Tuesday, February 20, 2018

Mechanical Stuff

Has it actually been over six months since my last post? Time flies when you're having fun. Not really a lot to talk about, just incidental nuisances with things unrelated to the electric nature of these cars plus a few minor electrical glitches. For instance:

The driver's side door handle on the Porsche broke. I mean broke as in "thirty year old metal fatigue". Replacements are available but a bit pricey. The good news is that it can be installed without disassembling the whole inner door panel. Unfortunately, no photos.

On the MG, the steering box was the only moving part that wasn't replaced when we did the conversion and it's become pretty obvious that it should have been. What started as a vague off center feeling in the steering became a scary lack of response to steering inputs. A new steering box was the order of the day and fixed that situation right away. It's nice to have the car go where you point it.

After I replaced the wonky steering box on the MG I was enjoying a test drive when I smelled a hot plastic electrical smell. Back in the garage I noticed that the Battery Management System had lost touch with a block of cells and after major disassembly found a burnt cell board and a main board that had oozed a bunch of silicone all over its housing. I know - Jack Rickard told me so - but after six years in service, I finally removed the BMS and bottom balanced the GBS pack.

Burnt Terminal
Bleed charge off with PowerLab 8
Final trim with home made resistor

After six years, the GBS pack is still at full capacity and reasonably well balanced. So now, BMS free one day at a time.

With all that done, it was time to tackle a two year old problem with a broken transaxle mount. This is the second time that the forward mount has broken, this time not as a result of drag racing, just every day use. The car remained drivable but made an annoying "Bump-Bump" noise as the rear of the motor bounced off of the rear cover whenever torque was applied. Since the mount was broken and could be removed in two pieces, we were able to do the replacement with the motor and transaxle in place.

The new mount has no rubber buffer and is a solid piece welded up from quarter inch steel. It's sold for "off-road use only". I suspect it would be pretty harsh with the old VW boxer motor but smooth as silk with an electric, and with any luck significantly more durable. It raised the rear of the motor enough to cause interference with the tachometer sensor on the tail shaft of the motor, so I had traded "Bump-Bump" for "Screech-Scratch". Simple fix for that is cutting a clearance notch in the rear valence.

The MG now has the drivability issues sorted out just in time for Spring weather outings.

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