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Old January 14th 2016, 04:25
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owdlvr owdlvr is offline
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Join Date: Sep 2008
Location: Canada - West Coast
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I considered trying to go through my photo library to find some highlights of the past two years, but quickly realized that it would take me forever, and I’d probably never get around to actually updating the thread. So, instead, I’ll simply start from today and if a project comes up that requires some history, I’ll tell the story at that time.



One such story involves the fairly ambiguous fresh air box seal. From the day I built the Rally Bug, I’ve had a leak I could never find. It wasn’t a big leak, sometimes I’d wash the car and it would have a few drips on the trunk carpet…other times nothing. Sometimes I’d drive in the rain and it would be damp under the trunk, other times nothing. Coming back from our Hagerty Fall Classic event, I hit the biggest rainstorm I’d ever been in. We’re talking 3-4” of standing water on the interstate, and rain just POUNDING down. As I’m considering where I can get off to wait this out (due to 1971 wiper technology) I suddenly noticed my legs were getting wet…REALLY wet. Where is that coming from!?! Oh, it’s only water dripping through the fuse box! I’ve since determined that the seal on my fresh airbox doesn’t actually seal against the hood. So far I can’t figure out why. The seal appears good, the box appears to be at the right height and the hood fits the car extremely well. Ah well, the search for a better seal begins!

Also on the Hagerty Fall Classic, we had some clutch issues. The event began about 5 hours away from my house, and I was almost picking up my co-driver at the Airport when I had the first crunchy shift. “Hmmm, that’s odd”, I thought. The clutch pedal felt the same, but it was as though it didn’t disengage the clutch. Visions of breaking cables, the hook on the pedal and a number of other possibilities filled my head the rest of the way to the start location. As the weekend progressed, things got worse. I adjusted the cable, no help. Any shift was a question mark. Sometimes you’d put your foot on the clutch and it would work like butter. Other times you’d put your foot on the clutch and it definitely wouldn’t disengage…but it felt the same everytime. We finished day two and three with me shutting the car off at each stop, and planned on using the starter to get the car rolling if the clutch didn’t work. The weird part was you’d come to a stop sign, and the car would want to stall with the clutch in. The moment you went to start it, though, the engine would spin freely just fine…even if you never moved your foot off the clutch!?!

We figured it must be the pressure plate failing, but when I finally pulled the motor in November I got a bit of a surprise:



So, apparently the pilot bearing failed. Fair enough, I think it’s the same one from when I built the car in 2012. It’s got a LOT of miles on it. Must have started seizing, and eventually failed completely. I presume, from what I’m seeing here, that the clutch was probably working fine, and the bearing bits were keeping the engine connected to the transmission ‘just enough’. Bizarre, but the best theory I have.



But that’s a really long around the block story about the next project for the Rally Bug. Adjusting the clutch cable, the fact that over the years I’ve found the 901 to beetle clutch cable isn’t perfect and the fact that I’d like to move to dual masters on the brakes eventually means the clutch cable simply has to go. The ‘big’ project this winter is a hydraulic clutch setup for my car.

Researching it, the early Porsche 901 box I use is going to be a bit of a challenge. I bought the SACO hydraulic clutch kit for a beetle, but quickly realized that I won’t be using it. The external slave would have to either a) be mounted below the frame horn or b) require a bent and convoluted connection to the clutch fork. Couple that with the fact that know the Porsche clutch requires more pull travel vs a beetle setup, and it’s not going to be a simple installation.

So, if its not going to be simple, we should make it even less simple…right? I don’t mind a challenging initial install, as long as once it’s all setup it works and requires little playing with it. Bending linkages just right, figuring out the ideal spot to drill a new leverage ratio into the clutch fork, etc etc. seemed like the external kit was going to be too much work. So, I started looking at concentric slave cylinders.



A concentric slave cylinder replaces the throw-out bearing, and clutch fork with a hydraulically operated bearing. Once setup, there are no adjustments. It automatically compensates for clutch wear, it feels the exact same from the first shift to the end of the clutch life. There is a Saab unit which is often adapted to transmissions for a cheap(ish) option, but we’ve got a pile of Tilton Racing stuff here for the MK1 Escort project, and I sort of got swept up in using one of those…plus all the dimensions were in the catalog, so I didn’t need to buy one to see if it would work!



After measuring up the 901 Transmission and related clutch parts, the Type 1 Engine, and using the Tilton bearing dimensions, I came up with the following adapter ring:



The ring will require some modifications, as the inside of the bellhousing isn’t flat. What this does give me, however, is all the important locating points and a spot to start modifying from. But, I need the part in my hand…So, bring on the 3D printer. I’ve been meaning to buy one for a few years, but never seem to get around to it. With the technology becoming popular though, I had this one printed for $13 and picked it up the next day.



Before I can start modifying it, though, I need to pull the pivot ball from inside the Porsche bellhousing. On most 901 gearboxes this is actually threaded into the transmission. On the Early-Early 901’s, like mine, it’s pressed in. Okay, easy enough, a slide hammer should pop that out. Hmmm, I don’t own a slide hammer. Fine, went and bought one ($150) and discovered the jaws don’t go down small enough to grip the ball. Hmmm…I need access to a lathe or a mill.



All of this clutch stuff happened pretty much on the Christmas holidays. I just launched the registration for our first 2016 event on the weekend, so I’ve been pretty busy locking that down. For the past 2-3 weeks, though, I’ve been thinking about how I’m going to make the final mount once I modify the plastic version to fit. I don’t have access to good mill, and my skills on a lathe could create the basic disc, but wouldn’t allow me to lay out the bolt holes in an accurate function. Plus the backside has some radiusing on the mount that require a mill, not a lathe. Hmmm… I think I’ve figured out a solution, which I’ll be taking care of this weekend.

To be continued…
__________________
'71 Type 1 - Rally Project
'58 Type 1 - I bought an early!?!
'73 Type 1 - Proper Germanlook project
'68 Type 1 - Interm German 'look' project
'75 Type 1 - Family Heirloom
'93 Chevy 3500 pickup - Cummins Swap
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