i thought this was the ENGLISH language forum!!!

i got lost...right about page 1....where greg stated..."timing is everything"...lol...

you guys know WAY too much about this stuff keep going...i love a good science fiction story!!!!! vs

 

Wow, I love threads like this...realllly gets the old grey matter smokin...awesome. I have learned more about the inner workings of the VE in the past week or so than I have since i started reading posts here...GREAT stuff!

 

FLYZO Iam not sure what you are asking. the way I was taught was to set engine on #1 t.d.c. with the pin, then we made a pointer and attached it to front of block just above balancer and made are mark on balancer to match are pointer.that was our starting point then used timing light with paulse converter on #1 line and advanced pump till we got 16.5* . I felt there must be beter way so I bought the correct tool so I would know the pump lift. that great for our 1 st generation but then good ol cummins changed pumps on us AND yes when I checked my truck with dial indicator 16.5*=1.92mm lift

 

Beachcraft- You pretty much answered what I was after, a confirmation with the gauge and indicator both. I have not bought a pulse adapter yet, (have the dial indicator) , Talked to Ferret about theirs, and they said there could be a 7-10* loss between the piezo clamp and the time the light actually flashed, and an accurate baseline was needed to determine how much loss there was. So I have been trying to find someone that has used both systems on the same truck, that already had the loss figured in. Maybe some of the brands don't have that much loss??

 

B]Let me preface my info by saying that I KNOW there are some extremely well informed/experienced guys who read these posts and, I for one would dearly luv to have their input on this topic. If there is/are factors that are not being taken into account, please, jump in here....I am NOT a Know All Guru here ok....[/B]

There area a couple reliable methods of finding true TDC...one is to pull an injector and use a dial indicator....turn the engine over till you have TDC using the timing pin (which can be wayyyy out on some). From there you insert the dial indicator probe and work it back and forth till you find each extreme ( + and - ) with each you mark the balancer as noted in an earlier post. Then, also as noted, mark the midway point. That is your TRUE TDC.

Remember that the timing set (in mm's) ranged from 1.25mm in the later models to between 1.35mm and 1.40mm, depending on the CPL/model year. It should be marked on your engine data plate on the gear case cover. The main reason for the "all over the board" timing spec is primarily due to emissions requirements.

Ok, now the timing topic.....here's one more "hint".....
The timing piston has a finite range of movement due to it's physical length...it also has a "beginning of movement threshold" based on internal pressure....
The range of movement is limited due to it's physical dimensions and, the onset of movement is determined by pressure. (remember, that as the RPM climbs the supply side increases it's pressure and that, in turn, raises the pressure on in the distributor head.)

As that mechanical piston moves the attached lever-to-roller ring connection moves up the cam lobe and it's advance value is based on that physical range of movement, right.... So, what would need to happen to allow for an increase in the range of movement???......next, what would need to happen to "set" the onset of piston movement???....

We'd like to have more "dynamic" timing range AND we'd like to preset or predetermine the initial beginning (onset) of that movement.....
So far we've mentioned shims, springs, pressures......Remember this as well...we must replace the rear timing mechanism's oval cover plate to contain any pressure increases or it'll pop on us and leak.


Ok here is one more tidbit....if we preset the movement "onset" using one or a combination of the items above (relating to piston movement onset) AND you want, for some reason to have that process jump in much quicker, then, what do you need to do....what device will raise internal (supply side pressure by roughly 100% with the flick of a switch????
THAT would allow you do put on line an immediated max advance condition....any ideas on what that device is???

Ok guys, that's as far as I can go because I'm/we are still working on some bugs to be ironed out.....things like the max practical timing value for our engines taking into account cylinder pressures; going beyond the practical usable timing setting which may/will result in "loosing ground" rather than improving things...

OK, one last item on another topic....
I had a set of Lucas (POD's) reset to 270 bar, which I installed in my truck about 2 months ago.
Here are my preliminary findings....
They smoked like hell......I have been running my engine/pump with NO AFC fueling at all, I have a valet switch in place and have shut off the boost signal to the AFC diaphram.
Under heavy (WOT) I could pull about 30-31psi boost and see roughly 1050*F in OD.
With the valet switch ON, I gained about 3-4 more psi but a very noticable jump in response, I also had an increase in my EGT's under the same test conditions... I would peak out at 1150*F - 1200*F on a long WOT pull.

I pulled those injectors and re-installed my "stock" POD's set to 250 bar. With no AFC fueling I see a max of 25psi and 950*F - hard earned 1000*F.
With AFC fueling on line I would struggle to reach 30psi and about 1200*F.
The truck seems very noticably more sluggish, both with and without AFC on line....
The drawback when using the 270 bar nozzles was a nasty amount of blue smoke, even at idle. It would clear up once I got some boost built up but it was just plain ugly at a stop light or while crawling in traffic.

During these tests, I did not alter any fuel screw settings or timing in any way.
If any of you have the ability to duplicate this test and post your results, that would be a great help with deciding on an optimum pop off pressure for these nozzles.

Well, that's it guys...keep at it, I KNOW you'll work this out between you all....

pb....

 

So does rasing the 'bar' on the injectors slightly delay the onset of the injector spraying? Does it move it farther into the compression stroke timing wise?

And likewise, does lowering the 'bar' have the injector spraying earlier in the compression stroke?

Does the spray duration change since the pressure is different? Shorter spray duration, but delayed, with higher pressures?

huh? huh? huh?
Den

 

If you'll send me the smoke pigs I'll be happy to try 'em out. Not sure traffic behind me would like it much, though.

Thanks for the extra hint. I'll have to crawl under and take a look at that back cover.

 

Den, you're on the right track...normally when you raise the injector release (pop) pressure it takes longer for the pressure to build up to "release value"....so, you are delaying the event or retarding the timing....
The higher you go the more timing advance you'll need to compensate.
As for the injection duration time, it will usually happen in a fairly crisp, clean shot....keep in mind that the pump will need to be in fairly good condition to do this or do this for any length of time.
Even then the tip design still holds a small spot of fuel that is dropped (poorly injected) into the cylinder which causes the haze.. ".....darn, I know it was daytime a minute ago..."

The VE is nearing it's limits when you get up to the 270 bar range....that's just my thoughts mind you... but I think you'll find it's pretty close.
I DID hear the pump working harder...or so it sounded to me anyway....
I really didn't think that the difference would be so great though.....I mean, a full 5 psi drop was a surprise....
As I mentioned, even if I switch the valet on and allow AFC fueling on a custom cone to kick in, I still just make the 31'ish psi boost level.
These POD's are a nasty nozzle when you push them with alot of fuel....hmmmm....maybe I can find an alternative..., but for now, they just plain pump fuel and kill 'skeeters for hobby...
Oh well, back to drilling out the holes for more fuel....

Oh, hey, have you guys given any thought to what pump part(s) can be altered to give you more fuel ...????-----besides the little "foot" trick...

pb...

 

Hey Pastor Bob I might give you a call on Thursday when I am building my new pump. I have some ideas that I want to run by you. I might also try to sqeeze some more secrets out of you.

Stomp

 

Hey Pastor, couldn't the high boost and EGT you were experiencing be partly due to the slightly retarded timing? I know on my truck a little bit of timing makes a big difference in boost.

 

Jeremy,...you're always welcome to call and chat...if I can help you at all I will certainly try...

wannadiesel.....when I put in the higher pop off injectors I had a bit more timing added as well. As of that time/point, I have not altered the timing at all and the results have been based on zero changes on any adjustments other than the timing tweak to help with the higher release pressures....
I am speculating that the atomization once I'm off idle and pulling some boost is responsible for the improvement in boost numbers, in addition to perhaps pushing a tad more fuel thru the nozzle before it closed....
I'm still "working through" the situation/resuts/effects at this point....keep the idea's/thoughts coming...

pb....