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Dynamator Tech Session - 10/22

Published on 10/22/2016



When the generator on my BJ8 failed this summer, I decided to replace it with an alternator…I’m tired of the recurring generator problems. Rather than use a modern one, like in our cars today, I decided to get the “retro” version that looks like our cylindrical Healey generators. Peter Roses had done the legwork on this project when he installed one in his 100-6 (the details for this are on the website under Technical documents). This alternator is called a “Dynamator” (combined voltage regulator and alternator) and comes from a UK company, through a Canadian broker in Alberta.


The reason the Lucas generators and voltage regulators are prone to problems is that our cars today, with all their aftermarket improvements draw more current, thus the generator is overworked, constantly charging our acid based batteries. They overheat, and start throwing solder inside the generator and fail. The rebuilt one in my BJ8 only lasted about 18 months.


 I ordered the Dynamator, painted it Healey engine green and Peter altered my backup voltage regulator (essentially removing the guts, thus making it a terminal post) which allows us to bypass the Lucas voltage regulator and use the one built into the Dynamator without changing any wiring. We got together for the installation at Steve Kirby’s shop in Lake Forest by piggybacking on the British Car Swap meet being held there on Saturday, October 22.


It’s worthwhile diverging a moment to describe a few differences between Peter’s installation on his 100-6 and my BJ8. First, my Healey is positive ground, while Peter’s is negative. This resulted in me ordering a different model Dynamator, which required the additional step of installing a relay. We assumed that the remainder of the installation would be the same…and we all know the definition of “assume” (ass of you and me)! The other differences were learned mid-way through the installation.


Peter began working on the relay installation by mounting it under the dash, inserting it into the power line going to the “charging” idiot light. Thankfully, he is younger than me and can get under the dash and get back up again! I began by working with a team of surgeons removing the old generator and voltage regulator and (hopefully) installing the replacement Dynamator and replacing the regulator with the altered one. That’s when we discovered two problems. First, the stock generator has a mounting bracket wider than the new Dynamator. Second, when we removed the pulley and fan from the old generator, we realized that the shaft size on generator was narrower than the Dynamator, and we planned to reuse the fan and pulley. Thus, we hit a brick wall. We decided to stop the project and resume once we solve these problems. Either the broker shipped the wrong part or they don’t realize that a BJ8 (late model 3000) is different than the 100’s, 100-6’s and early model 3000’s.


To be continued…