what i would call modern......

Actually, it is a development of the ford kent engine that dates back to the Anglia of 1959, although most of it has had some extensive redesigns since, it is still the same basic design. I remember looking at a Ford Ka when it first came out and having a distinct feeling of deja vu when it first started up; it still sounded like my 20-odd year old fiesta 1.1L. The Ka uses a 1.3L OHV version with electronic ignition and fuel injection (early cars might have carbs but I can't remember).

MT

All for KA's were Fuel Injected IIRC. Tbh it's been around for donkeys years and still looks fresh and is still funky.. and it's a EVERY DAY, EVERY PERSONS car...what other car has done that?