Supporting > Engine Ancillaries
Fuel Injection Systems Part 2
Roger B:
The next step was to harden and lap the pump element. I ran the 1.95mm reamer through by hand to remove any burrs caused by drilling the inlet port, then heated the pump element up to a light orange, kept it there for about a minute and dropped it into a water bath. As expected, the 1.95mm pin gauge would no longer go in so I started lapping with 5 micron diamond paste and an Acro Needle Lap.
https://youtube.com/shorts/Gice8kHvOQI?feature=share
http://www.youtube.com/watch?v=Gice8kHvOQI
When the 1.95mm pin gauge would go through I changed to 1 micron paste and continued until the 1.97mm pin gauge would just go through.
I already had a 1.97mm helix, (I usually make them in pairs one from each end of a pin gauge. The procedure is in post 12 of this thread.) which fitted nicely into the bore :)
Roger B:
The parts were cleaned in a ultrasonic bath to remove the diamond paste residue.
I then checked the required plunger length once again and cut the plunger to length with an abrasive disc. The non-helix end was then annealed, whilst held in some large pliers to act as a heatsink, and threaded M2.
After a couple more checks the tappet was fixed to the plunger with Loctite.
Roger B:
Next up was the delivery valve. This could be modified from a commercial union but I started with a length of 6 mm brass hex. The union end was made first, using a 2mm centre drill to cut the cone. The other end was drilled 3.2mm to give clearance for the 3mm ball and the tip was turned down to 4.4mm diameter for a length of 1 mm to make the sealing face.
The ball valve seating in the pump element was then lapped with a 3mm diamond ball lap ready for a trial assembly. I first checked the fit of the plunger in the pump element and control gear. This tended to jam so I put the element in the lathe to polish the spigot that the gear runs on. It was bent :( I guess it distorted during heat treatment :thinking: I was able to straighten it to an extent using the end of a lathe tool shank to apply controlled pressure with the cross slide. The rest of the assembly was ok and the fuel rack moved quite smoothly.
The fuel inlet is a standard Regner M5 x 0.5 union.
Roger B:
And on the engine
Navigation
[0] Message Index
[*] Previous page
Go to full version