Getting my head around the pump mods to

[Baxter]

Okay, where do we start...
I run T3's(Vanagons), the JX (1.6TD) engine has a different LDA to the rest of the Bosch pumps I have seen, and looks like a turbo waste gate actuator.
The idea of having the LDA laid on it's side is to get the 1.6TD laid at 50 degrees under the lid of the T3 (Vanagon) without any lumps in your bed!

So, when messing with the injection pump you are kinda limited as to what you can do, if you fit a pump from a SB say, they you have to notch the lid to get clearance. The LDA fitted to he JX pump only has a certain amount of movement and runs out of movement at about .5 bar, give or take.

So, if you want to up the boost and fuelling you run out of on boost enrichment at .5 bar (7psi) Not good.

I would really like to use this style of pump for clearance issues, it makes the whole engine conversion much easier.

So, to be able to modify a JX pump I need to get my head around a few factors, like what am I actualy doing when I carry out some of the mods listed on the rest of the website.

First, a few VW T3 1.6TD engine and pump pictures.



My engine bay.




Sierra94's pictures I stole from elsewhere #1




Sierra94's pictures I stole from elsewhere #2



Starwheel adjustment.
As I understand it, when you do the star wheel adjustment you are adding spring tension to the diaphragm in the LDA, I presume this is to get the LDA to work over a greater pressure range. Is this correct?
So, to get the JX LDA to do the same thing I would have to add spring tension to the spring inside the sealed canister, which would mean either adding a spring to the outside of the canister, or opening the canister and either shimming it or replacing it with another of a higher spring rate, then using a pressure source set the LDA to reach full stretch at the prescribed boost level.

Boost Pin.
I think this will be another limiting factor in making this pump work with more boost as there is no choice other than using the standard one, as the pin is not really a pin but a shaft and a totally different style to those on a upright LDA pump. I think to modify this I would have to have something custom made. I take it a seeper angle on the cam would give a more aggressive rate of increased fuelling under boost?

Nylon washer
This is just basic tuning isn't it? Just making sure the LDA can work over a greater range, more movement? On the T3 pump I could do this by grinding the stops off, or moving the balljoint on the end of the LDA rod closer to the shaft.

Any input would be appreciated.

Simon.

[RabbitJockey]

nylon washer, just forget about it, i removed mine, it's un needed

[LeeG]

a 'Normal' LDA is shown on this diagram:
http://www.putfile.com/pic.php?img=4183069

I am going to guess that your pump probably has the reverse lever (#3 in diagram) but maybe not the guide pine (#4).  So you probably have a cam on the shaft the LDA rotates.  That cam should mimic the boost pin (# 8 )  by releasing the reverse lever as boost builds.  A ground pin in normal LDA releases the reverse lever sooner, you should be able to grind the cam profile to do the same thing, or get the same result by moving the ball joint closer to the shaft.  To extend the range of pressure the boost comes on over, I like the idea of a pressure bleed, and maybe grinding the stop to let the cam rotate further.

Pop the top off a pump so we can see what that cam looks like.


Diagram is from a Bosch VE manual someone linked to on here.

[Baxter]

I brought the pump top home, so Im going to take some pictures shortly.
I took the LDA off today, and it seems it's not as sealed as I though, once the 3x Tx30 sets were removed it all became clear! I can take the spring out, and it does seem to be an adjustable thing as it's already shimmed.
So, instead of using 5 on the diagram below I use shims to set the load on the LDA spring.

Im fairly sure that there is some room to do a bit of grinding.

[Baxter]

Lee G

a 'Normal' LDA is shown on this diagram:
http://www.putfile.com/pic.php?img=4183069

I am going to guess that your pump probably has the reverse lever (#3 in diagram) but maybe not the guide pine (#4).  So you probably have a cam on the shaft the LDA rotates.  That cam should mimic the boost pin (# 8 )  by releasing the reverse lever as boost builds.  A ground pin in normal LDA releases the reverse lever sooner, you should be able to grind the cam profile to do the same thing, or get the same result by moving the ball joint closer to the shaft.  To extend the range of pressure the boost comes on over, I like the idea of a pressure bleed, and maybe grinding the stop to let the cam rotate further.

Pop the top off a pump so we can see what that cam looks like.


Diagram is from a Bosch VE manual someone linked to on here.

Just quickly, I just had a quick shufty, and the pin and fulcrum are still there 3, 4 and M1 are present.
The shaft with the cam is different, instead of having a taper ground on the shaft the shaft turns and has a offest pin ground into it, bit like a big end bearing on a crank, imagine the main bearings are the shaft, and the big end is the cam, the pin rides on the big end, as it were.

I'll do a drawing after my chores! (well, you can hardly call playing with your 5 month old a chore... Bed time soon....)

[Baxter]

Okay, heh, I did a drawing...



 :lol:

Quite chuffed with that I am!

[Baxter]

Because VW never imported any stock TD vanagons to this side of the pond us yanks are probably not much use.  If you sent me a JX pump (and lines), I'd be happy to look spend some quality time exercising my gray matter regarding it's ins and outs.   :wink:  Cheers.

Andrew

As it happens I have a pile of them under the bench, you cover the postage and you can have one

[Baxter]

Okay, few more ramblings
The LDA lever returns to a stop.
If I de adjust this, this will give more movement on the lever, but I suppose this stop is set to set the position of the lever inside the pump (3) and therefore screws up the interaction between this and number 11.
So, better to leave this adjustment alone and concentrate on making the lever move further.
I have had a play and there is plenty more movement left if I were to grind the stop off, but the LDA push rod runs out of travel.

There is 24mm of linear movement on the LDA
The LDA push rod ball joint is 33mm away from the centre of the fulcrum of the boost pin shaft.
From stock there is 33 degrees of movement on the LDA lever on top of the pump.

If I grind the stop I think there is as much as 50 degrees of movement on the LDA lever.

So, to be able to set this up right I need to know how much boost I want to run, so lets run at 1 bar (15psi, give or take, using K14)

Correct me if Im wrong...

1. So, if I shim the LDA to get to full stretch at 1 bar (or use a bleed valve).
2. Leave the adjustable stop on the LDA lever where it is.
3. Decide on how many degrees I think I should get the LDA lever shoud turn(50?), then chop the ball joint off and move it further towards the fulcrum.

After that I should get extra fuel all the way up to 1 bar.

Now, to alter the rate I get fuel at I should be looking to grind the pin or re-make the Boost pin/shaft thinner.

Or am I missing something?
 :lol:

[Baxter]

Replied..

Next ramble, chances are I will use a bleed valve, just wondering if i could just use one bleed valve to do both jobs, fool the turbo and fool the lda.

[jtanguay]

tee off pressure going to the wastegate, one for the wastegate and one for lda... and just bleed before the tee and you are set

[Baxter]

I'd just spin the wastegate closed, but yeah, one bleed for both would work.  The downside to a bleed is that it is in effect a boost leak, albiet a small one, and so adds to pumping losses and decreases engine efficiency.

Andrew

Thats why I would really prefer to shim the  LDA, or see if a spring from a upright LDA's pump will fit the JX pump LDA

What surprised me was messing around with the pump, with the lever (3) and how little it actually moves between on and off boost. The lever that comes from the pump(11) has lads of travel in it but the LDA acting upon it probably makes it move by about a milimeter or so.

[Baxter]

Okay, some pump pictures.
Throttle levers and Aneroid removed, TBH I left it in the parts bath as it was minging, just imagine a turbo wate gate actuator, looks fairly similar!

Off boost (Aneroid removed)


On boost


Inside cover.


Boost pin/shaft.


Boost pin/shaft with lever.

[LeeG]

so you could file a ramp into the side of the round 'crank arm' bit so the pins moves faster.

Nice drawing BTW.

[Baxter]

I had another thought.  If you want to increase the psi range over which the internal cam moves then, as mentioned, you could increase the spring resistance to that motion.  Obviously the stock spring is inside the can, but (here's the idea) the auxiliary spring need not be.  You could simply add another spring to the exterior cam lever that resists the motion of the boost can.  Adding the spring to the exterior would be a whole lot easier than opening the can and swapping internally especially when trying a variety of springs to get the one that is "just right".   :wink:

Andrew

I originally thought about another spring on the outside, but it will look ***, plus it's only 3 screws to remove the can and swap the shimming, I think replacement of the aneroid spring, or shimming it will look tidier, be easier to adjust and be more reliable.
Remember the whole idea of the different LDA is for space reasons, more springs on the outside may cause interfearance with the engine lid.

Just read that back, sounds patronising! snot meant to be, just the way my Yorkshire accent comes accross!  :lol:

[Baxter]

I think I said that somewhere, but can't be arsed reading 2 pages to find it!
Thats what Oettinger did, grind the stops off basically, like you say, theres plenty of movement left in the cam and the pin if only the lever would turn further.

Like you say, the really limiting factor is the actuator, this is why I mentioned removing the ball joint from the lever and moving it inboad slightly (towards the fulcrum) so you have the same amount of movement on the puch rod but the lever moves further.

I don't think it will be that hard to do, I think the hardest bit will be finding another ball joint to use.

I even thought of re making the lever as it doesn't need to be that complex.