Well,

Today I had a few hours to kill, so I decided to take on my 3200 spring. It took about 5 hours total, as I spent about an hour and a half looking for that little spring that fell out of my hands that the 3200 spring attaches to. I tell you that my neighbors could hear me screaming obscenities for the entire time I spent looking. Consider I dropped it once, and found it, then dropped it again ! I was losing my mind, but eventually it popped in my view, and I never let it go. It was a real PITA to get the cover back on, but I figured out that if I backed the power screw flush with the interior of the cover, it went together with little fuss.

I can't stress this enough.... DON"T LOOSE THAT SPRING !


Here's the new spring in it's place...





The end result??????


HOLY FREAKING CRAP ! WHY ???? didn't cummins do this from the factory ? My truck runs like a rapping ape, and I did nothing to the power screw, pin, star wheel or anything else...

It moves like no other truck I've ever been in, never mind owning...

 

It seems like these threads come up every 6 months or so. Some one new will get one of these trucks and try this, then a few guys that were on the fence about doing it will jump on the new guys bandwagon and do theirs that they have had in the glove box for the past year or so. Funny how trends come and go in life isn't it?

Now for all you guys with the new found fuel at higher rpm's, I'd suggest getting a fuel pressure gauge on your truck and see how it's doing.

Have fun with the "new" trucks guys. Next time try clipping a few coils out of that spring or just get the 4200 spring, makes it even funner to drive.

 

I love my 4200rpm spring. Makes the throttle as touchy as a Hondas Vtec engine.

Sent from my DROID RAZR using Tapatalk 2

 

Love mine also Jon, well I did, that pump is on the shelf in the barn. As long as you can keep fuel in the pump they are fun up in the rpm range! Noises still make me a little uneasy above 3,000, but no harm no foul.....yet. If /once it happens will be a good excuse to the wife for the whole 411 cubic inch engine I want so bad.

 

Not on the fence, but for me was a fear of the unknown. I watched the you tube video's I found, but none of them were complete from start to finish. I was afraid that the FP would leak, or I wouldn't know how to do the job properly, and that's why I held off. Reality is that, if you take your time, inventory each part, mark your throttle index position, and never let go of that secondary spring, pin and cup, it goes relatively easy.

I pulled each throttle adjustment screw out, cleaned and lubricated them so that I can easily change the throttle stop positions. I removed my power screw cover, clamp and fixed the damaged threads on the screw, and cleaned and lubricated what I could. I had to adjust the throttle linkage as well, as my RPM's weren't were the were supposed to be when I started it back up, so a little fine tuning made it purr. I still haven't messed with the power screw, or any other mods yet, as I'm so pleased with the results as is. We'll see if Bill is right, and that only lasts a little while, as I fall off of that slippery slope, or not.

It took me forever to get the cap back on, as the lever inside the pump put so much pressure on the power screw, that I couldn't get the cap lined up. I fixed that by cracking loose the power screw nut, backing out the power screw till it was flush with the cap's casing, put the cap on bolted in place, and put the power screw back where it was when I started the job. Much easier.

I also, at Bill's recommendation, followed the sticky, and removed the bracket to gain access to the FSS, ground the rubber concave plug flat, and put the FSS back in place after cleaning the connections and lubricating the connectors that attach to it.

So far, so gooooood

 

this old man has been preaching this spring since the late 90s. didnt know the part number when i did mine nobody would talk about modifying these engines. i found it in the junk drawer of a diesel shop. the spring wire was almost double the size of the stock spring and i said THIS is me. there were a lot of doubters back then to.

 

Any of you guys move your nut to the outside, like I did ? I also put a slot in there to be able to move it with a screw driver as I saw someone else here did in a previous post

 

Yup, i did mine the same.


Now turn in that power screw!!!!!

 

The nut on the outside dont work so well when u've maxed the pump out,

 

I've put the 366 spring in a couple of my trucks but the current one just has mega travel to max throttle. Seems to work fine. Meh. The difference between backing out the high idle screw and installing the 366 spring is not any different from what I can tell for what I use the truck for. (towing)

 

Really? I'll have to try that and see.

 

Well, it's been a few days, and here are my experiences with the 3200 spring.

The truck idles better, although I have no idea as to why it would, if the spring isn't being utilized. I have had to adjust my idle down, as when I removed the top sector of the pump, i removed both screws to access the mounting bolts, cleaned them, and put them back. I finally have the low idle set where I want it, and it's never been better.

In the mornings, my truck used to "haze" quite a bit, meaning I'd get smoke out the tailpipe during warming. For some reason, I cannot explain, it's gone. It's been in the 40's here, and the truck starts up and idles perfectly, as I utilize the grid heaters, then upon initial start, I quarter throttle it, and release. It's never been better, and no obnoxious smoke.

Driving:

Well, I cannot convey the happiness this has brought me, as it's a different behaving truck. It has significantly more initial power, and even more on the major highways.

Starting off from a dead stop it runs smoother, has significantly more pickup, and pulls like it's being 1/2 throttled, as prior to doing the spring install. The low end power is significantly greater than before, which improves drive-ability, and on the highways, the extra power is there, as never before, for passing, accelerating, and overall smoothness of how the engine runs.

My Top END has increased dramatically, whereas I was on the parkway on Monday morning, and before I knew it, I was up over 85mph. In all honesty, I had never had the truck up over 80mph, as the truck wouldn't go over 80mph, as it felt as though I was just pushing the throttle down, and nothing would happen. The pedal had no real response past 80 MPH, and now it just wants to keep going.


There are two things worth notice... The truck sips fuel much less now, as I find myself barely using the pedal, as it has so much more response. I can't wait to fill it up to see just how it's changed.

There was an annoying "resonance" in the muffler at highway speeds, which seems to be less, as I'm not as much into the pedal. It still exists, but since I'm not depressing the throttle as much, it's much less often.


IMO, it's the best investment into these engines you can make.

 

Very nice explanation of the improvements, T man.

http://www.turbodieselregister.com/f...l-instructions

Here is a Governor Spring Report from Pastor Bob over at TDR as well. There seems to be a lot of data suggesting that the 366 spring is different than just adjusting the high idle screw:


Cool Governor Spring Report...

Ok guys, I've had a chance to run the governor spring for a bit now and here's what I've found...

First the spring really seems to override both the RPM AND Load governor functions/systems.
On a stock spring, you have both. The RPM will begin your defueling prior to your high idle limit setting. I think that defuel ususally is about 300 RPM (+-) lower than high idle. If the RPM warrants defueling BUT the LOAD requires equal or more fuel then defuel does not happen till later on. Either the RPM fully overrides the Load effect, or the Load itself decreases, resulting in defueling.
By using your high idle system you can run the RPM up to what you think is the safe max (usually around 3400 or so reliably, with stock springs). In doing so, you have basically drawn your "defuel" up to about 3000-3100 RPM, assuming load merrits the fueling to that point. It could be even lower if you cannot load the engine enough.

So, the spring pretty much overrides both. It will run pretty much "full fueling" right up to the governed speed. By that I mean the "physically governed speed", as in the high idle screw. If you have that backed out alot, then hang on when you go WOT with no load.... I flared OVER 3800 before I could lift off... shocked the heck outta me...
You will still have both RPM and Load impact your fueling, but it is significantly reduced.
I have found that the gov spring has literally dragged the max fueling point to pretty much were ever I've set the gov screw.
That results in a much stronger "feel" when doing even normal driving styles....
I have seen more EGT's with it too.... normal around town has gone up by roughly 100*F across the board. I find it's a bit longer dropping to/below 300*F at shut down too.

I was on the freeway today coming back from BD. At 70 MPH, I would lift my foot and feel like I wanted to lean forward from deceleration... but when I just touched the throttle it was just as noticable if not more in terms of pulling me back. All in all, a very positive/aggressive response.
With my current settings, which I've been running about 1 week or so now, my throttle rod is all but turned right out of the "*****" it is mounted to on either end. My idle is 850 RPM in "P/N". Thats as low as I can get it.
Admittedly, my "full fuel screw" no longer has the lock collar, and it won't go in any further. It's pretty much right up tight....
Around town, the EGT's are about 400-600*F with 600*F being a "peak" such as on start up from a light and pulling 1600 RPM or so.
It does come back down to about 450-500*F. This is also with a PDR HX35/14N/W. The HX 35 removed the 100*F temp increase form the spring change, plus another 50* or so.
It has also made major difference in my smoke levels. They are not any worse now than when I was running the 185's in the ole girl..
When I did my dyno run at BD today, the runs were about 15 seconds long. At the very end of the runs I had peaked at ... 1700*F ... at that point I was already reading 284 HP.. I think I could have done that HP at less time, maybe 10 seconds or so... Keep in mind I was over 40 psi, but since my guage only goes to 35, all I can tell you is I was at the "S" in BOOST... which I estimate at 40-42 psi. I'm putting the 16cm back on since HX spools plenty fast anyway..

The last item was unnexpected....whether this was from the spring or spring + extra fueling, I'm not sure, but I was running outta fuel after two quick blasts to 3000 RPM smoking the rubber and release, and repeat, I ran outta fuel at the pump. The engine wanted to fart and miss, it ran like I had just changed nozzles and was starting it for the first time. After about 15 -20 seconds, the thing evened out, and you'd never have known it happened.

So, all in all, I like the spring. I like the responsiveness it has brought with it, and the extra boost it helps generate...
You can get good response with even modest pump settings since it holds the higher fuel levels longer.
Not bad for a cheap spring...

**edit** The last observation would be this, if you are wanting a fairly standard approach to raising your governed speed and still maintain the normal RPM/LOAD defueling process then just use the high idle screw. Nascar Mark has shown that it works in terms of bringing your top end RPM up.
If you want the method that requires more work/time and potentially more risk, then use the gov spring method. This restricts the rearward movement of the control collar which regulates the fueling. The control collar only needs to move slightly to begin the defueling process and the spring seems to delay that significantly. Lastly the items that may see excess wear and tear are the pump plunger which is going to be doing alot more work, along with the cam plate, return springs, and control collar.
If you go into it knowing that, you'll do so with the knowledge that it is a more "stones to the wall" approach..

Remember, if it's not broke, you're not trying....

Bob..

 

Thanks Papecat...... Interesting and informative read

 

It's not hard to install, especially if you slide the throttle shaft through the cover. Like previously stated, an allen wrench with a swivel end is a must, and the idle screw is the hardest part to remove. I ended up shortening my idle screw a bunch so it was easier to put back together. A seal kit from Bosch is pretty cheap if you're nervous about starting a leak. The gains from that spring are worth the effort! I'm doing one on a friends truck next week.