Sooo, . . . . . Has anybody tried replacing the . . .

[RCCUMMINS89]

That's what we have already done.

[cubedeficient64]

Shit Sorry mate I read it wrong thought you had shimmed it up to increase spring pressure only. Unless you could find a similar size gerotor pump and machine e to fit I don't think you'll get any consistency from the vane pump. I think the external pump way is the answer.
There are some cheap nos ve pumps for generators floating around how much different from the highway version are they? Id like to get one and pull it to bits and do some measuring up

[RCCUMMINS89]

A cam plate and a spring would work perfect.

The vane pump is extremely consistent..... til you lay the hammer down, then one drops the case pressure too far and loses their advance......once one sets too much of a pre load on the spring in order to gain the proper driveability at high rpm and light load.

[BC847]

There are some cheap nos ve pumps for generators floating around how much different from the highway version are they? Id like to get one and pull it to bits and do some measuring up

Unless I'm mistaken, most sport a H/R that's smaller than 12mm and/or the IP is built to go on the passenger-side of the engine.

[BC847]

So I got nothing done to the truck like I had planned.


I'm missing some fuel as I can only get the EGTs up to 1300*f or so. I figure I've not gotten things fully right since swapping the IP. With all the recent months of going to the beach, I've left well enough alone. Normally, I can pull the 12PSI fuel inlet pressure down to 10PSI but with starting the day, it's not wiggling. Running the fuel-screw in does give it more fuel . . BUT the idle comes up as well (can't reduce it anymore with the usual means). I think I've got to re-index the throttle and reset the main fuel-screw.

For the moment, it'll get up to 1400*f or so. The 12PSI inlet pressure drops to 11PSI. A little better.

Sitting here ciphering the throttle cage thingy.


Anyhoot, got the case-pressure gauge under the wiper-blade. Just goofing round, running the stock/OEM pressure regulator that came with the new IP, 6x016" injectors, etc, I get:
- Approximately 60PSI @ idle.
- Approximately 150PSI @ 2500 engine RPM just winding it up in 3rd gear (no load, just winding it up).
- Stabbing the throttle, while wound up to 2500 has the case-pressure drop about 20PSI.

I wonder how much more it'll drop once I get the danged throttle (full fueling) mess sorted.

>grumbling/whining< I hate doing stuff like this as I always take it stupid far detailed. Granted, it usually proves WELL worth it, but it's a pain in the ass none the less.

[RCCUMMINS89]

LOL ya I hear ya.

I'm the same way, even with other things.

I got my bow (archery) tuned in so well last year that no matter what I refuse to change anything because I am such a perfectionist I know that I'll be re tuning it and re sighting it in for 20 hours.


Same goes for my truck, I notice if anything is off at any rpm and will tune it and tune it and tune it to get it perfect (if I'm tuning it in)

[RCCUMMINS89]

So, I got it on....... FINALLY.

And word of advice...... ask felllow forumers before asking an injection shop something , I was told that I could just block off the ksb tube...... ya, don't do that.

So anywho I made a new line and got the whole mess back together and it works just as I had hoped. It needs a new retainer design as it doesn't spin easily (going to get fixed).... but I can set the preload high enough that my truck doesn't rattle harder and harder as I rev it up (like it always has). It has the same rattle to it from idle up to way too high of an rpm for stock springs.

[BC847]

mmK.

I finally got to it myself though I didn't mess with the timing light to see what's going on where . . . just yet.

Anyhoo. Folks if you've been keeping up, RCCUMMINS89 & crew have been whittling on some metal based on our discussions here. He's been kind enough to have me included in the development of the thing.

So they carved out a chunk of iron such that it includes:
- The pocket that the timing piston's spring would sit in, in the KSB assembly, less the KSB circuit.
- Said pocket's been made deeper than the OEM design so that one might gain the potential increase in timing device stroke, similar to that the M&H Timing Spacer affords.
- An adjustable shim for the timing piston's spring. Such allows altering the pre-load of the spring by way of an O-ring sealed bolt that moves a spring retainer.



The adjustment bolt includes a jam-nut to lock it:





The spring retainer nests in the end of the spring and is supported/located by the adjustment bolt in the pocket:







Remove the KSB assembly and slip that boy in there. (I included well over an eighth of an inch of spacers to help get it in better range, based on your comment about wishing you added more)





I then installed a NON KSB case-pressure regulator in place of the KSB type regulator:





With an 850 engine RPM, the original regulator presented with about 60PSI case pressure. Installing the NON KSB regulator had it initially present with about 50PSI. Watching the case-pressure gauge, I adjusted (tapped) the regulator so that I now have 75PSI at 850 engine RPM. On flat -level highway, in 2nd gear, and bringing the engine up to about 3200 RPM, has the case-pressure at about 140PSI. I think I'll have to run a stiffer spring if I want to go higher.

Stabbing the pedal to WOT has the case-pressure drop about 25PSI (I think. It was dark outside, and the gauge is under the wiper-blade. I'm having to shine a flashlight on the blame thing to see it. Work with me. Somebody's got to drive. )

I'll have to play with it over the next few days. Gonna be going to the beach again Friday so I'll get to see how it can tame over-advanced timing at highway speeds (1800 ~ 2100 engine RPM).

So far so good though.

[RCCUMMINS89]

I'm wondering if the non ksb style regulator doesn't move enough fuel into the pump for our application.

It was brought to my attention by a fellow member that each of the pressure regulators (there are a lot of diff. ones) have different sized holes in them to by pass fuel. Ours are designed to put the most fuel into the case. This is why I decided to keep my original regulator and hook that tube up to the spacer.

25 psi, that's not bueno.

[BC847]

The regulator dumps excess pressure back to the vane-pump's inlet port.

It's my opinion the hole relates to the quantity of fuel that can be dumped. A stiffer spring will raise the pressure as the case pressure has to overcome the spring's force, to move the plug, and open the spill-port.

[RCCUMMINS89]

Agreed...... that it shouldn't really make any difference on the hole size. But at the same time I wonder if there is something we are missing, because why would they make smaller holes for our's?


So, you're at a point where you can't raise the case pressure anymore on that reg? If you need a stiffer spring, send me the specs and I'll track down a stiffer one to try.

[BC847]

why would they make smaller holes for our's?

If we recognize that the regulator doesn't go wide open to start, but more of the orifice edge being exposed initially, we then realize that the rate of dumping fuel can be tailored once the set-point is reached. Make sense?

Further, unless I'm mistaken, our Cummins 6BTA is the largest application of the VE. Seems that with effectively one size of vane-pump being used, coupled with an application using larger injectors (fuel demand), there would be a need to better control the regulator's dumping of fuel such that the action doesn't present with spikes and dips in case-pressure while the regulator . . . is regulating.

So say the voices.


As far as raising the case pressure, I think going any higher than what I've currently got it set at is a waste of time if the vane-pump can't match the demand of the H/R.

Which, interestingly, brings us full-circle to my original post: Anybody ever screw around with the over-flow restriction port?

[RCCUMMINS89]

My voices agree........

[RCCUMMINS89]

Is that much fuel really being lost out that port though?

[BC847]

Is that much fuel really being lost out that port though?

Granted it might only be 0.010 ~ 0.020"", but at 150PSI . . . . . . . yeah.