posted February 05, 2003 17:11               

If it will bolt on, it will work. The intake butterfly which is the throttle must be changed, and the vacuum line from intake butterfly to pneumatic pump.

So there is a throttle linkage issue.

It has probably already been done.

posted August 04, 2003 20:51               

quote:

---

Originally posted by JimmyG:
No, not all the differences are internal. I have found out that some ordinary dextas were indeed fitted with the minimec pump. According to my source, the minimec pump was fitted to Dextas from engine number 1530251. The only thing you may have to watch is the horsepower of the super dexta pump. After June 1963 the pumps were uprated to 44.5 hp instead of 39.5 hp previous to that date. If the plate on the side of your pump reads P 4588 then it is a 39.5 hp minimec pump, but if it reads P 4696 then it is plated to 44.5 hp. your engine should have a 39.5 hp pump fitted.

Regards, Jimmy

---

Well...
Nice to find some numbers...
"P4588"=39,5hp-engine, and "P4696"=44,5hp-engine.

Apropos Simms Dexta/Superdexta fuelpumps.
Here follows some Fordson part numbers:

957E-993101A
957E-993101B
957E-993101C
957E-993101D
960E-993101

Which is the identification number (engraved number) on respective pump.

posted August 04, 2003 23:25               

Part No. 957E-993101-A - Pneumatic Governed pump used in Dexta from 1 Nov 57 - Mar 62. England only. Not sure of number on pump.

Part No. 957E-993101-B - Not sure as i have no listing of this number in my parts lists. I would assume it coresponds to the pump used for export models.

Part No. 957E-993101-C - Pneumatic governed pump used in the Dexta from 1 Nov 57 - Mar 62, German export model. Not sure of number on pump.

Part No. 957E-993101-D - Mechanical governed pump used in the Dexta and Super Dexta from April 62 - may 63. Pump stamped P4588. ( 33.5 hp )

Part No. 960E-993101 - Mechanical governed pump used in the Dexta and Super Dexta from June 63 - end of production. Pump stamped P 4696. (44.5 hp )

Hope this helps.

posted August 05, 2003 07:28               

But i´m still a bit confused about the fact, that they used the No. 957E-993101-D (Mechanical governed pump; stamped P4588) in both Dexta and Super Dexta.
Did they use the same engine (with the same power) in both Dexta and SuperDexta from April 62 - may 63?

The same matter holds for Part No. 960E-993101 (Mechanical governed pump; stamped P4696).
Did they use the same engine (with the same power) in both Dexta and SuperDexta, from June 63 - end of production?

Something is quite strange...
I thought that diffrent engine sizes would have diffrent injectionpumps.

posted August 05, 2003 11:25               

According to my information the Super Dexta from april 62 to may 63, was fitted with a larger version of the Dexta engine, bored out to 152 cu in (2500 cc). It had the mechanically governed p4588 simms minimec injector pump and developed 39.5 hp. The standard Dexta remained in production, ( 144 cu in engine ) but was fitted with the same type of fuel pump.

It seems that the info in my last post was'nt altogether correct. It turns out that from June 63 till the end of production in sept 64 the injector pump used on the Super Dexta was changed to the P4696 minimec pump which boosted power to 44.5hp. BUT, it turns out that the standard Dexta kept the P4588 minimec pump, and hp was unchanged. Sorry for any confusion.

posted August 06, 2003 06:46               

Guess the Super Dexta, manufactured from June 63 till the end of production in sept 64, (with the P4696 minimec pump and boosted power to 44.5hp), was the so called "New performance super dexta".
As i can see, the "New performance super dexta" perform engine revolutions up to 3000 rpm.

Do you (or anyone else) know if they did any more changes on the engine than change the injectionpump to the New performance super dexta, in comparison to the Superdexta made from april 62 to may 63?

posted August 06, 2003 12:26               

As far as i know the only differences between the ordinary Super and the New performance Super were:

-The injector pump.

-The injectors ( Dexta and Super Dexta Injection Nozzles has two 0.35mm holes, BUT the New Performance Super Dexta Injection nozzles has two 0.32mm holes )

-The colour scheme ( New performance Supers were painted blue/grey )

-The rear tyres, ( standard tyres for the ordinary Super were 11x28, while standard tyres for the New Performance Super were 12x28 ).

As for the increased revs, according to my manual, they were not increased to 3000 rpm, but from 2225 rpm on the ordinary Super, to 2450 rpm on the New Performance models.

No doubt i may have left something out, but to the best of my knowledge these were the main differences between the two models. If i've left anything out i'm sure someone else on the BB will help.

Regards Jimmy

[This message has been edited by JimmyG (edited August 07, 2003).]

posted August 07, 2003 07:32               

I belive you, Jimmy.
2225 rpm on the ordinary SuperDexta and
2450 rpm on the New Performance SuperDexta,
Sounds more resonable.

Two questions in this matter remains:

1. Are you sure, Dexta and Super Dexta Injection Nozzles has two 0.35mm holes, while the New Performance Super Dexta Injection nozzles has two 0.32mm holes.
If that statement is correct, the injection nozzles to the 44,5hp engine is smaller, than to the 39,5hp engine.

2. Do you know, if those horsepower is according to the SAE or DIN method?

posted August 08, 2003 00:01               

The informatoin I have about the engine rpm and the size of the injector nozzles for the ordinary Super and the New Performance super, came from an original operators handbook for the Dexta and New Super Dexta printed in May 1963, just before the release of the New Performance range.

As for why the injector holes are smaller on the New Performance Supers, I'm not sure. Perhaps Brian would be able to shed more light on that particular matter. I can only guess that a smaller hole would spray a finer mist of diesel into the engine , thus helping combustion??

Unfortunately, I have no answer to your second question, but i'm sure someone on the BB will know.

Regards, Jimmy.

posted August 08, 2003 11:36               

the HP raises when going to higher RPM's ( reading of the Power-RPM curve of the engine) . Of course, the engine-pump combination has to be able to go to these higher RPM's.

One of the things that helps going to higher RPM's is to increase the opening pressure of the injectors plus adapting the pump to be able to deliver these higher pressures.
As the bore/stroke size is the same for both Super Dexta and NP Dexta(I guess), there is no added value to inject more diesel because there will not be more oxygen(read air) in the combustion chambers. Thereby the injected volume of diesel must be the same. So injecting the same amount of diesel at a higher pressure explains than why the nozzles must be smaller (0.32 vrs 0.35)

Can you check the opening pressures for the nozzles for the NP Dexta in your manual ? (eg the Dexta has 160 bar)

Brian, am I in the same line as your knowledge ?

posted August 09, 2003 08:02               

'Injectors:

Dexta and Super Dexta: Injection nozzle has two 0.35mm holes.

New Super Dexta: Injection nozzle has two 0.32mm holes.

All Dexta models: Angle of holes to vertical-30 deg and 80 deg. Release pressure- 160 atmos. '

From what this states, it seems that the injector operating pressure for all models was the same???
I'm getting confused!!

posted January 13, 2004 21:39               

My parts list seems to be to old for the New Performance Super Dexta.
Was the cylinder head for Super Dexta and New Performance Super Dexta the same?
Was the pistons for Super Dexta and New Performance Super Dexta the same?

The question is, why the injection nozzle holes got smaller, while the engine power was rising.

Can the answer be that the engine become direct injectioned?

posted January 14, 2004 00:47               

Engine power [HP/KW] is related to the torque a engine gives, and the revolutions it makes.

The standard formula for the power in kw is: P = M x w. In words power = torque x engine revolutions. When filling in for torque [newton x meter] and for the engine rpm the speed in [radial x second] it gives a result in Watts. Divided with 1000 it gives the engine power in Kilowatts. But when you use this formule with the given facts in hp and rpm you get a fictive number for the torque what the engine gives, but it can be used.
I find this: 39.5HP/2225rpm = 0.0177528 torque.

0.0177528torque x 2450rpm = 43.49 hp. This is approximately 44.5 hp. But this is only correct when you count with a constant torque independant of the engine speed. Normally torque increases whith engine speed, this depends on the engine design. Bore/stroke, valve timing, valve lifting etc. I think whith the new injector type a better combustion is possible and a higher torque is given by the engine. Together with the greater engine speed this results in more HP power.

This is just a idea I have, I'm not familiar with engine tuning of designing. But in my education I frequently have to work with power, torque en rotation speeds.

If anybody has questions or comments I'm very pleased to hear about that.

Kind regards,
Emiel

posted January 14, 2004 08:02               

Super Dexta:
Maximum power 39.5 hp
Maximum engine rpms 2225.
Minimec injection pump "P 4588"
Injection nozzle has two 0.35mm holes.

New Performance Super Dexta:
Maximum power 44.5 hp
Maximum engine rpms 2450.
Minimec injection pump "P 4696 "
Injection nozzle has two 0.32mm holes.

All Dexta models:
Angle of holes to vertical-30 deg and 80 deg. Release pressure- 160 atmos.

Still i can't figure out why the injection nozzle holes is smaller on the New Performance Super Dexta, than the standard Super Dexta.

Can the answer be that the engine become direct injectioned?

Was the diesel consumption also increased?

Is it the same part.No. for the cylinder head for Super Dexta and New Performance Super Dexta?

posted January 14, 2004 18:53               

May be you should take a look at the super dexta specifications located on this site! I'm reading them right now, and I find it very interesting.

I'm sorry I can't tell you about the cylinder heads and the direct/non direct injection. I do not have any Dexta documentation. But I think the NP Super Dexta does not have direct injection, because a direct injected diesel engine needs a later timing because the combustion starts earlier and a higher compression. Compression ratio and injection timing are identical on all dexta modells!

Kind regards
Emiel

posted January 15, 2004 00:51               

I still dont understand why the size of the injector holes were decreased, but in answer to your other questions, I can tell you that the NP Super Dextas were not direct injected, and the fuel consumption was probably slightly increased due to the higher revs.

Also, according to my parts list the cylinder head for the dexta was the same from the start of production in 1957 until the end in 1964, and the pistons used for both the Super Dexta and NP Super Dexta are also the same.

So I can only assume the increased Hp has come from the uprated pump and smaller Injector holes. - Only my thoughts!!!!!

Regards,

posted January 15, 2004 07:45               

quote:

---

Originally posted by Emiel:
"Maybe you should take a look at the super dexta specifications located on this site! I'm reading them right now, and I find it very interesting"

---

Well...
Nice you find them intresting. Unfortunately the specifications on this site is not complete or correct.
For example:
"The 1963 new performance Super Dexta (F3.152 engine, diesel), blue/grey; these had their output power increased to 44.5 HP due to increased engine revolutions up to 3,000 rpm. They were only made from June 1963 until September 1964."

posted January 15, 2004 08:07               

Perkins did also construct the 152ci.in. engine for the smallest Volvo-tractor.

From 1964 it become direct injectioned.

They changed the pistons and the cylinderhead.

posted January 15, 2004 14:28               

Injection pressure is not given by pump, but by Injector adjustment. The amount of Diesel is given by the pump. I think the gouverner is different adjusted in the NP super dexta. If the pump gives more diesel, injection lasts longer automatically!

And about the information on this site, 3000RPM is shown on the tachometer. In the scans are the correct values for RPM given for all types of diesel dexta.

Volvo used the perkins version of the p3 after Ford stopped building the dexta in 1964? Then the engine can be modified for use in Volvo tractors. But I'm not familiar with Volvo,so I can't say anything about that!

Kind Regards
Emiel,

posted January 15, 2004 18:44               

============================================
still dont understand why the size of the injector holes were decreased
=============================================

it is not easy to explain the working of an injector in a few words, but lets give it a try (as an engineer)

- The pressure as indicated in the manual is the opening pressure of the injector. This is the pressure that the valve needs to open.
Very strange, but the size of the holes is irellevant for this pressure (up to a certain level). The valve is a little cylinder moving upwards with at the end a conical nose to regulate the opening between valve and seat. The more this valve moves upwards, the bigger the opening area is, and the more volume of diesel can be injected. The pressure is regulated by applying more pre-load on the back of the injector-spring.

- The total volume of spayed diesel is regulated by the pump. So also here, size of the holes is irrelevant because this is regulated by alowing the injector valve move more. The volume is fully controled by the pump-setting.

The size of the holes is only changed
a) to have a more stable injection pressure
b) a better spray-patern in the cylinder (longer pray-length and a thinner angle of the diesel "cloud" towards the cylinder)
c) to improve the quality of the Diesel cloud as the drops have to be as small as possible.
d)....

There is a lot of info available about this kind of injectors but do not worry to much about all this.
It's better to have a nice running engine and not knowing why than having a non working engine knowing why it is not working and not able to solve it .

Regards
Jos

posted January 16, 2004 08:08               

quote:

---

Originally posted by Emiel:
Volvo used the perkins version of the p3 after Ford stopped building the dexta in 1964? Then the engine can be modified for use in Volvo tractors. But I'm not familiar with Volvo,so I can't say anything about that!

---

They all looks the same as the Fordson 144/152 engines, except for the injectionpump (CAV instead of Simms).
Of course you can recognize the direct injectioned ones, by looking on the cylinderhead.
In the spare parts book (http://www.olssonsiellos.se) most of the spareparts for Volvo and Ford-144/152 engines have the same partnumbers.

ps
Sorry for my bad english, I;m not used expressing myself in English at all.

posted January 16, 2004 10:42               

I will take a look in the link you gave me this weekend. Try and find out what I understand from the Swedish language.

But for as far as I know, the AD3 perkins series are the engines used in the MF 35 and 135 series tractors. I'n not quite sure, but these are slightly modified engines in comparison to the ones Ford used. Here a part of a table I have on my hardisk about Ferguson tractors: The Ford engines are perkins F3.xxx, the perkins are P3.xxx or Ax.xxx
MF van 1936 tot 1964
Type trekker Motor type Vermogen (pk) Bouwjaar
Ferguson Brown 24 1936 - 1938
Ford Ferguson 24 1939 - 1946
TE-20 24 1946 - 1950
TE-A20 28 1947 - 1956
TE-D20 26 1949 - 1956
TE-H20 23 1950 - 1956
TE-F20 Diesel 27 1951 - 1956
TD-20 24 1948 - 1956
FE-35 Goudbuikje 37 1956 - 1958
MF-35 Standard 23C 33 1958 - 1959
MF-35 A3.152 37 1959 - 1962
MF-35X AD3.152 45 1962 - 1964
MF 65 A4.192 MK2 54/58 1962 - 1965
MF 25 A4.107 25 1961 - 1963
MF 65 AD4.203 MK2 54 1962 - 1965
MF 30 A4.107 25 1963 - 1964

posted January 16, 2004 11:09               

No Dexta or Super Dexta had a direct injection engine, however Perkins did change to direct injection engines around 1964/65 and from memory, these were badged as the "A" series. They were fitted to MF tractors and others.

Also no Dexta reved as high as 3000 rpm. My car has 150mph on the speedo but this is optimistic to say the least.

The Super Dexta HP was measured higher up the rev range but its torque figures remained measured at around 1100 to 1200 rpm.

HP is a function of revs. Torque is a measurement of an engines ability to turn.

This is the important measurement as far as tractors are concerned. You can have a 200hp engine in a car but fit that engine in a tractor and it will not work because it does not have torque. On most tractor engines the torque is about 20% lower at rated power rpm and increases as the engine revs drop under load. This function is known as torque back up.

If an engine has a flat torque curve with little rise between maximum torque generated and maxiumum power, when it is overloaded it will stall very easily.

This is pretty basic but it is how it was explained at Ford.

regards

posted January 16, 2004 18:19               

After a close study of my parts manual, there are only 2 differences between the P4588 pump of the Dexta and Super Dexta and the P4696 pump of the NP Super Dexta -

Firstly there are different sized tappet spacers used in the pump,

And secondly a different delivery valve and guide assembly was used.

This, I presume delivered more fuel?

BUT!!!

The parts list also states that the injector assembly has not been changed from 1957 right through to 1964. This contradicts what is stated in the operators manual.

The only thing the parts list confirms is that there were different injectors installed in the US version of the Dexta throughout its production life.

Regards,

posted April 02, 2005 08:25               

Part No. 957E-993101-A - Pneumatic Governed pump used in Dexta from 1957 - 03/1962. For the British (domestic) market only. Not sure of number on pump.

Part No. 957E-993101-B - Pneumatic governed pump used in the Dexta from 1957 - 03/1962. For the France market only. Not sure of number on pump.

Part No. 957E-993101-C - Pneumatic governed pump used in the Dexta from 1957 - 03/1962. For the German market only. Not sure of number on pump.

Part No. 957E-993101-AR - Pneumatic governed pump used in the Dexta from 1957 - 03/1962. For the USA market only. Not sure of number on pump.

What is the differences between those pumps?

My Dexta is manufactured in february 1962 (02/1962) It is equipped for the Swedish market. My injector pump is marked: "SIMMS - SPE 3A60S 593 - A46 - Z1" Which one is it (of those above)?

posted April 02, 2005 10:30               

If not specified, the pump would be a UK build unless your tractor came from one of the countries listed.

posted April 06, 2005 08:13               

Power is a function of the air fuel mix too. Altitude and temperature will also affect the power so this is perhaps why the pumps were set differently for different markets to get the same power output.

Just my thoughts.