Model Number:

[Rob]

Hi there, what was the model number for the chassis when factory equipt with a V-12 Detroit engine on an R model?

I need to get a radiator manufactured for mine and have to have some sort of baseline for fitment.

Thanks,

Rob

[Superdog]

A V12 powered R model would have been a R771.Near as I know,none were ever built,only Western RL and RS models were available with V12's.

[Rob]

A V12 powered R model would have been a R771.Near as I know,none were ever built,only Western RL and RS models were available with V12's.

Thanks Mike, I contacted these folks: http://detroitradiatorcorp.com/ as far as building a radiator for me. I want to go with a "side by side" configuration, (radiator, charge air cooler) as to leave room for an a/c condensor up front yet retain the original shutters. They will build anything by request but I'm wanting a rather "custom" installation. They need the heat generation potential of the engine to build an adequately sized core. Knowing that some type of Mack chassis was factory equipt with the V-12 Detroit, saves a lot of guesswork as they have the parameters, but needed a model number to associate to.

I'll keep you posted on progress.

Rob

[LilRedDave]

Just a thought, but 2-cycle Detroit's never required a charge air cooler. The turbo feed directly into the blower and some models had intercoolers. But to install a 12V71 with a CAC would be unnessary. Just a thought.

[Rob]

Just a thought, but 2-cycle Detroit's never required a charge air cooler. The turbo feed directly into the blower and some models had intercoolers. But to install a 12V71 with a CAC would be unnessary. Just a thought.

Hi Dave, thanks for your thoughts. I had wondered about the lack of a charge air cooler on two cycle Detroits myself. I've seen in marine applications the intercoolers sandwiched between the bottom of the blower, and intake manifold and have heard they are restrictive. With the added height, they would not fit under the hood of a truck without modification.

My engine is from a genset and has two T18 Garret turbochargers that are plumbed to the air boxes. It would be entirely possible to not use a charge air cooler as the engine is much higher in horsepower than I will ever need as it sets.

Thanks,

Rob

[LilRedDave]

I would say that you wouldn't need to use a CAC at all plus with the 12V you'll need all of the cooling space you can get. While it would help, the plumbing would be a nightmare. Are you going to detune the engine at all or run it as is? Gen-set engines, and especally a T engine would have high output injectors that are desinged to flow the most amount of fuel at a constant high RPM, not the best for a truck. You'll end up washing out the kits and slobering. Do you have any pics of the engine you're working with or if you could give me the serial number I could tell you what injectors are in it. The number will start with 12VA******. Sounds like a neat project. Love to help you out.

Edited July 25, 2007 by LilRedDave

[Rob]

I would say that you wouldn't need to use a CAC at all plus with the 12V you'll need all of the cooling space you can get. While it would help, the plumbing would be a nightmare. Are you going to detune the engine at all or run it as is? Gen-set engines, and especally a T engine would have high output injectors that are desinged to flow the most amount of fuel at a constant high RPM, not the best for a truck. You'll end up washing out the kits and slobering. Do you have any pics of the engine you're working with or if you could give me the serial number I could tell you what injectors are in it. The number will start with 12VA******. Sounds like a neat project. Love to help you out.

Hi Dave, I've maintained this engine for the last 17 years of it's service life and when it was time for replacement, I kept it. There are N80, green tag injectors installed. Both turbochargers are Garret T18A40's with .96 A/R on both turbine and compressor sides. They spin up really fast. The spec sheet that the vendor supplied many years ago lists the engine at 586HP at 1800 rpm. There is no listing for torque nor any curves supplied with the package. Slobbering, or "wet stacking" was never really a problem with this engine as it had "load shed" with it into a load bank. I keep it in tune to load the genset to 60% of rated capacity when running and supplying emergency power. I could go to 85% capacity but that just wears the engine much faster.

I do have photos of the engine but not on this old computer. I will post a couple pictures in a bit. I can't really remember the engine number but it is a 12V-71N series and the first four of the model number are 7103-XXXX. It is a left turning engine, (looking at the rear of engine) and has a "00" flywheel housing mounted. I have purchased a very good running 8V-71 engine to switch out flywheel housings, and flywheels, etc to make the V-12 a truck engine. It will be installed into a 1977 R-795 Mack. (More on this truck in the feedback section if I don't get a couple of parts that were paid for).

I've found a couple of pictures from another place I visit so I'll try to get them over here. Hey what do you know, that worked!! Anyway, I plan to use the truck for pleasure only and it will not be a real working unit. This engine has just over 6300 hours on it and has had the oil changed at 200 hour intervals since new. I suspect that unless something is grossly out of kilter, it should work well for my application.

Any and all help and insight appreciated.

Thanks,

Rob

[mart]

I just just found your post now - today Dec.

14,2007- and noticed that it actually dated from

June & July 2007! - so I apologize if my reply

here is out of date. How is this project going? Did

you get the engine fitted? Did you get a rad built

for it yet? This is truly an amazing project!

I love those old "Deetroit 'Buzzen"Dozens"!! I've

had some first hand experience with a truck

somewhat similar to what your doing. Back in the

early 1990's - for a brief time, (a couple dozen or

so Toronto ON to Bakersfield CA round trips

hauling refrigerated meat and produce), I drove

an 85' 9370 International Eagle that had a

twin-turbo 12V71 gen-set engine swapped into

it. What a truck! Fuel mileage wasn't the greatest,

about 5.5 mpg loaded and pulling hard - down

to about 4 in the mountains - and maybe 7 mpg

if you drove it easy and real carefully. But talk

about power - and with dual 6 inch straights the

sound was absolute music...albeit somewhat

loud music! Absolutely nothing sounds as

sweet as V12 Detroit at full chat!l The truck had

originally been equipped with a tired 425 hp

3406 Cat that finally threw a rod out the side of

the block. The owner - (not me I only drove the

thing!) found a deal on a very low hours, surplus

540 hp at 1800 rpm 12V71TT industrial engine

that had been used as stand-by generator and

decided to put that into the truck. For a rad - he

had a rad shop build a custom unit that was

externally, loosely based on an OEM rad for an

International with an 475 hp 8V92 Silver Detroit

motor, but with two extra cores added. Basically,

you want/need the biggest rad with the thickest

core your rad shop can fit into your Mack. While

maybe not absolutely necessary - to help keep

things cool, he also added a pair of externally

mounted Lubrifiner bypass oil filters as well.

Being mounted outside the hood they definatly

helped lower peak oil temperatures -which meant

that much less heat having to be handled by the

rad. As for CAC- while most Detroit truck installations

didn't use CAC- it's still a good thing to have on any

turbocharged engine if you can fit it. Even "high flow

but low - in fact, almost neglable boost pressure"

conditions that a turbo- 2-stroke Detroit typicaly operates

at , cooler charge air still contributes to cleaner runninsg

and better fuel mileage. Fit it if you can. On the International

.we kept the "original CAC unit used with the 425

Cat in front of the rad and had the rad shop modify the

tanks to accept a second inlet, fed by the right bank

turbo. The cooler air from the CAC allowed the engine

to be turned up with oversize #96 injectors ( the

originals were #90's) and still run clean without loading

up, slobbering or excessive smoke. With the 96's and

CAC - and with the governor set 2300 rpm - the truck

dyno'd at 525 hp -at the ground! ( Not bad considering

the engine was originally rated at 540 hp at the fltwheel)

Another thing with Detroit 2-strokes - they inhale lots of

air - almost twice as much as a 4-stroke diesel for the

same hp, so both for clean running,power and mileage,

it's important to use high capacity, low restriction air

cleaners. On the International, we fitted a pair of large

Donadlson external units, originally spec'd for a KW

off-road logging truck with a 3408 Cat. I'm sure these

contributed to the power and relatively clean

running. Also, being external, they brought in much

cooler outside air which helped a lot too. Likewise

with exhaust flow too. Detroits put out a lot of exhaust flow

and don't like restriction in the exhaust. We used 6 inch

straight pipes. With the turbos, the noise wasn't too bad

- unless and until you where really gouging on it. If dual

6 inch straights are too loud for you, or will cause problems

at the scales, at least use the biggest diamiter pipes - and

the largest capacity, low restriction mufflers you can fit.

Good luck with your project! Please do keep us informed of

your progress! Feel free to e-mail me either on or off list

too if you

want.

Mart

===============================

Hi Dave, I've maintained this engine for the last 17 years of it's service life and when it was time for replacement, I kept it. There are N80, green tag injectors installed. Both turbochargers are Garret T18A40's with .96 A/R on both turbine and compressor sides. They spin up really fast. The spec sheet that the vendor supplied many years ago lists the engine at 586HP at 1800 rpm. There is no listing for torque nor any curves supplied with the package. Slobbering, or "wet stacking" was never really a problem with this engine as it had "load shed" with it into a load bank. I keep it in tune to load the genset to 60% of rated capacity when running and supplying emergency power. I could go to 85% capacity but that just wears the engine much faster.

I do have photos of the engine but not on this old computer. I will post a couple pictures in a bit. I can't really remember the engine number but it is a 12V-71N series and the first four of the model number are 7103-XXXX. It is a left turning engine, (looking at the rear of engine) and has a "00" flywheel housing mounted. I have purchased a very good running 8V-71 engine to switch out flywheel housings, and flywheels, etc to make the V-12 a truck engine. It will be installed into a 1977 R-795 Mack. (More on this truck in the feedback section if I don't get a couple of parts that were paid for).

I've found a couple of pictures from another place I visit so I'll try to get them over here. Hey what do you know, that worked!! Anyway, I plan to use the truck for pleasure only and it will not be a real working unit. This engine has just over 6300 hours on it and has had the oil changed at 200 hour intervals since new. I suspect that unless something is grossly out of kilter, it should work well for my application.

Any and all help and insight appreciated.

Thanks,

Rob