Can I hone just 1 cylinder?

[2INSANE]

Customer brought over a 6.5 NAVSTAR optimizer 2003 that was rebuilt by Milton in 2010 and had only 20 miles put on it in 12 years. 6 of the glow plugs had melted but I was successfully able to get them out without breaking them. Converted the IP from 24v to 12v and I did a 10 second dry test run on it and a compression test.

All cylinders are well above 400 psi except cylinder #2 which is at 265. I removed the head and found a long deep scratch in the cylinder wall.

I have never done a lower end before. Can I hone just the 1 cylinder and replace just the rings on one piston without affecting performance of the other cylinders?

If so, how much material can I hone off of the cylinder, what tool do I use to measure cylinder width, what specs should the rings be?

edit: pictures added

[DmaxMaverick]

A cylinder hone is a finish process. It is not a corrective option. Honing and new rings won't correct a deep gouge. That requires boring, then a hone to prepare the cylinder for new rings.

[Robyn]

I agree with Maverick.....

Just a suggestion.
Get that piston out of the hole and get a look at the rings.....

The one heavy score does not look good...BUTTTTTTTTTTTTTTTTTTTTTTTT...
But I am looking at the piccy on a 60" screen
The score is down in the hole far enough that it is not as big of a worry as if it was near the top of the hole...

Was this caused by the ingestion of a failed glow plug or parts of ?????

My thought is this.

Get the piston out and see wassssup there.

My bet is the piston and rings are messed up.

If this is the case.....Use a bottle brush hone to smooth the cylinder wall, stuff in a fresh piston and rings and give it a go......MAIN THING....GET THE HOLE SMOOTH SO THERE IS NOT ANY HIGH SPOTS...

Its going to have a tad more blowby than would be preferred......but that groove will fill with carbon and things will likely work OK

Certainly not a perfect scenario.....but I think it can be saved without a complete Overhaul

Just cover the crankshaft and other parts up top to prevent grit from the honing getting into stuff..
Clean the bore well with a clean rag an solvent to get all the grit out.....

Main thing is to smooth up that scuffed area....
I will bet that a fresh piston and rings....a light massage of the cylinder with a bottle brush hone and that hole can be coaxed up to 325 psi or above...

Get the piston out and get some pics for us to see..then we can tell more about what will/will not work to save things...

If that is a standard bore I have a good used piston sitting here

Measure across the skirt and get me the size.....I have 4 sitting here...They are all different select fit sizes....We will get one that's close.....
(1) used piston
(1) Fresh ring set (Single)
(1) Head gasket
(1) Set of head bolts
This bad boy can likely be saved pretty cheap....and live to battle the Mountain pass once again.

Rings are available in single sets.....Try
https://www.ebay.com/itm/15461588302...3ABFBMnPTova9g

[2INSANE]

Machine shop options are slim pickings locally to get a bore job done or anything done… it would have to be a garage job.

The glow plugs were pulled intact but there is evidence of the sides of 6 plugs that melted. It gives me reason to believe this issue is why the freshly rebuilt military motor got pulled with only 20 miles on it in 2010. When I noticed that 6 plugs were melted, I shop vacuumed the crap out of the intake ports and glow plug ports hoping to get any loose debris out. Unfortunately damage was already done Pre purchase.



Ok that sounds like it is worth a shot trying to fixing it. I’ll get some more tools and let you know measurements!

[Yukon6.2]

Having just bush fixed a 6.5...
I would go with Robyn's game-plan
One of the engines i pulled apart had a worse score in a cylinder and was running fine other than coolant pressure at the time.
The score in the cylinder was about 3/4" wide.It was a patch job fix,but not noticeable when it was a running engine.Not the reason of coolant pressure.
Robyn's pistons are in good shape i have one in my bush fix 6.5.

[2INSANE]

Having just bush fixed a 6.5...
I would go with Robyn's game-plan
One of the engines i pulled apart had a worse score in a cylinder and was running fine other than coolant pressure at the time.
The score in the cylinder was about 3/4" wide.It was a patch job fix,but not noticeable when it was a running engine.Not the reason of coolant pressure.
Robyn's pistons are in good shape i have one in my bush fix 6.5.

3/4” wide! Wow! Nice work fixing it!

Robyn’s plan is in the works!

[Robyn]

Keep us in the loop....

[Robyn]

It does not take much in the way of METAL to Fubar a cylinder....The jacket on the glow plugs are harder than a whores heart.....A small chunk likely got wedged between the cylinder and the piston.

I am going to hazard a guess that the rings and piston are chewed up on the side with the damage.
The ring lands are going to have damage as well and could have caused the rings to stick in the grooves.

The top ring groove has a hardened insert to protect the piston...

[2INSANE]

I got the piston out, disassembled and cleaned in the parts cleaner.



Top ring has very very light scoring.



Center ring has some deep scoring that can easily be seen and felt. When I removed it, it seemed like there was something wedged between the ring and piston. Basically seized on the damaged side.



Bottom ring with the spring looked ok.

The piston has a ton of scratches on it that I can feel with my fingers. Should I buy your piston or do you think it is ok?

[Robyn]

The Skirts look pretty good.
IF IT WERE MINE.
I would make sure there are no foreign objects jammed into the piston anywhere...Clean up the little beast with some 400 wet/dry paper using some diesel on it.

Make sure the piston is smooth with no ridges sticking up.....Wash well and put it back on the rod.

Make sure the new rings fit easily with no tight spots in the grooves.....

Put the end gaps at 90 degrees from the fire chamber in the piston and the top and second ring gaps 180 degrees apart to give the best chance to hold compression well.

Take the bottle brush hone to the bore and smooth it up keeping the tool moving up and down at a fair pace.

AS I SAID BEFORE.....COVER THE CRANK...WELL...

Use some lube like WD 40 ON THE HONE....

Get a decent cross hatch...make sure there are no high ridges from any of the scratches.

Wipe clean....lube up and stuff that bad boy back together.....

CAUTION....Be sure to BLEED ON IT A LITTLE

GOOD TO GO...

Just to clarify.....This is not AAA+++ Practices....but I think she will run pretty good....

Not sure what the rings listed at ebay were.....find a set of military chrome rings.
The top ring in your piccy looks like a moly filled ring ....these do not handle crap at all...
There is a moly filled center and a little band top and bottom that is cast iron.
The moly gets trashed by the crud and there goes the seal.
Moly rings require a very smooth finish.....
Chrome rings will wear well and deal much better with the less than perfect surface.
The slight imperfections will fill in with carbon over time and should be pretty good...
I have put together worse in a pinch and ran it for years.....

They used chrome rings in the HMMWV so the sand in the desert would not knock out the rings so easy.....At least that is what some of the fellas I have talked to that were in the sand box said.

I have some military packaged rings that are chrome...but they are .020 OS


Just a thought 60G glow plugs on a 12 volt system.....

Give it a go......The bleeding portion is very important

[2INSANE]

The Skirts look pretty good.
IF IT WERE MINE.
I would make sure there are no foreign objects jammed into the piston anywhere...Clean up the little beast with some 400 wet/dry paper using some diesel on it.

Make sure the piston is smooth with no ridges sticking up.....Wash well and put it back on the rod.

Make sure the new rings fit easily with no tight spots in the grooves.....

Put the end gaps at 90 degrees from the fire chamber in the piston and the top and second ring gaps 180 degrees apart to give the best chance to hold compression well.

Take the bottle brush hone to the bore and smooth it up keeping the tool moving up and down at a fair pace.

AS I SAID BEFORE.....COVER THE CRANK...WELL...

Use some lube like WD 40 ON THE HONE....

Get a decent cross hatch...make sure there are no high ridges from any of the scratches.

Wipe clean....lube up and stuff that bad boy back together.....

CAUTION....Be sure to BLEED ON IT A LITTLE

GOOD TO GO...

Just to clarify.....This is not AAA+++ Practices....but I think she will run pretty good....

Not sure what the rings listed at ebay were.....find a set of military chrome rings.
The top ring in your piccy looks like a moly filled ring ....these do not handle crap at all...
There is a moly filled center and a little band top and bottom that is cast iron.
The moly gets trashed by the crud and there goes the seal.
Moly rings require a very smooth finish.....
Chrome rings will wear well and deal much better with the less than perfect surface.
The slight imperfections will fill in with carbon over time and should be pretty good...
I have put together worse in a pinch and ran it for years.....

They used chrome rings in the HMMWV so the sand in the desert would not knock out the rings so easy.....At least that is what some of the fellas I have talked to that were in the sand box said.

I have some military packaged rings that are chrome...but they are .020 OS


Just a thought 60G glow plugs on a 12 volt system.....

Give it a go......The bleeding portion is very important

Ok sounds great! I measured the bottom of the skirt twice and came up with 4.09. Is that a .30 over piston?

[2INSANE]

How wide should the ring gaps be for all 3? Also what grit bottle neck hone should I use?

[Robyn]

4.050" is a standard piston...Sounds like the beast has been bored .040" OS

Ring end gap...... Top ring.... .010" -.020"............Second ring .029"- .039"
Oil ring gap is a ???? depends on what type is used...Most sets will include a little spec sheet with what is needed..


Get a Flex hone (Bottle brush) for 4" to 4-1/4" cylinders depending on what you get for rings....240 grit will do for cast iron or Chrome.....If you go back with moly filled (Common) then step up to 320 grit....Moly does not like a rough surface AT ALL.

When measuring the piston.....Mic them just a touch below the center line of the piston pin for a good number....

Good bet this Mil engine had sucked up a bunch of sand ....that is likely why it was bored .040" OS

Could have had a failure of some other nature.... most 6.5's will run 250K and still have decent usable bores......020" to .030" is a normal oversize on rebuild that need some help..

.040" tells me that this beast had taken a beating....

Military stuff....a crap shoot, and they can be let idling for looooooooooooong periods of time.....Hard to say what happened..... But usage is hard usage with them.

Gonna have to scare up a single set of .040" rings...
These are not as common as the .030" size or standards.

[2INSANE]

4.050" is a standard piston...Sounds like the beast has been bored .040" OS

Ring end gap...... Top ring.... .010" -.020"............Second ring .029"- .039"
Oil ring gap is a ???? depends on what type is used...Most sets will include a little spec sheet with what is needed..


Get a Flex hone (Bottle brush) for 4" to 4-1/4" cylinders depending on what you get for rings....240 grit will do for cast iron or Chrome.....If you go back with moly filled (Common) then step up to 320 grit....Moly does not like a rough surface AT ALL.

When measuring the piston.....Mic them just a touch below the center line of the piston pin for a good number....

Good bet this Mil engine had sucked up a bunch of sand ....that is likely why it was bored .040" OS

Could have had a failure of some other nature.... most 6.5's will run 250K and still have decent usable bores......020" to .030" is a normal oversize on rebuild that need some help..

.040" tells me that this beast had taken a beating....

Military stuff....a crap shoot, and they can be let idling for looooooooooooong periods of time.....Hard to say what happened..... But usage is hard usage with them.

Gonna have to scare up a single set of .040" rings...
These are not as common as the .030" size or standards.

Awesome! I’ll get some better measuring tools to get more accurate readings.

Also on the bottom of the oil pan there was a lot of RTV chunks from the oil pan being overloaded with the RTV. There is also small traces of what looks like sand on the bottom of the pan too.

I am thinking the whole lower end will need to be taken apart and have every part cleaned in a hot tank. What are your thoughts?

[Yukon6.2]

The block with the groove is toast as far as i am concerned.
But the last guy thought it would run for a while,which it did.

[2INSANE]

The block with the groove is toast as far as i am concerned.
But the last guy thought it would run for a while,which it did.

I agree it’s risky. Customer has been contacted and we are deciding what steps to take next.

[Robyn]

I do not think it needs to come all apart...NO HOT TANK NEEDED...

IF IT WERE MINE.
With the bores as large as they are now.

Get the other head off as well....Check for damage... IF NO OTHER DAMAGE

Wash out the pan....fresh oil filter, fresh oil...
Clean out the intake well.
Remove ALL the injectors and inspect the precups for any trash from damaged glow plugs.

Inspect the cylinder heads well....Disassemble each valve and look for damaged valves/seats....Blow out all intake and exhaust ports.....

If all is well.....clean the decks and the heads well to receive fresh gaskets and bolts...
Clean all head bolt holes in the block..../run a proper tap through each one to clean the threads.
ALL GOOD....

Stuff the one slug back in.....BUTTON THE BEAST UP.....

Yank the turbo off and inspect the hot side wheel for damage from the debris coughed out from the dying glow plug parts.
The turbo is spinning like the mill tails of hell...and trash from a dying glow plug can ruin the turbine....

Check the injector nozzles for surface damage....should be none...but give a look anyway....

Blow out the exhaust crossover pipe...just because....same with manifolds.....Do not leave anything that can bite you untouched....

[2INSANE]

I do not think it needs to come all apart...NO HOT TANK NEEDED...

IF IT WERE MINE.
With the bores as large as they are now.

Get the other head off as well....Check for damage... IF NO OTHER DAMAGE

Wash out the pan....fresh oil filter, fresh oil...
Clean out the intake well.
Remove ALL the injectors and inspect the precups for any trash from damaged glow plugs.

Inspect the cylinder heads well....Disassemble each valve and look for damaged valves/seats....Blow out all intake and exhaust ports.....

If all is well.....clean the decks and the heads well to receive fresh gaskets and bolts...
Clean all head bolt holes in the block..../run a proper tap through each one to clean the threads.
ALL GOOD....

Stuff the one slug back in.....BUTTON THE BEAST UP.....

Yank the turbo off and inspect the hot side wheel for damage from the debris coughed out from the dying glow plug parts.
The turbo is spinning like the mill tails of hell...and trash from a dying glow plug can ruin the turbine....

Check the injector nozzles for surface damage....should be none...but give a look anyway....

Blow out the exhaust crossover pipe...just because....same with manifolds.....Do not leave anything that can bite you untouched....

Ok. It is a N/A Optimizer. I do have the turbo stuff from a 95 donor so should be good on that side of things. Compression numbers are above 420 on the other cylinders.

[2INSANE]

Here’s another Newb lower end question.

Would the other 7 cylinders benifit if I turn the block upside down and spray brakekleen between the pistons and the cylinder walls to clean out any sand, dirt, build up, etc that could be lingering on top of the top ring or is that a bad idea?

Also would it be safer to hone the bad cylinder with the motor upside down?

[Robyn]

Get the other head off just to be sure there is not any junk lurking.

The engine is out....Checking the other side is easy now....Doing this over again is a PITA.
A little chunk of crap rattling around may not have caused issues...BUT IT COULD....
Just a PLAY IT SAFE THING....
Poor engine has had a thrashing already....Let's save it....

No need to wash things..Just roll the engine over and as each piston drops down about an inch or so....wipe the cylinder wall with a WD40 dampened rag....Just to catch anything.

Just enough WD to make the rag sort of sticky....

Do that after you clean the decks off.....

Before honing cram some rags down in the hole with the crank throw DOWN...

Just protect the journal is all.

After you are done....wipe the cylinder down with a rag dampened with brakleen....

Clean the cylinder walls well....Lube lightly before stuffing the Piston/Rod assembly back in.

Make sure the decks are spotless clean and wipe with clean rag and brakleen to leave a dry oil free surface....just before you drop the heads/gaskets on....

With the engine on a stand you can roll it over with the bad hole angled down at a 45 degree....Still cover the rod journal...