Ever drive your Spit with the engine fan disconnected? You know, just around the block on a cool day, not long enough to boil over the engine. Try it. You'll find the engine is much quieter and even revs a little easier at the top end. Needless to say I tried it and I was convinced an electric fan would make my car smoother and more efficient, so I went down to the local discount auto parts store and bought a Hayden 12 inch cooling fan and brought it home. It's working now, but I think you can learn from my mistakes!!
First of all, installing the fan itself is a breeze, no pun intended. The fan is a little bigger than the radiator, height-wise, but there's plenty of width to work with. I mounted the fan so the top of the fan was flush with the top of the radiator - it looks good! To attach the fan to the radiator you push these plastic rods through the fins and push on a one-way disk that holds them to the radiator. To take the fan off you have to cut the rods, but you can get a mounting kit for a few dollars, if this becomes necessary. That was the easy part.
In addition to the fan itself I bought the fixed temperature thermostatic switch kit which includes a relay and wiring harness. The switch itself has two electrical connections and a threaded rod which screws into a brass rod which you stick into the fins on the radiator, and here's where it can get interesting. At this point, you should have read the directions, carefully, and you would probably have no trouble at all. On the other hand you may look at this simple switch and say "I think I know where this goes!" Overall I've installed this switch five times in four different spots!
The first spot was just above the outlet at the bottom of the radiator, poking in from the cool air side of the radiator (because the wiring worked out so nice). I didn't really have any trouble pushing it through, although it was quite a tight fit. After you push the rod through you break off the extra that sticks out past the radiator. Well, I broke off a little too much, so that was mistake number one (that I knew of, really it was mistake number two!). After hooking up all the wires I fired up the engine and stood back, watching the temperature rise and waiting for the fan to come on. I watched the temp gauge get hotter and hotter and hotter and finally the fan came on and I thought "Whew!" Imagine my surprise when the fan only ran for a few seconds and then shut off!! Clearly the switch positioning was causing the fan to come on late and shut off early, especially since it was "downwind" of the cooling fan.
So, keeping to same side of the radiator, I moved the switch up to the top, above the fan, on the outlet side of the radiator, still poking in from the cool side of the radiator. At this point I'd already broken off the blunt end of the brass rod and had to poke the raw end through the fins. Well, I was in a little bit of a hurry and again the rod was a tight fit. I wiggled it around like the last time and was pushing it through when suddenly the rod went through and I could hear a tiny sucking sound as air was drawn into the radiator through the small hole I just created in the vertical cooling tube! Needless to say I was not happy!!
I took a few days off after that. Then I drained the radiator and decided to try to fix the hole myself. Don't worry, this story has a happy ending. With the radiator on the bench I clamped a needle nose vice grip to the top of the cooling tube, to dissipate any extra heat from the pencil torch I would use to solder the hole, to avoid melting the joint where the tube mates to the top of the radiator. After finding the actual hole I applied some liquid flux to the repair area and got out the pencil torch. Heating the repair area I applied some lead based solder several times as I was at first afraid to overheat the repair. Eventually I was satisfied I had gotten as much solder into the hole as I could so I decided to leak check the repair before reinstalling the radiator. I rubber banded a latex glove to the outlet port of the radiator and filled the radiator with water. It didn't leak so I thought I would pressure test the system before putting back in the car. I reattached the inlet and outlet hoses to the radiator and looked around for a way to close off the ends of the hoses. Here's a handy tip for you: it turns out the inner diameter of the hoses is jsut about exactly the same as the out diameter of the common plastic soda bottle or oil bottle cap. So I stuck one cap in each hose and applied hose clamps. I blew some 20 psi into the overflow bottle tube to pressurize the radiator. This worked great! The radiator didn't leak so I put it back on the car and continued...
The new switch position helped a bit but still wasn't enough, and I boiled the engine and had to run the fan manually to cool things down! Still coming on late and turning off early.
So I figured I'd move it over to the bottom of the inlet side of the radiator, poking through from the cool side of the radiator, being very careful not to poke any more holes! This worked pretty good but the fan still came on a little late and still shut off a little early. It was good enough to be able to drive the car but a couple of times it boiled over just a little bit after parking.
Now I knew exactly what to do! I moved the switch to the top of the radiator an inch or two under the inlet port, still poking in from the cool side. This was marginally better but I was still not satisfied by any means. But now what?! I couldn't get the switch any hotter or make it run any longer... or could I?
In desperation I searched the web and found Hayden's web page and found a phone number for tech support. Oddly enough the instructions with the fan and relay kit had no phone numbers or addresses of any kind. Anyway the guy at tech support told me to push the switch through from the engine side of the radiator so it would get hottter while the car ran. I was a little skeptical but I had nothing left to lose, so I tried it and what do you know, it worked great!! Problem solved!
So finally after all that I decided to take a peak at the instructions and see what they said. Sure enough it was there in black and white: put the switch 3-4" from the inlet of the radiator, poking through from the engine side.
Ah, well, I said you could learn from my mistakes and I wasn't kidding!
A picture is worth a thousand words, so here goes:
The top manifold is from my '74 1500, the bottom is from a Mark IV (also a 1500cc engine). As you can see the ports are much larger on the Mark IV manifold which results in much better breathing from about 3500 RPM and up, as noted in a Road and Track article from 1974. This makes the car much more fun to drive. There's no threaded hole for EGR, although there is a blank spot for it, and there's no port for the anti run-on circuit. Everything else is the same. I bought the Mark IV manifold on Ebay for $3 plus shipping!! Try it, you'll like it!
My transmission had a chronic oil leak, or so I thought. Turns out the clutch slave cylinder was leaking! You can determine if your slave is leaking by checking for brake fluid dripping from the drain hole at the bottom of the transmission bellhousing. I ordered a rebuild kit and here's what the old and new parts looked like:
In both pictures the new seal is on the right. Now you know what a bad seal looks like!
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