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Thread ID: 118745	2011-06-19 02:17:00	Any Mechanics here?	hueybot3000 (3646)	PC World Chat

Post ID	Timestamp	Content	User
1210483	2011-06-19 02:17:00	So I bought a Mitz Legnum 98 with the 2.4l (4G64). It was blowing a heap of light blue smoke so I thought no worries Ill replace engine and sell it or maybe keep it. Yesterday I got carried away and started stripping engine just out of curiosity to see what's wrong with it. Has 170k on it and it had quite a bad miss when I drove it home. First things I looked at were oil and anti freeze. Oil was black but clean (no traces of metal) and coolant was very clean. So I ruled out head gasket. I have read that a common problem with the engine could be valve seals? Anyone heard of this? Today I might pull the head off anyway but how would I tell if the valves are seating properly? I know my way around engines as far as maintainence and have rebuilt a couple of bike engines but cars engines are a bit more complex :eek: Also noticed the intake manifold right through to the cylinders is coated in oilly sooty stuff, I know a little build up is normal but this seems like quite a bit? Could a inlet valve not sealing result in it running rough and cloggin the intake up with rubbish? Any help would be great	hueybot3000 (3646)
1210484	2011-06-19 02:24:00	I reckon you have a piston with broken rings on it or a scored bore. To check the valves with head off upend it and fill combustion area around valves with kerosene. To check in place smash out a spark plug and adapt an air supply adaptor to to it turn it over by spanner watch valves go for tdc valves closed apply air if its valves the air will rush out exhaust or intake manifold or if rings piston rooted into sump and out breather. Be warned the if not tdc the piston may fly down with the air pressure and if you are holding the spanner you will utter the word ****	prefect (6291)
1210485	2011-06-19 02:38:00	I reckon you have a piston with broken rings on it or a scored bore. To check the valves with head off upend it and fill combustion area around valves with kerosene. To check in place smash out a spark plug and adapt an air supply adaptor to to it turn it over by spanner watch valves go for tdc valves closed apply air if its valves the air will rush out exhaust or intake manifold or if rings piston rooted into sump and out breather. Be warned the if not tdc the piston may fly down with the air pressure and if you are holding the spanner you will utter the word **** +1, blowing smoke is either a too rich fuel mixture or most likely blown oil rings on a piston/s....	SolMiester (139)
1210486	2011-06-19 02:49:00	I reckon you have a piston with broken rings on it or a scored bore . To check the valves with head off upend it and fill combustion area around valves with kerosene . To check in place smash out a spark plug and adapt an air supply adaptor to to it turn it over by spanner watch valves go for tdc valves closed apply air if its valves the air will rush out exhaust or intake manifold or if rings piston rooted into sump and out breather . Be warned the if not tdc the piston may fly down with the air pressure and if you are holding the spanner you will utter the word **** Cheers for that, will attempt it . Broken rings would appear in the sump would they not? At least a sign of it? Also does the intake usually have oil in it? Ive seen soot but not this oilly before	hueybot3000 (3646)
1210487	2011-06-19 03:16:00	Agree with Prefect and SolMiester. If can check compression with gauge in spark plug hole, and oil as described here (autos.yahoo.com) to isolate whether if valve or rings are the culprit.	kahawai chaser (3545)
1210488	2011-06-19 03:32:00	Compression test would actually be the smart way to start while the head is still on. Will have to track down a tool though. Few pics...was quite hard to get the oil to show in the pics but the sooty stuff is alot wetter in real life, not soakin but will smear rather than crumble if that makes sense	hueybot3000 (3646)
1210489	2011-06-19 03:38:00	That engine is a GDI type (gasoline direct injection (en.wikipedia.org)), and the oil burning is a common problem with them. The deposit you see in the intake manifold is collected soot from the EGR system (exhaust gas recirculation (helps in keeping exhaust emissions down)) and oil mist from the PCV system (positive crankcase ventilation) and dust (if you don't have a decent air filter (K&N?!)), trouble is with these engines the intake manifold and intake ports are not washed by fuel like conventional engines so eventually clog up, causing the engine to run too rich which 'poisons' the oxygen (O2) sensor in the exhaust. End result is the bores are washed by excess fuel which results in excessive bore and piston/ring wear (especially oil control rings). It can be avoided by regularly cleaning out intake tracts (tho this never happens :)). Broken rings would appear in the sump would they not? At least a sign of it? Not unless they have smashed their way past the piston (you would hear that!).	feersumendjinn (64)
1210490	2011-06-19 03:39:00	I've got one of these, I had to have the valve stem seals replaced (quite a common problem) because it was blowing too much smoke to get a WOF. The mechanic said they looked like bakelite, all brittle and not sealing at all. So I'd say look there first. With the intake manifold, they have an exhaust gas recirculation system that helps with emissions and fuel economy when cruising. If you run them on crap fuel, and especially if they are burning oil, the intake will therefore get clogged with whatever's in the exhaust, and has quite an effect on performance and economy. These cars need to ideally be run on 98 octane (BP Ultimate), as they are spec'd by Mitsubishi to run on 100RON (not obtainable in NZ). Under no circumstances should you run it on 91, that will make it sound like a tractor and clog up the intake manifold with soot. When it's running nicely, you should be achieving around 8L/100km fuel economy on the open road easily, to give you an indication. Don't be concerned if it idles at ~500rpm and shakes a bit, that can't be avoided as the idle is controlled by computer and can't be manually set. It's annoying but I've found nobody who can fix it. Good luck :)	ryanjames.powell (13554)
1210491	2011-06-19 03:44:00	Wow cheers for the info guys, explains the soot! Being fairly new to engines I was confused by the soot. Did gettin the valve seals replaced fix your problem? How many k's has your car done? This car actually got a warrant at the beginning of the month so it cant have been going on too long. Or the mechanic who gave the wof was a bit dodgy lol I will do a compression test, can these be done turning it over by hand? I have removed everything around it so would be a pain to hook everything back up to turn it over on the starter, unless i just gave the starter a feed from the battery?	hueybot3000 (3646)
1210492	2011-06-19 03:46:00	Not unless they have smashed their way past the piston (you would hear that!). I had figured that but wasn't 100% sure. It actually sounded quite smooth when it was running even with the miss. I had a TS185 engine in a grass kart when I was younger, the sound of the piston scattering itself through the engine at ridiculous revs was just bliss to me! :rolleyes: EDIT: On a side note the info about the intake getting clogged up is very useful. If this engine is going to be to much $ wise to fix I will look at sourcing another and will definitely clean it out before it went in the car. I paid 400 for the car with reg and wof and otherwise very tidy condition. The gearbox (tiptronic) felt tight and changed smoothly so hopefully once the engine issue is sorted it will be a good car.	hueybot3000 (3646)
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