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tats
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(Need a Spot)
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07/11/06 12:02 AM
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scratches on cylinder wall
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My Montero SR 95 had the notorious smoke issue, like other owners do. After waiting for the traffic lights, I got bluish smoke. I suspected the valve seals. So, I took the heads out and got overhauled. Now, I noticed these scratches. Mechanics said my Montero won't crank after reinstallation. I had better get another engine. Do they look that serious?
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powerRam50
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(Body Damage is Cool)
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07/11/06 12:05 AM
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Re: scratches on cylinder wall
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i have seen worse.since it ran before i woul think that they screwed up on putting it back together.
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Racer4
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(Mudrunner)
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07/11/06 12:26 AM
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Re: scratches on cylinder wall
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Notice the scratch that goes all the way to the top of the cylinder in your photo. That was caused by debris on top of the piston, not the rings which do not travel to the top of the cylinder.
It was dirt/debris that started your problem. If it were me, I would take some scotch brite and clean the cylinder in a sidways motion. This might get rid of 60% of your problems. What do you have to loose? Just head gasgets and some time. Good luck, I hope it turns out for the best.
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tats
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(Need a Spot)
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07/11/06 12:43 AM
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Re: scratches on cylinder wall
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What quick responses! I love this place. Thank you, guys.
Yes, it was running good before the overhaul, except the oil burn. BTW, I did not remove any pistons, only heads (yes, to do that, I had to remove lots).
Worth to scotch brite a bit, reinstall the heads, and try?
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PHIL
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(Mitsubishi Section Editor and Moderator)
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07/11/06 01:22 AM
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Re: scratches on cylinder wall
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So you left the block as it was? And now the problem is it won't turn over? Wonder if the rings are sticking to the cylinder walls a little? Maybe a shot of oil down each might do the trick?
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tats
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(Need a Spot)
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07/11/06 01:33 AM
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Re: scratches on cylinder wall
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I have not yet done any. Still trying to find out if and how much I can get a new short block. Or, if there is any better way. I will post whatever I do.
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LRJ4x4
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(Web Wheeler)
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07/11/06 02:10 AM
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Re: scratches on cylinder wall
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Run a finger nail across the scratches, if you just feel them then it's fine. If you nail catches then you can try a little scotch bright. It's not a show stopper but you will use a slight amount of oil.
Won't turn over ??? It ran when you brought it there?
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Winston
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(Rock Warrior)
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07/11/06 10:37 AM
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Re: scratches on cylinder wall
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Quote:
Mechanics said my Montero won't crank after reinstallation.
The failure to crank is a "prediction" by his mechanic. I don't think the engine has been reassembled yet. I think the prediction is BS.
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powerRam50
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(Body Damage is Cool)
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07/11/06 12:39 PM
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Re: scratches on cylinder wall
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did you do the work o a shop?it is vey posible the timing belt is not set ight o thee is a wie not hooked up,or somthing like that.if it an before the heads came off then there is NO reason it should not run after.
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Re: scratches on cylinder wall
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Has the engine ever overheated? Cylinder scoring like this can be the result of overheating (piston expansion). I think it will still smoke regardless of the heads, but I don't see why it wouldn't run.
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Kevin C
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(Trail Leader)
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07/11/06 01:46 PM
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Re: scratches on cylinder wall
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I agree… Should run but may still use oil. The piston top and the wall looks very clean like that cylinder is pumping a lot of oil. How do the other piston tops look in comparison?
Were the valve seals bad enough to account for the amount of oil you were using? In particular were you getting one plug that was fouling or had more deposits?
Basically, will putting on fresh heads get you an engine that is useable?
Kevin
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tats
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(Need a Spot)
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07/11/06 02:04 PM
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Re: scratches on cylinder wall
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I (and the shop) have not reassembled yet. So, it's just a prediction. After reading these comments here and hearing from friend's opinions, I started feeling that it should run, just like before the overhaul. The smoke issue might stay, though. Regarding overheat, I haven't had any but previous owener might have. (I bought this truck 3 years ago. That time, it had 70,000 mile. I changed the timing belt right after that. I changed transmission this year. Now it has 99,000.) A mechanic also asked the same question when he looked the scratches. I remember the transmission guy also asked about overheat. I should ask them to re-install and try if it starts or not. Unfortunately, I have to totally count on the shop now...
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arm755
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(Need a Spot)
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07/11/06 05:38 PM
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Re: scratches on cylinder wall
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My friend. I have the same problem like you have and the same SUV with an 6G74 3500cc engine and same year; the only diference is that hace 230,000 miles. When I stop at a traffic light at idle speed and wait for about a minute its starts to smoke. My mecanic told me that I have to change the the piston-rings and the valve seales. There is something curios when the oil amount in the engine drops from 4.7 Liters to about 3 liters the smoke disapears, so that tells me the its more posible that the piston rings are the problems and not the valve seals.
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fasteddy
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(Web Wheeler)
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07/11/06 10:02 PM
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Re: scratches on cylinder wall
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When I save the image and look close at the honing pattern, the diagonal honing marks seem to continue thru the vertical scratches in almost all of the cases. That means some scotchbrite may well do the trick. I'd take a good close look at the honing pattern under strong light and evaluate it in person, then make your best call. If the honing pattern is mostly complete, you'll see slight oil burn. I'd look for piston rocking, too. Rotate the piston to about 3/4 of the way up the bore, and carefully measure the distance from piston top to block top on both the exhaust and intake sides. Now rotate the piston past tdc to about 1/4 the way down the bore, and repeat measurements. measuring tool must read to .0001, like a micrometer depth gauge. You're looking for piston rocking, and you may hear a slap as the piston cocks the other way as it passes tdc and bdc. Rotate more vigorously to get a more distinct sound. You should have been able to hear piston slap (like vavle ticking but louder) at and just off idle in the engine before if you have a collapsed/collapsing piston skirt.
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LRJ4x4
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(Web Wheeler)
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07/12/06 02:15 AM
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Re: scratches on cylinder wall
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Depth micrometer to .0001. I checked one out of the tool room once, it came with a case and a armed guard 
He had orders to shoot me if I dropped it 
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tats
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(Need a Spot)
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07/18/06 11:50 PM
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Re: scratches on cylinder wall
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They re-assembled and the result is... good so far. The smoke issue I had before the overhaul is gone. I did some Scotch Brite in a sideways motion, as suggested here. Did it work? Yeah, may-be. I will check if it still burns oil later.
Though it cost $900+, my Monty is back. It got a new water pump, thermostat, T-belt, belts, spark plugs, etc. Next stop would be shocks?
BTW, the ABS indicator doesn't go off. I remember this thing need to be reset. How can I do...
Photos - removing heads
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LRJ4x4
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(Web Wheeler)
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07/19/06 12:13 AM
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Re: scratches on cylinder wall
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Good deal, 
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Re: scratches on cylinder wall
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Good work! thank you for the pictures, I'll be getting into this soon enough!
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