OK... In (relatively) stock mode... which years were "our" trucks most efficient? I had a 94, which was phenominal. I have an 06 which is not. The 04 had all the power down low in the RPM's where I tend to use it. The 06 has the power all above 2000 RPM. It's taking getting used to.

Now I realize I can fix the bottom end on the 06 by using a smarty, but I doubt I'll get back to the economy I had. I started wondering which generation of engine is the best for economy and bottom end torque... Yes, there might be a project here. We'll see the condition of my new truck when it arrives... an 04 with engine damage. How bad is presently unknown... I'm going to be asking for advice as I've never really had to do anything with my trucks, or had the time... That is starting to change (the time thing so far...)

Yes, when she arrives, I'll give an update on condition etc. Unfortuneatly a "sight unseen" purchase, but... it looks to be a great buy...

 

1st gens win this, but they aren't for everyone.

 

Common rails just don't make the down low grunt of mechanical injection. That why they are going to six/eight speed transmissions in the new trucks. the old truck you could get it done with three to four gears. Sure missing the old truck on this cross canada tour that I'm on. Been waiting for the CR issues to show its nasty side. Works great, when it works. Electronic stuff rely on all the electronic stuff to work. As any electronic instruments, they don't always stay in calibration for very long.

 

So... if this engine turns out to be an expensive fix, is it feasible to put a pre-98.5 engine in there? I know it has been done before... Is it a route I should be considering?

It seems to be pretty cheap at the moment to pick up a pre 98 2wd truck for cheap to use as a donor... The other thing I like is the (much) cheaper injectors. Picking one up, doing a "freshening" of the engine, and install? Some electrical work, I'm guessing... It's an auto tranny, so that might have some concerns (never owned one with an auto before)...

Anything I'm missing?

 

Hi Mike,

while I agree that the 12V's make their torque at lower RPM than the new CR's, aren't the torque/power band's on those engines much narrower than the new CR's?
Then wouldn't more gears behind an engine with narrow power band be better? Just like the big rig's with really narrow power bands & 15+ speed transmissions?

For example, in your direct case, wouldn't 6 gears be much better in your 24V for cruising around & towing??

 

The wiring on the '04 truck with an auto trans could be a real challenge.
The dash is connected to the ECM as is the auto trans. You will need to keep the stock ECM in the truck, even though it is no longer controlling the engine plus you most likely will need an aftermarket, standalone transmission controller.

This swap would be much easier if it was a manual trans truck.

If this is your 1st Cummins major work or 1st Cummins swap, I would have to recommend that you try to repair the truck back to stock.

 

A 4gsk or 5 gsk will fix that problem. As good as the CR is at making power, it still isn't in the same leaque for power at P7100 pump. With the P7100, there are gobs and gobs of fuel available, the trick is getting it to burn decently. The CR has the ablity to adjust timing and fueling duration, unlike the P7100, thats why they melt down when tuning goes wrong.

I have three 12V's in various different stages of repair. I have a fresh stock 12V (nearly stock) ready to go, just need to get the rods resized. I can sell it as a short block or a fully dressed engine (including turbo, injection pump). I prefer the non 53 storm block, just cause I like dual oil drains. The pre-storm blocks come with 14mm main studs, VE use germany crank/rods. Very nice once you debeam them and knifed edged, and adjusted the balancing pads some. Almost as good as billet rods, when using the ARP rod bolts. I can also build a 24V P7100 engine very easily, and possibly a CR5.9L P7100.

Tate has the 6.7L P7100 fix for ya if asking/need.

 

Yes your correct, but built RFE68 are pricey but the three/four speeds got the job done. Tons of million mile near original engine VE trucks, not so many original (never be worked) million mile CR. P7100 are decent engines, you should drive one, its difference than a CR. Its like instant throttle response.

 

I want to correct myself, the rack on the P7100 is adjustable and adjusts the amount of fueling available. So its variable and adjustable, forgot about that this morning. The gauges and start P7100 soleniod aren't too bad. I would use the 2wd out of 98, for the most part it should work. You could also look into converting the 06 transmission to a RH valve body (mechanical). The newer auto will be more durable stock than the old one stock. If its a built transmission, that changes everything. I bet you could convert CR it just like people convert VP trucks. Using the stock transmission might take some head scratching but nothing to difficult. I would use the existing CR block and just put a 12V gearbox on it. Change the CR gears/oil pump and crank gear to VP stuff. Drill two holes so you can install two locating dowels to insure the correct gearbox lash/placement. After that the 12V gearbox housing bolts on, with a few adjustments. You'll need to get some 24VP P7100 lines, and 24CR cross tubes to VP made. 24V injectors. I prefer to use a VP head, cheap and easy to find, I have three spares. A 03 block has dual oil cooling jets and use metal squirters on the pistons. Not sure if I would use the newer 06 pistons as they tend to melt/break rings easy. 24VP pistons are cheap, but you'll have to adjust the piston skirt for oil coolers squirter. Hopefully that make some sense.