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National injector setup


Jrtm

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As title is there a correct way of setting these up once theyve been stripped cleaned and put back together?

Mine were so bad it would only start on 1 cylinder then eventually kick the second in on removal the coke was so bad 1 injector was vertually blocked, stripped cleaned and rebuilt,

I thought i put the neadles back in the same place but ov not, is it a case of just adjusting them bit by bit till i find a position it starts and adjust till its running right?

Ive got it to the point it will almost start but not quite, by the time ive achived this ive run out of energy to keep trying.

P.s. feeding the starter motor more food hasnt helped.

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Yes, when i had them off i put them back to where i thought they should be put them onto the fuel pump and i got a fine mist and they creaked. It almost runs but just dosnt fully fire.

My other option is i might not have the fuel pump perfectly setup but it went back together with the bar set between the 2 marks and the brass half cogs in the middle ive checked and with it right back (bar pulled out) i have no fuel and pushed in have full fuel so i cant see it being the pump as if i turn the fuel shut off it dosnt stop the fuel untill its turned right back.

It might be im just not turning it over fast enough. It would often take 3 attempts in the cold but 1-2 in warmer weather.

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Blow off pressure in the book is 1750 lbs per sq inch or 123 kg per sq cm.

It is well worth getting them set accurately, I bought a tester cheap  from  the internet and now start on 2 cylinders.

https://youtu.be/6NbPN91plIE Is worth a look for anyone new to injectors, if the injector pump is in good condition with the injectors out but connected you can see the pattern and turning the engine slowly get an indication of a dribbling injector.

Warning for anyone new to this 1750 lbs will inject diesel  straight under your skin!

If things are near to being running and it is cold, a hair dryer, hot air gun or blow lamp (in order of risk) across the air intake manifold with the filter removed will often be enough to get her to fire.

If compression is a bit low a squirt of oil into the cylinders will often increase the seal on the rings for a few turns.

Swapping an injector from a running engine (or borrowing someone's spare) would prove whether it is the injector or not, it is a pity you are not nearer!

I don't know who could check you blow off pressures in your area but they will need to be set for the engine to run at its best, the time it takes the pump to get to blow off will I believe vary with the pressure and effect the timing, I had a lazy cylinder until I set mine, you could currently have two!

 

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Hi bob yes i was coming to the same conclusion, i can send them off to a place in warwick or as you have done get a hand pump tester,

I think i had 1 cylinder almost there but as i have the time (boat not needing to be moved) ill try and get a tester unless i can send them to you and pay you for your time of adjusting them, my worry is buying a hand test pump and it not fitting the injector.

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Nearly all vintage injectors from  CAV Bryce; Bosch etc. have the same thread at the inlet.  It is metric too because it was originally made by Bosch . Pop testers of the same vintage use the same standard thread as well.

N

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41 minutes ago, billybobbooth said:

So really any hand injector nozzle tester should fit them?

I can get a cheap one for about £60-£80 means i can clean and rebuild my injecotors every year if it works

Yes, provided it comes with the right the interconnect pipe!  If a 19mm spanner fits the nuts that hold the pipe to the injector and to the pumps then the thread is 14 mm x 1.5mm pitch.  More modern injectors are on a 12 mm thread.  Most of the pop testers on Ebay and Amazon seem to come with pipes to fit both.

I would not dismantle your injectors any more often than is essential.  Every time you open one up it increases the likelihood of getting some dirt in.  That would cause all sorts of grief and might even wreck the injector body.  Fuel pump and injector work should really be proper clean room stuff.  If it works and doesn't smoke then leave well alone is the best approach.

N

  • Greenie 2
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Thats why had to take it appart as it wasnt working properly to the point one of the injectors had carbon inside and didnt work properly. Ill check it has the correct thread on the pumps thank you for help

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