Namerow

Kudos to Kats for being able to finally produce for us a well-organized set of clear photos and graphics, c/w parts numbers. I still have a few questions, though. The M-bar mounting/isolation scheme for the Early S30's with the angled halfshafts (SoP to until 71-06) appears to use a unique isolator design, in which the rubber core extends out around the lower end of the metal outer shell so as to provide a soft lip for the plain-metal-washer lower 'stopper' to sit on. This apparently didn't work very well (the rubber lip probably sheared off over time). Does any one have a photo of this early-version isolator (PN 55476-E4100 or 55476-E4101). In the section view of the early-version isolator, the clearance gap marked as 'A' is intriguing. In the FSM, it's called 'B' and comes with the following explanation: "Replace differential mounting rear insulator if the dimension 'B' is less than 5mm." I believe that the lower 'stopper' (washer) is supposed to sit on the hard stop created by the square step machined into the bottom of the tapered mounting stud. Then the securing nut gets torqued to 60 lb-ft. The lower stopper doesn't even touch the insolator. So that means that the 'A' (or 'B') gap is intentional and the hanging weight of the Diff would be entirely taken up in shear by the rubber core of the insolator. This would be quite different in principle from the later style arrangement with the rubber-faced lower stopper. In that later design, the hanging weight of the Diff would be taken through the rubber stopper and into the tapered mounting stud. Makes me wonder why they even retained the rubber core for the isolator in the later design. Comments, anyone? As Kats photos demonstrate so nicely, there were at least three different M-bar mounting/isolation schemes used over the life of the 240-260-280 models. The early #1 version (angled-halfshaft 240) and the final #3 version (280Z) are easy to position in the Z's chronology and well-documented in Kats' photos. The 'middle' #2 version, however, is puzzling (it's the one that uses the thick/concave rubber-faced stoppers with no ribbing, top and bottom). Depending on how you read the parts numbers, this version may (or may not) have applied to the entire run of later 240's and the 260 and we should be seeing photo evidence of this style of stopper frequently. But that doesn't seem to be the case. Most of the suspension/drivetrain photos I've seen over the years show the deep-ribbed stoppers that were used on the 280Z. Comments? More specifically, does anyone know the production dates over which this 'middle' version (thick/concave rubber-faced stoppers with no ribbing) was used... 71-05 to 73-07? (i.e. later 240Z only) 73-08 to 74-11? (i.e. 260Z only) 71-05 to 74-11? (i.e. later 240Z and 260Z) To add to my confusion, the FSM for the 260Z continues to show the early-style insulator design (ref. Figure RA-13).

And now that you've seen 'The Might Duke' in action, have a look at this video promoting what I'm going to guess is state-of-the-art for contemporary, high-end collision repair systems. Pretty cool stuff, featuring a, 'Infiniti' 3D laser measurement/alignment system working in conjunction with x-y-z adjustable support pedestals. The rack is sold under the 'Car Bench' brand name. The pull-arm system is sold under the 'Piranha' brand name.

This promo video from a collision-repair equipment manufacturer just happens to feature a 280ZX for the initial demo sequence. The ZX has structural damage to the left-front and panel damage to the left rear. The video offers an interesting perspective on how our cars' structures respond to this kind of straightening operation. Everything you see here was probably done on a hurry-up basis and strictly by eye, so as to focus on demonstrating how the equipment works rather than the niceties of procedural details. Or, at least, I hope that's the case!

IIRC, there's a CZCC thread from about two years ago in which the poster illustrated a tank repair where he split the tank along the join seam. An option worth considering? Another option, of course, is to just find a replacement tank that's in better shape.

Nissan seem to have had lots of complaints about rear-end noise for the early cars. The text in the Mar-71 TSB bears this out to some extent, although it implies that the problem showed up only in cars with the automatic transmission. The (expensive) change in the entire diff mounting scheme that occurred in 71-06 is a better indication that the issue was significant (at least, as far as customers were concerned) and affected both the manual and automatic-equipped cars. According to the online 'Car Parts Manual' reference, the factory made a change to these 'castellated' rubber washers as of 71-04 (roughly the same time that it changed the diff mount design so as to straighten out the halfshafts). There's anecdotal evidence to suggest that the change amounted to making the 'fingers' longer. That would make them more compliant (which would help cut down on the transmission of gear whine noise into the rear cabin area). If somebody has a picture showing a set of NOS early washers in their factory packaging (PN 55474-21000 or 55475-21000), we'll know for sure. Unless you're dead-set on originality, it may be better to go with the long-finger versions (the ones shown mounted on the studs in your picture), working on the theory that 'original' isn't always 'best'. Also: Given that there are two different PN's for these castellated washers (irrespective of vehicle manufacture date), can someone comment on whether this means that there's an 'upper' and 'lower' washer? If there is, what's the difference and how do you tell which one is which?

It really does look like a mess. I'm surprised that you've been able to clean the dirty stuff off the uncovered part of your drive without any residual staining.

There clearly is a correct process. And one that produces consistent, high-quality results. If there wasn't, there wouldn't be a plating industry. Our problem is the none of us knows with certainty what that process is, and how whether it scales successfully from industrial-size batches to little, hobby-sized batches. I've recently been associated with a university-based research project being conducted with a big commercial plating operation located in southwestern Ontario. Next time I'm visiting that campus, I'll see if I can break out some time to have a chat with the prof who's leading the research team. It would be interesting to hear what he has to say about do's and don't's for these hobby-scale plating set-ups. My fear is that he'll start showing me chemistry equations, in which case I'm doomed.

'wavy' 'rippled' 'serrated'

No worries. I didn't have any knowledge on the subject until I saw this thread and became curious. The Sugarman article is an interesting read, for anyone interested in learning how extreme-pressure lubes work differently from garden-variety greases. And now I know why gear lube stinks so bad (sulfur).

hmmm... I tried just hooking my shop vac up to the cabinet so as to help reduce media 'air pollution' my workshop. It didn't seem to work very well, so I dropped the idea and switched to setting the cabinet up on a workmate in the back yard. It never occurred to me that that the vacuum hookup might also serve to reduce clouding inside the cabinet, so thanks for the tip. I think I'll continue to only use the cabinet outdoors, though. I've done enough damage to my lungs over the years without adding silica dust to the mix.

"The early extreme-pressure (EP) additives were based on lead salts of fatty acids ("lead soaps"), "active sulfur" compounds (e.g. thiols and elementary sulfur), and chlorinated compounds. During the 1950s the use of lead soaps was eliminated and replaced by zinc and phosphorus compounds such as zinc dithiophosphate." Source: Monitoring Active Sulfur in EP Gear Oils, and Other Options for Monitoring EP Additive Depletion - Arnold Sugarman - online article in MacineryLubrication.com For more details, click on this link: http://www.machinerylubrication.com/Read/496/active-sulfur-ep-gear-oil So: Based on Sugarman's article, it's not entirely clear on whether an automobile halfshaft manufactured in Japan in the early 1970's would have been assembled with an EP grease using lead-based EP grease. Unless there are some real detectives out there, we may never know for sure.

A rebuild kit (pistons, seals, etc) for the early brake m/c seems to be NLA. Where did you find yours? Or did you just re-use your original internals?

Bring a trailer? (Blue is probably hitching his up right now in NS. ) Show the picture of JF's front yard to your significant other and watch her form the words, 'Forget about it, bub.'

Check this out... https://www.kijiji.ca/v-moteurs/ouest-de-lile-qc/pieces-datsun-240z-260z-280z-nissan-280zx/1338314838?enableSearchNavigationFlag=true I count seven or eight Z's in the yard. Not sure what kind of condition they're in.

I have a benchtop-size cabinet and have the same opinion. Bigger is better. The makers of my cabinet were clearly focused on their bottom line, because there is not even a centimeter of excess air hose length provided between the siphon tube and the gun. As for there being any visible lighting inside the cabinet, I gave up on that hope long ago. I do all my blasting now by feel. It's impossible to see through the cabinet's hatch window unless I replace the plastic-sheet overlay for every job (no thanks). The puny little fluorescent light provided by the manufacturer doesn't do much to help. All that aside, the blast cabinet is w-a-y more effective than sandpaper or wire wheels when it comes to de-rusting steel parts and getting them ready for primer and paint. Does a nice job on aluminum castings, too, provided you're careful to mask off any machined surfaces.

Good write-up. It'll be interesting to see whether the Polyvance filler lives up to expectations. I did this job myself about three years ago. I using SEM's 'Bumper-Bite' flex filler, because it was recommended by others. I don't think Polyvance was even around at that time. I think that the weakest link in the dash-crack repair chain is the limited bonding area offered by the exposed edges of the hard-vinyl top layer. If you chamfer those edges at a 45 to 60-degree angle, you increase the width of the bonding surface by about 50%... but it's still going to be only 1/8" - 3/16" wide, at best. Better, but still not much. As with all adhesive joints, it's important to make the most of what you have in the way of bonding area by making sure that everything is ultra-clean beforehand and paying attention to the adhesive manufacturer's recommendations -- if any -- about preferred surface condition (roughed-up vs. smooth).

Thoughtful (as in, well thought out) summary. Thanks for taking the time. I keep reading innuendos on Bring-a-Trailer to the effect that certain collectors are paying $50K and up for early 'Condition 1' Z's, but it seems like these are restricted to low-mile, 'mint-in-box', original-paint cars. Your results suggest that the best that most (sane) hobbyists can achieve is apparently going to be 'Condition 2', and the resulting vehicles don't seem to be bringing much more than $30K, making it a barely break-even proposition. Not that starting with a similar-vintage Alfa GTV would probably be much different -- other than adding 50% to all the numbers!

Learned something new. Thanks.

I think they're just generic, auto body shop shims. Should be available for pennies at a nearby shop in your town. Does anyone have evidence that Nissan used body shims in the assembly of Z's?

So the bolts you removed from the head are M8 x 1.25 metric, but the threads in the head seem to be 5/16" x 20? Maybe a PO (or mechanic) got there before you with the same goal of cleaning up the threads, but bungled the job by using a 5/16 x 20 tap. The metric bolts might still 'fit' afterwards. Still, I think it's more likely that your metric tap-and-die collection may have a 'visitor' from the SAE family that lives in the drawer next door

Another impossible-to-find reproduction candidate for the talents of Steve at nix240Z.

5/16" = 7.938mm. Difference is 0.78% 20 TPI = 1.27mm pitch. Difference is 1.6% Any chance a PO decided to force 5/16" bolts into the head, leaving you with a mongrel result?

Thanks. I hadn't checked WoodWorkerB's site for many months, so this installment was new to me. He does great pictorials of his projects. Highly recommended to anyone who may not have seen his library of Z restoration tasks.

When you get around to doing this repair, please take some pictures and post them here for the rest of us to take a look at. I've never seen a seal replacement performed with the shaft still in place. Not saying it can't be done. I'd just like to see some pictures of the job being performed.