Bosch Pumps. What's Different?

[ColinJack]

http://www.sparepartstore24.co.uk/689026-bosch

Looks like I got a bargain

[andypdq]

Remember, it includes VAT

[Jim Archer]

And that's at a 25% discount you know

Jim

[andypdq]

If the cam plates are the same in all Transit pumps, I cannot see how any of them will be much different from any other. Apart from differences in the rate of advance, dictated by internal pump pressure settings and the charectaristics of the advance piston springs, they will all be the same.

The way the pump is designed, I can't see that there can be a "low" or "high" pressure pump, they will all generate a huge ammount of pressure relative to the injector popping pressure, the difference will be in injectors

I'm beginning to think that 145 and 146 pumps being especially suitable for the turbo conversion is an old wives tale, unless their advance charectaristics are more suitable than others.

Anyone with any evidence, as opposed to heresay on the above?

[dieselhead123]

If the cam plates are the same in all Transit pumps, I cannot see how any of them will be much different from any other. Apart from differences in the rate of advance, dictated by internal pump pressure settings and the charectaristics of the advance piston springs, they will all be the same.

The way the pump is designed, I can't see that there can be a "low" or "high" pressure pump, they will all generate a huge ammount of pressure relative to the injector popping pressure, the difference will be in injectors

I'm beginning to think that 145 and 146 pumps being especially suitable for the turbo conversion is an old wives tale, unless their advance charectaristics are more suitable than others.

Anyone with any evidence, as opposed to heresay on the above?

As you say Andy, the choice of pump when fitting a Bosch unit is not relevant, unless you also intended to remove the 'turbo injectors' already fitted to your engine, (blue/pink/brown), and fit the post 97 two stage 'non turbo' injectors, (33704/33706), as these would benefit from the higher pump pressure.

The reason the later pump is specified is simply because the static timing setting is closer to that required on the turbo engine, (this is set by Bosch when the pump hub is installed onto the pump shaft), to set the pump to the desired 0.68mm lift at TDC, CAN require more movement than the slots in the belt sprocket provide when using the earlier pump.

The static timing on the later pumps was altered so as to meet the then newest set of emission requirements set out by the EEC, the same reason the Bosch pumped turbo engine was only sold outside the EU.
The later pumps do not have the electrically operated cold start device fitted, hence the need to alter the static timing on the later pumps, this reduces emissions during the warm up period. By increasing the pump pressure, the timing is advanced in line with pump rpm so that the same level of advance is achieved at high rpm as was with the lower pressure pump.

To sum up, the later pump has the static timing set slightly retarded compared to the early pump, this counteracts not having the cold start advance unit, (this actually 'retards' the timing on a cold start!), but to achieve the desired level of timing advance at high rpm, the later pump has a higher internal operating pressure.

Now, the static timing is not relevant if when installing the pump, if you use a DTi to set the pump timing, so as said, there is little to choose from when selecting your pump, although the availability of the cold start unit on the earlier pump does mean that you can utilise it if you choose.

The reason I personally prefer the early pump is for the reason you have stated regarding pump pressure and it's effect on the timing advance unit, given that the early pump is intended to run with a lower internal pressure yet still produce the desired level of timing advance necessary for high rpm running, replacing the pressure regulating device, so as to increase pump pressure and therefore increase timing advance at high rpm, is somewhat simpler than changing the timing device piston.
The above said, I would still change the timing device piston to the one used in the 154 pump, (1 463 104 622), if I were stripping the pump down as it is different to the one used in the 145 pump.

Sorry to 'ramble on' a bit lads

TIM

[psv-hgv-flt]

85ps injectors, when you get it running i bet you will go for the 100ps injectors (if you no the problem you are heading for with 85s.)

[F111ORY]

Hi, Thanks to dieselhead123 for that explanation . As a synopsis of your reply am I correct in saying that apart from fitting a Landrover 200Tdi cam plate , what we are looking for in a pump for a Turbo engine is less initial advance for easier starting and better cold emissions, followed by weaker advance spring/higher internal pressure to give more advance at high RPM.

Regards Rick

[andypdq]

Hi Tim,

Thanks for that, it seems I was on the right path but specific info on pump internals is hard to come by for those of us with no trade connections.

Low and high pressure pumps refers to internal opperating pressure, not delivery pressure, correct?

The reason the later pump is specified is simply because the static timing setting is closer to that required on the turbo engine, (this is set by Bosch when the pump hub is installed onto the pump shaft), to set the pump to the desired 0.68mm lift at TDC, CAN require more movement than the slots in the belt sprocket provide when using the earlier pump.

So the ideal method is to pull the hub, set timing with DTI, lock the shaft then refit the hub with the timing pin (drill bit!) in

To sum up, the later pump has the static timing set slightly retarded compared to the early pump, this counteracts not having the cold start advance unit, (this actually 'retards' the timing on a cold start!), but to achieve the desired level of timing advance at high rpm, the later pump has a higher internal operating pressure.

If the later pump is set to earlier settings, ie slightly advanced static timing, this should lead to easier cold starting and a bit more overall advance at higher rpms. I dare bet the advance is set conservatively and a bit more high speed advance would be beneficial.

The reason I personally prefer the early pump is for the reason you have stated regarding pump pressure and it's effect on the timing advance unit, given that the early pump is intended to run with a lower internal pressure yet still produce the desired level of timing advance necessary for high rpm running, replacing the pressure regulating device, so as to increase pump pressure and therefore increase timing advance at high rpm, is somewhat simpler than changing the timing device piston.
The above said, I would still change the timing device piston to the one used in the 154 pump, (1 463 104 622), if I were stripping the pump down as it is different to the one used in the 145 pump.

I'd be intersted to know what is different about the 154 advance piston, does it allow more degrees of total advance than the 145 piston and does it use a different spring?

I've been thinking of tapping the pump body and fitting a pressure gauge to find out what's happening. I have approached my local diesel engineer regarding information on internal pressure settings, but no info was forthcoming, blood from a stone would be a doddle!

AFAIK the internal pressure can be adjusted by knocking the pin in the centre of the pressure regulator in or out as required, it comes down to adjusting you sophisticated fuel metering instrument with a hammer

I'm coming to the conclusion the best place to start in order to get the ideal pump is to drop the complete internals of the LR tdi pump into the Transit pump body, complete with LDA pressure compensator and go from there.

Any information on internal pressure settings for both the Transit and Land Rover pumps would be golden!

Thanks and regards.

Andy

[dieselhead123]

Additional high speed advance is necessary is you intend to carry out a governor mod to increase rpm, once you get to the rpm level where the injection sequence is not completed before the piston reaches TDC then any additional rpm will not yield any additional power.

According to my research, the advance piston provides a maximum of 16 degrees advance, (please note, I have not yet confirmed this from a verified source), but I have heard stories of the advance piston being 'shaved off' a bit to allow additional advance beyond the factory limits, but this was in a 6000 rpm engine!
I doubt any of us would want to run the di much above 5000, so the factory 'limit' might still be acceptable.

A balance has to be found between a set up that provides the necessary advance to sustain higher rpm and the lower amount of advance necessary to achieve good cold start ability, this is where an externally operated 'advance' unit may be useful and something that does seem to be a fairly common fitment on these pumps when fitted to turbo charged engines.

The selection of alternative advance springs would be 'trial and error', unfortunately, Bosch do not publish spring rates for these parts, but it would be reasonable to assume that pumps fitted to smaller, and therefore higher revving engines, would have lighter springs as they would need more advance to sustain their higher rpm limits.

TIM

[Jim Archer]

Surely a higher speed engine would run either a heavier spring or a lighter bobweight for a given advance rate?

What is the issue with 85PS injectors? I'm running these with a 141 pump and no probs as yet.

Jim

[andypdq]

Hi Jim.,

A heavier spring would reduce the rate of advance. The faster an engine spins, the more advance it needs. By installing a heavier spring you would be spreading the availailable advance over a larger rev range, whereas what is really needed is extra advance than the standard setup provides, to cater for the engine's requirements at higher than design revs.

I'm not really interested in megga revs. Because there is no mechanical pump available that is specifically designed for a turbo version of this engine, all the conversions out there are a compromise and far from ideal. The key is tuning the advance profile to suit the chasecteristics of the engine and fitting a manifold pressure compensation unit.

As for the 85 hp injectors, I don't know.

Regards.

Andy

[dieselhead123]

The manifold pressure compensator unit is exactly what is required for a turbo engine, something fitted to most similar turbo engines that use this range of pump, including the 154 pump used on the TD Transit.

I too ran my engine with 85ps injectors, pink spot, prior to fitting the 130's, but I have never had a set of 100/115's to try. I purchased the 130's because they were cheaper than the 100/115's, apparently this is something to do with USA tax legislation as the 130's are not classed as vehicle parts!

TIM