Captain Obvious

Nice car and lots of stuff to talk about, but I'll start with a quickie... If you drill a hole in the bumper shocks and drain the oil out, they should compress. But if you try to compress them with the (hard) rubber bumper accordion ends in place, you'll be trying to smash them down as well. Won't go easy or pretty. If you're going to push the bumper in, you need to remove the rubber ends first. And then you need to figure out something to cap the ends instead.

Nice work. Making parts like that sounds like it would be a simple matter, but they're really not easy. Especially to really make them right. So are you cutting the splines with the part mounted in the lathe? Using the whole carriage in manual mode like a shaper? Little nibble at a time? :)

The difference between those is only 20 thousandths. You really think that would be enough to make it not work? Did you buy some of the GM adapters to poke around with? I'm thinking there's got to be a relatively easy way to come up with something. Do you have a pic of the part you made? Neat project. Seems like the kind of non-profitable work I would get hooked into!

I had a bunch of parts plated professionally a while ago and noticed that the hardened ones came back very different than the non-hardened parts. And not in a good way. I'm guessing it comes down to the amount of carbon in the base steel. Seems the extra carbon makes them harder to plate? Those distributor spring clips would certainly be a higher carbon content than the typical hardware used on the Z.

One time when I was assembling rear bearings, I went through all sorts of gyrations to prevent assembly force from going through any of the bearing balls. I've since decided that it wasn't worth the effort. On subsequent jobs, I've found that the press fit category of the outboard bearing race into the hub bore was a relatively light press fit and didn't require a lot of force. I'm assuming that Datsun designed it that way.

Haha! Yeah, sorry for the glare. Those parts are too nice for my car. That's why they're in a box. Haha!

Great. Hope the rest of the project goes smooth.

Wow that's a lot of work. It looks great, but I can't help wondering if there would have been an easier way to skin that cat. He says from his comfy armchair...

Love the mission summary. I've heard it put this way... Misfires leave oxygen in the exhaust stream. AFR pics that up and interprets it as "lean".

I dug into some boxes here and took some pics. Apologies to @Yarb and everyone else for the incorrect info I posted earlier. Here's the 280Z linkage. View from the top: From the bottom: And here's a close-up where you can see washers on either side of the spring: And here's a shot where I'm holding the mounting bracket with the second return spring: And since I had boxes open, I pulled out a ZX throttle body. Looks like this: So it appears (to the naked eye) that the torsion spring, washers, and center tube are the shared between the Z and the ZX, but the part where the linkage ball and socket joint attaches is different. I believe that part pictured above is from a ZX, not a Z.

Yeah. now that you mention it... It appears that the spring anchoring hole does not exist on the lever part you have there. The spring and washers look fine, but that lever looks like it might not be the right part. I'll look at the parts tomorrow with fresh eyes instead of digging through old pics. I hope I didn't give you guys bad advice when I said they were correct.

Terrapin, I think those parts look perfect for any of the 280s, including the 78. I believe the linkage attachment piece is from a ZX, not a Z. Details a couple posts below. Exploded 280Z throttle body for reference:

There are a lot of web sites that proclaim to have flow rate calculators to predict the change in flow with respect to a change in fuel pressure. I haven't dug deep into any of them, but for example.... >> https://injector-rehab.com/knowledge-base/flow-rates/ And related to the topic, I recently tested a batch of injectors and got about 160-190 cc/min (using a stock FPR). So assuming the injectors I was checking were close to "as designed", then I can corroborate the 188 cc/min belief.

Ding DIng! We have a winner! I don't think we needed the entire song lyrics quoted, but we have a winner! Wango Zee Tango!!! Hahahahaha!! Now go pretend your face is a Maserati and sorry for the diversion!!

Honestly, I was just using this as an opportunity to drop the talcum / Malcolm reference. And surprisingly enough, it's not as simple as a quick google search. It seems a little more obscure than that. I know someone will get it, but they'll have to honestly know it. So... Game on!

I have a friend who's a big bicycle rider / repair guy and is always putting inner-tubes in bike tires. He says the popular technique in the bike realm is to get a little talcum. He borrows it from Malcolm. He says it's great lube for the inner tube to squirm around inside the tire while getting everything mounted up and inflated. I'm thinking that would work great on the windshield seal as well if you're looking for an alternative to corn starch?

Sorry, but no. I never looked into a purchasable tool to release those Yazaki contacts from the shell. I made one on the lathe. I'm travelling right now, but will take some pics when I get home in a couple days (if you haven't figured out an alternative by then). I also think I have a sketch from when I was designing my tool. That might help identify something on the market that would work. I think/thought @SteveJ may have turned up a tool on the market for that? Maybe?

This is the point of polishing it.

Ewwwww. That all sounds messy. Hope anyone who was innocently caught up in that comes out OK. And I hope anyone not innocent is held accountable.

Gotcha, and makes sense. You can't tell from the pics above, but I took that grinder with the wire wheel mounted outside and I'm doing that cleaning out in the yard and wearing a mask. No way would I want that cloud of dust inside.

Oh, and despite the brass color, I think the wheel on my grinder is fine steel bristles. I think they're brass coated, but steel. Use a light touch. The junk came off surprisingly easy for me.

OK, so it wasn't simply a valve lash issue. Not surprising, but too bad. And those valves look a whole lot worse on the stem side than the cylinder side. Definitely enough carbon chunkies to cause the leakdown you saw. Smoking gun there. So as for cleaning up the valves.... Two words. "Wire. Wheel":

Haha!! I know it's a longshot, but the insides of the cylinders really don't look that bad. In order to leak that much past the exhaust valves, I would have expected everything to look worse. Longshot, but here's hoping it's something simple like a valve lash issue!

Are you sure the exhaust valves in cylinders 1 and 2 were not being held open by too little (less than zero) valve lash? The whole thing doesn't look caked with exhaust carbon that would cause such poor leakdown results. I know... I know... I just have to ask.

I'm not sure I would trust loctite there, even the red stuff. If that nut comes loose, you could lose a wheel. Highly unlikely, but just not sure I would trust a loctite bond and ONLY a loctite bond. So I've done rear wheel bearings a couple times and I've switched over to the newer style of deformed thread nuts they used on the 280ZX cars. I'm not sure how the thickness of the newer ones compares to the older ones, but if it's thin enough and the deformed threads are down far enough, they could be a simple solution. The newer nut looks like this. Photo credit @ Blue: