The Dynamic Advance thread...

[Alleslowbuged]

Hi,

@Mark,
the diagramm is not my own, i hve get it from a german turbodiesel forum, but can not remeber who has orginally measure the points.
So non of the measured pumps in the diagram was my pump, but both of the used pumps was stock for VW 1.6 IDI pumps.
I have also seen yesterday, that my measurement regarding the advance timing was agood fit with the diagramm (did check that before).

And also yes, i have also found different advance timing strokes (two versions, if i rember right) in serveral stock pumps, but do not have an
idea how the differents are related to car type or year of manufacture.

The coloured points are just the measurement which than getting combined with a line.

As i have read, the ignition lag is nearly independ from circumstances, but will decreae a bit as higher the temperatures are. In my knowledge this is also
the reason, why idi could rev higher than di, as the temperature in the prechamber is higher than in the hole cylinder of the DI engines.

And last but not least, i am sure that lowered compression will be contraproductiv for all, as long you does not bring the cylinder pressure (before injection)
to the same value (as with higher compression) due to higher boost pressure.

@carrizog60
The cover plate looks like the one i have used, regarding the spring please look in the pump build thread, i have used a special shim screw arrangemend, which alows adjustable
stroke

Best Regards    
    

[carrizog60]

i have used a special shim screw arrangemend, which alows adjustable stroke

cant see how or what you are talking...can you explain better or post a pic?

as for the pumps that in stock allow more timing advance:
wont that also produce more hp?
why they used 2 types of pumps?not hp related i bet...emissions?

also if higher temps benefits the burn at high rpm why diesel coolers are used?

[Mark(The Miser)UK]

i have used a special shim screw arrangemend, which alows adjustable stroke

cant see how or what you are talking...can you explain better or post a pic?

as for the pumps that in stock allow more timing advance:
wont that also produce more hp?
why they used 2 types of pumps?not hp related i bet...emissions?

also if higher temps benefits the burn at high rpm why diesel coolers are used?

If you go to the German link, there is a pic. Also it's in English [mostly]

He is using a bolt and nut as an adjustable spacer.
Surely adjustment of this only limits advance range, and not the rate of advance. Also the delay before dynamic advance begins.Not sure of the use of that final point, but I'll think of one

Best state would be to have all spring and no shim, with spring strength selected through iterative trials

[Alleslowbuged]

Hi,

sorry for the confusion.
If i will find a bit time between christmas and new year, i will make a revised version of the pump build thread here in english.
The screw is the limiting stop for the piston, the screwhead + shims makes the pre-stressing. So in fact it is not an "adjustable"
limiting stop, but i can change the value just by change the screw.

Here are some more details from the VP37 stuff, which i used:

The VP37 spring has a free length of 50,7 mm and a solid length of 25,7 mm.
The stock pr-stressing is 6,1 mm, by using 2,2 mm shims.

If i would have put that together with the VP37 cover plate in my special VE pump, with the changed static position of the piston,
and use my stock 3,2 mm shims instead of the VP37 2,2 mm, i would came out with a maximum stroke of 18,4 mm
due to the solid length of the spring. The pr-stress would be 6,6 mm in that arrangement.

Due to the fact, that the piston can dip 4mm in the VP37 cover plate, the max. stroke due to the piston would be
19 mm. But both values are only theoretical, becuase even the enlarged channel will not allow that much stroke, so
without a special limiting pin, the stroke were limited due to the channel in the casing, what would be not good.

What i have done, and can be seen on the pictures is, that i have took a coach bolt and grinded the head as long,
as it will fit in the VP37 cover plate. The thread will be inside the spring and the head worked like a shim, due to the
the spring also fixed the position of the bolt. To prevent swarf, i put a small shim between the cover plate (alu) and
the coach bolt. So actualy the max. stroke is limited due to bolt.

With all that done we get following values:

max. stroke due to piston / cover plate:          19,0 mm
max. stroke due to solid length of the spring:   17,0 mm
max. stroke due to piston / coach bolt:           12,7 mm (is less than what would be possible due to the enlarged channel)

By following the math from my previous post, the stroke of 12,7 mm is equal to 14,7° rotating angle IP or 29,4° rotanting angle
crank shaft, which will bring proper dynamik timing up to 5900 rpm.


@ Dieselstink,
to be honest, i did not have checked if the roller cage can hit the governor. But thanks for the chain of thought, i will check next time.

Best Regards
   

[carrizog60]

and what about spring tension?

its the same?that would also affect timing advance ratio...

[carrizog60]

other thing...
what stops the piston on its initial position?the cold start lever?by how much you can shave the piston on that side before he hits the pump case?

like this thread

[R.O.R-2.0]

well, its a great thread, but its gotten soo far away from the initial post that i cant make heads or tails of this thread now.. the last 2 pages have had about nothing to do with the rev limit, or governor, or anything..

weve gotten side tracked to timing advance woes.. i got lost many pages ago..

[Mark(The Miser)UK]

well, its a great thread, but its gotten soo far away from the initial post that i cant make heads or tails of this thread now.. the last 2 pages have had about nothing to do with the rev limit, or governor, or anything..

weve gotten side tracked to timing advance woes.. i got lost many pages ago..

Come on give people a break; the sending of tendrils of thought around the workings of the dynamic advance helps those who arent as naturally gifted  as you.
Maybe you'd prefer p-mails to open discussion...

Perhaps you have the answer as to why the yellow dot pump has a faster rate of internal pressure rise relative to rpm increase, yet needs to be advanced more statically, and rumour has it that, the timing spring is relatively weak, creating even earlier advancement. Sounds like it would be more suited to a motorcycle

[Mark(The Miser)UK]

This might be interesting, if the bigger  number means, the more rpm's are attainable when modified
 
I understand the red highlights to be the pump's maximum rated power output rpm. [half crank speeds]
Most pumps from the mk2 era are 4500rpm, but note AAZ pump is rated higher, and the 107 group mostly 5000rpm.
Most Nissan pumps are 5000 rpm for their engines, interestingly, though they appear to have used the 1.6TD at one stage, or at least shared this pump...

0 460 494 039 068130108M VE4/9F2100R48 VW CS/KY

0 460 494 182 068130180F VE4/9F2250R223 NISSAN/VW CY/JR
0 460 494 267 068130110Q VE4/9F2250R328-5 VW SB

0 460 494 323 028130109G VE4/9F2300R420-14 VW AAZ

0 460 494 084 VE4/9F2400R66-13 AUDI/VW JK/CR,JK

0 460 494 002 68130107 VE4/9F2500R16 VW

[carrizog60]

IMO shaving the piston is not the best approach.  Custom milled end caps or end cap spacers would be the way to go.  You can't shave the cold start end of the piston because it has the rod in it for the cold start.  Getting enough movement for the roller cage to hit the governor on both sides is easy.  The roller cage hitting the governor is the limiting factor

are you sure?
the piston isnt the same at both sides?

so,how much can we shave the piston before it hits the governor cage(or pump wall or what limits movement)?
i dont need to shave or add spacers to the cover as the vp37 cover has a deeper hole so the piston wont be limited by the cover.

[Mark(The Miser)UK]

well, its a great thread, but its gotten soo far away from the initial post that i cant make heads or tails of this thread now.. the last 2 pages have had about nothing to do with the rev limit, or governor, or anything..

weve gotten side tracked to timing advance woes.. i got lost many pages ago..

Come on give people a break; the sending of tendrils of thought around the workings of the dynamic advance helps those who arent as naturally gifted  as you.
Maybe you'd prefer p-mails to open discussion...

Perhaps you have the answer as to why the yellow dot pump has a faster rate of internal pressure rise relative to rpm increase, yet needs to be advanced more statically, and rumour has it that, the timing spring is relatively weak, creating even earlier advancement. Sounds liUK it would be more suited to a motorcycle

I've been thinking about the 1.15mm 'Yellow Dot Paradox'.
 "Thinking" because I don't have one, and suspect that they never came to uk

If to supplement a greater advance, the starting position orf the cage was more retarded; that would give the greater range.

0.15mm on the piston cam @ the operating region of a 'standard' pump equates to some 5-7 degrees crank, or 2.5 to 3 degrees on the  pump...
Does this make sense?

[carrizog60]

for low end torque i preffer tdi engines as they can handle loads of torque at low rpm...

[carrizog60]

today went to basement and removed the timing end cap.

so i am using 1.6td spring(brownish)as i believe that i read somewhere that it would have less strenght and provide a faster advance rate.
this spring has a lenght of 36,78mm.

the end cap i am using(from vp pump)provides 8,45mm more travel than the VE does.

assuming that without the end cap the pump wall would be the second limiting factor,for how much can we increase the stroke before he hits the wall?

my concerns now is how much do i have to schim to make sure that the end continues to be the limiting factor.
any difference if its the piston or the spring that hits the cap?
and this increase in stroke would provide advance until what rpm?

unfortunally i didnt get to take measurements when the pump was without the guts and now i dont feel joy to have to take all apart again to check this...

and i suck on this maths lol

so any help would be great

edit: compressed spring lenght is 17mm.

i have taken some pics on the clearence from governor when  piston is hitting the wall as other interesting mesurements.
soon as i can i will post the pics

[carrizog60]

i did that with a spare pump i had laying around.
thought the spring would also compress,if it dosent then i have to get a device like alles did to limit piston movement and only schim the spring enough so it can stay tight...

[carrizog60]

not with this VP cap,its a deeper hole than stock VE

pics for thoughts

piston just before hitting the pump wall inside:



and the clearance to governor:


now with spring thats going to be used(1.6 gtd):


and with cap without schims:



so the difference from the cap hole and the piston protusion will tell me the size of the limiting screw to be used right?
unfortunally i dont see a way to check the gains in travel and advance over stock,maybe alles or others with more skills will schime in

if anyone needs more measurements just say