No mess fuel injection timing and some short cuts to getting there.

Started by playdiesel, August 15, 2020, 08:54:46 AM

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playdiesel

Out the gate I want to stress that this is not a primer for how to spill time an engine. Please use search if that term is foreign to you and once you have read the many good posts here on the site. You do need an air compressor or air tank and a blow gun with a rubber nozzle or some home adaptation.
If your Listeroid has timing marks on the flywheels ignore them unless you have verified the accuracy and where they reference to on the engine. Find TDC and make your own mark. 500-650 RPM engines time at 20° BTDC,  850RPM engines at 26°BTDC. I don't build engines to run at 1000, your on your own there. The formula to place your injection timing mark on the flywheel is flywheel diameter x 3.14. divide that by 360 then multiply by degrees of advance. Then measure ahead of your TDC mark that distance and place your injection timing mark.
Short cut hint #1 is to NOT try to loosen the pump adjustment with the pump installed, remove the pump then remove the adjustment bolt with a 21MM socket. Clean and oil it so it turns easily in the lifter, sure save lots of aggrivation and takes 5 minutes.

Short cut #2 is to pay attention when you remove the pump. Always due that with the lifter down. IF when you loosened the bolts the pump was lifted up off the mounting by the return spring inside the pump then your timing will be advanced waaay before 20 degrees, that assumes that the cam is properly timed.  Most 1000 RPM engines are shipped that way.

Short cut #3 set the pump down on the mounting, and set the lifter bolt so it just hits the pump piston, does not hold the pump up but no clearance either. Sure is easier to turn that bolt from the top with the pump removed isn't it??? LOL Now that you have it close , run the lock nut down with your fingers, set the pump back on and tighten the bolts.

Now finally we are ready to spill time the easy way and without a mess to clean up. Remove the hex fitting from the top of the pump. There is a spring under it don't loose it. Next remove the delivery valve with your fingers and set all aside on a clean rag.
open the rack and wrap another rag around the blow gun and give the top of the pump a quick shot of air to remove the fuel. The rag keeps the fuel from going everywhere.  Next roll the engine over until the fuel lifter starts to rise, you will be approching your injection timing mark. Now place your finger lightly over the top of the pump and with your blow gun blow air in the pump inlet. You will feel it coming out the top of the pump. Now advance the engine a few degrees and check again with finger and blow gun, repete until air flow stops. Adjust the lifter bolt until you achieve air shut off at or very near your injection timing mark,, don't fret over it too much as this your coarse adjustment.
Easy short cut #4. is to use needle nose pliers to turn the bolt and hold it while you tighten lock nut, you did remove and clean it up right?? LOL

To fine tune the adjustment turn the flywheel forward past the injection mark to TDC. Next dribble a little fuel in the top of the pump, just a few drops , the more you use the more mess you have. A handy way to do this is with a can of WD40 or other oil with a straw on the can. Now place your air gun against the iinlet and give it a little air, there will be a little bubbling in the element due to the clearances. Then turn the flywheel backwards SLOWLY, away from TDC and toward your injection mark, when the oil sprays out the top of the pump stop and look at your mark. realize that when it sprays you are a couple degrees advanced of port closure, aka injection start. Recheck and adjust until you have it right, which is port closure at your timing mark. Button everything up and be proud of the mess you did not make and having your injection timing perfect.


Fume and smoke addict
electricly illiterate

BruceM

A great tip, Butch, I've printed it from my Lister binder for my next major service.  Thank you!