Captain Obvious

There shouldn't be any significant vacuum in the tank. There's a check valve built into the gas cap that's supposed to prevent that. (Funny that there's another thread running at this exact same time talking about the same thing. ) Here's some pics of the check valve. If you're truly getting a vacuum in the tank, maybe your check valve is plugged up? Here's the cap where you can see the air intake passage bulges: Here's the air intake passage from the side: Here's the check valve. I pried it up with a screwdriver: And here's the air intake hole on the under side of the cap where the air intakes get to the edge:

Page EF-22 of the 73 manual page has a decent cutaway dwg of the cap. It also describes how to test the check valve: 1. Wipe clean valve housing and have it in your mouth. 2. Inhale air. A slight resistance accompanied by valve indicates that valve is in good mechanical condition. Note also that, by further inhaling air, the resistance should be disappeared by valve clicks.* 3. When valve is clogged, or when there is nor resistance, replace cap as an assembled unit. Nice, huh? * I used #2 from the 74 manual because it's funnier. The other two are from 73.

I don't have documentation back to 71, but I've messed with later year fuel caps and if the OEM cap is functioning properly, I don't think it should be leaking like that. Back to at least 72 there was a check valve in the cap that was supposed to let air in (to replace gasoline taken out to run the engine), but not let air back OUT. Are you sure your check valve is working properly? If you've not ever messed around with one of the caps, it's the spring loaded metal disk on the inside center of the cap. If you pry that disk away from the cap, it opens an air passageway to the little radial bumps bent into the outside of the cap. The ridges that run perpendicular-ish to the grab handle? On edit - Found some pics. here's the cap where you can see the air intake passage bulges: Here's the air intake passage from the side: Here's the check valve. I pried it up with a screwdriver: And here's the air intake hole on the under side of the cap where the air intakes get to the edge:

The gaskets "packing" #20 on that diagram seal the lids to the distribution blocks, not the blocks to the cam towers. I don't know if they originally came with a gasket between the towers and the blocks, but I'd put one in. I'd use gasket material though instead of RTV because I think it would be more forgiving to the vibration? All of the blocks I've messed with had been chewed up a little on the back side from vibration against the towers.

If they wrapped a non-hardened shell around a hardened cylinder, then drilling it would be a breeze. But if these new ones pan out, of course that would be even easier. With the new ones, while they're off the car before you install, you might test the hardness with a file. If you're going to drill for a zerk, you could pull the caps off to clean out any chips. Of course, there's no guarantee that there's the same passageways in the bodies of new ones, right? You'll have to pull a cap or two to check. Either way, this could be a great find! New non-greaseable ones are still better than old dry non-greaseable ones. Keep us posted!

Don't want to pre-emptively bust your bubble, but seeing as how the cap is actually the outer race for the rollers, I'm sure it's hardened You got any carbide drill bits? Haha!

Yes, I believe the #5 inhibitor is for automatics only, so 1, 2, and 3 only makes sense for manual trans without A/C. Thanks for the help with the 78 point of view.

Thanks for the thoughts. Here's something that you might be able to do remote... This is a snippet from the 78 manual with a sketch of the late style relay bracket: Is that what yours looked like, because if so, it's completely different than the 77 version.

Seeing as how the yoke is actually the inner race for the rollers, I'm sure it's hardened. You got any carbide drill bits?

Of course that counts!!

Haha! No secrets! I got nothing but the ocean.

No worries! Bob, Thanks for the confirmation on the trans in your car and Chas, thanks for the pics. Those are great shots. I appreciate the help from both of you! PS - Bob, yeah Chas' car is a lot cleaner than mine too, but I don't let it get to me. Mine's much faster, and if he doesn't believe that, he's welcome to bring his around for a good ol' fashioned drag race. :laugh:

Great! I'd appreciate any pics. The issue for me is that I'm planning some electrical changes and I'm wanting to repurpose some of those mounting locations for other things and I don't want to put something new in a location that I'll regret using at some future time. I have a manual trans car so the seat belt interlock location is up for grabs, but can't figure out that other set of mounting holes on that front side. Anyone got pics of a 78 bracket configuration? Rossiz, if you're reading this, can you maybe stick a camera down in there and take a couple pics of the 78 design? Maybe they had holes laid out in 77 but didn't use them until 78?

Thanks for the help. I'm assuming your car is a manual trans? That would make sense that you don't have the seatbelt starter interlock relay.

Eastern Beaver (and no, it's not what you think). They are the only small onesie/twosie order friendly source I've found for the original Yazaki connectors used on the Zs. They don't have them all, but they do seem to have some of them. Here's their main connector page: Connectors And they've got one for sheaths: Sheaths If you're going to place an order with them, send me a PM because I might want to piggyback with you. Help you make minimum and split the shipping from overseas?

Thanks, but I don't think so. That stuff is mostly on the interior above the fusebox and I'm out in the engine compartment. Here's some sketches from the 77 FSM that seem to corroborate that the solo relay attached to the bracket in my pics above is for the air conditioning compressor. And it also appears that one of the relays to be mounted on the front side is for a seat belt interlock on the auto trans cars (#4 in the diagram). But what's got me is that I've got room and mounting holes for TWO relays on that front side, and I have absolutely no idea what the other one would be for: Here's another sketch from the FSM that shows a little more detail about the seat belt interlock relay.

This is a pic of the relay bracket from a 77 Z. There are mounting holes for relays that my car does not have. Does anyone know what the relays are that screw to this side? What are the functions of the two relays that screw to those four mounting holes on the side that faces forward toward the headlights: And for posterity, here are the other three sides. This is the side that faces the engine. The four screws attach the two fusible link blocks: Here's the side that faces the battery. The relay in the pic (I believe) is for the air conditioning compressor: And here's the side where the voltage regulator would mount:

[joke]Maybe he means you plug it in and then play with it for months trying to get the tuning right.[/joke] :paranoid:

I'm assuming they were licensed to be an authorized rebuilder of such things and were given enough info from Hitachi or Bosch to be able to test the module as a black box. Attach this cable and hit the "test" button. Probably runs through different simulated temperature, RPM, and air flow rates and then measures the pulse width output accordingly. As for the solder touch up, it doesn't seem to me that it would be that difficult to re-wave an already done board. Pretty much all you need to know is the outside dimensions of the board so you have locations to attach it to the fixture, right? Of course, I've got no idea if they are actually doing such a thing, but it doesn't sound that unfathomable. And, yes, I have verified (in my very limited experience of maybe three ECU's) that there are no electrolytics. Wait a minute... Are you talking about the module, or their owners?

That's awesome. Probably terrifying from the driver's seat, but awesome!

It's just boiler plate marketing. I wouldn't get my hopes up about anything specific.

Yeah, that's the guy! So he does architecture too, huh?

Heh! You're old. Where oh where are you tonight? Why did you leave me here all alone? And sorry... Can't help you with your quest. Thankfully I never needed to look for a replacement.

And here's why it needs to be replaced:

Jay, That lower bearing is definitely different than the later racks then. Both the bearings on mine were balls and they were bot the same. I'm with you... If you don't have a confirmed correct replacement for that bronze bearing in hand, I wouldn't mess with it. As for adding pics of the older rack style to that rebuild thread, I think that's a great idea. Would add to the resource. CanTechZ, That drawing is fine. Drawn by esteemed draftsman M.C. Eschersan.