Strange looking wear on my 5.9 cylinders

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MileHighDart

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Please take a look, this is the 5.9 I bought to put into my Dart.

I found two very strange looking stains, or wear marks inside cylinders 6 and 8. Plus on cyl #4 there is a dent in the edge of the piston and a corresponding scratch in the cyl. Obvious something made its way through that cyl. The longer scratch isn't bad, the shorter 1 inch or so scratch is pretty deep.

Look at the pics and let me know if you've ever seen anything like the stains, or if you what might have caused them. Was hoping to just hone and rering this thing, don't have the cash to bore it and buy pistons and spend a bunch of money at the machine shop.

cylinder#6.jpg


cylinder#8.jpg


cylinder#4-1.jpg


cylinder#4-2.jpg
 
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MileHighDart said:
Please take a look, this is the 5.9 I bought to put into my Dart.

I found two very strange looking stains, or wear marks inside cylinders 6 and 8. Plus on cyl #4 there is a dent in the edge of the piston and a corresponding scratch in the cyl. Obvious something made its way through that cyl. The longer scratch isn't bad, the shorter 1 inch or so scratch is pretty deep.

Look at the pics and let me know if you've ever seen anything like the stains, or if you what might have caused them. Was hoping to just hone and rering this thing, don't have the cash to bore it and buy pistons and spend a bunch of money at the machine shop.

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looks like water set in it for a while. work the deep scratch w/ some 320-400 grit sand paper, go 'lightly" then ball hone the cylinders, and put it together w/ a new piston , and fugitaboutit!
 
I see the reflection of your piston, but I really don't see what your talk'n about. Maybe draw circles around what you mean
 
If the pistons are tight and the ring grooves are not worn, then I'd hone and go. It won't be as good or as durable but you can sure drive it for a while. The bores do look pretty shiney, so for sure need honing. A lot of bore taper will wear out rings in a hurry so check the taper, but since you can see the old pattern so well, it may be just fine.

I am not sure I would worry over the scratch... the ring gap will lose more compression than this ever will. Just work the edges of the scratch a bit smooth so the ring ends can not have an chance to catch on it.

How deep is the ring ridge at the top? You can break the lower edge of the ridge so that the new rings do not come up and hit it and have any breakage problems.

I would reuse that piston in a heartbeat if there are no signs of cracks around the tiny bit of damage.

Make sure you thoroughly clean the crud out of the the ring grooves, and check the ring side clearance in the grooves. If too loose, the rings will just twist up and down and the ring seal will not last long at all.
 
run it. quit coffee and put that in a jar. In a year, youll have enough to get +.010 pistons and a bore job...but you wont feel any difference till then. Your that far in, remove the piston and check the rings. at least clean them out and position the gap away from that scratch. Knock that bugger off the piston top with a file so it wont cause a knock.
 
pishta said:
run it. quit coffee and put that in a jar. In a year, youll have enough to get +.010 pistons and a bore job...but you wont feel any difference till then. Your that far in, remove the piston and check the rings. at least clean them out and position the gap away from that scratch. Knock that bugger off the piston top with a file so it wont cause a knock.
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I don't know where you will find .010" over pistons but this is good advice. Dingle ball hone it and move the hone WAY faster than you think. Better yet take it to a machine shop and have them deglaze with their rigid hone CK-10 or whatever they have. Your engine will rock with a little more clearance and fresh cylinder surface. Get 4.005" rings and set gap tighter than whatever its at now and you will have a decent piece. J.Rob
 
Thanks for the reply's everybody. I'm thinking I'll take the advice here and just pull it apart, hone and re-ring it. Was kind of worried about the "water stains" or whatever, thinking they might be hot spots. I'm sure they will disappear with a hone. We'll see, going to try to get that going right away. I'll finish disassembly today, and go rent a ball hone. I'll post pics of how it cleans up.
 
It might just be that some fuel dripped down in there..... If it worries you and you take the block to a shop, have them run a bore gauge down that hole and see if it is distorted. Or borrow one....
 
nm9stheham said:
It might just be that some fuel dripped down in there..... If it worries you and you take the block to a shop, have them run a bore gauge down that hole and see if it is distorted. Or borrow one....
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That stain is fuel or some other solvent. Not coolant or water. J.Rob
 
Take a compression ring and push it down square just past the ridge with a piston and then mic the gap, then mic it at the middle and bottom of piston travel. The difference is the bore taper. .005 is usually the max allowable. use the circumference of 12.56637 as a STD 4.00 diameter piston. plug the deviation of the ring gap (.016 is max) into a calculator and add it to this diameter. devide it by pi (3.14159) and you'll get new diameter. Lets say you got a gap difference of 0.0160 thats about the limit. 12.582 is the bogey of a .005 cylinder diameter taper.. I had a stain like that and I used a stone glaze breaker but couldnt get rid of it. It was then that I realized...it was only a stain.....a smooth stain.....
 
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RAMM said:
That stain is fuel or some other solvent. Not coolant or water. J.Rob
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What bugged me about it was that there was no place where it looked like the rings were sitting to cause the mark to be where it is.
Maybe the rings were at the top edge of the stain and the piston was holding a puddle of something there between it and the wall.
The other thing was the dual pattern (pattern within a pattern) but that could have been where the skirt was actuall touching I guess.
 
it looks like that stain seeped past the cloudy ring area and just settled between the piston and the wall. Check out the acid elevation in used motor oil, it may have been the culprit.
fig_2_oil_life_cycle.jpg
 
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pishta said:
it looks like that stain seeped past the cloudy ring area and just settled between the piston and the wall. Check out the acid elevation in used motor oil, it may have been the culprit.
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That's what I was thinking.
 
TrailBeast said:
That's what I was thinking.
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Well, the oil I drained out of this engine was black as black can be. And the dark brown coloring on all the internal stuff, tells me that this thing didn't get many oil changes.
This engine had been sitting for a couple years, so possible I guess that it was lying on its side and oil got up between the piston and the wall and just sat there.
 
MileHighDart said:
Well, the oil I drained out of this engine was black as black can be. And the dark brown coloring on all the internal stuff, tells me that this thing didn't get many oil changes.
This engine had been sitting for a couple years, so possible I guess that it was lying on its side and oil got up between the piston and the wall and just sat there.
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Yep.
 
TrailBeast said:
What bugged me about it was that there was no place where it looked like the rings were sitting to cause the mark to be where it is.
Maybe the rings were at the top edge of the stain and the piston was holding a puddle of something there between it and the wall.
The other thing was the dual pattern (pattern within a pattern) but that could have been where the skirt was actuall touching I guess.
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Or the engine was laying over on its side and it just pooled on the side of the bore...oh... that's been said...
 
nm9stheham said:
How deep is the ring ridge at the top? You can break the lower edge of the ridge so that the new rings do not come up and hit it and have any breakage problems.
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There is no ridge around the top at all that I can feel, just discolored around the top (above the top ring). And now that I have the pistons out and I've started cleaning them up, they all look great, ring grooves seem nice and tight. No scratches on the sides of the pistons, even on that number 4 that has a little ding in the top.
 
pick out a compression ring and do what I asked, push it down the bore with the piston and measure the gap in a few different depths. Thats about as accurate as youll find on bore taper. 3X more accurate than a ID mic...actually 3.1416X ;-)
 
MileHighDart said:
There is no ridge around the top at all that I can feel, just discolored around the top (above the top ring). And now that I have the pistons out and I've started cleaning them up, they all look great, ring grooves seem nice and tight. No scratches on the sides of the pistons, even on that number 4 that has a little ding in the top.
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There is a spec you need to measure with a feeler gauge: ring side clearance and can be found in the manual and a lot of reference books. Clean both rings and grooves good before checking. If you clean it up and the old rings meet the spec for ring side, then the new rings will just be better.

You can measure ring side clearance by simply inserting the outer edge of a loose ring (off the piston) into the groove and inserting the feeler gauge. Google 'ring side clearance' and you will find pix to illustrate.

And there are tools to clean the carbon out of the grooves, but you can using the square butt end of an old ring.

Good deal on the ridge and general piston condition!
 
nm9stheham said:
There is a spec you need to measure with a feeler gauge: ring side clearance and can be found in the manual and a lot of reference books. Clean both rings and grooves good before checking. If you clean it up and the old rings meet the spec for ring side, then the new rings will just be better.

You can measure ring side clearance by simply inserting the outer edge of a loose ring (off the piston) into the groove and inserting the feeler gauge. Google 'ring side clearance' and you will find pix to illustrate.

And there are tools to clean the carbon out of the grooves, but you can using the square butt end of an old ring.

Good deal on the ridge and general piston condition!
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I haven't actually measured for ring side clearance, but I have been using a broken off piece of one of the old rings to clean out the grooves. Dad taught me that a long time ago. I have an old ring groove cleaner, but none of the bits fit the grooves very well. Probably cause the grooves are 1.5 mm on the magnums
 
Got busy today with a 320 grit ball hone. Had to buy one from summit, couldn't find one to rent.
Anyway bores cleaned up real nice. Those stains disappeared as soon as I started honing. Bores look great now, but made huge mess on the front of my garage door flinging oil all over. But that will clean up too.

IMG_20170318_125533880_HDR.jpg
 
Nice cross-hatch, should seat pretty good. Id use iron rings on that hatch now.
 
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