Zed Head

Those guys from 2003 seem pretty cool. The rear countershaft bearing would be the one in the adapter plate. Just looking at the picture of the gears you can see so many spots where that high frequency buzz could happen. Gear teeth touching slightly maybe. Gears slightly out of alignment. It doesn't sound like a tooth count problem, that would be a major problem. The fact that it happens when the countershaft is loaded suggests that the helical cuts of the gears are pushing two parts together, or one of the shafts is loose and being pushed away from the other. So something is slightly misaligned, or loose. When the countershaft isn't loaded the gears are just along for the ride. No noise then suggests they are moving just fine, it's the load that makes the difference. It's a bummer. I'd drop the oil and see if metal flakes show damage happening. It will give you a clue at least.

On my 76 I found that the brake lamp check warning relay was powered all the time after using Blue's Tech tips wiring. It drained the battery over a day or two. I ended up using the fuel pump power line to power the relay and disconnected it from the constant power wire. Might not be the same on 77. Seems like Nissan changed things around every year. Something to be aware of. I think that Blue's tech tips are specific to 77 so should work. Here's the link from SteveJ's sig link. (The AtlanticZ page is so tiny now...). https://www.atlanticz.ca/zclub/techtips/alternatorswap/index.html

I think it's a countershaft issue. 4th gear is direct through the main shaft. Not sure what exactly it might be or what to do about it.

Check the rock arm wipe pattern before installing. If he didn't dress the valve stem tips you might need new lash pads. Those three odd valves might cause an imbalance between cylinders. Combustion chamber volume, as mentioned. They look more massive also, and might hold heat, or not handle high RPM as well. Might be fine, but for $60 it might be worth swapping to stock valves. I don't have any experience building engines, I just absorb a lot. They look like lawnmower engine valves to me. No offense. Can't find anything similar on the old internet either.

It's late somewhere. There's so much stuff out there.

Just replayed it. I see and wish I hadn't. The 70's...

Jimi fingers

Ron Burgundy's inspiration... https://www.youtube.com/watch?v=3i0DMbCKnAg

Canada is having problems. It's weird how the US media just ignores what's happening up there. I only became aware because I came across a Canadian radio station while driving.

Another orange one for comparison. Resto'ed with a driving video. Not so sure about the wheel choice. https://bringatrailer.com/listing/1973-datsun-240z-159/

I have one of those horizontal spinner machines and find that I can just throw about 20 masks in and wash on gentle cycle. The spin gets them pretty dry, then hang them up. Got some hypoallergenic non-scented detergent.

The overall state of things. The future feels better but the present is still pretty bad.

Washington state is seeing an increase in cases. The restaurants are allowed 50% capacity indoors. I met some relatives over the weekend and made us all leave to find outdoor seating. I think that "capacity" is set by the fire marshal and means how many people can you pack in to a space. A lot. 50% is still a lot. It felt crowded and everybody takes their mask off as soon as they sit down. I felt dumb as soon as I walked in. There's a certain county that might be contributing more to the state numbers. Lots of flags there.

The guy got off to a bad start and couldn't correct it. Never got good pictures back up. And, no driving video.

The seller left too many things undone and set his reserve too high. No sale.

Oops. My memory was that there was something different. Got the times wrong. When did Nissan stop calling any of their cars Datsun? In other words, when was the Datsun name retired? Wikipedia says 1986. https://en.wikipedia.org/wiki/Datsun#:~:text=When Nissan took control of,Datsun brand in March 1986. I should have looked at the pictures.

An orange Z is up today. Seems like it should do well. Survivorish. Good start for a resto maybe. https://bringatrailer.com/listing/1972-datsun-240z-165/

Seems like they'd know that it's a Nissan 280ZX. It is nice though that the ZX's come up with a "Datsun" search. Easier.

Also amazing that they apparently worked fine.

We're just starting at different ends of the spectrum Racer. You're at "this is how it's normally done". The "right way". I'm at "what is possible" to be done. Look at that big block main bearing cap and you'll see that there are possibilities outside of normal manufacturing specs.

I'll stop after this. Here's a cap surface that looks kind of knurled. But it's just a factory machining flaw. The engine ran. Good info in the article though. https://www.enginelabs.com/engine-tech/enginelabs-blueprint-series-the-keys-to-proper-block-align-honing/ (Right) JGM’s owner, Ryan Peart, showed us this big-block Chevy main cap out of a running truck engine...

This moved "Edit" button is really screwing me up.

Fun topic. p.s. I think I've been using "journal" incorrectly. Replace all of my "journals" with "saddle". https://www.mahle-aftermarket.com/media/local-media-north-america/pdfs-&-thumbnails/cl77-1-205r.pdf

Valve guides and pistons experience friction and wear from movement. Main bearing saddle journal knurling just raises a static surface so that the actual bearing can be placed on top of it. It's a different application. I'm not saying anyone should do it, I'm saying that it should be possible and has decent odds of working. As shown by the apparent fact that people do it. There's a difference between following instructions and understanding enough to write them. No offense. Kind of surprised at the resistance. Here's some ingenuity. Seems outside the "accepted practice", but apparently it is okay in their world, but they know what they're trying to achieve. And they had a deadline. https://www.enginelabs.com/engine-tech/blueprint-series-measuring-and-setting-bearing-clearances/#:~:text=Never mix bearings of different,the proper housing bore diameter. "Some performance bearing companies like Federal-Mogul offer optional bearing sizes such as 0.001 undersize or oversize inserts that make it much easier to set an ideal clearance. In our case, we needed 0.011-inch undersized on some of the journals and 0.009-inch-undersized bearings for the front two. Federal-Mogul offers these and saved our bacon. This allowed us to increase or decrease the clearances to get closer to our ideal. While mixing half-shells is acceptable practice, never mix shells with more than 0.001-inch spread and always stay within the same manufacturer. In other words, never mix a 0.009 bearing shell with an 0.011-inch version. One down side to performing all these customized clearances is that we were faced with purchasing two (and in our case, three) sets of main bearings for one engine. So do all measuring before you buy the bearings. The same is true with rod bearings... The best way to fix this would have been to have the engine align honed to establish the proper housing bore diameter. In our case, the engine had to go back together due to deadlines beyond our control so we did the best we could. The final 0.0035-inch clearance is well within factory tolerances, but it is also 0.0005 inch wider than we would prefer..."

Open your mind, just a bit. Imagine. Where's that racer's edge? It's a thing. https://www.google.com/search?rlz=1C1SQJL_enUS862US862&sxsrf=ALeKk01ZNoDPG6LyF_XQ9GV88CT2vdY9Ig:1619128301557&source=univ&tbm=isch&q=knurling+engine+block+main+bearings&sa=X&ved=2ahUKEwiw54n66pLwAhVQjp4KHdTGCOQQjJkEegQIChAB https://mysql1.racingjunk.com/Engine-Machining/184133622/Main-Bearing-Cap-Knurling-Tool.html How about shims? https://www.speed-talk.com/forum/viewtopic.php?t=28780