Hi . I am doing some rings on #3 piston . Upper and middle rings are completely cracked . Lower ring looks ok .

Problem :

I put the piston on the bench , washed my hands , came back , and the upper and middle rings were removed/fell off by another mechanic , while he was looking at the piston . The bottom ring is still installed on the piston right now .

Now , i don't know if there is specific direction the rings need to be installed onto the piston . (If one side of the ring need to be facing up or down)

All i can tell is that the shape of the rings do look different .
(One of the rings looks tapered on both sides . I really can't tell on the other ring . Both rings are in many pieces)

Also on both rings , there is a recessed edge on the ring , on one side . I don't know how to explain it .
I might be able to take pics of the ring pieces , but i don't have a good camera , and the rings are at work .

I will order parts on monday . I just don't want to put it back together with upside down rings . Please help . Thanks

 

35 year diesel mechanic, inside bevel always goes up.

 

reread your post if the ring is tapered both sides it is a keystone ring, if there is a top and bottom there will be a dot on the top.

 

According to the FSM, the top ring is tapered on both sides. The second ring is beveled on the ID of the rind, on the top. The marks sound like identifier marks, which should face up. Ring gaps go 120 degrees apart, but it doesn't look (or say) if there is a specific orientation for a specific ring.

 

Thanks for answering shortie and tate .

One thing i did notice is that on one of the pieces , i think there was a small circle engraved on one side of a ring piece (looked like this --> o . I don't know which ring the piece was from .

Is that the mark you are talking about ? I'm not sure if the new rings i get will have this , but i'm pretty sure the rings will be ordered from the local freightliner dealer (if that helps any)

I guess i can order the ring set and see what they send me .

 

Hello again .

I ordered some parts for the cummins 5.9 isb turbo , and cummins has made identification of the rings pretty easy .

The top (compresssion) ring is marked with a "top"(meaning this side up) on it and a "o" mark . And the ring is tapered on both sides . It is chrome .

The middle (intermediate)ring is marked "top"(meaning this side up) on it , and it is square cut . It is black in color .

The bottom (oil) ring can go either way . But it is in two pieces . It comes as one ring . You can try to put them on the piston as one piece , or you can put them on the piston one piece at a time .

The inside piece is a wire with a spring around it . Spread the spring gap open on the wire , and put it on the piston . Then put the outer piece on the piston , over the spring piece , and then spin it so the gap of the outer piece is 180 degrees of the gap of the inner piece .

If you want to put them on the ring at the same time , just spin the two gaps of the ring so they are in the same place . Then you can spread them with your fingers and put the ring on the piston as one piece . After it is on , spin the inner piece so its gap 180 degrees of the gap on the outer piece (or until you can see the white mark on the inner piece)

The oil ring is kinda hard to explain , but once you see it you will under stand . Also cummins marks the gap on the inner piece white . So when you spin the gaps on them 180 degrees , it is easy to tell .

Also like tate said , the gaps of the 3 rings need to be 120 degrees apart from each other when on the piston .

Right now i have the piston/rod assembly installed in the block , and i am changing all the connecting rod bearings because they looked worn .

The cummins piston kit came with the piston , rings and wrist pin snap rings . The wrist pin came seperate in a different box and part number .

I ordered two packs of con rod bearings . (6 in a pack)

This is the connecting rod bolt torque procedure i am doing :

Step 1 : torque to 22 ft lbs
Step 2 : torque to 44 ft lbs
Step 3 : turn bolts 60 degrees

 

Did you get new rob bolts as well? Whats the price on the piston kits?

 

No , i didn't order new rod bolts . Does anyone think that will be a problem ?

The receipt for the parts is at work . I will post the price list here monday night . Although my work might get a discounted price from them because they deliver parts to us alot .

 

Do you have a service manual? It could answer your questions about repair procedures. If any given fastener is torque to yield, then it would have to be replaced, as they are not re-useable. That information is not on the fastener.

Reading a manual before proceeding might guide you to having the job done versus doing it yourself.

 

I now have a manual for isb engines , that is where i got the torque specs from . And the pictures shown were not good for the piston rings , and i wasn't certain if my work parts dealer was going to get Cummins parts or parts thru an aftermarket source .

I don't believe it says anywhere to replace the bolts . Although it might have been a good idea to do so . I currently have 3 rods torqued down now .

If anyone thinks it is going to be a problem , i could order the bolts .

 

I've heard the rod bolts are the weak link in these engines. I know on the 4bt forums, they say to replace the rod bolts if you have the oil pan off.

 

There is nothing in the repair manual or QSOL about rod bolt reuse. We normally reuse the bolts, don't recall ever haning a problem with doing that.

If you feel safer replacing them, then that's what I'd do personally.

 

Doesn't replacing the rod bolts require resizing the rods?