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Discussion Starter · #1 ·
I recently bought a 1984 Isuzu I-Mark sedan diesel with A/T. Everything has been great so far except it uses extreme amounts of oil. Like 1 quart every 80 miles. I love the car and don't want to get rid of it, but I recently got a ticket for excessive smoke and was told I either have to fix it or sell it.

I just checked the compression and have 420 at the highest and 400 at the lowest. These seem like good numbers to me, but I'm not very familiar with this engine at all. I was thinking it might be a broken piston ring or stuck rings, but the compression check makes me wonder.

Does anyone have any idea what might be wrong? I really don't want to get rid of this thing. I'm not afraid to do engine work if I have an idea where to start. Help me keep it!

Thanks for your time,

Matt
 

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mrshoes said:
...but I recently got a ticket for excessive smoke and was told I either have to fix it or sell it.
Where do you live, that they'd ticket you for that? I need to stay away from there!

Does your I-Mark vent its crankcase back to the breather? I know they introduced that in the P'ups in '84.

Jack
 

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Discussion Starter · #3 ·
Hi Jack, I live in California. Where else would they do something like that? Yes, crankcase vent goes into the intake. There doesn't seem to be that much blow by though. The intake manifold is cleaner than a whistle.
 

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are S-10 diesel eats oil nearly as bad but has 275 compression on one piston, and the other three avrege 360psi or so.
starts and runs, but WAY short on power even by the very slow standards of a S-10 diesel.

is the smoke coming from the tale pipe :?: or some where else?
what color is the smoke, and does it change as the engine worms up?

engine hard to start or have a miss as it starts up when cold?
even in 100% city driving a I-mark with the auto trans should be getting 26 to 30 mpg

if the smoke is coming out the tale pipe, one way or another its getting in the chamber.
and i can only think of a few ways for oil to get in there.

rings, valve seals, cracked piston or maybe valve or possibly a head gasket leaking oil on to the top of the engine pistons, a cracked piston liner would let water in not oil....hmmm :? :?

other than being over filled with oil, or something to do with the sealed crank case system, i can not think of any thing else right now......
 

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Discussion Starter · #7 ·
I get lots of smoke from the tailpipe until its hot. Oil is definitely getting into the chamber and lots of it. In some ways it acts like valve seals, but I've never known bad seals to cause such a small engine to consume so much oil. A cracked piston or broken piston rings will definitely cause a diesel to drink oil, but usually comes with a loss of compression, at least that's what I think. The I-Mark doesn't have a turbo, I believe they were all naturally aspirated. I get between 32 and 40 mpg with a mix of city / highway driving.
 

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First thing you should do is a compression test.. If you did already and have a low hole it might be a cracked piston. If it quits smoking after warming up it's because the crack gets smaller. Anything valve train related would not Likely change, nor would a broken ring and or an internal leak.
What's the blow by look like coming out of the valve cover??? Cold and then warm.
 

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Forgot does it run really rough like a dead hole ???
It could be valve guides dumping down when it's sitting , then it has to burn that out....
 

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Discussion Starter · #10 ·
well I have 400 to 420 psi across the cylinders, its consistent at least. I've never owned one before, but It seems to have the power it should. It acts like valve guides to me because it smokes on start up and then if I go down a long hill at the bottom I'll blow a big cloud of smoke... or in stop and go traffic or idling it will start smoking.
 

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the 400 to 420 psi is very normal for the engine being 25+ years old, it was a little more when new but only 30 psi or so.

for the 2.2L 375psi is considered time to over hall by Isuzu there 21 to 1 compression. but they run OKish tell 350
i can not remember the 1.8Ls compression off hand its likely something close to that.

haa found something that says its 21.5 to 1
 

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Well it sounds like it is just the top end leaking oil past the valves. Bad thing is your oil consumption. It will also crud up the valves and eventually probly burn one. You might just look for another head to go through and then change it out. It's runable just an oil eater...
 

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watch it dosent start running off its own oil and blows up :p i heard a funny story about that happening to an isuzu diesel from my shop teacher.
 

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Discussion Starter · #15 ·
Well I took the injectors out and put a half cup of pb blaster in each cylinder. I let it sit overnight and then changed the oil the next morning. I also changed the fuel filter (which was full of water and what looked like red dirt) and swapped out the 180 degree thermostat for a 195 degree one. I took it out this afternoon for a long drive and tried to drive it much more aggressively than normal. It seems to smoke much less and has more power, but I haven't figured the specific numbers on oil consumption yet. I was hoping that a combination of higher temps and soaking the cylinders with penetrant would loosen up any stuck rings. It could be that running hotter just makes a cleaner burn so the smoke is not so obvious.

Will post more later when I have specific numbers. If the problem has not been fixed I will tear the engine down, here's to hoping I can still get parts for it.

Matt
 

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mrshoes said:
Well I took the injectors out and put a half cup of pb blaster in each cylinder. I let it sit overnight and then changed the oil the next morning. I also changed the fuel filter (which was full of water and what looked like red dirt) and swapped out the 180 degree thermostat for a 195 degree one. I took it out this afternoon for a long drive and tried to drive it much more aggressively than normal. It seems to smoke much less and has more power, but I haven't figured the specific numbers on oil consumption yet. I was hoping that a combination of higher temps and soaking the cylinders with penetrant would loosen up any stuck rings. It could be that running hotter just makes a cleaner burn so the smoke is not so obvious.

Will post more later when I have specific numbers. If the problem has not been fixed I will tear the engine down, here's to hoping I can still get parts for it.

Matt
MATT IS YOUR ENG SMOKING BLACK , SMOKE OR IS IT ALL BLUE, SMOKE, BLACK IS OVER FUELING BLUE IS OIL RINGS OR VL STEM SEAL S, OR POSSIBLE BROKEN OIL CONTROL RINGS,BUT THAT IS PRETTY RARE , YOUR ENG DOESN,T HAVE CYL SLEEVES IT IS MADE JUST LIKE A GAS ENG WITH A SOLID ENG BLOCK, DO YOU HAVE ANY IDEA IF THE ENG HAS EVER BEEN OVER HEATED , OR CAN YOU HEAR ANY ODD NOISES BESIDES THE NORMAL DSL NOISE , THESE ENGS ARE NORMALLY PRETTY QUITE AFTER WARMING UP, A SCORED CYL WALL FROM A SEIZED PISTON IS NOT UNHEARD OF FROM OVER HEATING , NEED TO KNOW WHAT THE SMOKE COLOR IS, FROM THE NO,S ON YOUR COMP, READING S IT DOESN T APPEAR TO BE A SEIZURE OR THE NO,S WOULD BE MUCH LOWER , THEY SHOULD BE OVER 400 AND THEY APPEAR TO BE . THEY A RE ONLY ABOUT 440 WHEN NEW ,JERRY
 

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********** said:
I have a motor sitting in storage if you end up needing one.
If you go this route, you will likely need some of the A/T stuff from your old one--unless **********'s engine is also from an A/T. You will need the flex plate and either the injection pump or at least the kickdown mechanism from the pump.

Jack
 
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