Injector burning up

[R0B]

I have a fair few un reconditioned ones here.I wouldn't ask for more than a tenner each for them.I may be wrong about £25 for a reconditioned one but I don't think I'm far off.

[itchyfeet]

http://forum.club8090.co.uk/viewtopic.php?f=19&t=156490" onclick="window.open(this.href);return false;

[syncroandy]

E D I T. Apologies a new injector is required as well as a fix to whatever else is the cause. Still think a compression check is in order though.
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I don't think we're all on the same page..

The OP states three good injectors have been fitted and subsequently melted..

it's not an injector problem then is it ? Or have I missed something ?

[martin83]

That cylinder could be running lean or hot. Causing detonation "pinking" damaging injector tip. LPG does have a higher octane rating which resists detonation or pre ignition, But does tend to cause accelerated wear on valve seats and spark plugs.
Check spark plugs and if possible for iridium plugs for LPG.
What kind of LPG system is it running injection or mixer?

[ronsrecord]

The LPG conversion was done by gasure 7 years ago - not entirely sure if it's injection or mixer - but I suspect mixer.

[syncroandy]

I'm assuming we're familiar with how these engines are built.. What goes on inside the cylinder can't directly affect the injector, which is fitted to the inlet manifold and should be kept quite cool by the air flowing past it and fuel flowing through it. Possibly a lean running condition or some other issue has damaged the inlet valve or seat, causing hot gases to get past and damage the injector tip.

This is only a surmise, I've never seen that happen myself, just saying it's a possibility, unless someone can prove otherwise.

[ajsimmo]

^ That's exactly what I said. For there to be that amount of heat near the injector, there must be something wrong around the inlet valve. Maybe a tiny leak on the valve seat which occasionally ignites the petrol that's coated and is still evaporating around the back of the valve? Over time that might burn the injector tip. That might explain why it doesn't do it on LPG. What does the collective think of my/our logic?

[itchyfeet]

compressing check then next?

[syncroandy]

Sorry Andy missed your post amongst all the others..

over and out.

[ronsrecord]

Thanks chaps - compression test it is!! If it is the inlet valve, how big a job is that to fix?

I love this forum - not on much nowadays, but I really appreciate the input when I do have a problem. Big thanks to you all.

[ajsimmo]

Manifold off and leak down test would be useful. Squirt some fluid (brake cleaner or similar) into the port then you might hear bubbles.

[max and caddy]

Would suggest checking the valve clearance and timings first...seems you have a flame front in the inlet manifold for some reason...it certainly shouldn't happen and is potentially dangerous ..a backfire or stall could result in a burning airbox for example.