Starting to hate my 5.9

[Curt 5.9]

Ok, so after 3000 km after the rebuild my 5.9 is burning oil yet again and i got pressure coming from the blow by tube, iv had it with this already, so next question should i get a rebulit motor for $7200 with 3 years or 100,000 km warrenty and just drop it in, or rebuild the motor again and add some go fast parts as long as its cheaper than $7200 of coarse haha

[gneal02]

Originally Posted by Curt 5.9

Ok, so after 3000 km after the rebuild my 5.9 is burning oil yet again and i got pressure coming from the blow by tube, iv had it with this already, so next question should i get a rebulit motor for $7200 with 3 years or 100,000 km warrenty and just drop it in, or rebuild the motor again and add some go fast parts as long as its cheaper than $7200 of coarse haha

Who did the rebuild?

[Curt 5.9]

Myself and a mech. did most of the motor when i wasnt too sure (im more of a 2 stroke sled head than a diesel mech.) Im not sure what wrong now but its a pain

[steelhead01]

not the engine's fault. hundreds of thousands of Cummins are rebuilt every year successfully.

rings aren't seating. what brand? hopefully, not some non Cummins cheapy brand?

new Cummins pistons?

did you have it bored at a machine shop or just dunk a ball scrubber down the holes?

chrome/moly rings on the known to be extra hard cast iron cylinder wall of a Cummins ISB block need to be worked hard to seat.

worse if the engine machine shop did not diamond hone to 30ra and then plateued finished with a cyl. bore brush to remove ridge burrs.

hook up to at least 10k on the arse end hook and take it out for a workout.
at least 1 hour with EGTs above 1000d.
5 to 10 hours on the road towing
hammer it as hard as your tranny will take.

if still won't breakin and rings seal, pull engine. have the block tanked and bored at a real engine machine shop that does Cummins. have the pistons tanked and mic'd including ring groves.
put new Cummins rings in. use the same bearings and go for it.

nothing to lose at this point but $$$$$$ of your money in another rebuilt engine.

[Curt 5.9]

Nope engine was not bored was honed with a ball honer and head was rebulit and valves and seats were also reground and only quality cummins parts were used, reused pistons no signs of wear or anything. I worked the living piss out of this engine pulling a 25' trailer with a 1/2 ton ontop of it too boot for at least 5 hours to break it in but still useds oil. It was using oil the first time due to a broken oil ring and after the rebuild a few hundread km after it is doing the excact same thing as before. I talked to a guy at NADP and says the oil rings break due to tolerances not right in the cly. so wouldnt surprize me that it happened again cause it was not bored out.

Originally Posted by steelhead01

not the engine's fault. hundreds of thousands of Cummins are rebuilt every year successfully.

rings aren't seating. what brand? hopefully, not some non Cummins cheapy brand?

new Cummins pistons?

did you have it bored at a machine shop or just dunk a ball scrubber down the holes?

chrome/moly rings on the known to be extra hard cast iron cylinder wall of a Cummins ISB block need to be worked hard to seat.

worse if the engine machine shop did not diamond hone to 30ra and then plateued finished with a cyl. bore brush to remove ridge burrs.

hook up to at least 10k on the arse end hook and take it out for a workout.
at least 1 hour with EGTs above 1000d.
5 to 10 hours on the road towing
hammer it as hard as your tranny will take.

if still won't breakin and rings seal, pull engine. have the block tanked and bored at a real engine machine shop that does Cummins. have the pistons tanked and mic'd including ring groves.
put new Cummins rings in. use the same bearings and go for it.

nothing to lose at this point but $$$$$$ of your money in another rebuilt engine.

[steelhead01]

Cummins have to be at least bore honed to roundness. usually takes less than 0.005". the block bore cast iron on a Cummins has such high carbon content in the iron, it's extra hard.
ball hone does nothing except puts some purrty scratchs on the surface.

get it diamond bore honed and plateaued at a diesel machine shop that knows what their doing.

double check the ring gap when you install. pays to be a couple thousanths loose on the ring gap because of the tighter spec'd gaps for the HPDR. reduces ring breakage. make absolutely certain that the pistons meed Cummins specs for roundness.
get a quality micrometer, no cheapy Chinese garbage.

piston ring grooves have to be spotlessly clean, NO carbon. mic the ring grooves for specs.

ONLY use Cummins rings from a Cummins parts dealer, lots of crap out there sold as Cummins.

[AA BEN]

Stellhead is telling you like it is. He is 100% on the money.

[crb54990]

i agree totally. A ball hone will just follow the contour of the cylinder. So if the cylinder has any taper or out of round, you are wasteing your time. The piston to cylinder wall clearence is very important. Number 5 and 6 need to have at least .005-,006 in them due to the heat in the back of the block. When I bored and honed my block I put .006 clearence across the bored. something else a lot of people do is dunk the whole piston in a bucket of oil. when dunk the piston you get oil in the ring lands where there isn't suppore to be engine oil. plus when you put the finish on the cylinder and plateau hone you are knocking the peaks off the so all you have in the cylinder is the vally. oil will fill the valleys of the hone up and the rings will take forever to seat. I used a light machine oil like WD40. as you turn the engine you can see the rings lapping in.

Another thing is, if you did your own valve job valve recession is critical.

If you bore it 50mm over which comes out to .020in make sure you get the head gasket that is .010 thicker.

Rig end gap is critical. I went to the big side of the spec on the ring end gap because of everything growing as it heats up. so if it calls for .036-.048in, I went towards the .048. I have close to 10,000 on the over haul and havent had to add a quart of oil to the engine.

Make damn sure you get the pistons in the right way. don't always go by the markings on the piston for front. an easy way is to make sure the notch is located on the correct side as the cooling nozzle.

Don't buy cheap parts. most are junk

[Tazman40]

Ya im gonna bet that you have a cylinder out of round.Pretty common in diesel engines.My cousin rebuilt his big Cat in his motor home 3 times before he got smart enough to check the cylinders.Found 2 out of shape.They will never stop burning oil if they arent round.

[Christopher_]

Originally Posted by steelhead01

Cummins have to be at least bore honed to roundness. usually takes less than 0.005". the block bore cast iron on a Cummins has such high carbon content in the iron, it's extra hard.
ball hone does nothing except puts some purrty scratchs on the surface.

get it diamond bore honed and plateaued at a diesel machine shop that knows what their doing.

double check the ring gap when you install. pays to be a couple thousanths loose on the ring gap because of the tighter spec'd gaps for the HPDR. reduces ring breakage. make absolutely certain that the pistons meed Cummins specs for roundness.
get a quality micrometer, no cheapy Chinese garbage.

piston ring grooves have to be spotlessly clean, NO carbon. mic the ring grooves for specs.

ONLY use Cummins rings from a Cummins parts dealer, lots of crap out there sold as Cummins.

2007 5.9 rebuild needed:
Are there any internal engine parts that it is acceptable to use non cummins ( Mahle pistons for example) ?
Boring .010 or .020 over does that weaken the cylinders too much ?
Is it completely ill advised to go with a reman long block from a reputable rebuilder that provides a warranty?
what is the exact procedures I should request at the machine shop to ensure there are no cracks in cylinder sleeves/block and head ?
* I could care less about extreme power / I am not doing any heavy towing - just need the truck to run reliably

Thankyou

[dozer12216]

Perhaps a cylinder leakage test would be a starting point before tearing down. A maching shop can easily verify cylinder bore for being concenentric. Perhaps there is something amiss with your rebuilding procedures. Could the injectors be giving you a problem??

[Black Diesel]

I plan to send my block to Shane @ Wicked Diesel as he uses a deck plate while honing. Which as far as I know about honing, it seems to be more accurate than a straight hone.


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