So who has bumped the power on a 6CTA cummins

[aztec]

ordered pac brake 3k-4k springs anybody got install instructions

 

[74M35A2]

ordered pac brake 3k-4k springs anybody got install instructions

It comes with them, I bought the same GSK and have not installed them yet. If I remember correctly, it says to measure the stock retainer height first, remove and swap springs while leaving the inner one (?), and then set the retainer height to the same as original, say 0.050" for example.

I'll post the instructions in a day or so if I can find them.

 

[aztec]

thanks my gsk should be here tomorrow i will update

 

[MtnSnow]

Yes it comes with the Instructions.

 

[n2energy]

"do thefull fuel screw. It's 2 nuts on the back of thepump. Then, you can fiddle with the screw on top to fuel harder in the lowerrpm, as described in the next paragraph.To therear of the pump on the top is 2 different allen plugs. The bigger one isthe fuel rate, and the smaller is the star wheel, or pre-boost smokeadjustment.To do the fuel you take off the plug with either a 3/8" or 10mm allen wrench. Now tie up the fuel shutoff sol.or pull cable in the run position and you will see the adjustment screw. Youmay need to put a brick or such on the accelerator to keep the screw in theright spot under the hole. Break the jamb nut loose with a 3/8" or 10 mm deep socket. A good trick is to use a skinnyscrewdriver that fits inside the deep socket you just used on the jamb nut. Asyou hold the nut with the socket, back out the screw(CCW) about 10 turns, thensnug down the nut. Now pull out the socket & screwdriver to makesure you didnt go too far. Run the accelerator lever to make sure the screwdoesnt come in contact with the pump. If you go too many turns, you'll see whatI'm talking about. Then if it's ok, a good snug on the jamb nut and it's done.Note #1: if you get the screw too high, it'll hit the top of the pump and makethe rpm stick. Note #2: If you drop the screw inside the pump you can retrieveit easily with a pencil type magnet, and it's not that easy to get out. Untiethe shutdown sol. and remove the accelerator weight tool. Under the smallerallen plug is the star wheel. Take the plug off with either a 5/16"or 8mm allen wrench. Spin the star wheel towards thefront of the pump(rotate towards the pass side) to increase low endpower(smoke)and away for less low end smoke(essentially releasing the tensionon the spring inside). The governor spring mods, and accelerator stop screw arethe same as the newer 466's described above, except you cant use a Dodge/Cummins P-pump set of governor springs. I'm working on gettinga shim to work on these MW pumps.
-11/1/09-
I got the shim ideanailed down, but I dont have a victim to test it on.
Withthat governor, there's no 3k gov spring kit, but you can use one from a 12valveDodge/Cummins. Depending on the weights inside the gov, it could rev to 2600 to2900 with a 3k kit, and around 3100-3600 for a 4k kit. You can also make your own. Take out the smallest spring inthe gov spring pack. Make/ grind down 2 washers that fits the diameter of thespring and still fits in the stud. Make sure it's around 1.55mm thick for bestresults. Put a washer in each set of springs, and tighten to 2 -4 clicks pastthe factory setting(measure the original stud protrusion). You should hitaround 3200 like that, as long as you have the fuel and timing."

 

[74M35A2]

Anybody have leads on performance injector nozzles? They seem a little harder to come by for 8.3 injectors. I'd like to go larger than stock, as I just bought a used but clean Holset HX50 turbo off eBay for $200 (genuine, not Chinese clone), and wish to do both at the same time to my 6CTA8.3. The stock turbo is an HX40, which can push good pressure, but I am concerned about back pressure. I bought a boost gauge which shows pressure on both the turbine (exhaust) and compressor (air outlet) sides simultaneously. 1:1 is optimal but nearly impossible to achieve, and anything approaching 2:1 or greater is too restricted. I don't want to use the marine injectors, as they are not the optimum spray angle, the run hot, and are smoky. But they are easily available and they do make power though. I'd like to simply get EDM'd injector nozzles for the correct spray angle (144 degrees, marine are 155 degrees) and assemble/pop test them onto my existing injectors, while having the pintle/seat re-lapped in as a rehab step. Performance nozzles should be much lower cost than entire injectors. There is a physical relationship between piston bowl design, injection timing, and injector spray angle.

If this all works well, then I want to remove the intercooling core of the JWAC (aftercooler) as many state it is restrictive once power is increase, and instead try to fit a more conventional intercooler up front of the radiator.

I have an appointment set with a local Cummins dealership to bump the injection timing up to 16 degrees. A lot of research on the motorhome web sites indicate that fuel economy increase are really measurable, and power adders take better hold, once doing so. They say the engine just runs better, and as long at 17-19 degrees or so is not exceeded, it if field proven to be fine. 2 hours of shop labor time is less cost than the timing tools to do it myself, otherwise I would just do it.

I plan to do some measured acceleration tests to establish baseline data. Also want to find the restrictions on the intake side such as the mushroom cap, air filter, and seemingly choked off 90 degree rubber elbow going into the turbo (though this is after the restriction meter). Maybe somebody thought this was a flow adder, but all of the class 8 trucks coming through my place just have round conventional elbows on them.

 

[nevrenufhp]

Adding the video for the full fuel adjustment nuts. Just to add to the 43 pages on this thread.
https://youtu.be/e3InnotLRAE

 

[Ford Mechanic]

Why did you need the special socket? Could you have loosened the 10mm and then just put a 14mm in there to turn the nut or did I miss something? Does the 14mm need to be held for some reason?

 

[JohnnyBM931A2]

You know... After reading through this thread multiple times, I think I'm more confused than well informed
So far I've gathered the following helpful bits of data:

-The 8.3 is easy to turn up, and is rated for 3,000rpm
-Don't use the marine injectors, because the spray angle is not right for our engines
-Keep EGT's below 12-1300 degrees
-Be extremely careful when modifying the pump, as some of the small parts are very easy to lose
-It's best to add upgraded governor springs when doing pump mods, so you will keep the fuel from cutting out under hard acceleration

Does that sound about right? I'm still trying to figure out all of the settings, etc. I would love to bring my 8.3 up to 300hp. So far all I have done is upgrade the air filter with a new one from TMG, and add the new cage that they made. Soon I will be buying and installing the pyrometer/boost gauge they sell that mounts on the dash. After that, I'm still not sure exactly what to do.

 

[Ford Mechanic]

From what I understand, the gov springs are basically like a rev limiter

 

[nevrenufhp]

Why did you need the special socket? Could you have loosened the 10mm and then just put a 14mm in there to turn the nut or did I miss something? Does the 14mm need to be held for some reason?

It wasn't a required thing, it just made it easier to do. The 14mm nut fits pretty tight, so it is actually faster to back out the 10mm, then back out the 14 to meet it. The socket was a gift from a 5 ton owner with a lathe.

 

[MtnSnow]

Yes the Gov Springs are the Rev Limiter.

 

[nevrenufhp]

You know... After reading through this thread multiple times, I think I'm more confused than well informed
So far I've gathered the following helpful bits of data:

-The 8.3 is easy to turn up, and is rated for 3,000rpm
-Don't use the marine injectors, because the spray angle is not right for our engines
-Keep EGT's below 12-1300 degrees
-Be extremely careful when modifying the pump, as some of the small parts are very easy to lose
-It's best to add upgraded governor springs when doing pump mods, so you will keep the fuel from cutting out under hard acceleration

Does that sound about right? I'm still trying to figure out all of the settings, etc. I would love to bring my 8.3 up to 300hp. So far all I have done is upgrade the air filter with a new one from TMG, and add the new cage that they made. Soon I will be buying and installing the pyrometer/boost gauge they sell that mounts on the dash. After that, I'm still not sure exactly what to do.

There are many different marine injectors for an 8.3, and I believe the people posting that were referring to a 5.9 with the 370 marine injectors. I have seen 5 or 6 part numbers for 450-480 injectors for an 8.3. Of course, the best ones cost the most. I just don't have exact spec for them because they are direct from Cummins. I'll get the details soon though. They make 350hp (give or take a bit)with these MWpumps.

 

[JohnnyBM931A2]

There are many different marine injectors for an 8.3, and I believe the people posting that were referring to a 5.9 with the 370 marine injectors. I have seen 5 or 6 part numbers for 450-480 injectors for an 8.3. Of course, the best ones cost the most. I just don't have exact spec for them because they are direct from Cummins. I'll get the details soon though. They make 350hp with these MWpumps.

Good to know

 

[Rmtaunton]

You know... After reading through this thread multiple times, I think I'm more confused than well informed
So far I've gathered the following helpful bits of data:

-The 8.3 is easy to turn up, and is rated for 3,000rpm
-Don't use the marine injectors, because the spray angle is not right for our engines
-Keep EGT's below 12-1300 degrees
-Be extremely careful when modifying the pump, as some of the small parts are very easy to lose
-It's best to add upgraded governor springs when doing pump mods, so you will keep the fuel from cutting out under hard acceleration

Does that sound about right? I'm still trying to figure out all of the settings, etc. I would love to bring my 8.3 up to 300hp. So far all I have done is upgrade the air filter with a new one from TMG, and add the new cage that they made. Soon I will be buying and installing the pyrometer/boost gauge they sell that mounts on the dash. After that, I'm still not sure exactly what to do.

You missed one thing you really need to put an EGT on it and this is not the same pump used in the normal rv's or tractors but yes the motor will rev much higher I am going to turn low fuel back down a bit and get new springs

 

[JohnnyBM931A2]

You missed one thing you really need to put an EGT on it and this is not the same pump used in the normal rv's or tractors but yes the motor will rev much higher I am going to turn low fuel back down a bit and get new springs

Pyrometer measures EGT In my post I mentioned that I will be installing one soon. Just have to hold off on more mods because I am spending so much on Christmas presents.

 

[Tornadogt]

Some pumps have a different nut in place of the 10mm I made this tool from a socket and just cut down the sides to make a spanner socket..

Edit this 2nd photo is of the more common locking 10mm nut...

 

[Ford Mechanic]

Some pumps have a different nut in place of the 10mm I made this tool from a socket and just cut down the sides to make a spanner socket..
View attachment 598206
Edit this 2nd photo is of the more common locking 10mm nut...
View attachment 598207

Pic of your special tool?

 

[74M35A2]

Pyrometer measures EGT In my post I mentioned that I will be installing one soon. Just have to hold off on more mods because I am spending so much on Christmas presents.

What are you buying me?

 

[74M35A2]

Pic of your special tool?

Ummmmm, really?