6.7 or 5.9 rebuild?

smokeblack13

smokeblack13

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May 3, 2009
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The 5.9 in my 04.5 is coming apart because of blowby and a miss at idle. #2 and #6 have some scoring on the walls which I'm guessing are a couple broken rings. I've read about some guys swapping in a 6.7 and running the 5.9 ECM with 03 style nozzles. I can either rebuild my 04 with qsb pistons and 03 nozzles balance the bottom and do head work or swap in a stock 6.7. What would you guys do? My plans are for a street strip truck eventually 750+ hp fuel only.
 
6.7 gets my vote. Just because I like the 6.7's

I have no other valid points
 
6.7 gets my vote. Just because I like the 6.7's

I have no other valid points
 
SeeYaLater5.9 said:
6.7 gets my vote. Just because I like the 6.7's

I have no other valid points
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Then you got nothing, the guy probably wants the pros and cons, you dumb tard

The 5.9 has been around alot longer then the 6.7, the early 03-04.5 nozzles and pistons will withstand more abuse then the later generation, in general the 5.9 can withstand upwards of 900hp on stock internals.

The 6.7 is a good engine also provided you remove all the egr stuff on it, beefier all around however I do remember something about the engine blocks blowing at anything past 900hp maybe more and the Con rods won't live, if someone more intelligent then the poster above could chime in about that so you could also correct me if I'm wrong.




Sent from my smartass phone
 
The injectors on the 6.7 are better and the rods are known to go earlier but that's because of the increased torque. The head gasket can be an issue again because of the longer stroke and cylinder pressures. The 6.7 head flows more then a 5.9 and can spool a bigger charger. With a 66mm turbo, bigger pump, nozzles, lift pump, springs and pushrods along with some tuning 750+ on a stock bottom end is a given. Figure about 10k in parts and labor to get a stock 6.7 with good street manners to 750+.

I'd go 6.7 all the way after owning a 12v, '03 CR and a 6.7.
 
I also saw some guys were saying try would run 5.9 crank with 6.7 block. Are their problems with running higher rpm with the 6.7? If I build the 5.9 it will be built to run 4k rpm. I haven't read into the 6.7s much to know what they can handle. So far everyone is saying stock 6.7 over built 5.9 I was not expecting that one.
 
They run the 5.9 crank to lower cylinder pressure and reduce torque saving the rods.

Why does it need to run 4k rpms? You don't need the rpms to spool the charger.

You can make ~775/1700 at 3k with a 66mm.
 
I would like to be able to run 4k in my 5.9 if I pull. What are people paying for 6.7s engines? There's a guy local that wants 4k for a 07 with 109k miles
 
canadiandiesel said:
Then you got nothing, the guy probably wants the pros and cons, you dumb tard

The 5.9 has been around alot longer then the 6.7, the early 03-04.5 nozzles and pistons will withstand more abuse then the later generation, in general the 5.9 can withstand upwards of 900hp on stock internals.

The 6.7 is a good engine also provided you remove all the egr stuff on it, beefier all around however I do remember something about the engine blocks blowing at anything past 900hp maybe more and the Con rods won't live, if someone more intelligent then the poster above could chime in about that so you could also correct me if I'm wrong.




Sent from my smartass phone
Click to expand...

Whoa there! Easy there Internet badass.

internet-tough-guy.jpg




Tobin
 
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Stock 6.7 rod's are good for about 750 if you can keep the torque out of it. 12V rod's are not helping that much you honestly want billet if you want to go all out. Your not going to like the price.

While I like the 6.7 and the Hybrid a built 5.9 is still cheaper and more reliable.
 
5.9 12v rods usually will bend, not break. CR rods are more likely to break and make windows.

Tobin
 
Is there any way you can get a 6.7 and just do billet rods? That's going to be the weak link. Don't get me wrong though, I love my balanced 5.9.
 
If I build the 5.9 I was planning on doing oversize valves, milling off intake and doing port job on each side. If I do this will it walk circles around the 6.7? I'm just trying to decide if the 6.7 is really worth it. If I end up doing the 6.7 it will eventually have billet rods but probably not before the 650 mark.
 
A 6.7 with a 64 or 66 turbo, lift pump and some nozzles will get you 650. I'm assuming you already have a lift pump and tuning for your 5.9 so for $3k you'll be around 650 with the 6.7.

....but if you're asking if a modded 5.9 will produce more hp and tq then a stock 6.7...of course it will.
 
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No I'm asking if a modded 5.9 head will flow the same or close to the same as a 6.7 head with the same mods. Obviously the added displacement of the 6.7 will be better but will it be a big enough difference to offset the weak rods?
 
I don't think the rods are as weak as everyone thinks they are. They aren't any weaker then any other cr rod. Folks are getting 750-900 out of them.

highest hp stock motor 6.7? - Competition Diesel.Com - Bringing The BEST Together

Although I'm a 6.7 fan if you have a 5.9 already and can do most of the rebuild yourself with a little $$ for machine work you might be better off with the 5.9. The head work on the 5.9 will get you the flow of the 6.7. Price out the 5.9 machine work and compare it to the cost of a 6.7. A complete 6.7 longblock for $4k probably isn't bad.
 
Your going to have to buy a long block cheapest I seen was $2500 then it's going to need rod's. Even 12V rod's in a 6.7 break at around 900 Bean's and Brown's have both destroyed them. Something about the torque. But 12V rod's seem to hold up just fine in a 5.9 . But as Bean say's if you plan on ever going all out don't chance it and go Billet. Also pushrod's in the 6.7 is another weak link when you want RPM .
 
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