Turning Up the Pump

[tobyS]

I typed in “MW pump” on YouTube and the first two videos are for both adjustments, published by a user here.

Thanks....I never thought of typing in "MW Pump"....but I'm not doing the modification yet.

Wes is on the thread and can speak for himself.

 

[Jbulach]

Biggest thing is to get the pyro installed first. Can’t undo a roached engine, and not many of us have the super trucker EGT ESP...

Toby your M929 is the exception, until we get it consistently pulling to 2100rpm I wouldn’t consider it moding or turning up.
I need to get gov springs installed in mine before pulling the hills to Haspin this fall to get some more data. Been a busy summer but will keep you post on how it goes if I make it happen.
Ironically I’m getting ready to change the batteries as we speak. Quite daunting, my back hurts already...

 

[M543A2]

Every one we own has been turned up to the maximum. We have run them this way for many years with no problems. The important thing when driving a truck with a turned up pump is operator understanding about what is going on. Installing an EGT gauge and boost gauge help you monitor and keep in safe ranges. Full throttle for a time within safe EGT and boost parameters is OK and will do no damage but when a driver chooses to floor it and hold it there while showing off or heavy pulling for a long time will certainly risk damaging the motor. Guys who do that is where the mantra I get so tired of hearing espoused here "Turn them up and blow them up" comes from. It simply is not true with a knowledgeable operator and proper engine management. Turned up the truck will start better and is a pleasure to drive. We even increased our top RPM so when you have been at full throttle and shift the motor does not drop down through the RPM range during the shift the turbo will still be spinning up and will instantly be there to pick up the load again after the shift. So, we do all of this, use wise driving practices, and have never damaged an engine. We bought a truck from the Indy base, started to drive it home, and had to stop and turn it up to feel we were safe!
I might add that the type of head gaskets is critical here. You want to have the head gaskets with the weep tabs projection at each cylinder on the right side of the engine. They have separate fire rings for each cylinder, much better than the stock gaskets. A weak spot also is the rear of the head. Some motor models have an extra cooling passage back there while others do not. With no cooling passage there the gasket is at risk because of fast heating up there if you do not let the truck warm up before applying full fuels. I know everyone is going to want me to tell them which model I am talking about in each case above but I will have to get that later. I am right now three weeks out of brain tumor surgery and still getting my feet under me so to say. I am doing very well but lots to keep up with after that absence for work etc. I just at this time wanted to relate our experience with turned up trucks and for you not to fear it if done right.

 

[tobyS]

Wally....sounds like you are healing up...take care.

I guess I will need the EGT and springs as a good start point. "Turning it up" will mean one click at a time, not going for the max setting. I assume I'm on the lowest.

What thermocouple do you use for those temps? Any great deals on the gauges I should know about? I know I will be torched for not searching, but what is the best deal on the springs to do 2350 RPM?

 

[Jbulach]

This is the EGT gauge I went with, comes with K probe that has a straight metric thread. Not the purest looking, but I liked the programable high end alert, as well as external output for a light or buzzer, that I haven’t got around to installing yet. I just went with a cheapo boost gauge. I haven’t bought the springs yet, but I believe the 5.9 12v p7100 3000rpm springs are supposed to work, and get you about where your wanting. They can be had for $32 on Amazon, or up to $220 on Ebay.

If your sure your fuel and air systems are clean and tight, as well as the throttle lever is going all the way to the stop, you might want to just tighten your springs 3 or 4 clicks and see where that gets you, and if your idle remans stable. My truck will free rev 2300, and pulls on the road up to around 2150 with no mods. Hmm...maybe I should go 2-3 clicks with the stock springs first and see where that puts me?

 

[simp5782]

If you aren't working the truck. You do not need a pyro. You won't load it enough to bog it that much unless your an idiot intentionally trying to burn it up.

Toby, start by turning the aneroid. Turn it all the way in the direction of the motor. Then turn your fuel screw out 3 turns to start. You drive with some sense so you should be fine.

 

[Elijah95]

If you aren't working the truck. You do not need a pyro. You won't load it enough to bog it that much unless your an idiot intentionally trying to burn it up.

Toby, start by turning the aneroid. Turn it all the way in the direction of the motor. Then turn your fuel screw out 3 turns to start. You drive with some sense so you should be fine.

Normally, anything you say I’m 200% behind it, but with my truck being timed and low fuel and main maxed out, I could peg my 1600° gauge mounted in the rear half of the manifold on a decent sized grade with the hammer down, or from a dead stop floored to 55mph it would get toasty. With that said, backing down to 3/4 throttle would drop 400°+ and easily become manageable. I could see where someone with a heavy foot and a partially clogged aftercooler that many of these trucks suffer from could be a disaster

 

[Jbulach]

If you aren't working the truck. You do not need a pyro. You won't load it enough to bog it that much unless your an idiot intentionally trying to burn it up.

Toby, start by turning the aneroid. Turn it all the way in the direction of the motor. Then turn your fuel screw out 3 turns to start. You drive with some sense so you should be fine.

He’s only getting something like 1900 rpm at WOT, plus I believe he’s wanting to go above 2100 to compensate for dropping down to 395’s, will the aneroid and fuel screw adjustments increase the rpm?

 

[simp5782]

No but he will have more power from the get go with the aneroid adjustment rather than having to wait for boost from the rpms. I think he has a rod adjustment problem over a different spring configuration

 

[simp5782]

Normally, anything you say I’m 200% behind it, but with my truck being timed and low fuel and main maxed out, I could peg my 1600° gauge mounted in the rear half of the manifold on a decent sized grade with the hammer down, or from a dead stop floored to 55mph it would get toasty. With that said, backing down to 3/4 throttle would drop 400°+ and easily become manageable. I could see where someone with a heavy foot and a partially clogged aftercooler that many of these trucks suffer from could be a disaster

The second sentence of that top paragraph applies to you. If you arent pulling get out of it. You are just wasting fuel. You will feel it when you are not doing gaining or holding your own. Your truck isnt pulling at WOT if the egt is that high.

Dont feel bad i can hold mine half way to the floor climbing just about any hill with even a 5ton wrecker on the trailer and 35lbs of boost never gets above 1100 and i can hold speed. Sometimes i get a little uppity and hold it to the floor and walk away from big trucks on those long hills.

High egt temps will also be less if you could turn your fan clutch on before you start to climb the hill To keep the coolant cooler thru the aftercooler. I see about a 150 degree difference in egt with my fan on/off

 

[tobyS]

Wes is right about fuel. The issue of RPM is more of a top speed and getting there thing (and getting the tranny to shift better). I've been down in muck and can't get it to spool up. It's a good and bad thing. I find myself backing in low TC range with a load and have to be in low to pull out. If I could get some power, I may be able to stay in high (backing up)...but I may have power to break the TC then too, when I back into the hole in low range. That darn TC problem is a limitation of the 929.

Thanks Jbulach for the temp gauge link...I saw that one. There are several different ranges I noticed on pyro's. Looks like I should have 1800f even if I won't use the upper end, while 1300f might peg. When you mount the probe, where are you putting it? We did testing for UL and used to drill a small hole and glue the thermocouples in (a hundred or so). I'll use the probe in SS....my J TC is limited by using solder in the twist and won't work at that high temp. I'm thinking a wrap of high temp insulation over it, by the turbo. Do I really need the boost gauge?

I'm working on the deuce so will rely on info here to get ready for these mods on the dump (accumulating parts). Thanks guys.
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[Jbulach]

Wes is right about fuel. The issue of RPM is more of a top speed and getting there thing (and getting the tranny to shift better). I've been down in muck and can't get it to spool up. It's a good and bad thing. I find myself backing in low TC range with a load and have to be in low to pull out. If I could get some power, I may be able to stay in high (backing up)...but I may have power to break the TC then too, when I back into the hole in low range. That darn TC problem is a limitation of the 929.

Thanks Jbulach for the temp gauge link...I saw that one. There are several different ranges I noticed on pyro's. Looks like I should have 1800f even if I won't use the upper end, while 1300f might peg. When you mount the probe, where are you putting it? We did testing for UL and used to drill a small hole and glue the thermocouples in (a hundred or so). I'll use the probe in SS....my J TC is limited by using solder in the twist and won't work at that high temp. I'm thinking a wrap of high temp insulation over it, by the turbo. Do I really need the boost gauge?

I'm working on the deuce so will rely on info here to get ready for these mods on the dump (accumulating parts). Thanks guys.

I have all the same problems off-road, and do the same with low range an such. But I want to do my mods in a logical order and see the results with real data for comparison.
Yes, I can top 1300 with a good load, on big hills. I still need to change my alarm temp from 1100 to around 1275.This is where I mounted my probe. I just went a little at a time with the tap until I could just get the straight threaded probe in without fear of twisting it off, and it sealed great. No, you don’t need the boost gauge. Thats why I went real cheap, like $15, but found it nice to see that I’m getting exactly what most other people are reporting bone stock. I always wondered because I thought my truck accelerated exceptionally well while empty. The other thing is you can tell exactly when the pump de-fuels, and helps you learn how to max out your shifting RPM which in turn help you control your EGT, also why I want to see what a bit more RPM does for me. On that note, I would not Dick with your fuel until you get your low, max RPM issue figured out, if you haul heavy on the road at speed like I do. I think that would guarantee you’ll burn your motor down if your short shifting and lugging with more fuel.

 

[Steelreaper80]

I keep hearing that changing the timing to 16 degrees is the sweet spot for the 8.3. Is this correct? What are they set at stock? Thanks Jbulach for the photo of the prob location. I was wondering where everyone installs them at.

 

[74M35A2]

This one is a pump turn up thread, but........I got that # from a lot of study on RV boards. They are a large user group of the 8.3L and always in hard quest for more power and fuel mileage.

If I remember correctly, our timing is a very conservative 10 degrees.

The general consensus was that the largest single impact it has when done alone is fuel economy. From there, each power mod would have a larger effect once the timing was bumped. It also supposedly lowers EGT's. 16 degrees was the do-not-exceed value to keep reliability for stock 8.3L block/head/gasket/bolts. Besides the head gasket letting go, the block top deck surface on 1990 produced engines and slightly older are prone to cracking if pushed hard with very aggressive boost and timing figures.

There are a few different ways to set it, detailed here in the 8.3L mod thread and the free online Cummins Quickserve parts and service web database. I don't think many here have done it, myself included, just studied deeply how to on all the several ways. A few here may have, but not many. You can do it in your driveway via injection pump gear clocking, or send your injection pump out and have the injection timing changed internally (easiest way, about $150, then pin time to re-install the pump, easy gravy job).