1973 2.0L Rustoration, Restoration turned OT garage build Options

[Superhawk996]

I purchased my first 914 back in 1987 (1973 1.7L) and had that car for nearly a decade and I personally put over 100,000 miles on it before it ultimately fell victim to a negligent driver that drove into the back end of it at about 40 mph while the vehicle was stopped at a red light. That rear end crash totaled the vehicle but what is amazing is how well it crumpled (early crush zones!) due to the kink in the frame where the halfshafts are. Everyone walked away unharmed.

I replaced it with a 1991 Miata. Great car in its own right but I've always missed my 914.

Purchased this "replacement" in May 2018 as a known poster child for a complete right side longitudinal rustoration.

This vehicle had been put into storage inside a pole barn around 2004 as far as I can tell.

Vehicle initially purchased in non-running condition:
Engine couldn't be started.
Transmission shift linkage was disconnected
Half shafts and CV's were in pieces, and the wheel stubs were not installed therefore the vehicle couldn't even be rolled without risking having the rear wheel separate from within the bearing.
Fiberglass laid into the floorpan . . . that can't be a good sign.

Vehicle looks great . . . until I got under it.

I spent the better part of the summer putting the items above back together and trying to confirm that it would:
1) Run under its own power
2) Drive though the neighborhood and shift though all gears.



Looks pretty nice eh?

Here is what is lurking underneath once the rockers came off.



and when I started cutting back the rust. Oh my . . . .

[Superhawk996]

Spent a bit of time getting the 914 clock working.

Was initially non-functional when I first applied power to it.

Took a bit of poking around on the various forums to try to figure it out. Estimate to repair was about $285 from Hollywood Speedometer. I'm sure they would do a great job but that isn't in the cards right now.

Although I was able to get it working, it sill isn't fit for use and the front plastic lens is scratched. Oh, and the inner bezel is painted red (as are all my other gauges) -- Oh, the things people do (IMG:style_emoticons/default/headbang.gif) to these cars! so at some point in time it may go in for a professional repair.

In the meantime, the curiosity of how it works and the itch to repair it was killing me.

When I first got it, the factory seal on the back of the clock was still in place which was a good sign. That meant only the front of the clock had been opened up to paint the inner bezel. Looking at the outer bezel closely did show signs of this but overall, it was done reasonably well and carefully without mauling the bezel too much.

Opening the back reveled the internal thermal fuse was open.

However, I put a jumper across it, and the clock still wouldn't run. It didn't start ticking on its own. I did eventually find that if I put some light finger pressure on the main spring gear that it would tick. I figure this was due to a gummed up mechanism.

Flushed the mechanism with denatured alcohol.

Repaired the thermal fuse. This one is a bit tricky. The back of the case says to only use 120C low melt temp solder. I can't seem to find this at a resonable price. I think the only solder alloy close to that temp is Indium based and the only places I could find it were about $250 for about 10 grams of it.

I did finally find some commercially available solder with a 138C melt point at Micro Center. Close enough for Government work. Certainly better than 60/40 Tin/Lead electronics solder with a melt temp of 188C but I'd rather eventually fix this in the long term. Luckily I have a power supply that I can do current limiting on so no risk in the short term.



https://www.mgchemicals.com/downloads/tds/tds-4902p.pdf

Powered it up and voila! Or so it seemed.

Although it would run it wasn't self winding properly.

This is the most ingenious thing about the clock. When a set of contacts close, a solenoid is actuated which winds the clock. As the solenoid reaches the end of travel, the inertia of the winder mechanism carries it just a bit further than the contact on the solenoid arm, and opens contacts, and shutting off the solenoid. All this happens in a fraction of a second.

So what was happening is that although the contacts appeared to be closed, there were ever so slightly shy and not making electrical contact. I suspect this is due to mechanical wear, arching, or maybe something has gotten bent over the years. I tired cleaning the contacts but no luck.

I found that by putting a small shim (tip of a small tie wrap!) on top of the solenoid arm, it added just enough preload to close the contacts and to allow the winding mechanism to operate on its own.

Video below is with the tie wrap tip, taped into place with a small bit of green masking tape.


https://www.youtube.com/watch?v=NCQlqokfIPI


If anyone has more information on these clocks or has a more successful long term repair idea, I'd love to hear it. Otherwise I may eventually use a bit of glue to hold the tie wrap in place until I decide if $285 to restore the clock is worth it. Not likely in the short term until I get this car back on the road . . . I already have a $15 clock in my garage that works!

Also, I've found that a 1/2 Amp fast blow fuse is adequate to protect the clock in the short therm. The solenoid measures about 9 ohms so maximum steady state current flow would be 1.33 Amps by Ohms law. However, a solenoid is an inductor and inherently limits current in-rush and its inductance will be much higher than 9 ohms. I could dig up the equation to figure out the instantaneous inductance but that is too much work when trial and error works as well. Anyway, when I use a 1/2 Amp fuse, I can see the filament "bend" as the mechanism closes and current flows heating the fuse wire. However before it can get hot enough to blow, the current stops. In the long term, this bending of the fuse filament will fatigue it but for now, it works fine to protect the clock.