Monday, 5 January 2015

Ready for the HCR and more EFI work

Well the Dolomite passed its MOT this week, so its all ready for the HCR :) save for an oil leak from the oil pump which will get some attention this coming weekend - it needs the pump to block oil seal O ring replacing. Why does this car have so many oil leaks ?

In the meantime I have been mocking up the crank sensor to tooth wheel arrangement on a spare timing cover with a spare crank pulley that I have.

Using a standard sensor bracket from, there's an easy mounting method, which puts the sensor in the correct position behind the crank pulley - I want to mount the trigger wheel to the inner flange, and not the rubber mounted part, so the trigger wheel sits behind the pulley.

The pick up bracket can then mount to the redundant fan bearing mountings (as I have an electric fan mounted on the radiator)

This mock up was done with a 6.5"  wheel which is a little large as it obscures the timing mark bracket holes, and also partially shrouds the timing cover fixing bolts

however the height is just right, and there is clearance behind the trigger wheel and the cover.

Upon measurement of the inner pulley flange I found that I could use a 5.75" trigger wheel, as the pulley wheel diameter of 5.25" still leaves the teeth protruding by 0.25" and spaced away from the V belt outer pulley

I have now sourced the 5.75" trigger wheel and its just right

It clears all the various mounting bolts, and will also let me fabricate a new timing mark pointer, which will mount to the existing bolt holes and come round the sensor (leaving enough clearance so it doesn't affect its operation) - I'll make this as a simple pointer and scribe additional timing marks on the pulley itself. I also want to accurately mark tdc, but more on this next time.

Next job is to get the trigger wheel machined out and mount it to the pulley. I'll then drill some slotted holes in the sensor mount (to allow some timing variation adjustment) so my edis will fire at 10 degrees btdc once its adjusted correctly.

With the sensor mounted at about TDC, the 9th tooth will need to be under this, with the missing tooth clockwise from the 9th tooth - edis needs varying "missing teeth" offset dependant upon the number of cylinders that the engine has.

Once the mechanical work is done, I'll mount coil pack and edis module on the inner wing to test, as without the connections to the microsquirt the edis will work in limp mode, and if all is correct fire at 10 degrees btdc. I am going to use wasted spark.

I have also traced the Davis Craig controller issues (on the RBRR) to high voltage spikes from the alternator, and back emf pulses from the overdrive solenoid, and knowing how microsquirt hates voltage spikes, I need to fit a more modern alternator. A simple reversed polarised diode across the overdrive solenoid wiring will remove the back emf spikes from that.

Next time (hopefully) edis and trigger wheel testing

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