8.3 ISC inframe rebuild...

[Audeamus18]

Anyone here have any experience with rebuilding/turning up an 8.3 ISC w/CAPS?

My current engine rating is 260HP/660 TQ (CPL 2690) and I'm looking to "turn up" the factory rating to 350HP/1050 TQ (CPL 2695) by changing the injectors and pistons as prescribed by a Cummins Application Engr.

The best/most cost-efficient way I've found to accomplish this is by ordering an inframe rebuild kit (RP934155) which includes the needed pistons and ordering the injectors from a reputable shop.

This will be a DIY project and any guidance/wisdom would be greatly appreciated.

[TJones]

Originally Posted by Audeamus18

Anyone here have any experience with rebuilding/turning up an 8.3 ISC w/CAPS?

My current engine rating is 260HP/660 TQ (CPL 2690) and I'm looking to "turn up" the factory rating to 350HP/1050 TQ (CPL 2695) by changing the injectors and pistons as prescribed by a Cummins Application Engr.

The best/most cost-efficient way I've found to accomplish this is by ordering an inframe rebuild kit (RP934155) which includes the needed pistons and ordering the injectors from a reputable shop.

This will be a DIY project and any guidance/wisdom would be greatly appreciated.

There are some good you tube videos of engine inframes. I haven't found one for the isc. Will you transmission be able to handle the increase in torque?

Ted

[Audeamus18]

Not sure what the difference(s) are between my MD3060, 2500RDS, General purpose trans and an MD3060MH (motorhome) trans, but they often run with 330-350HP and 900-1050TQ stock.

I plan to ask my Allison rep for clarification.


Has anyone else attempted either an ECM flash or a change in components for more torque? I'm curious what others have experienced with this setup.

[TJones]

Originally Posted by Audeamus18

Not sure what the difference(s) are between my MD3060, 2500RDS, General purpose trans and an MD3060MH (motorhome) trans, but they often run with 330-350HP and 900-1050TQ stock.

I plan to ask my Allison rep for clarification.


Has anyone else attempted either an ECM flash or a change in components for more torque? I'm curious what others have experienced with this setup.

I think the md3060 are rated to around 700 ft lbs of torque. I wonder of the MH version is the same transmission just not expected to last as many miles. To get the higher horse power and torque will you also have to go to a bigger turbo or is that taken care of by reprogramming?

Ted

[family wagon]

I've replaced the injection control valve which is in the middle of the stack of the CAPS pump. Also replaced a head gasket and head bolts. That 8.3 head is HEAVY and the bolts are torqued pretty hard - I used a cheater bar. Did all of these at home, but I don't have any video or pictures.


You'll need the Cummins 'engine barring' tool. It's a little gear that goes in through a hole in the bell housing. It engages with the starter ring so you can turn the engine over manually. That's the only special tool I recall needing so far, but there could be others needed for pressing in/out the cylinder liners or something.



You can find a wealth of information for free through Cummins Quikserve. Create an 'owners' account for yourself, add your ESN, and poke around for the service info. It gives instructions, drawings, torque specs, etc.


I'd love to turn mine up some day too.. keep us posted.

[Audeamus18]

Ted,

My current turbo HX40W (3591020) is also on the CPL2695, so I'm assuming so, but I'll have to double-check with Cummins.

The only true 8.3 ISC overhaul vid I've found was on a 6CT Marine, but it did cover most of the components. I'll admit I'm nervous about this, but still determined.

[Audeamus18]

Thanks for the note on the barring tool! I've seen it being used but didn't know the nomenclature.

Was the inj. control valve for a bump, or repair? My first order of business is adding a FASS fuel pump and replacing the fuel lines. Keeping that CAPS happy is a priority.

Anyone had or heard of any success with swapping larger intake/exhaust and/or straight pipe? I see that often in the light-duty world and assume it couldn't hurt.

Michael

[cadillackid]

https://www.allisontransmission.com/...k.pdf?sfvrsn=2


it looks like the school bus version are good for 300 HP.. and the 3200 Motorhome is rated for 450..


some of the notes are confusing. and remember these ratings are for new units with 5th gen controls.. 5th gen controls often work wit hthe newer engines for SEM.. SEM defuels the engine on shifts to prevent glazing the clutches on steep shifts.. during up or downshifts is the most likely time for a transmission to break...



I dont think SEM was available on the ISC in the years we are talking.. so take the ratings at face value...



-Christopher

[Audeamus18]

Got some great news from my local Allison Distribution branch, Stewart & Stevenson in Houston, TX.

Apparently, the only difference between my MD3060 and the MD3060MH version is a TCM flash or "recalibration"...and a retarder (I'm looking into the PacBrake PRXB = $1,273 for parts). This flash would take care of 6th gear OD unlock and increase HP/TQ capacity, all for 1hr labor = $158!

I'll just need to remove the TCM from the trans and bring it into the shop. Then we start the fun part