I've decided to do a Cummin's conversion

[n8in8or]

That's up in the air right now, the 47RH has a an electronic speed sensor but I'll have to figure what to do to adapt it to the VSSB.

That would be cool if you could use that existing sensor - it makes the installs so much cleaner/easier.

 

[FellowTraveler]

That would be cool if you could use that existing sensor - it makes the installs so much cleaner/easier.

Dakota Digital makes an interface I may use but I have and adapter that may work anyway to try.

I'm using this to control lockup & OD, it plugs in w/o the mechanical speedo cable adapter. https://www.hgmelectronics.com/products-compushift-controllers/csm-chrysler

 

[Husker6.5]

Can't you take your tach signal off the alternator? Or swap in the GM alternator if the MOPAR one doesn't have pulse output? I believe there is an adapter bracket available to convert a GM alternator to the Cummins block.

 

[FellowTraveler]

Can't you take your tach signal off the alternator? Or swap in the GM alternator if the MOPAR one doesn't have pulse output? I believe there is an adapter bracket available to convert a GM alternator to the Cummins block.

I make my own brackets that's not the issue its the 8 grove pulley for GM tach signal can't be had for good rpm signal, the most accurate would be mechanical or the transducer type mounted on a hard fuel injector line I'll be using.

Yes, there is an adapter to calibrate the signal from the dodge unit to GM tach but I can't justify the additional electronics.

 

[THEFERMANATOR]

Hundreds out there have used the alternator output. You can either use the dakota digital box or recalibrate your tach to make it work. Have you measured your crank pulley yet? Iirc, the cummins crank pulley is a good bit larger than the GM one, so that would change which alternator pulley you needed.

For the speedo, you can either go with a GM rear transfer case half to run the 40 tooth tone wheel and GM 2 wire magnetic pickup vss(Dodge used a 3 wire hall effect style). Or run a cable driven speedo, and buy an inline magnetic speed sensor pickup and use a cable driven speedo output setup on your transfer case.

 

[FellowTraveler]

Hundreds out there have used the alternator output. You can either use the dakota digital box or recalibrate your tach to make it work. Have you measured your crank pulley yet? Iirc, the cummins crank pulley is a good bit larger than the GM one, so that would change which alternator pulley you needed.

For the speedo, you can either go with a GM rear transfer case half to run the 40 tooth tone wheel and GM 2 wire magnetic pickup vss(Dodge used a 3 wire hall effect style). Or run a cable driven speedo, and buy an inline magnetic speed sensor pickup and use a cable driven speedo output setup on your transfer case.

Yep, measured the pulley and all available 8 grove pullies were smaller or bigger so I would need the Dakota box for calibration.
I'll look into this some more.

 

[THEFERMANATOR]

Yep, measured the pulley and all available 8 grove pullies were smaller or bigger so I would need the Dakota box for calibration.
I'll look into this some more.

But what about the diameter of the crank pulley? If the crank pulley is larger, then you have to use a larger alternator pulley. And you can also adjust the tach by cutting the fixxed resistor out and putting an adjusteable potentiometer in it's place.

 

[FellowTraveler]

But what about the diameter of the crank pulley? If the crank pulley is larger, then you have to use a larger alternator pulley. And you can also adjust the tach by cutting the fixxed resistor out and putting an adjusteable potentiometer in it's place.

Honestly, I had not thought about that approach and it would work.
As always FERM thank you.

 

[FellowTraveler]

Honestly, I had not thought about that approach and it would work.
As always FERM thank you.

Well, I just went to measure the crank pulley and completely forgot I had a Fluidamper which I had already sold "hopefully someone can measure one for me."

I have been gathering parts and found a new HX40w "Cummins cobra head down pipe" this cobra head was the one used on the 8.3 ltr 12 valve Cummins" also bought a few 1st gen Ram Cummins down-pipes to check firewall clearance. If I go w/boost spool valve it would have to be a DB unit because the exhaust on my center manifold is split 3 x 3 w/each side driving 1/2 of the turbine

Waiting on more parts fluidamper, HX Super 40, misc. small parts etc..

Powder coated the (6) valve covers and hi-flow intake runner on manifold a nice black crinkle coat.

 

[Nosferatu49534]

That looks sweet.

 

[WarWagon]

Well, I just went to measure the crank pulley and completely forgot I had a Fluidamper which I had already sold "hopefully someone can measure one for me."

I have been gathering parts and found a new HX40w "Cummins cobra head down pipe" this cobra head was the one used on the 8.3 ltr 12 valve Cummins" also bought a few 1st gen Ram Cummins down-pipes to check firewall clearance. If I go w/boost spool valve it would have to be a DB unit because the exhaust on my center manifold is split 3 x 3 w/each side driving 1/2 of the turbine

Waiting on more parts fluidamper, HX Super 40, misc. small parts etc..

Powder coated the (6) valve covers and hi-flow intake runner on manifold a nice black crinkle coat.

What measurements do you need? I am not clear on any relevant 12v differences so this may not help...

I use a 6.7 viscus damper Mopar 68143868AA on the 2003 24v so I can change the belt without undue drama vs. the in the way fluidamper unit. It may not stick out as far as the FD. Word is the FD unit does better with less gear rattle in the MT *shrug* Mopar's unit works for me. The FD is also known to oddly rattle on the 24v engines and FD is not interested in figuring out why on the troublesome rigs. No excuse for FD to not check out a volunteered truck with this rattle issue, period. That said I skipped the FD rattle odds due to my usual bad luck and used a 6.7 diesel fluid damper Mopar part number 68143868AA for around $250. It required the Fan drive pulley to be changed to the 6.7 part number as well to clear and change the belt w/o taking bolts out. Part number for 6.7 fan pulley is 4930580. Mopar or Cummins may be cheaper as Mopar is cheaper on the damper itself last I checked.

 

[THEFERMANATOR]

Fluidamper is much interested in rechecking things. Sort of like how theres over 20 broken duramax cranks after just having installed fluidamper's because in there infinite wisdom they thought adding almost 6 lbs of rotating mass was a "good idea".

 

[FellowTraveler]

Fluidamper is much interested in rechecking things. Sort of like how theres over 20 broken duramax cranks after just having installed fluidamper's because in there infinite wisdom they thought adding almost 6 lbs of rotating mass was a "good idea".

You have me re-considering the Fluidamper idea now.

 

[WarWagon]

Correction/clarification: I use the 6.7 fan pulley as it's required to clear the 6.7 Cummins damper. Side benefit is belt change ability w/o removing bolts.

Also note the lifetime of a viscus damper is documented to be limited to around 1/2 million miles in big rig engines. Lifetime with no miles stated on pickups assumes the engines are not going to make more than TBO miles of 1/2 million and the rare ducks that make 1 million are ignored. Our 6.5's are lucky to go 250K...

Simply request a new damper under the lifetime warranty IF you reach the 500K mark on it. No mater how many engines it takes to get there...

http://www.overdriveonline.com/got-fatigue-your-crankshaft-damper-may-be-the-problem/

http://www.overdriveonline.com/caring-properly-for-engine-dampers/

 

[Pepperidge]

Fluidamper is much interested in rechecking things. Sort of like how theres over 20 broken duramax cranks after just having installed fluidamper's because in there infinite wisdom they thought adding almost 6 lbs of rotating mass was a "good idea".

hopefully the ATI(?) balancer I have on the LB7 is good huh?

 

[THEFERMANATOR]

hopefully the ATI(?) balancer I have on the LB7 is good huh?

The ati/socal has been fine. They went lighter with it whereas fluidamper went heavier. Theres been more than a few completely bone stock trucks that have had crank failures shortly after installing fluidampers. I started to do one because I know the viscous fluid damper is a good design to make an engine run smoothly, but I'm not willing to take a chance.

 

[FellowTraveler]

Here's the rare HX40 Cummins cobrahead I'll be using for my project. It's highly sought after by those building compound turbo setups which has driven the price up.

FORD has went to this design and claims 30+ HP gain over round elbows.

 

[n8in8or]

Here's the rare HX40 Cummins cobrahead I'll be using for my project. It's highly sought after by those building compound turbo setups which has driven the price up.

FORD has went to this design and claims 30+ HP gain over round elbows.

View attachment 49395

That's a sweet looking piece!

 

[FellowTraveler]

That's a sweet looking piece!

I suspect this is what will give you more of those ponies you've been looking for.......w/your amazing build.

 

[n8in8or]

I suspect this is what will give you more of those ponies you've been looking for.......w/your amazing build.

I'd love to find one of those.