How much cylinder wear before you bore and go to larger pistons?

[moparguy]

Got the head off the project truck and the cylinders look ok, no scratches or grooves in the cyl. walls, however all the factory hone marks are gone. I was hoping the dusting from a bad airfilter had only taken out the rings.



I'll pull the pistons the afternoon and see if I can comeup with a inside dia. mike to check bore dia. and taper (may have to resort to feeler gauge to check piston to cylinder wall clearance).



Question to the group, how much wear is to much for a hone/ring job. Remember, not trying to build a ProStock engine, just a farm rig.



Thanks, RR

 

[n7gxz]

Usually about . 010" is when you start looking at going oversize.



Kevin

 

[lmills]

. 010" ??? That seems a bit much. Unless there is that much difference between applications

 

[WDaniels]

The factory says if you measure 1mm over to replace the cylinder sleeve.

WD

 

[n7gxz]

What cylinder sleeve? The 5. 9 do not have sleeves in them from the factory. Yes you can get sleeves to put in during a rebuild but from the factory they are parent bored blocks just like a gaser.



Kevin

 

[WDaniels]

I believe there are sleeves in the cummins engine. Not like the ones you can just knock out. They have to have one end machined, then the sleeves taken out and new ones put back in.

WD

 

[Forrest Nearing]

5. 9 has no sleeves

 

[Joe G.]

The 5. 9 has no sleeves. The service manual is very clear on that. There are sleeves available for overhaul. The block is bored to accept them. The instructions in the service manual give exact details on how much wear requires an overbore. Anything beyond that requires a repair sleeve to be installed.

 

[RCenters]

piston to wall 5 ths is ok



im rebuilding one now myself and just had another honed

 

[RTillery]

I would try to get hold of a bore gage and if not, an inside and outside mic combo. If I could find more that . 001" to . 002" taper or out of round, I would start considering a rebore. Once you get the ID, you can use the outside mic to also check the pistons and see if your clearance is within acceptable limits and check for collapsed skirts. Check the skirts at 90 degrees to the piston pin at pin level and at the bottom of the skirt. Look for consistency on the pistons. If all seems ok, you might try getting hold of a ball hone or a flex hone you can run with a hand drill to break up the surface of the cylinder, reestablish a cross hatch, and allow new rings to seat.



Generally, if you cannot see or feel wear right at the top of the ring travel, you can get by with lightly honing the cylinders, slapping on a new set of rings, and be good to go.



Good luck and let us know what you find.