Easier Fix for a Buzzing Lionel E unit
I was trying to fix a friends Lionel 6-8772 GM&O GP-20 diesel from 1977. It had running problems in reverse and the E unit buzzed loudly. Searches of OGR forum, and the internet yielded the following suggestions: clean the drum; tear apart the unit and install a rubber bumper on top of the plunger; install a bridge rectifier to convert the coil to DC and bend the pawl. Well I did not want to do more harm than good (especially on somebody else engine!) so only the first appealed to me, but cleaning the drum with contact cleaner did not help.
Some expressed problems with the bridge rectifier causing the coil to run hot. Another expressed the opinion that older E units had paper insulating the wires in the coil and newer E units did not and that caused buzzing. That may be true as I have a couple dozen older E units ( 1977 is late model to me) and none have ever buzzed like this one. If it was mine I would have put in a bridge rectifier and monitored the coil temperature.
I decided to try adding a small piece of inner tube rubber to the top of the slot on each side of the E unit that the pin holding the plunger rides up and down. This did not require tearing the E unit apart. I cut two small 1/16 inch square pieces of rubber with a X-acto knife and using a tweezers, glued them into the top of the slot to act as a bumper for the pin. I used Pliobond rubber cement but super glue would probably also work.
Well, it worked and 90 or more percent of the buzzing noise is gone, though the plunger is still vibrating, at least it is quiet.
As a further note, the running slow in reverse was solved by taking out the brushes, and rounding off the edges of the contact end, cleaning the rotor with lighter fluid, tightening a loose screw holding down the rotor cover and correcting play in the rotor moving up and down by tightening a set screw stop on top of the brush cover over the rotor shaft. I am thinking the last cure, stopping the rotor motion, was the problem since the engine was slow only in one direction.
The Gp-20 is now GOOD to GO !
Charlie
