Engine/Transmission (1994 - 1998) injector/turbo decision

[superscout]

Hello All, first post. Been a "Lurker" for years but finally joined up a few months ago. My '96 2500 needs attention due to lack of maintenance (my fault) I now have a number of things to replace. Exhaust manifold is cracked so ordered a new one (3pc), injectors are leaking so ordered new ones (+80HP Bosch) and turbo has a cracked vane (HTT is on backorder for the S-300). I don't want to do a marathon parts replacement over a weekend, I'd rather do 1 thing each weekend so I have some time to relax. The exhaust manifold is a no brainer but the problem is if I put the injectors in before the turbo will I end up with issues (massive smoke) or if I put the turbo in with stock injectors will that create a different problem? I'm just trying to get my ducks in a row before I start wrenching. Everything in the engine bay other than the BHAF is bone stock. I just gotta get this done by the end of April so I can leave TX and go home.

 

[crabman]

First thing is to make certain that you have ALL the gaskets that you will need before you start.
Wash the engine compartment.
Have something that is sturdy and will support your weight and is high enough to make working on the engine easier. I made 2 that are 18"W x 33" L x 17"H.(height depends on your height)
Use kroil or pb blaster to soak all bolts/nuts for several days that are to be removed.
IMO, I would start @ by replacing the E/M and use studs instead of bolts for the fasteners.
The turbo could be done at the same time or later(second).
Injectors last, be very careful and do not loose any of the speciality bolts for the return lines.
I use a injector brush to clean out the injector bores. >Brush, injector bore #3822509 cummins only part, $12
I always use something to cover the fenders and battery & even lay something thick & soft across the radiator area.
Lay some type of cloth under engine to stop and bolts/nuts/washer or whatever from balancing to the void.
Always have good lighting!(whenever possible)

 

[superscout]

Thanks for the answer. I ran an auto shop for 10+ years so know gasoline and driveline intimately (specialized in imports) but know enough about a diesel to just be dangerous. I have the manifold and injectors but am waiting for the backorder to end on the S-300 and was hoping I could take 2 wknds and do those then wrap up with the turbo but I'll just wait on the injectors until I get the turbo in.

 

[crabman]

If you never have replaced injectors on a 12V cummins, here is a link to a YouTube video: https://www.youtube.com/watch?v=2vCF1QkGQ7s
He doesn't disconnect the negative battery cables which I always do before doing any engine work.

 

[superscout]

Thanks for that crabman, I hadn't actually witnessed them being R&R'd before so that does clarify the process. The big issue I'm having is learning the dynamics of a diesel, ie fuel in to turbo size to intake size, etc. Gasoline engines are simple, injector duration or metering rods if it's carb'd can be changed to compensate for a bigger cam or intake and with a turn of the distributor timing changes but those options aren't available on my 12V so I'm trying to learn what all is effected when I change XX part. For example I know going to 80hp injectors requires a larger turbo to operate efficiently but what are the effects of putting in the big turbo with stock injectors or putting in the larger injectors with the stock turbo? I'm reading everything I can to understand the P-Pump and AFC and I feel I know enough to really screw something up with those 2 parts so for the time being I'm staying away from them. On the other hand I won't hesitate to install a clutch, rebuild my transmission, drop in new gears or work on the electrical system because gas or diesel it's all the same. In fact does anyone know if there is a manual of book out there explaining diesel theory? Not model specific necessarily just a generic book.

 

[CharlieFoxtrot]

Where are you in TX? I'm in Katy at the moment, and have 75HP injectors with a stock turbo. If you're nearby you could check it out. "Too much" smoke is a personal taste thing, but I'll say I don't like smoke at all, and the only time mine is excessive is if I floor it from a stop or at lower/off-boost engine speeds.

 

[superscout]

I'm in (H)Odessa so there really isn't any easy way to meet up. I'm Ok with slight hazing but not constant smoke, I will only have to run the stock turbo until High Tech has the S-300 back in stock so I think I'll be Ok. Thanks for the answer.

 

[superscout]

Last update. Injectors and exhaust manifold are in. Wow. Glad I listened to CharlieFoxTrot. Just running around town the truck is substantially more "driveable" than with the 215's in it. No smoke from a dead stop and nothing driving like an adult. If I romp on it then it WILL lay down clouds of smoke, but I expected this and it will be remedied as soon as I order the S300. I drive through a lot of residential so try to keep the smoke at an absolute minimum all the time.The important part is I don't lay down the 6' trail of black I did before from a dead stop and I'm not hazing under light throttle in 4th gear. The only down side is I can't jump in, fire it up and go back in the house for a few minutes while she warms up, on a cold start in the morning it sounds like I have a 3/4 solid lifter race cam but that does go away after about 2-3 minutes after my exhaust temps climb up a bit and I can live with that.

 

[JMcCoy]

It won't take long and you will be up to speed on the fuel turbo thing. A diesel is different from gas, where gas has a set air fuel ratio you are looking for. With a diesel, fuel makes the power (and heat), and the turbo's primary function is to cool it down. Make sure you have gauges if you don't already have them. Once you get the turbo in, start playing with the fuel plate. The GSK was probably my best modification to date. It really changes the drivability. Keep us posted.

 

[GAmes]

Although not as easy as with a distributor the timing can be changed, and since you have bigger injectors I recommend it. The problem is, there isn't any vacuum (or computer) advance, you need to do some testing of different settings to find the one that works best for you and your engine. Smoke/haze is unburned fuel, i.e. money wasted. Setting up your afc and finding the correct timing will give you optimum mileage, best throttle response and maximum power. In case you have been searching, here is a ton of info about the 12 valve.

http://www.cumminsforum.com/forum/94-98-engine/