The Caveman Chronicles

[regcheeseman]

Got any more pics Tommy?
I assume this pin moves via that diaphragm and the pins shaping allows a sprung pin to track down the surface shaping to modify the fuel / boosted air ratio to change? Reg?
So the pins shaping is a result of trial and error to maximise the fuel or is there a profile that people grind it too?
Can you buy these pins reprofiled & tested?

Five hours on one pump reads like lots going on and not just "swapping" parts over.

Sort of...

A lever runs on the taper, the lever is just a throttle limit stop.

The throttle lever in the pump (and the QA on a TDI) moves the spill collar.

The pump piston has a drilling down the centre from the high pressure area, the drilling escapes sideways out of the pump piston about halfway down. This pressure release hole sits under the spill collar.
As the pump piston drives forward it creates injection pressure, as the escape hole passes through the spill collar it becomes exposed and all pressure at the pump head (and thus injector) is released and injection stops.

The more throttle you apply the further the spill collar moves and the longer the delivery stroke of the piston is effective - the spill collar is your duration and the closing of the injection window.

So. the boost pin allows the spill collar to move a fraction further and thus the injection quantity is increased.

Just think of the LDA as an adjustable throttle stop.

It means that off boost you cannot deliver excess fuel but as soon as the boost comes in and there is the air available then you can add more fuel.

An NA pump can deliver as much fuel and make as much power as an LDA pump, it will also make black smoke if you mash the throttle with no boost on.

Lots of crap on the interweb regarding tapers and few know how they work.

Most pumps have a decent taper, shitty pumps like the AAZ Umwelt (that the internet raves about) have a pointless 1mm step rather than a taper. So fitting an overpriced ebay 'performance boost pin' can have a good result and hence the hype.

I'm off to find out about the LR wonder parts, modding the advance is pretty simple, controlling the effects of those mods will be interesting as I doubt any two pumps will respond the same.

LR pumps have weak gov springs and they love a gov mod, I've made a few trials buggies fly in the past...

The golf boys used to swear by landy pumps for mTdi builds, I took a landy pump apart to see what made it mTDi - feck all, it's a pretty normal TD pump, not even a tdi style two stage camplate

[regcheeseman]

Ps. I don’t for a second believe my donor LDA pump came with a boost pin like this.....

It did - pretty standard asymmetrical boost pin.

[TommyP]

It did - pretty standard asymmetrical boost pin.

Wow. The old boys has the shitty AAZ style pin then.

Cracking explanation on the pump, it even made sense to me.


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[TommyP]

Do the LR boys use two stage injectors in their mud pluggers?

Yes, Bosch 2 stage I believe. I read up to be sure the other night when you asked before. Not got any specific info on break pressures of nozzle types tho, I’d have to dig deeper.


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[regcheeseman]

Here’s the link I showed you the other night:


https://stegs4x4.co.uk/product/dynam...ce-spacer-kit/


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Ha, what a fucking joke.

You don't change three things (casually forgetting to mention the one that made all the difference in your sales pitch) and then get quantifiable results. I'd suggest that the massively ground boost pin (that looks like one of mine) made the difference and possibly turning the fuel screw up until it rolled coal had a significant effect on the the power.

I'd like to see what the advance spacer does in isolation. I'm sure it'll get results.

[Activ8]

Cheers Reg.
Appreciate that.
Got one of these 6 cylinder pumps on the bench. Do you know much about these?

[S49]

Is that so you have a spare cylinder for Justin or Ron then Rob?

[TommyP]

Ha, what a fucking joke.

You don't change three things (casually forgetting to mention the one that made all the difference in your sales pitch) and then get quantifiable results. I'd suggest that the massively ground boost pin (that looks like one of mine) made the difference and possibly turning the fuel screw up until it rolled coal had a significant effect on the the power.

I'd like to see what the advance spacer does in isolation. I'm sure it'll get results.

I ordered a kit without the boost pin. The one in mine is fine. I’ve just got the spacer


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[Activ8]

Is that so you have a spare cylinder for Justin or Ron then Rob?

I've wanted a 6 cyl 2.4d for years and bought these pumps to play with Si. The equivalent Merc's fetch some serious torque and the build quality is superior to modern engines. Did you ever work on the 760 (?) 2.4TDIC?

[S49]

Yes I did, very sturdy old lump. They also did a D2.4.

[regcheeseman]

I ordered a kit without the boost pin. The one in mine is fine. I’ve just got the spacer


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I was thinking about this last night, I had a 2.4 hybrid that smashed the advance cover off the pump (and never worked out why) but I've never noticed witness marks on the standard cover that would indicate that the advance shuttles travel was limited by the housing. Pretty sure the shuttle travel is limited by the mechanism, so no matter how much you offset the housing it'll make no difference.

That said, some pumps have a flat steel cover rather than the concave ally one, the steel one definitely bears witness marks which may be the reason for different material - to act as a limit stop.
can't remember what the landy pump has, but it is conceivable that bosch were told to limit advance and reduce Nox emissions and fitted a flat plate.

When I get your pump back - I'll have a play and see what might be the case.

And yes, your boost pin is fine.

[regcheeseman]

Cheers Reg.
Appreciate that.
Got one of these 6 cylinder pumps on the bench. Do you know much about these?

Yep, same pump - different pump head and camplate, poor thing must be working hard delivering 6 times per rev

[TommyP]

I was thinking about this last night, I had a 2.4 hybrid that smashed the advance cover off the pump (and never worked out why) but I've never noticed witness marks on the standard cover that would indicate that the advance shuttles travel was limited by the housing. Pretty sure the shuttle travel is limited by the mechanism, so no matter how much you offset the housing it'll make no difference.

That said, some pumps have a flat steel cover rather than the concave ally one, the steel one definitely bears witness marks which may be the reason for different material - to act as a limit stop.
can't remember what the landy pump has, but it is conceivable that bosch were told to limit advance and reduce Nox emissions and fitted a flat plate.

When I get your pump back - I'll have a play and see what might be the case.

And yes, your boost pin is fine.

Pump was supposed to be collected today but wasn’t. ****s.


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[Activ8]

Reg,
If you've been stripped of your spare 2.5tdi pump do you want me to send you one? Or just the missing parts?

Looked at boost pin grinds and there seems to be an absurd number of diy designs. Do you have a boost pin template / measurements an amateur can grind it to? Or do you offer a "grinding" service?

[TommyP]

Yet again ParcelFarce haven’t picked up the pump Reg. I may even bring it down to you one day if you’re happy with that? I tried calling them to see what was going on and I got cut off. Signal where I’m working is dogshit.






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