Captain Obvious

So what the heck is the "Cooling Fan Motor Sub-Harness? Nobody has ever noticed them before?

Haha! Your WAG is not correct. There is only one wire on the flasher switch that is normally hot. I'm saving the boobie prize for myself. I love those. :laugh:

This suggestion has a problem and won't work. Bonus points to the first person who can figure out what that problem is. :bulb:

So... I'm looking over the wiring diagram trying to figure out the cleanest way to get an always hot voltage line to my new radio install and I see these on the wiring diagram: Anyone know what these connections are all about? I went to the garage to see if they really exist, and they did (at least on my 77 they did). They are present but unused and are located above the passenger's right knee above the relay bracket. Lo-n-behold, one of them is hot at all times just like the diagram says it should be. So what's the deal? Was that some option that I don't have? Was there a factory electric fan installed in some cars? It's on the wiring diagrams for 76, 77 and 78. I don't have one for 75 so I don't know about that year.

That engine looks awesome. What did they offer that in?

I just measured my red 5-speed pattern to be 1.050 OD. I don't have one of the earlier plastic patterns here to measure, but I did measure the recessed hole in a wood knob to be 1.080. I don't know anything about the ones offered from ebay. So, it's be as much of a difference as I mentioned above, but it might be enough that you'll have to fill the gap to keep it from looking funny.

The later metal cloisonné style maps are slightly smaller in diameter than the earlier plastic ones. Maybe an eighth of an inch or so? If you try to use the cloisonné style on your wood knob, there will be a small ring gap around the outside edge. If you try to use a black-n-white plastic style in your black plastic faux leather knob, it might not fit into the hole. You might be able to force it in, but I've not tried.

It's not deadheaded. It's got a hole out to atmosphere at the end, right? That's the whole reason it leaks! With a small almost deadheaded leak like that, the "normal" flow direction doesn't really matter... Remember you've got both absolute and differential pressure in that system. Thermal expansion provides the absolute and the water pump provides the differential. Either one of those pressures is capable of forcing coolant out a leak hole. In your case, I suspect that the absolute is forcing water "backwards" up that tube and out the leak hole. And BTW, I found lots of gunk in those tubes when I was messing with that stuff on my 74.

First round's on me!! I'm buyin'!!

Haha! Yeah, I figured as much. I know you know your stuff and it had to be something simple like that.

I'm guessing that you're talking about the tension/compression rod bushings in the front suspension and the sleeve that fits over the threads on the T/C rod... If that's the case, you should be able to hold it in a vice while you twist the T/C rod out of the sleeve? Might not work because the sleeve is pretty thin and if you squeeze it, it might ovalize and clamp down on the threads. Other ideas? Hit the shoulder of the sleeve with a hammer and chisel or screwdriver? Drive it off a little at a time? Cut it off with a hacksaw? Be careful not to get into the threads on the rod. Try some heat on the sleeve in conjunction with the above?

Nope. The ground for the fuel pump relay is hard wired on connection #72. The ECU really has absolutely no direct link to the fuel pump operation at all. The only link between the ECU itself and the fuel pump operation is indirect. By that, I mean... The engine won't run without the ECU and the vane in the AFM won't close the fuel pump contacts unless the engine is running. But other than that, there's no link. In short, the only way the ECU controls the fuel pump is through the use of air. Remember, we're talking 77 (and prior) here, but I believe the above applies to 78 as well. You would just have to change references to AFM to oil pressure switch instead.

All of the bars I've refurbished started with the original tubes. I've not made replacement tubes to date. Sometimes I wonder if it would be easier to remake the tubes from scratch as well, but so far, I haven't done that. I'll dig out my notes tomorrow in the shop...

Yeah, interesting that the hole diameters are different. I have never messed with it, but I've heard there is a flow restrictor in the oil passage leading up from the block into the head. The prevalent theory being that you could completely open flow the oil in the head (like dumping all your oil out of a cracked spray bar) and you would still have enough pressure at the crank that you wouldn't waste your mains. You would ruin the upper end, but the crank should survive. If that's the case, then maybe they opened the holes in the cam so it wouldn't shoot so far? When it's not leaking all over the place, those spray bars really spray. Like... Multiple inches of spray. With the holes in the lobes, you only have to hit the follower. Anything sprayed on the underside of the valve cover really doesn't do you any good. Just thinking out loud...?

I'm sure it was a simple use of the wrong acronym, but for the sake of clarity and completeness, the above is incorrect. It's not the ECU that controls the fuel pump, it's the AFM and the fuel injection relay (above your left knee under the dash) that control the fuel pump. You could completely remove the ECU from the car and if you lift the AFM vane, the fuel pump will run. But back to the real point... Other than the fuel pump, I don't think there is anything else that you would have to spend any attention on when converting to carbs. The FI harness is it's own entity and separate from everything else. The only things it makes contact to are FI specific components and the battery.

That's cool. Wasn't well-known to me that they changed it. That design is definitely better than the original. Not easy to clean out and still has the same stress/strain issues as the first design, but if it can handle it without failure, then no prob. They couldn't have offered that version for long... I've done bars for as late as 75, and in 77 they went to internally oiled? Maybe that was a 76 only thing?

I measured some variability in the diameter of the holes and they range from 0.046 to 0.049 inches. I only have one bar at my disposal at this time, so it's a very small sample size. Also keep in mind that I have no idea who's been poking those holes in the past, and with what. They looked clean and un-messed with, but who knows what's been done to that bar in the past 40 years. But all caveats aside... My guess is that they used a 1.2mm drill in production and the diameter would change some depending on exactly which bit they got from the tool crib that morning and as the drill bit dulled in use. Out of curiosity, what size holes did you find in your cam? Is it a stock cam or aftermarket?

The A11-601-000 ECU is for 77-78 auto trans. If you've got a manual trans, you should be running a A11-600-000. I don't know what the difference is and I'm not sure if it's really a problem, but that's what the documentation says. So, was your car originally an auto, or do you think the ECU was replaced with the wrong one at some point in the past?

And I forgot something else about the ebay locks... The ebay locks do not have the "return to center" feature that the stock locks have. Your stock locks have two springs that balance the lock position to the middle when you aren't turning the key. The ebay locks have no such feature. They will stay anywhere you leave the key. Not a big deal, but I kinda like that return to center feature of the original locks. I'm not crying about losing it, but I do think it was neat. Apologies for the multiple additions, but it's been a while since I messed with my locks and this stuff is coming back to me piecemeal. Something else I forgot to mention. You said: I'm not positive, but I believe the lock cylinders themselves are identical right to left. Only the arms are different. So if you find two old usable locks, you can mix and match the arms from your original set to get a R and a L.

Not so definitive... My PO proved that the ebay locks are an option. They are clearly not an easy drop-in option, but they are an option if you run out of other simpler avenues. In my limited lock work, I've found that there are two things that commonly happen with the stock door locks. First, the pot metal cam on the back smears out and you can't get enough travel to actuate the lock. This is the problem you have, and you can clearly see this by pulling the retainer clip off the back and getting a good look at the cam and follower. The other thing that happens is that the lock cylinder and wafer tumblers wear on the inside of the lock. As this wear occurs, the lock becomes finicky and eventually gets so bad that the correct key will no longer turn the lock. This wear, unfortunately, you cannot see without taking the lock apart and that means dealing with the crimped on chrome face cap attached to the outside face of the lock assy. Your sticky stock locks were probably a combination of worn cylinders and wafers/springs that were corroded in place and stuck in their slots. The WD-40 hopefully freed up the tumblers, but it won't do anything for the wear. If you're going to drop in a different pair of stock locks (or a pair of ebay locks), you'll have the multiple key situation. And if you decide to have the locks keyed alike, or do it yourself as I have, you'll get the opportunity to evaluate the guts for wear.

I forgot to mention that I also see that you have the pin 12 altitude compensator switch connection (which makes perfect sense since you're in CA). The non-CA cars (like mine) do not have a contact in the number 12 position on the harness side.

It's not just the tilt. It's the tilt combined with the fact that the front carb has the bowl on the uphill side of the nozzle while the rear carb has the bowl on the downhill side. If both bowls were on the same side (either side), then the tilt wouldn't mean squat.

And if the cam and follower stuff doesn't make sense, let me know and I'll snap some pics. I've got both types in the shop but haven't taken pics of that detail.

Yes, the longer arms came with the significant door redesign in 77, and yes, you are right in that the ebay door locks will not easily work on your 78. However, the problem isn't just the length of the arm. It's also how the arm fits onto the back of the lock cylinder. If it were as simple as the arm length, you could just move your old arm over to a new ebay lock, but you can't because it won't fit. In fact, most of the auctions for the door locks include some generic BS note about "You may have to move your arm over from your old locks". But it's BS because you can't! The problem is that the older style locks have a different shape cam and follower on the back of the lock and they cannot be mounted onto the newer ebay style locks. You're OK if you have a pre-77 Z because you can just use the new arms on the new locks, but the 77 and 78 guys are left a little cold. Here's what my PO did... Cut the new arm from the ebay lock in the middle. Cut the 77-78 style arm from the original locks in the middle. And weld the two of them together to make a 77-78 arm with the new ebay style cam follower hole. It wasn't a great welding job, but it's certainly strong enough. It's ugly, but it's behind closed doors. Pun intended. Remember though... I'm not a locksmith.

Assuming the car is an auto trans, you're fine. The reason the contacts don't match up perfectly is that there are a couple locations that aren't used when the car is being driven, but are used for diagnostic purposes. On the harness side for example... Pins 20 and 21 on the wiring harness don't make any connection to the ECU, but can be used to verify the functionality of the fuel pump signal and cold start system respectively. And on the ECU side for example... Pins 11 and 26 are test output locations for the injector signals. They aren't used for anything when the ECU is in the car, but they could be probed to see what the injector drive signals are doing. I don't see anything wrong with what you have there.