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Head off, replace rings while exposed?

You guys forgot to mention cutting the ring land at the top of the cylinder if you are going to hone.

Also know that if the cylinder is worn, getting the piston out the top may not be easy since the rings may hang on the land.

Also not mentioned is grinding the rings to get the gap correct, or at least checking it during assembly.

Personally, I have done it successfully, but without experience, there are way too many ways to screw this up. If you are going to all that effort, pull the engine and have the block bored and buy a new set of pistons and rings. If you pull the block and strip it down, the machine shop costs drop drastically. While it is apart, check the rod and main bearing clearance.
 
Thanks all. I’ve found someone to help me replace the piston (found a Knick on the edge) and hone the cylinder.

I’ll update here after this next phase.
 
Another hang up: piston has some burn damage, hoping from running coolant in there too long. I’m ordering new pistons with rings. Found a local shop to can take off the rods and press on the new pistons.

So, I’m going with new piston heads and honing all six cylinders.
 
linksvu said:
Another hang up: piston has some burn damage, hoping from running coolant in there too long. I’m ordering new pistons with rings. Found a local shop to can take off the rods and press on the new pistons.

So, I’m going with new piston heads and honing all six cylinders.
Click to expand...


Burn damage? Coolant getting into the cylinder doesn't cause burnt/melted pistons. Sever overheating, bad rod bearing, or a bad injector can cause piston damage. Make sure to mark and keep track of which rod goes where and the orientations.
 
lawsoncl said:
Burn damage? Coolant getting into the cylinder doesn't cause burnt/melted pistons. Sever overheating, bad rod bearing, or a bad injector can cause piston damage. Make sure to mark and keep track of which rod goes where and the orientations.
Click to expand...

How does a bad rod bearing cause a melted piston? Also the rods are all the same, they're location in the motor doesn't matter.
 
sidewaysstarion said:
How does a bad rod bearing cause a melted piston? Also the rods are all the same, they're location in the motor doesn't matter.
Click to expand...

If he is not doing the crank/bearings then I would say it does matter. Those parts have all gotten acquainted in a specific orientation. Best to maintain that rather than expect them to break themselves in a second time and wind up with good oil pressure.
 
I plan to carefully/accurately mark the rod parts so they go back in the same way.

Now, the debate if I buy a ball-hone or just use the loaner spring kind with the three stones...
 
Either hone will work. My preference is the ball hone.
 
sidewaysstarion said:
How does a bad rod bearing cause a melted piston? Also the rods are all the same, they're location in the motor doesn't matter.
Click to expand...


Doh, I meant to say wrist pin. A stiff or seized wrist pin will cause the piston to drag in the cylinder, with the damage most evident on the lower skirt. In my opinion a burnt cylinder is usually a symptom and you need to figure out why. You don't want to spend all the time rebuilding and then find out when it melts another piston that the fuel injector was bad.


Pics of the bad piston? I'm curious what it looks like.
 
Most of the car parts stores that have "rental tools" will have a ridge reamer, hone, and ring compressor.
 
Attached is a pic of the burned piston. No other piston showed anything close to this. I’m hoping it was the aftermath of it being run too hot and/or too long with coolant in the oil.

Found an awesome machine shop who removed my old and pressed on my new pistons for $60.

Now I’m finishing up honing the cylinders and then I’ll set the rings.

Here’s to hoping this was all worth it...

8a4b39a75024adc3f76fec1b463f69c1.jpg
 
What do your main and rod journals look like?

What does the bore of that cylinder look like?


I can tell you right now you are wasting your time.

The advise you got of just honing that bore was bad advise.



Fail.
 
four_shot said:
At this point it would be most cost effective to replace all 6 sets of rings. The pan isn't rocket science to remove (if not already done). And the head already being off makes the effort almost negligible. In for a penny, in for a pound.

As for necessary...without disassembly and inspection by a knowledgeable repair person, its anyone's guess. A couple rules of thumb:

Deep scratches in an updown direction are not a good sign.
Keep pistons, rod caps, and rod bearings together and oriented so as to be reinstalled in the same bore, direction, and position.
Take lots of pictures before and during disassembly.
Rent (or invest in) a good piston ring compressor!
Click to expand...

There is some block damage that needs attention. Pull the block and get it machined.
 
I think that pic is showing the piston damage deeper than it is, or timing was lucky when they stopped running the engine - it did not damage anything to my eyes.

The cylinder this came out of looks very good to me (pics). These are after honing the cylinders and I applied a coat of oil to protect the walls. You can just barely see vertical marks on the second pic. They cannot be felt by hand and appear to be just beyond what the stones will mar from the honing.

d693012f60940d79430d3cc7040b6f38.jpg
9ef42f0642ae36f70fd7c36870de8601.jpg


The rod (well, all of them) were checked to be straight. And the bore measured within spec, as best I could.

Is there something else I should be checking?
 
You may get by..........who knows.......

But, it's a half-assed way of doing it.

There was no reason not to pull the engine........NONE, other than laziness.

And the reality, it was probably more work to do it half-assed.
 
Except I do not have a hoist nor was this to be a rebuild job.

Hindsight is always clearer; had I known I would have replaced the pistons, I would have pulled the entire block and not bothered with everything else.
 
those 3 main gouges in the cylinder wall look pretty significant and devastating to me, in my opinion that block needs to be bored. i have built several engines with damage less significant than that and regretted it. take a fingernail across those gouges, you will feel it. also that is not a melted piston, that is a piston that has been beat to hell against your cylinder walls.
 
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