Whats the best cummins motor? how is a 5.9 12 valve??

[rdn2blazer]

I've searched and see ALOT of discussion on the 6.2/6.5 motors but not much on the 5.9 12 valve. There is alot fo diesel discussion and I can read it all so I'm asking a new Q rgarding this spicific 5.9 12 valve motor. What the best years? do they make good HP and most importantly TQ numbers. Are/were they reliable motors? Are they heavy, too heavy for a full size sway, would it be a con weight wise compared to a BB chevy with Al heads, intake, water pump etc.? I may have a line on more then one. Still waiting on word if they are available or not. Thanks.

 

[76zimmer]

Hey Rob, lots of cummins swaps going on right here at CK5....look a little and you'll find them, but when I was inquiring, the easiest bang for the buck is the 94-98 P pump engines....a little hot rodding and they are quite powerful.
After that the 24 valve and electronics start to complicate things (at least for me)

 

[-stew-]

I dont have much personal experiance with them, but i wanna learn all i can so ill chime in. What I know is what a coworker says, and I'd listen to any advice he has to give. He says the 98 and a half and OLDER motors are the best. I believe they are known as p-pump motors. They have a dowl pin in the timing cover that needs to be secured or else it can come out and cause catastrophic damage. We have Cummins 6bt (5.9l) and 4bt (3.9l) in a **** ton of equipment here at work and they are bullet proof. A Cummins swap is on top of my to-do list as soon as I buy a house. Im not looking to make a **** ton of power, i just want the fuel mileage, power and reliablity. Ive been told a 4bt with minor mods can make 600 pound feet easy. 6bt weighs around 900 pounds. Idk. That's all I got.

 

[plyr2k]

Cummins*

Up until 93 they were rotary pumped engines. Easy to get a little more juice out of, but not all of them were intercooled. In 1994, when dodge revamped the trucks, they changed the injection system to what is commonly known as a "p-pump" This is a Bosch p7100 inline all mechanical injection pump. It's super easy to tune up and get power from. 94-95 autos were rated at 160 and manuals 175. In 1996 ratings went up. Autos were 180 and manuals were 215. A lot of hot rod guys like the 180 pump for turning it up. The 160 pumps had a fairly common problem of breaking a plunger and barrel inside the pump. Causing one cylinder to go to full fuel. My 94 did this. It's actually more rare then common.

A long block weighs 900lbs.

 

[Hogback Fabrication]

The 6BT (5.9L) Cummins (no "g" in Cummins) is quite a bit heavier than a big block, in the neighborhood of 400-500 lbs heavier.

Generally speaking, the newer the engine the more power it had from the factory. The 12 valves make more low end power and spool the turbo at a lower RPM, the 24 valves make more top end but need a couple hundred more RPM to get the turbo spooled.

89-93 is the first generation, they're easy and cheap to modify and can make good power. They're the most efficient of the 6 cylinder Cummins engines, partly because they have dynamic timing (like the mechanical advance in a SBC distributor). They're good to about 350hp/800-900ft.lbs. before you get into really expensive fuel supply mods.

The 94-98 12 valves can make more power because they have a healthier fuel supply, they are similarly easy to mod. They're not as efficient as the early motors but still good.

The Cummins actually fits pretty well into the old Chevy trucks. As far as efficiency is concerned, I don't think you'll do better than a 6.2L but there is so much more power available and it's a MUCH heavier duty engine. My truck (K30 with 37's, 4" lift) averages about 15 +/- just daily driving and exactly 20 on the highway driving 70 (averaged over the last 13,000 miles or so). I know it would do better at 60 but I would prefer to drive faster, my best tank was 25 mpg.

 

[crawlink5]

I went with the 4bt due to weight and the 4bt in the c30 class vans was made to replace a small block. The 4bt weighs about the same as a big block. 25 mpg. Can be turned up a lot

http://www.4btswaps.com/forum/forum.php also has just as much info about MANY diesels. If it can be shoehorned into a 1/2 ton to 1 ton truck they are trying it.

I keep hearing that the 6bt is around 1100 to 1200 pounds. I didn't want to fully box the frame at the time.

 

[ben427]

If I were doing a swap on a chevy truck, and not looking for retarded power, I would look for a rotary pumped (ve pump, not vp) 4bt. Not as heavy as a 6BT and still torquier than many big blocks. The rotary pumps are wicked easy on fuel as well as stated above, and offer better driveability than the inline (P7100) pump.

 

[rdn2blazer]

I went with the 4bt due to weight and the 4bt in the c30 class vans was made to replace a small block. The 4bt weighs about the same as a big block. 25 mpg. Can be turned up a lot

http://www.4btswaps.com/forum/forum.php also has just as much info about MANY diesels. If it can be shoehorned into a 1/2 ton to 1 ton truck they are trying it.

I keep hearing that the 6bt is around 1100 to 1200 pounds. I didn't want to fully box the frame at the time.

Thank you for the link and info, thanks to all you guys for posting up. I need to find out what type of cummins these 5.9's my bud has a lead on are. I'm finding the weight of a complete BB chevy 454 is about 685lbs. with all stock steel heads and Int. & Exst. manifolds. I actually thought they were heavier then that, like closer to 1000lbs. Learn something new everyday.

 

[-stew-]

I went with the 4bt due to weight and the 4bt in the c30 class vans was made to replace a small block. The 4bt weighs about the same as a big block. 25 mpg. Can be turned up a lot

Do you find the 4bt to shake and vibrate a lot? The equipment we have at work with 4bt's shake and vibrate a whole lot, especially at idle. Wondering if this is from the motor or more of just a condition of these machines.

 

[crawlink5]

they do shake at idle. The vibration I don't find to be bad - I don't feel it. Depends on the motor mounts and you can idle it a little higher which helps. They are very loud though - plan on sound deadening.

You are looking at about 775 lbs for a 4bt, 975 for the 6bt from what I found online. You may find different numbers elswhere.

 

[imiceman44]

Do you find the 4bt to shake and vibrate a lot? The equipment we have at work with 4bt's shake and vibrate a whole lot, especially at idle. Wondering if this is from the motor or more of just a condition of these machines.

4 cyl diesel in general shake at idle. No real way around that