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1.8 Injector pump replacement woes


Nick BMC

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My injector pump has been leaking from the throttle shaft, stop shaft, housing for shafts gasket and now a new leak from pump body to the head where injector pipes are fitted. It is not useable anymore as it spills more fuel than it sends to injectors, so i ordered a reconditioned one.

 

The new pump was reconditioned some time ago by a man who has passed away and stored in sealed plastic for some years.

 

The pump looks good but where the anti stall screw should be is a bolt and rubber o ring instead. I am now thinking the bolt was put there to stop air getting in and i need to remove it from old pump and put it on the new pump. Should i be doing this or is it normal to have it blanked off?

s-l1600.jpg

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OK ,I havent seen one of these motors for 40 years......but just maybe there is a change in pump components over the years causing your new pump to be 180 out,.....TDC is easily found by turning until one cylinder has valve rock ,split the difference,and lever one valve down to touch the piston......this is TDC on the exhaust stroke on that cylinder,and TDC firing on the opposite cylinder.......check the pump timing through the window for the firing cylinder............(Its also possible your late mate has put something back in the pump 180 out ,or upside down.....All the markings on the drive plate are right way up with the pump on its base.   The large and small notch correspond)

Edited by john.k
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6 hours ago, Nick BMC said:

New pump fitted and bled correctly. it runs really rough and wont go above idle. I know from reading here that I can not get the pump 180 degrees out but it seems like it is. Anyone know what the problem could be?

 

 

Try slackening, but not removing that bolt and see if it helps.

 

It has all he hallmarks or an ebay "bargain" so anything is possible. We now know the drive shaft pulls out of the rotor after an email is removed so that implies  splines but I don't know if they have a master spline or not.  If not it would be eask to get them fitted in all sorts of incorrect ways.

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OK,Ive pulled reversible governor  71397/64 to bits,and IMHO ,the bolt shown is a bleeder,and will have a flat on the thread...........the governor I have here has only one tapped hole ,on the side ,and it is a bleeder......There is no anti stall device,nor any provision for one in the casting...............................As mentioned ,all the drive is blind splines ,its not possible to install the pump any other way in the drive couplings................the motor has been running OK,so the fault must lie in the replacement  pump,or the installation of the pump ,including bleeding.........I know from experience that pumps on tiny motors with miniscule fuel delivery can be problematic to bleed.

Edited by john.k
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31 minutes ago, john.k said:

OK,Ive pulled reversible governor  71397/64 to bits,and IMHO ,the bolt shown is a bleeder,and will have a flat on the thread...........the governor I have here has only one tapped hole ,on the side ,and it is a bleeder......There is no anti stall device,nor any provision for one in the casting...............................As mentioned ,all the drive is blind splines ,its not possible to install the pump any other way in the drive couplings................the motor has been running OK,so the fault must lie in the replacement  pump,or the installation of the pump ,including bleeding.........I know from experience that pumps on tiny motors with miniscule fuel delivery can be problematic to bleed.

 

Thanks for the info about the rotor to drive shaft splines.

 

Early pumps did have a bleed screw there but also a carburettor type idle speed screw set at an angle as per the diagram below. The OP's image does not have such a screw and the size of that machine screw indicates the pump would normally have the idle damper there with a bleed screw in the top of it. If that machine screw is too long it must prevent the governor valve rising and I think that would prevent it delivering more fuel so it may well only idle badly or not even start.

 

https://injectionpumps.co.uk/wp-content/uploads/2018/03/CAV-DPA-Hydraulically-Governed-Injection-Pump-Exploded-Diagram.jpg

 

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With respect,,the diagram shows the geared plunger type governor.........the reversible governor  is different,and a bit simpler .....probably cheaper to make too.......the reversible governor has idle and max speed screws external to the mechanism ................I wonder if the pumping plungers are free in the OPs pump....long term storage can cause components with close fits to gum up.

Edited by john.k
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I know that diagram is not the one for the OP's pump. I also know that the hydraulic DPAs came with a number of differences related to their application. In my experience the 1.5 came with the pump I showed the diagram in its earliest form and all the later ones, apart from the odd one that had a mechanical DPA, had the hydraulic governor that included the idle stabilisation device. Now, the 1.8, being a newer engine design has, on all those I have seen and I must admit it is not that many because I was off the tools by then, have all had the pump as fitted to later 1.5s, so should have the idle damper adjustment. The OP's pump does not so I question if t really is a 1.8 pump or if it has had the idle damper removed for some reason and replaced by an ordinary set screw. If it is the later then that screw could be impeding the governor valve if it is too long and I know of the odd time a pump has been returned from a diesel shop with the idle damper screw right down has prevented the engine revving.

 

If it is the wrong pump then the OP should find the flat on the screw you mentioned.

 

I also wonder if the governor housing has been replaced with one from the scrap box.

 

Whatever the problem it is going to need more investigation because that pump is unlike any have seen on either 1.5s or 1.8s. However that is not to say I don't think a bitza or incorrect model of pump can't be set up to suit a 1.8 fuel delivery wise.

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I am feeling really stupid, I took out the idle blanking bolt and installed the idle adjuster from the old pump but there was no difference. I assumed the pump was dodgy.

 

Woke up this morning after a long night installing the pump and immediately noticed i had connected the fuel in and out the wrong way on the fuel filter housing. I switched them back to the correct connections and the pump fired up perfectly!! been out driving it about in strong wind for 1 hour and the engine is producing far less smoke than it ever has the 4 years i have had it. The ebay pump is perfect and I am super happy with the job the old boy has done with it. I paid £90 and didn't need to give my old pump in exchange. 

 

Just goes to show after a long day and night best to stop before 1am as this is too late to be doing mechanics under a head torch and expect to not make simple mistakes as to which way an arrow is pointing on a filter housing.

 

fine tuned the idle bolt as per the bmc manual again and all seems good. Not even 1 drip of fuel anywhere on the pump OMG!!!!!!

 

 

  • Greenie 1
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I forgot to say thankyou to all who replied with sound advise. My father always tried to teach me that i do not need to call a man everytime i have a problem and to try and do things for myself, and it has really helped me. Not mentioning names of course but there is another lady boater here who calls an engineer just to check the oil level on the dipstick in-between services as she does not want to get it wrong. 

 

  • Haha 1
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The ebay seller is js0569. the lady is working her way through all the stock and knows nothing about pumps but I would say there are some bargains to be had there if anyone else is looking for an injection pump that was refurbished and tested on a machine by an old-school engineer.

 

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