Cummins 6CTA8.3 Injection Timing

[74M35A2]

Yeah. This is right out of the Cummins service manual, 300-370psi. I read where some have done it simply with the hand primer built into the fuel pump.

 

[Jbulach]

Yeah. This is right out of the Cummins service manual, 300-370psi. I read where some have done it simply with the hand primer built into the fuel pump.

If it can possibly be done with the primer, I think a grease gun would work excellent. Flip the plunger seal and squash until it will hold fuel or submerge the entire gun in fuel. With a check valve or an extra set of hands you could likely manually regulate your pressure...

 

[WillWagner]

opcorn:

 

[74M35A2]

Will, that was the response I was looking for when I published that I was going to run diesel fuel through my pressure washer. I already bought the gear puller, so I need to get a banjo adapter fitting and a plug to block the banjo outlet port and then away we go.

 

[74M35A2]

Bought the 14mm banjo adapter fittings, and confirmed the electric pressure washer can be dialed down to the target 300psi. We're clear for launch. When I'm done, it will make a cool flame thrower.

 

[74M35A2]

Good news for others. Some additional digging reveals that you can do this with the hand prime button and not 300psi. Simply remove the delivery valve core from the delivery valve holder, which is directly under where the injector line attaches to the pump. I'll probably surrender the 300psi method and go this way instead, even though I now have all needed to do it. Sorry to disappoint. I know a bunch of you were waiting for me to come posting sans eyebrows.

 

[74M35A2]

Wanted to post a link to a well described method of injection timing check and adjustment, via the spill port method. This is decently written, and for a P7100 pump, but same method is used for the MW pump, or most any inline pump for that matter (A, P, MW, etc...):

http://www.trucktrend.com/how-to/engine/0807dp-bosch-p-pump-diesel-fuel-injection/

 

[Mos68x]

This is probably a stupid question for most, but I've never done this kind of work since I was a gas gear head.

Does an IP adjustment require the pump to be off the motor? All I've seen for pictures seems to be the front engine/IP, though it could be the back I guess.

 

[74M35A2]

Timing adjustment can be done right on the engine. Also does not require a high pressure feed pump to do so. The Harbor Freight steering wheel puller fits the pump gear perfectly, and even includes the correct bolts. Does not require to pull the pump at all.

You could pull the pump and send it to a pump shop to have them advance the timing from 8 to 16 degrees so you can just install it and go if you want. I was quoted $100 to do this before I studied how to do it various ways. Then you just reinstall it and pin time in, meaning there is a push pin on the pump and one on the back side of the timing gear case. Once you can push both in, zap the gear on, and done. You can pull the pump and leave the gear in place without opening the timing cover.

If you are even moderately mechanically inclined, best way to do this is just buy the Cummins degree tape that goes on the crank balancer, make a zero pointer from some wire and bolt it down, then study and use the spill port timing method. Remove the #1 delivery valve in order to use low pressure for the spill port method. It's easy.

 

[Chris H]

Hi,
I apologize for jumping in here as a complete newb- I just signed up last night. I'm just wondering if it's possible or worth it to swap a p-pump onto one of the military 8.3's.
Thanks

 

[74M35A2]

Yes it is possible. General consensus is if you want to exceed 300hp, then you should. Up to that point, not necessary. You can turn the MW up, increase the injection timing, and add larger injectors. To keep EGT and smoke down, after 300hp you will also need to remove the after-cooler mounted in the intake manifold cover "tent", and change to a front mounted charge air cooler, possible turbo upgrade also from HX40 to HX50 or HX55.

So, there are some other things which can be done first, before just jumping to an expensive P pump. A P-7100 pump from a 5.9L Cummins will work, but you need to block the oil inlet port on the gear case to pump mount, and run an external oil line, which is easy. You also want to make sure you get a 12mm P-7100 pump. Not an A pump, not a 10mm or 11mm pump, and the rotation needs to be the correct direction, DT466 P-7100 rotates opposite direction of what a Cummins uses.

Read all the posts in this thread, there is a lot is useful info in here.

 

[Chris H]

Excellent information 74M35A2. Thank you

 

[74M35A2]

There are a lot of knowledgeable and experienced people here. Please consider their opinions also, across all topics.

 

[Chris H]

For sure, thank you.

 

[Ford Mechanic]

So I noticed on the IP of my 923 with 8.3 there was elongated holes where it mounts to the cover. Could you not loosen the nuts and rotate the IP to adjust timing with a strap? It didn't look like it would move but a 1/4 in.

Sent from my SM-G900V using Tapatalk

 

[74M35A2]

That is just for build variance discrepancies, ease of mounting. All 6 injector lines would need to be bent, and there may be a hidden pump support bracket that would not line up anymore. Yanking the gear from the front is super easy and you only need to remove the plastic cover with the tach drive adapter to do it. Harbor Freight steering wheel puller is the exact tool, and even includes the correct bolts to do so. I used it in the middle of a junkyard with limited tools and it worked perfectly.

Degree your damper, or buy the Cummins magnetic degree tape.

 

[brazengoat06]

Update ������

 

[74M35A2]

If you are asking me, I bought a 400hp Cummins ISL (8.9L) common rail EFI + VGT roller cam engine from a 2005 RV. I did it just to whip Simp's truck next time he comes poking around MI again. Install during Sept.

Timing bump on any 8.3L should help mileage greatly though, and small power bump.

 

[simp5782]

If you are asking me, I bought a 400hp Cummins ISL (8.9L) common rail EFI + VGT roller cam engine from a 2005 RV. I did it just to whip Simp's truck next time he comes poking around MI again. Install during Sept.

Timing bump on any 8.3L should help mileage greatly though, and small power bump.

Ruh roh shaggy that isnt a small cam anymore. It is bound to happen.

Sent from my SM-G935P using Tapatalk

 

[Chris H]

What do you recommend the timing be set to? 17•?