New to forums in general. Looking for help on why my piston rings on rebuilt 7.3 haven't seated yet. 12k on engine since it was rebuilt. It blows some blue smoke on take off. You can see the blowby when the oil filler cap is removed. The engine builder used Mahle pistons and rings that were installed on the new pistons. Is there anything that I can do to get the rings to seat or did engine builder break an oil ring when building it.

 

Sounds like somethings wrong.

 

That's why I'm here. Trying to figure out what to do next. Rebuilt it in hopes of not having to buy a new truck. Truck runs great. I'm wishing that I had spent the money on a new one now.

 

What year 7.3?

 

I've heard of people dusting a little bonamy powderthrough intake inolder style Gasser's to seat rings but i never tried it does it use any oil because i think u would get a little blow by on diesel if not using oil its probably normal rings should be seated in that many miles

 

2001 7.3L I put some extras on it while I was rebuilding it. It has new Alliant 100 hp injectors, new Garrett GT38 ball bearing turbo, high pressure crossover hose, 4" exhaust turbo back,new air intake, triple disc billet torque converter,etc. I actually did this for pulling my fifth wheel not racing. The fuel milage is not too bad either. Old motor had 123k on it when it broke a piston and it was totally stock. The wrist pin scarred the cylinder wall so bad that the block had to be replaced. I just bought the wife a new Ford Fusion and wanted to keep my truck until I could pay off her car. Couldn't get anything for the truck with a bum motor anyway. I am still almost as scared of the new 6.4L as I am of a Dodge.

 

It does use a little oil. Not really sure how much as I noticed an oil leak coming from the oil cooler and have not repaired it yet waiting to see if I'm going to have to pull the motor again to find out about the blowby. I did a compression test on the engine this last weekend and then was told that my efforts were fruitless due to the oil rings being on the bottom of the piston.

 

Some blow by is normal,,but if it's excessive, it'll show up in the inlet to the turbo, and the intake elbow wet/oily,and eventually asoil build up in the CAC tubes.. Excessive blow bywould indicate loss of compression,most likely not just oil ring/s, and might be easier detected with a leakdown test through the glow plug hole to pinpoint either one bad cylinder or multiple..Kind of a balance test.. If you could pin it to one cylinder a bore scope might reveal the piston top washed from passing oil if a single damaged ring.. All washed would mean bore problems, or ring issues.. Could have been bored (replacement was bored?) out of spec, or honed to coarse, rings gaps not offset ect.. I'd think if it were a bad/damaged oil ring, it would smoke at cruise speeds.. How much is 'some' smokeon launch? What help has the engine builder offered?

 

Engine builder asked me to switch to Rotella 30 instead of 15w-40. I did that roughly 1000 miles ago.He said that maybe it is overfueling and washing the cylinder walls and wants to unplug the chip and run it like that for a while.
No smoke that I can tell at cruising speeds. It may even be getting better at not smoking on take off. It is not a lot of smoke. Hard for me to quantify the amount of smoke. I did take the intake tube off when doing the comp. test and there was some oil residue in it. The thing that concerns me the most is when you take off the oil filler cap you can see what appears to me to be oil mist or steam or something to my untrained eyescoming up 6" out of the fill tube. He wants to run the truck longer and see if the rings will go ahead and seat. I use the truck to pull my travel trailer and to get back and forth to work. I just want for it to be right. I don't want to have a major problem when I'm off with my family and maybe no telling how far from home.

 

Can you explain the leak down test and how that works?