Monday, January 18, 2016

Baby Needs New Shoes

Checking out from Pro Automotive after the drive shaft repair, Keith noted that the rear tires were showing sidewall cracks and he sure would hate to see a blowout and the trail of sparks when the battery boxes drag the car to a halt. As usual, Keith is right, so we paid a visit to the tire store over the weekend for new shoes. Turns out all four tires were the same age (2009 vintage) and the fronts would be showing signs of dry rot soon enough, so I had all four replaced.

The replacements are the same model 195/65 r15 Falken tires that came off. That size seems to be a bit odd and not available from every manufacturer, also  sadly unavailable in low rolling resistance tires. Due diligence on Google turns up that Falken, although it sounds vaguely Scandinavian, is the performance brand for Sumitomo Tire company, and pretty well rated on the review sites. I don't know how many miles may have been on the old set, but they showed very little wear for seven year old tires.

I was pleased with the way Discount Tire handled the whole affair. They let me drive the car into the service bay so I wouldn't have to explain the startup process. They used hand tools for removal and installation rather than pneumatic impact guns, then hand torqued the lugs. They wire brushed the studs and wheel mount areas and even asked where I wanted the balance tape mounted.

It's probably psychological, but the car seems even smoother, so between the new drive shaft and new shoes, we're making progress toward a more civilized ride.

Thursday, January 14, 2016

Getting the (half) Shaft

Happy New Year!

I haven't updated this blog for a while, been waiting for resolution on a mechanical issue that reared its ugly head just before Christmas.

The Porsche had been running GREAT! I had put two hundred miles on it and was using it as my daily driver, running errands around town and buzzing down the highway for appointments downtown. Bit by bit, we were fixing some of the rattles and clunks that always seem to go along with a custom build. As my confidence grew, I figured the time was right to get the wife on board and share the EV grin with her. We drove it out to meet a friend for dinner at our local Applebee's, enjoying the time together and the conversation. As we left the restaurant and turned onto the frontage road, it sounded like a coffee can full of rocks and there was no power going to the rear wheels. The trip home was on the back of a flatbed wrecker with the wife having one of those "I told you so" looks on her face. The tow truck deposited the Porsche in my garage (these guys are good!) and there it sat until the Christmas and New Years activities subsided, all the decorations were put away, and all the leftovers consumed.

I was fearing the worst, as I tend to do, thinking the likely culprit was the weld on the motor to driveshaft coupler. Finally last week I pulled the inspection plate off the top of the coupler housing (no small feat) and was relieved to see that the coupler looked perfect. That was a huge happiness because I really didn't want to disconnect everything and pull the motor out and then re-engineer the coupler. So the next line of thought and a good bit of Googling led to the suspicion that the driveshaft to transaxle coupler may have worked loose or stripped its splines. That was only slightly less distasteful in that the transaxle would have to be pulled to make that replacement.

This morning I had the car towed over to Pro Automotive to have the experts put it on the lift and work their magic. Bob just called and told me the right hand axle shaft had failed. I'm delighted! Not only can the motor and transaxle stay where they are, it's really a pretty straightforward repair.

We've ordered a replacement that is a bit pricey, but is an OEM quality German manufactured part as opposed to the "remanufactured" ones that I had sourced when we did the conversion. In this case I fear that "remanufactured" is an industry term for "cleaned the gunk off a used one and sprayed on some Rustoleum".

A recurring theme among the community of EV conversion guys is the frequent breakage of something in the driveline after the conversion is complete. You may recall that I had a transaxle graunch in the evTD, and the same sort of thing has happened with alarming frequency to other EV conversions. No drag racing this time, but with the strong regenerative braking on the Porsche, it's no surprise that there's more stress on the driveline than its thirty year old parts can handle.

I'm anxious to get the car back in service and already have some plans for improvement. Stay tuned ...

UPDATE Friday, January 15, 2016

Bob called to let me know the Porsche was done and ready to be picked up. They shipped the part overnight from somewhere in Illinois and Robert had it installed by 10:00am! Probably couldn't have gotten one from a warehouse in Dallas any quicker. The car runs great and feels smoother than before. It's good to have it back on the road.