AAZ pump on AHU?

[stewardc]

I was just thinking of building a TDI-M for my Mk 1. I have a good AAZ pump. Does anyone have one on an AHU? Is it enough for this engine?

[nkb]

i have an aaz pump on my ahu

[nkb]

do you mean stock aaz pump?

[stewardc]

Yes, it's presently stock. What mods did you do? Should I send it to Giles for a refit? How does yours work???

[Slave2School]

I think you would require at least a 10mm pump head and tdi camplate if you want any sort of decent performance.

[RabbitGTDguy]

I think you would require at least a 10mm pump head and tdi camplate if you want any sort of decent performance.

kudos to that....you'd at the very least need to do this to make it work properly for supplying the TDIs fueling needs...


Joe

[MichaelBuck]

oiuyt

[935racer]

Yep you'll want to upgrade the plunger and camplate at minimum, personally I would find a cummins 4bt pump and start from that, so you have the 20mm drive shaft vs. the IDI's 17mm shaft.

[RabbitGTDguy]

Yep you'll want to upgrade the plunger and camplate at minimum...

Dave,

You mentioned swaping the camplate and plunger only...but with a 9mm head, the 10mm plunger will not fit. He needs to use the plunger and head assembly together. Can't use a 9mm head with the TDI's 10mm plunger and vice versa. Plunger and head needs to be matched. Could get away with not swapping the camplate but it would not be of the correct profile for a DI specific engine.

Just don't want the wrong info floating around...


Stewardc,  

Cummins pump is IMHO the best route to go, not just because I have done it and it works great. If you have the AAZ pump, its a good starting point unless you have the $$$ and access to the cummins pump. Also, depending on what your power goals are the cummins pump in "stock" form could be too much for you as it usually has a 12mm head which might be too much fuel in many applications. If your going all out...thats great and its not to say if you got the cummins pump you couldn't put a 11mm or even a 10mm TDI pump head in it. We've done a few of those as well.  Depends on what you want to do...

 In either situation it'd be good to have a TDI pump for parts.

Joe

[935racer]

Yeah I thought it was common knowledge that the plunger and head assembly have to be matched, but I suppose its good to clarify.

[RabbitGTDguy]

[Tintin]

Just to clarify to make waste time for somebody, a TDI came plate that does not function with the control lever and control shaft of AAZ pump, you need to found a cummins control lever or other to match witch aggressive TDI came plate.

More the came plate is aggressive, more the control lever need a long travel, each came plate will match witch specific control lever.

[RabbitGTDguy]

Just to clarify to make waste time for somebody, a TDI came plate that does not function with the control lever and control shaft of AAZ pump, you need to found a cummins control lever or other to match witch aggressive TDI came plate.

More the came plate is aggressive, more the control lever need a long travel, each came plate will match witch specific control lever.

I'm a little confused by this one. By control lever, do you mean the control lever that is in the pump held in on either side with the triangular 13mm bolts or the throttle lever up at the top of the pump that the linkage assembly, gov. assembly, etc. attaches too?

The control level of a min/max style gov. setup must be used with a min/max style gov. assembly and the same goes with the "variable speed" gov. setup. The control lever and must be used with a "variable speed" gov. assembly.

There should be no issues in using the AAZ throttle level/caged gov. assembly, and control lever with the TDI style camplate as the control level in the pump "pops" into the camplate assembly without issue. Many hybrid style pumps have been built using these parts without issue. There have been some issues with the plunger feet not matching to specific camplates that people are using, etc. but with using an entire TDI head/camplate/plunger assembly, there shouldn't be issues. We set a friends mTDI up this way with no issue.

I personally used the cummins 4bt pump base (entire pump, 12mm, specific camplate) with a IDI 1.6 TD control lever, gov. assembly/throttle linkage, LDA and modified boost pin with no issue and it works great!!!

but...there were some experiences...

I can tell you for a fact that the cummins assembly WILL NOT WORK if you plan on using the VW style gov assembly in conjunction with the cummins 4bt throttle lever. The two pumps first off are of a different style gov. setup. and the control level is directly related to the style of gov. each pump has.
I tried a configuration of my cummins 4bt pump without removing the cummins control level and utilziing the vw gov. assembly and it made the engine do scary things. You could get it to start, and idle....but then, if you applied throttle it would slowly start to rise in RPM's and then.... almost want to run out of control if you didn't shut it down! Also...upon removing it and inspecting it, they operate quite a bit differently. The fingers for the LDA cover on the cummins lever vs. a VW lever are on the wrong sides and there is a different construction to the control level itself. Its much more "bulky" and operates differently than the VW unit.

The cummins control level could be used in conjunction with the cummins gov. assembly (single spring...not caged), but you would have to be able to install a spring of a high rating so that you could rev. the pump up to the 4000rpm mark as many of the cummins pumps (depending on what application they came off of, etc.) only rev. to 2500rpm, 3000rpm, 3200rpm.  Karl, the other one that worked on the first cummins pumps in the states here with me is using the cummins style setup in the vanagon applications with a higher RPM rated spring installed and likes the results which makes sense as the vanagon is a much heavier beast that a MK1 (like mine), would act much more like a bread van, etc. that the cummins 4bt was in needing to "load" the engine a bit more to get it going,etc. which is part of why the cummins setup is the way it is.

I've contemplated trying the entire cummins setup in the MK1...but I don't know if I'd like its operation in a light car.

For the cummins pump swap though...if using the cummins pump you'd need to have the control lever, throttle/gov. assembly, and LDA from a AAZ or even a IDI 1.6TD motor. If using the AAZ pump, you'd want to have a 1.6TD boost pin as well or diassemble the LDA's of the two and swap in the boost pin and carrier assembly from the cummins LDA so that you have a boost pin with some profile (as the AAZs isn't anything more than flat unless you make it yourself). The cummins LDA can also be used but the finger level that acutates the LDA under load is on the wrong side for using the VW style control lever....so that'd have to be removed and swapped.

There are alot of options here....alot of pump options, heads, plungers, etc. and yes, the more aggressive the camplate style is, the better for the TDI itself and there is a relationship between the camplate and the size of the head on the pump, not to mention the type of motor the camplate is made for (IDI vs. DI).  Thats something we've discussed before.

K....thats enough for now. Thought I'd share my experience with building my pump


Joe

p.s. there are other considerations beyond just using the cummins and IDI parts, etc. Timing internals in the bottom of the pumps, some of us have played with distribution valves between the DI specific pumps, etc. Just lots of options and I don't know if there will ever be a "best" solution for the mTDI crowd as there are so many variations of the VE pumps (cummins 4bt alone...i've counted 5 diff styles of pumps with varying options in between alone).

[Tintin]

Joe, i agree with your reply, I could not have explained also precise with my english,  I did not think of the LDA pin in my intervention, I  post a pic later so that people understands what one speaks.

Control lever (speed control) Yes it's a lever held in on either side with the triangular 13mm bolts, and the control shaft it's a throttle lever up at the top.

You can trust me, I tested all that I says, I built several M-TDI pump and i test different set-up.

The cummins or low RPM range pump control shaft is not adapted as you mentions (need a stronger spring)


On these pic, the right control shaft is from 1.6/1.9 pump, it is not the best solution, it does not give enough travel, the left shaft is from a DI pump, check the cummins control shaft, it gives as many travel as that of left shaft, but the cummins design spring is not the best


For the control speed, the right piece is from 1.6/1.9, and the left piece is from cummins, one sees clearly the distance between the axis and the hole......  there are some different model of distance, the good distance between the axis and the hole of this part is too important than a control shaft travel


On these last pic, the first pic is a idle position control sleeve on the plunger, and the second at full throttle, look at the distance covered,  it must be also important in proportion of the aggressivity of the came plate:
 


I post pic later of the different LDA pin, right and left position.

[RabbitGTDguy]

I can see exactly what you are saying now... I believe I misunderstood a few things in your post... makes good sense.

Question for you... its difficult on this side of the pond to find a DI specific mechanical pump with the corret gov/spring setup as per the vw style "caged" spring assembly. I did notice in doing my pump the amount of travel that the IDI unit had vs. the cummins unit but couldn't come up with a solution for it.

Is it possible that the difference in travel between the cummins unit and the VW unit has to do with the gov. setup itself? Do you have a DI specific throttle shaft w/ caged gov. assembly that has the same amount of travel and/or have you measure it against the vw caged setup. It seems to me that the extra travel that the cummins throttle shaft assembly has is more do to the "pull" it would need to have on the single spring than having to do with a specific difference between IDI and DI specific pumps. My pump will easily rev out past 4200rpms + if i want it too without issue, etc. Again on the control level too... the differences there with the locating pin mounting, etc. would make sense with the differences in respect to the types of gov. assemblies they are as well. In operation (and I did try it), the cummins gov. setup is very different than the VW setup in operation and you def. don't want to mix the parts as we said. The bosch VE manuals also describe this too. I don't see issues in using the VW specific assembly as a whole as long as you do it in this fashion, but if there is a mechanical setup out there that operates like the caged VW assembly that is DI specific, I'd like to see more info on that.

Do you have access to these parts on your side of the game?  For instance... a DI "longer travel" throttle shaft/caged gov. spring assembly and a DI specific control lever? I'd be interested in getting one if possible as it is a major drawback that I've seen to the pump thus far in it configuration (also, there are those on this side of things selling the 4bt pumps now, modified for mTDI but with the 1.6 parts, etc).

Are you suggesting the use of a different control lever for proper operation? Obviously not the cummins one stock...but maybe not the VW ones either? Let me know. Very interested and the pics tell a great amount in detail!!!

Joe