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rebuilding 2nd gen 12v cummins

8K views 16 replies 4 participants last post by  FordCummins74 
#1 ·
im new to the fourms and im just barely starting out with diesels have been studying about them for sometime now but still know very little about them going to a diesel mechanic college soon though and im thinking of doing a 12v cummins swap into a 06 superduty but i wanna rebuild the engine rather than buy one with alot of miles on it ive found one that needs rebuilt and is very cheap here in town but the cylinders are messed up rly bad i thought about taking it to a machine shop and boring it over but whats the max you can bore a 5.9 12v over that wont weaken the walls :confused013: want to use it for heavy towing and any upgrades for power and torque i wanna try and push 700-800 torque and 300-400 hp
 
#2 ·
If you're gonna keep the horsepower goal so low, why don't you just stud the 6.0 and do an egr delete, then an sct tuner. Youd be right in the horsepower range you're looking for. A 12v swap is way too expensive for such a low horsepower goal. Just way too much trouble.
 
#3 ·
thats just starting out after saving up more money i plan to add more hp i dont have much worry with money with my new job paying at 30 an hr 10 hrs a day 5 days a week plus electronics are the thing i hate the most in diesels thats the main reason im going to do a 12 swap i wanna make atleast 500-600 hp once i start learning more about diesel so i know exactly what im doing
 
#4 ·
Well if that's the case I'd go ahead with the swap. I'd find a good motor first. Where I'm from, you can find good running 12 valve ppump motors with under 150k for $1200. you'd have a lot more than that into rebuilding/boring one out.
 
#6 ·
More than likely you won't have to rebuild and machine the engine, my project truck has almost 300k miles and still has the original cross hatch honing. The max bore for the Cummins would be around .040, I'd personally would try to avoid having to bore the block that far just in case if something happens in the future to the engine that would require machine work.

If you're wanting to tear into the engine to learn about it then I'd recommend pulling the head and taking a peak at the engine. You can take a look and see how the pistons and cylinder walls look and determine if you need to or want to rebuild the engine, but more than likely they'll be fine. Then clean the mating surfaces up, take the head to a machine shop to be checked out. During this time it would be a good idea to have the head o-ringed if the head is in good condition. Then you can put the head back together with some upgraded valve springs and some head studs and as a result you'll have an engine that's almost ready to support 650, you would just need a few more "bolt on" parts to make it happen.

Also, can you try and add some punctuation marks to your posts? It would make it a lot easier for us to understand your posts.:thumbsup:
 
#8 ·
Wow, that's pretty cheap! That'll definitely be a good engine to learn on. If you able to I'd recommend a mild bore, but depending on how bad the walls are you may have to bore out to .040.

The machine shop I normally go to charges around 500 dollars to bore and hone the block if you bring just the block in and have it cleaned already, add another 600 dollars or so for a rebuild kit, add in the head work like I mentioned. This should give you a rough idea of how much it'll cost if you try and do most of the work yourself. The head for my truck was junk, a new head that was o-ringed cost me about 950 plus shipping, another 110 dollars for me to add the aftermarket valve springs.

I'm looking forward to seeing how this build turns out for you. :thumbsup:
 
#9 ·
There is one big concern with that swap you may not have considered. It is called emissions. Many here do not care a bit about the emissions any of their vehicels actually produce. The problem is that several states do care about those emissions. If you put an older engine in a newer body you may not be legal to put on the road in your state.

One person was going to do a swap into a newer truck. They ended up selling off the parts they bought for the swap. The problem was their state changed its rules so you could no longer put an old motor in a newer bodt because of emissions rule changes.

I have no personal problem with anyone putting an engine from 1927 into a 2012 vehicle. I think it should be completely legal to do. The problem is that certain states have a very different idea about this.
 
#10 ·
i dont think my changes are saving, but i live in idaho and someone put a 94 cummins into a 01 superduty and doesnt seem to have a problem with emessions. We do have emssions testing but its for semis dont understand why just semis but good enough for me lol.

Also got into a agrumeant with my father and his friend they say if i bore even .010 over i would have problems with egts any thoughts on that?
 
#11 ·
Also got into a agrumeant with my father and his friend they say if i bore even .010 over i would have problems with egts any thoughts on that?
That's the first time I've heard of that. Displacement would be slightly increasing, spray pattern and bowl location would not changing, I'm not sure. I would think EGT would drop very slightly, probably not measurable. I could be wrong but if there's an increase (which I'm 90 percent confident will not happen) it will not be enough to make a noticeable difference. I'll do some research and see what I can find, maybe someone who's been building engines longer than I have will chime in.
 
#12 ·
ok i heard from one of my friends that someone took a 5.9 12v and rebuilt it as a 6.2 12v by increasing the bore and stroke would it be possible and if so would there be any power diffrence or would it be a deep tone to the engine rather than much power?

It would be cool to rebuild a 12v to come close to the 6.7 but i dont want to end up weakening the engine.
 
#13 ·
It's possible to stroke it, but it'll be expensive (5k minimum) and not worth it for your goals. The 5.9 without being stroked can and has made well over 1,000 hp. Even if a 12V or 24V is stroked out to 6.2 liters or higher the head would never be able to take advantage of it, the Cummins head in general for the B series is absolutely terrible and is a huge bottle neck.
 
#14 ·
Alright probly just bore it .020 over and rebuild,the truck will be a sled truck in the future but for now it will be for daily driving and work

After i get through college though ganna be about 5 years of college i wanted to do another project and thats drop a 6.7 cummins into a 08 superduty, reason why is beause i like the looks of the 08 to present super duty truck in and out plus the 6.7 cummins is the only electronic controlled diesel engine ill own.

i also have one more question that has been bugging the **** out of me or sometime now, im hearing rumors that you can special order the new super duty trucks with a 6.7 cummins as long as u pay the extra charges is this true?
 
#15 ·
if i can ill have it honed out if it needs bored then ill bore .020 over and was thinking of porting the heads but i wanna do that mainly for egt reasons ive heard of the cummins getting way to hot hauling heavy loads if anything i wanna keep the egts under control perferably without a water/meth kit. If anyone can tell me any good ways to keep egts under control that would be awsome my first thought was to get a twin ram air intake for more air to the back cylinders
 
#16 ·
Your'e going the right direction, porting the heads will help a little, but it isn't cost effective until higher power levels and it might not be noticed much during day to day driving. Getting air to the back cylinders with a twin ram intake is not a bad idea, you won't see a drop on the EGT gauge since it's reading a combined total for all the cylinders, instead it will help to equalize the temperature between the different cylinders. I would never purchase once since they're too expensive, but if you can fab one up I would recommend it.

Other ways to reduce the EGT would be upgrading the turbo to something like an S300G (like the BD Super B single) or something that's similar to that. If you purchase a turbo that's too big it'll end up making it harder to tow with, the only way around that would be to use a small set of compound turbos so you can have your cake and eat it too. Bumping the timing to around 16 degrees will also help, a little higher if you add the head studs and O-ring the head.

As for the Super Duty and Cummins you can already by the F650 and F750 Super Duty with the Cummins and with your choice of an Allison or a Fuller transmission. I'm not sure about the special order for the F550 or lower.
 
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