5.9L 12V Performance Discussion of 12 Valve 5.9 Liter Dodge Cummins Diesels with P7100 Injection Pumps Related to Performance and Longevity
View Poll Results: What should I do with my blow-by ridden motor?
Swap for a junkyard motor and do basic mods
2
15.38%
Rebuild the motor with hi-perf parts
11
84.62%
Voters: 13. You may not vote on this poll

Rebuilding motor with badass parts vs. putting in used motor from junkyard?

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  #31  
Old 04-20-2010, 12:12 PM
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have a compression test ran, thats the best way to determint the condition of the cylinders,
and if do put new rings in it just buy the bearings for it, i dont see the bearings costing more than $150 for both sets, when the caps are taken off and the old bearings are put in you risk the chance off spinning it, if you talk to the mechanic they can probably pull the pistons out from the bottem without pulling the motor out of the truck,
 
  #32  
Old 04-20-2010, 12:15 PM
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Why doesn't this poll have a 3rd option: Sell It!
 
  #33  
Old 04-20-2010, 12:48 PM
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Never heard of pulling them from the bottom, but I don't have the experience with these Cummins pulling the pistons out. I guess it's possible that they have enough room, but thought the crank would always be in the way.
 
  #34  
Old 04-20-2010, 01:15 PM
94 12valve's Avatar
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Originally Posted by wes-cummins
have a compression test ran, thats the best way to determint the condition of the cylinders,
and if do put new rings in it just buy the bearings for it, i dont see the bearings costing more than $150 for both sets, when the caps are taken off and the old bearings are put in you risk the chance off spinning it, if you talk to the mechanic they can probably pull the pistons out from the bottem without pulling the motor out of the truck,
how do you plan on getting the pistons out from the bottom?

Take a look under the truck and ask yourself would I rather attempt pulling them from the bottom, or will I take the 2 motor mounts that are left out and just pull the rest of the motor.

You will need to lift the motor to get the oil pan anyway which means the only thing left holding the motor in will me the 2 mounts ... way easyer to just pull the whole thing.

---AutoMerged DoublePost---

Originally Posted by guhfluh
Never heard of pulling them from the bottom, but I don't have the experience with these Cummins pulling the pistons out. I guess it's possible that they have enough room, but thought the crank would always be in the way.
it is in the way here is a pic of what will be in the way after you get the pan off

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Last edited by 94 12valve; 04-20-2010 at 01:15 PM. Reason: Automerged Doublepost
  #35  
Old 04-20-2010, 03:56 PM
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Originally Posted by guhfluh
When you put your foot on the pedal and start it, it starts up and hammers on the bearings before they have gotten any oil pumped through them. The only oil that is there is residual.

When you keep your foot off of it and turn it over, there is less load on the bearings before the oil gets pumped back to them.

Using a FULL synthetic oil helps dry starts extremely, where regular dyno oil shears at like 300psi, full synthetic shears at like 8000psi. You can easily make 300psi of force starting a big diesel, but 8000psi sounds a lot better protection to me. Once running with full oil pressure, I don't think the synthetic is a whole lot better, but dry starts is where its at. That being said, I don't run full synthetic because of the expense of changing it so often but If I had some of those real good bypass filters and could run my oil for 15k, then I'd run full synthetic, but 3k mi and 3 gal per change gets expensive.

I would really be suprised if your truck has excessive blowby. I would bet its just fine.

Now, if you ran it out of oil, the bearings might be toast and depending on how long you ran it, the crank, cam, lifters, etc might also. A good oil analysis might be able to tell you, like mentioned above. Other than that, they need to pull the pan and pull a main or rod cap off and look.
Good input. The diesel shop claimed it was a lot of blowby, I dunno though. I suppose when I get it back (assuming it makes it to the house..) I can take a vid and put it on youtube. Would it be ok to go with synthetic oil on my 256k mile cummins w/ blowby? That wont harm anything?

Originally Posted by NadirPoint
Why doesn't this poll have a 3rd option: Sell It!
Or a 4th option; stuck with Ford!
 
  #36  
Old 04-20-2010, 04:11 PM
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idk my bro did the one in my pickup himself for 2gs without labor but it's bored out and he went all the way through it
 
  #37  
Old 04-20-2010, 06:50 PM
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Zach is correct, you can rebuild the motor for less than 2 grand but labor is gonna kill ya. My question is gonna be even if you got the pistons out the bottom, how you gonna get them back in the bottom? If you find a way please explain. Good Luck.
 
  #38  
Old 04-20-2010, 07:40 PM
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How are you going to get them out through the bottom?! :pac1:
 
  #39  
Old 04-20-2010, 08:10 PM
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You can put modern synthetics in any engine of any mileage. I doubt it will help your blowby any, but I'd run it thicker than the standard 10-40 if I had a really worn out engine. 20-50 would be good probably, but whatever you run you have keep an eye n the oil pressure gauge....another reason you need gauges in your truck.
 
  #40  
Old 04-20-2010, 09:01 PM
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i believe what they meant to say above is that you can put rod and main bearings in without pulling the pistons but you cannot do rings without pulling the pistons out.
 



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