Read my rod bearing

[jwinnie]

I opened up the engine on the '92 because of a knock in the #6 cyl. I have not pulled any of the other bearing caps to compare and I still need to buy a plasti-gauge kit.

I originally suspected a scored cylinder as the culprit but upon pulling the head I instead found a horrible attempt at honing the cylinder by a previous owner.



So until I get this stuff measured up, does this look like normal wear? (other than the scoring) Or could this bearing be the source of my knock? Experts help!



John



I'm including some pics of a good cylinder and the #6.

 

[S.Morris]

Not sure that this is the knock but that rod has too much clearance.



Looks like the botched hone job filings all went into the block that didn't get cleaned! I would be suspect of all the crank journals after seeing those inserts.



Check the piston pin clearance carefully also.



Just for starters

Steve

 

[KOG]

That is UUUUUGGGGGGGGLY!

 

[cerberusiam]

I's say you found the source of the knock in the bearings. If the copper is on the bottom its a good bet thats where the issues is.



Forget the plastigauge stuff and get yourself a micometer set if you can. A lot easier to find issues with it.

 

[Scrappy]

new bearing time!

hows the crank look?

does it look good or is it scored too?

 

[RHestand]

IMO, don't worry too much about the knock.

When you see sloppy work like this, the eng. needs to be pulled, disassembled, hot tanked, inspected, measured, then rebuilt with new parts as required.

It's probably full of metal shavings from the nice hone job, and the previous problem/ problems the "mechanic" "fixed".

You would never be able to trust this engine, with anything less than the above.

It makes my blood boil to see this kind of work, especially to do it to such a great engine, as a Cummins.

Ray

 

[ata]

I don't think the bearing is your knock. Look at the difference in the CARBON build-up from the other cylinder at the top. I think you have a piston and cylinder problem. That hone job looks like they had to take a lot off of that cylinder to get scoring out of it. The bearing damage is probably from an earlier piston scoring. The grooves in the bearing look to big for honing debris.

 

[jwinnie]

Thanks for the replies.



I measured the cylinder today. I feared the worst but it measured a pretty consistent 4. 0175". The limit in the manual is 4. 0203".

I'm hoping I won't have to take off . 0028" to get the correct cross hatch on there.



The rod journal looks real good, no scoring at all and it measures well within spec. I have not measured the piston or wrist-pin yet. There are is no noticeable wear or damage to the piston, only some evidence of blowby.



I pulled the #4 rod cap. It looks nothing like the one pictured, no scoring and much more even wear.



cerberusiam, the worn copper part was the upper bearing. The worn area is directly in line with the connecting rod, made me think too much timing advance When I bought the truck, the pump was turned 1/4" past the mark and the old injectors were popping off about 215 bar.



RHestand, Relax man, you can imagine my blood was boiling too when I was peeling this can of worms open but I'm not going to condemn the engine because of a botched hone job. The rest of the engine looks real good so far, very clean, cam looks great etc. Don't underestimate how tough these engines are. I'm pulling this thing apart thinking "all this iron for 160hp??" The word "overbuilt" comes to mind.



If I get few good years out of it I'll be happy. If it all goes bad, Cummins South just quoted me $1913. 49 for a new short block



I'll update as the story unfolds.



John

 

[KOG]

"all this iron for 160hp??"

No, all that iron is for a continuous 400+ HP in marine applications. 160 is just to save the truck and transmission it's bolted to in the early models.

 

[cerberusiam]

the worn copper part was the upper bearing. The worn area is directly in line with the connecting rod, made me think too much timing advance When I bought the truck, the pump was turned 1/4" past the mark and the old injectors were popping off about 215 bar.

If it was all the bearings I would suspect timing but form the sounds of it the other one checked looked good.



Check that rod for out of round closely. It almost looks like it could be stretched and causing the extra wear on the bearing. Looks to be some hot spots on the bearig also that could indicate a not so round area when the rods bolts are tightened.



Either that or the OP did not replace the bearing when they did the piston and thats the result of scuffing the original.

 

[JLEONARD]

No, all that iron is for a continuous 400+ HP in marine applications

Not true. Max rated intermittent HP is 370. Meaning 1 hour out of 8 at full rated power.

Cummins South just quoted me $1913. 49 for a new short block

That is an excellent price. Wish I could do that good around here (Ct)

 

[PToombs]

I think that bearing looks slightly worse than a normal high mileage bearing. I wonder if it had a bad injector and that's what cause the excess wear.

I'm sure the timing and low pop pressure didn't help anything either.



If it was me, I'd throw a set of bearings in it, hone it, maybe replace the 1 piston so it will be a little tighter, and call it good. I've seen friends do less repair with worse damage and run things for years afterwards. Maybe get the timing set with a guage so you know where it is and have the injectors reset, if you haven't done it already.

Good Luck!

 

[jwinnie]

Well here's the plan. The piston looks good so it's just getting new rings.

The wrist pin and rod bushing were both worn to the limits so I picked up new ones today from Cummins. An interesting note: the Dodge manual says that if the wrist pin bushing is worn out of limits, the rod must be replaced , but Cummins sells the bushing for $7. 18. Still cost me $30 to have it pressed in and fitted, but better than $128 for a ReCon rod.

A new rod bearing and I'm calling it good for now.



This truck is not going to be my primary vehicle, otherwise I would go a lot deeper.



Pete, I bumped the timing back to stock and there's a nice shiny set of PDR 190's going in. Should smooth it out a bit.



John

 

[therabbittree]

my experience has the advanced timing is smoother. . but it could just be me...

 

[PToombs]

Until you get it too far. Then it clatters pretty good. I turned mine the 1/8 bump, then checked it later with a guage. It was at 1. 65mm. Then this spring I bumped it again, up to 2. 15. It ran better, but it had a definite clatter to it. A couple weeks ago I turned it back to 1. 65. It sounds better, and I hope my head gasket oozing slows down.

 

[jwinnie]

Well the truck is running again. With no more knock. I'm keeping my fingers crossed. I think I found my boost leak also

 

[cerberusiam]

I think I found my boost leak also

Yup, that would have a definite impact. :-laf

 

[PToombs]

Ahhh, yup, that might be it! :-laf



Things cleaned up really good for you, hope it comes out ok.