Hi everyone, first post here....

My 2003 BA egas / LPG engine has knocks, I tore engine apart, found there is melt metal on the edge of every piston. I measured the piston clearance to wall, there is at least 0.5mm to every piston. there is clear clicking sound if i push the piston. So I think it's piston slap?

I found it's hard to get the piston for LPG engine, found one suply but cost about $600, that is not worthy. Also I found cheap petrol one cost $200+ but the problem is that it's 0.5mm oversize. Can
I use the 0.5mm oversize one without touching the cylinder?

Or anyone can point me out where to buy the standard size BA piston, petrol or LPG doesn't matter, but not too expensive(<$300)?

Thanks in advance!


blown piston?


clicking sound when pushing piston:
https://www.youtube.com/watch?v=1haapY0DSGE

Proberly cheaper to just buy a low KM E-Gas Engine

thanks, you are probably right.

now I am thinking to get the standard petrol piston or to get a used egas engine.

the used egas engine is expensive tooooo
and fewer egas engine, a good one costs $800 easyly, I am very sad with egas:
no much saving on fuel, but cost a bit more on maintenance

If you are not saving much on fuel, then you do have other problems

it burns around 19L/100km, because mainly in slow traffic(average speed 23km/h on dash), the fuel consumtion should be all right. I mean the LPG used to be much cheaper than petrol so it saved a lot comparing driving on petrol, but not now as lpg price goes up a lot

You don't end up with pistons looking like that without a problem somewhere

I agree with you. A 11 years old BA engine with 180,000km shouldn't has all its pistons burnt like this?
I owned this car when it was about three years old at 2006 and was 115,000km at that time. I can't figure out what made this happened. The knocking sound started less than a year ago. what I am pretty sure is that it didn't run lean in past years, and it didn't run with low oil level/pressure, didn't run overheated.

The last major problem was LPG converter broken and coolant went into engine through intake, that happened before the knocking sound came up. My wife was driving when it happened, she stopped quickly after that so I guessed engine was not overheated.

I am not sure if the piston burnt is related to that?

This car had been driven with intermittent sticked brake for very long period, maybe for 7 years?
Untill one day in 2012 I fould the brake stuck and I adjusted master cylinder. Could this be the reason of putting too much load on the engine and slowly the pistons burnt? But again there was no overheated since I owned this car from 2006.

Vacuum leak making it run leaner and hotter ?????

Thanks

But this car has no vacuum leak, intake gasket good, hoses good. If there was vacuum leak on egas engine, there was always backfire.

Running too rich ???.....with LPG, if it runs too rich, it runs very hot.

really? Can you give me some links?

It did run rich for quite long time, because the ignition problem..... If running rich makes it hot then it makes sense!

I just remember being told back in the day that LPG was the opposite to petrol.
When petrol is too rich, the engine runs cooler, and LPG runs hotter.

Thanks cjh, this does explain why the pistons burnt. my car did a long time running rich, the exhaust smelled strange.

There are some posts support what you said as well:
http://www.fullboost.com.au/forum/showt ... ance-guide
http://talk.newagtalk.com/forums/thread ... etCookie=1
http://www.volvoforums.org.uk/showthrea ... 410&page=2

Good on you, thanks

update:

changed main&conrod bearing the noise gone. the pistons are all good.