# CAV DPA ‘mongrel’ injector pump to identify



## Bob Down (Jun 6, 2018)

Can anyone identify the model injector pump in photo. Note that it has an odd fuel input configuration unlike all the CAV DPA images and manuals I have trawled through on the net. Particularly would like to know what’s behind the screw facing us on the very back (perpendicular to the input line atop).










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## Ultradog (Feb 27, 2005)

Knowing what kind of a machine is this on would help.
Have you tried looking it up by make and model #?


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## Hacke (Feb 22, 2011)

Check the numbers on the blue plate and write them down: TYPE No DPA 324XXX (That is the "model") and SERIAL No R62XXXXX. Save that information. Good to have if the plate is damaged.

The thing at the end of the pump is the end plate with transfer pump pressure regulator. The usual type has the filter and regulator parts placed in one and the same bore. This one has the filter under the inlet, but the regulator parts are placed perpendicular to the inlet, behind the slotted plug you are referring to.

Behind the plug are a sleeve with a piston and two springs.

I do not know if it is just an older version of end plate, or if it is a regulator type better suited for arrangements with lift pump and/or hand pump for bleeding.


Pumpguy can straighten this out.


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## Bob Down (Jun 6, 2018)

Thanks for replies. It’s from a Massey Ferguson 65 mk1. I have type and model details recorded (photographed) but using them as reference does not show the configuration of my pump (thanks Hacke - I think you’ve cleared that up for me) in fact can only find one image of my configuration on the web! 


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## pogobill (Jan 31, 2012)

I couldn't find any, except for a pump on a MF35, but too small and rotates opposite!


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## Bob Down (Jun 6, 2018)

Type no. DPA. 3242133. S/N R 6263EZ. 


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## RC Wells (Dec 26, 2008)

That would be the OEM pump for a Perkins 4 cylinder 192 cubic inch diesel, refered to as A4.192. Engine was used in the MF 65 tractors.


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## thepumpguysc (Jan 25, 2015)

Yes that is a VERY OLD CAV DPA pump..the end plate is a very old style..{steel}
That 1 was made when CAV was in competition for the Perkins account w/ RoosaMaster.
CAV won out.. in the early 60's I believe & they STILL hold the account to this day..
Hacke answered the question.. its the transfer pump regulator..


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## Bob Down (Jun 6, 2018)

Hacke said:


> Check the numbers on the blue plate and write them down: TYPE No DPA 324XXX (That is the "model") and SERIAL No R62XXXXX. Save that information. Good to have if the plate is damaged.
> 
> The thing at the end of the pump is the end plate with transfer pump pressure regulator. The usual type has the filter and regulator parts placed in one and the same bore. This one has the filter under the inlet, but the regulator parts are placed perpendicular to the inlet, behind the slotted plug you are referring to.
> 
> ...


Hacke, can you categorically confirm the inner working behind the ‘screw head’. Is there a spring, a piston plunger and a spring? I’ve found a spring and a piston plunger but haven’t been able to extract anything yet from behind the piston plunger. Many thanks for your help all the way from South Australia 


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## thepumpguysc (Jan 25, 2015)

THATS ALL your gonna get.. The "start spring" is UNDER the regulator & can not be removed until the regulator. is removed.
IF u take a small screwdriver & push it to the bottom of the regul. you'll feel the start spring..
WHAT are u trying to accomplish.??


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## Hacke (Feb 22, 2011)

Bob Down said:


> Hacke, can you categorically confirm the inner working behind the ‘screw head’. Is there a spring, a piston plunger and a spring? I’ve found a spring and a piston plunger but haven’t been able to extract anything yet from behind the piston plunger. Many thanks for your help all the way from South Australia
> 
> 
> Sent from my iPad using Tractor Forum



I have no knowledge about this type of end plate, only a book, in Swedish, from 1963 where it is mentioned. I copied the parts of interest and translated the text.
It is all information there is to be found in that book about the end plate.

*Fig. 4.300*
A .Piston
B. Spring, that is compressed while feeding the pump from a hand pump.
*(My text:* Filling the pump before start, instead of gravity feed*).*
C. Hole that connects the valve to the outlet of the transfer pump.
D. Hole that connects the valve to the inlet of the transfer pump.
E. Regulator spring.

*Fig. 4.304*
The sleeve is pulled out with tool 7044/855, which has a small hook that goes into a hole in the sleeve.

*My text:*
I think the tool is like a pick tool.
I think the mentioned hole is the cavity above spring "E" in Fig. 4.300.
If you reach for any of the other holes and the tool slips, you will probably have a scratch inside the sleeve, and the party is over.

Edit
***
Just a thought:
It seems to be a, not mentioned, washer behind the slotted plug. If that washer is gone, the plug threads may bottom out or/and the regulator spring will be positioned a bit to the right. Could make a difference.
If the plug threads bottom out, the sleeve will not be seated correctly.
***

Edit again:
***
After looking closely I think it is not a washer behind the plug. It is more likely an o-ring. The plug goes metal to metal against the sleeve, and the o-ring is compressed in the space that the chamfer at the sleeve end makes with the bore?

There are circular symbols in the sleeve's groove at the right end of the piston in Fig. 4.300 and that is most likely an o-ring. Same symbols are in the space behind the plug.
***

Greetings from a snowy Sweden.


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## Bob Down (Jun 6, 2018)

We are seeking to understand the internal mechanisms in the event anything might need freeing up / unsticking. So far everything we have tried has resulted in non start. Taken cover off, checked actuation of off stop rack and throttle actuation, bled and bled, pumped plenty of injector cleaner through, still no fuel pressured through injector outlets so seeking to tick off other possibilities. Thanks all for your advice and assistance so far. Regards from sunny south Australia (recent temperatures over 45 degrees c)


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