Looks like you made a nice holding fixture. I would recommend a proper hexagon wrench, not an adjustable. As an an aircraft engineer, I am banned from use of anything but proper fitting tools.
Hi, you are quite right but I find using that massive, 2 foot long adjustable, which is in good condition, far more controllable than a spanner with a length of pipe. Fifty year old injectors can be incredibly tight.
Very informative and clear video thanks Wotjonsez. Im in middle of Ireland and have a working old Dexta. We still use on the farm for light work. Do you know how the Injector leak off line pipe back to the fuel tank works ? It's the pipe connected to each of the 3 injectors and running above them via a 3/16" brass pipe system back to the diesel tank, entering it near the air cleaner intake. I was expecting it to have fuel flow when the engine runs or is being cranked to start but mine does not. I was planning to use that fuel when cranked to supply a quick start glow heater to make it easy to cold weather start. So this is why I ask. It starts and runs ok. I think there's no air in the fuel system as I checked at the fuel pump bleed valve and at the fuel filter top bleed valves for any air and found none. Similarly pumping the manual fuel lever has no impact on this issue (as I would expect). The injectors would be very old, possibly never serviced or replaced. Might they need a bit of attention and that is why there is no fuel in that pipe ? or She runs but the fuel pump aint working optimally and not building enough pressure ?
Hi, Thank you. The leak back on all conventional injector systems is just about the same. Some diesel is forced to escape up the side of the needles into the injector body, it is fed back to the tank to stop the upper part of the injector pressurising, it should not be more than a dribble, the less the better. My Dexta is still used regularly and had been used as a scraper tractor for many years before I bought it. I have never seen more worn injectors than these ones in the video, which is why I replaced the nozzles and needles. If you look at my video about the 574 injectors, I take you through the process of cleaning injector nozzles with good results. My engine is absolutely clapped out but starts quite easily in sub zero weather using the original cold start system. Best regards, Jon
Injectors are machined to a tolerance of half a micron, you may improve them by cleaning them but you cannot "restore" them without specialist equipment and knowledge, they are usually done in a special dust free room so I can't imagine having all that rust around is too helpful either.
Well thank you for that. I don't think that there was such a thing as half a micron when these were made! The proof of the pudding is the fact that this tractor was very difficult to start, was very smoky and would not tick over; but now it does. Regards, Jon
Great video, it's a big help 👍
Looks like you made a nice holding fixture. I would recommend a proper hexagon wrench, not an adjustable. As an an aircraft engineer, I am banned from use of anything but proper fitting tools.
Hi, you are quite right but I find using that massive, 2 foot long adjustable, which is in good condition, far more controllable than a spanner with a length of pipe. Fifty year old injectors can be incredibly tight.
Very informative and clear video thanks Wotjonsez.
Im in middle of Ireland and have a working old Dexta. We still use on the farm for light work.
Do you know how the Injector leak off line pipe back to the fuel tank works ?
It's the pipe connected to each of the 3 injectors and running above them via a 3/16" brass pipe system back to the diesel tank, entering it near the air cleaner intake.
I was expecting it to have fuel flow when the engine runs or is being cranked to start but mine does not.
I was planning to use that fuel when cranked to supply a quick start glow heater to make it easy to cold weather start. So this is why I ask.
It starts and runs ok.
I think there's no air in the fuel system as I checked at the fuel pump bleed valve and at the fuel filter top bleed valves for any air and found none.
Similarly pumping the manual fuel lever has no impact on this issue (as I would expect).
The injectors would be very old, possibly never serviced or replaced. Might they need a bit of attention and that is why there is no fuel in that pipe ?
or She runs but the fuel pump aint working optimally and not building enough pressure ?
Hi, Thank you. The leak back on all conventional injector systems is just about the same. Some diesel is forced to escape up the side of the needles into the injector body, it is fed back to the tank to stop the upper part of the injector pressurising, it should not be more than a dribble, the less the better.
My Dexta is still used regularly and had been used as a scraper tractor for many years before I bought it. I have never seen more worn injectors than these ones in the video, which is why I replaced the nozzles and needles. If you look at my video about the 574 injectors, I take you through the process of cleaning injector nozzles with good results.
My engine is absolutely clapped out but starts quite easily in sub zero weather using the original cold start system. Best regards, Jon
Dexta should have cold start.
Injectors are machined to a tolerance of half a micron, you may improve them by cleaning them but you cannot "restore" them without specialist equipment and knowledge, they are usually done in a special dust free room so I can't imagine having all that rust around is too helpful either.
Well thank you for that. I don't think that there was such a thing as half a micron when these were made! The proof of the pudding is the fact that this tractor was very difficult to start, was very smoky and would not tick over; but now it does. Regards, Jon
@@wotjonsez2560 🤣👍