Zed Head

We had a big discussion about this quite a while ago. There's internet stuff that says the numbers mean something but when you compare the numbers with known facts about the transmissions, like year of car they came in, there doesn't appear to be any usable correlation. You can tell a lot just by the gear ratios.

Just a couple of things. Maybe we should go with factory nomenclature. That would be "propeller shaft" for the shaft we're talking about, and "drive shafts" for the two that go the the wheels. Some people use "tail shaft" to talk about the output shaft of the transmission, and tail shaft housing to mean the rear case of the transmission. On the measurements. I measured in exactly the same spots as EuroDat, center to center of the u-joint caps. early 240Z propeller shaft - 21.25" (540 mm) 1976 280Z shaft - 22.3" (566 mm) EuroDat's late 204Z shaft - 22.55" (573 mm) As for room inside the slip yoke for the transmission output shaft, the early shaft, I measured 4 11/16" by sticking a tape measure inside and eyeballing to the end of the slip yoke. 4.6875", 119 mm. Just to give some idea of engagement. But, I'm not sure what hits first, the output shaft inside the yoke, or the nose of the yoke on something inside the transmission. Also added a picture fro the 1976 FSM showing the yoke inside the transmission and what looks like an outline of the bearing. You could easily be only half-engaged in that bearing. It might be wallowed out already, damaged. Edit - also added a much better image from 1973. The best route might be to remove the shaft, examine the inside of the transmission for damage, and get a longer shaft. Might be overloading on data here, but it's fun to review all of this since I spend a bunch of time doing the same for the 71C case swap in the past. Which is still sitting in the garage.

I get 21 1/4" from cap center to cap center on my early, diff-forward shaft. It's not clear what "stock" means, and I don't know what shape the mustache bar was on the diff-forward setup, but it looks like you have the short shaft, when the long one would work. MY 280Z long shaft is a hair over 22 1/4". Looks like you have the short shaft when you could use the long one. I look at the angle of the halfshafts to determine if the diff is forward or not. In the improved vibration resistant setup (the factory modification and what they changed to for later cars) the shafts are perpendicular to the wheels when looking through the wheel well. In the early cars you can see that the shafts are angled forward. Did you try wiggling the yoke around like in your first video? That would answer part of the question. If the play goes away, then a longer shaft might be more stable. EuroDat mentioned tailshaft in his post. I don't know if he meant your transmission, but there are shorter versions of the 71B transmission. from trucks. Maybe you have one of those. Obligatory edit - to be clear, you do have the R180 diff? It hasn't been swapped to the R200.

Here's an old article. People have wondered about this for a while - https://books.google.com/books?id=CRDEneSREucC&pg=PA144&lpg=PA144&dq=smooth+tappet+surface&source=bl&ots=7Hum0yt51O&sig=DgXG_t_DAzbCNCNPCEvDyp7C-x0&hl=en&sa=X&ei=-AIzVd2fAoO3oQTo2IGwCA&ved=0CCQQ6AEwAQ#v=onepage&q=smooth%20tappet%20surface&f=false

Asperities are the enemy. Most failures occur during break-in or at startup (no oil film). Broken in engines have much smoother surfaces than new parts and are less likely to fail than new parts. I understand the feeling that roughness holds oil and oil is good, therefore roughness is good, but the counter argument is that oil is there to combat roughness, so smoothness is good. Seems like dealing with the devil. Could certainly use more study. If very rough is bad, and very smooth is bad, then there must be an optimum in the middle. Knowing that magic number could save some parts.

Odds are good(bad) that you connected the battery backward. Nissan did not use red and black like everyone else did. Follow the cables to be sure which is ground and which is positive. The cross member is actually what the engine is mounted on. Can't be removed without removng the engine too. You can get the oil pan off with everything in place though, it might take a couple of tricks. There are tons of parts for sale from people who decided to just tear the car apart and rebuild it from scratch. One year of looking at boxes of parts and you won't even remember it used to be a car.

Went out and looked at an early 70 shaft and a 76 4 speed trans. with a dust shield and I'd guess that you have 2 1/2 - 3" of engagement, when you could have about 4 - 4 1/2". So, not fully engaged, but not so loose that it would pop out. There is a bushing/bearing inside the transmission though that helps locate the slip yoke. You may or may not be engaged with that. One member here had a worn bearing, different style of transmission though, and it allowed some looseness.

While you're under there you might as well unbolt the flange from the diff and see how much room there is to push in the trans. I'm pretty sure the factory only left about 3/4 - 1". Pretty full engagement. No need for more play because the diff and trans are both locked in to place. The slip yoke barely slips. Actually, it may be that the u-joint got torn up because the propeller shaft tried to come out of the transmission, got cocked and broke the u-joint. The shop might have just reproduced a too-short propeller shaft. Also, it might be too short because you have the later diff location, but the early shaft length. Just throwing out some possibilities.

Here's an interesting web site and an article by a consultant. Doesn't seem to have an axe to grind either way. Put your own search terms in, I had ZDDP in the first link. Lots of good reading (except for the format, it's Powerpoint or giant screen mode...) on all kinds of lubricants, grease oil, synthetic, additives... http://www.lubesngreases.com/search/?zkDo=search&publication=all&query=+zddp http://viewer.zmags.com/publication/20213322#/20213322/48 Obligatory edit. Had the wrong page linked. Also interesting that he's talking about the phosphorous component of ZDDP. And one reason to lower ZDDP is because of the sulfur content. So you can search all three words and find much more stuff. Zinc, phosphorous, or sulfur.

The diesel oils do/did seem like a good option. But, I've seen some indications that diesel engines are or will be getting more regulated (good!), and may be using catalysts to clean up the emissions, and that the diesel oils are getting reformulated for that reason, just like the car oils did. The problem is that since ZDDP is not called out or spec'ed it could disappear with no obligation from the manufacturers to tell anyone. We'd never no. Might start another thread just to see if anyone has had a stock cam go bad, using plain old motor oil. Still curious. VR-1 and GT Racing oils are cheap enough though that the insurance factor makes sense. VR-1 is even available in the parts stores, no internet gyrations necessary.

It does look like it might be short. I think that the two dust/dirt shields usually overlap almost completely. Did the shop measure or did you, or did they use a factory specification? If they cut it to the early 1970 spec. it might be for the set-forward differential. Do you have the modification to move the diff back? Need more info. If you take a measurement, someone here can verify length. I have one of each style, short and long. Measure from the center of the u-joint caps. In the meantime, you could unbolt the shaft from the differential and push it in to the transmission to get an idea of how much engagement you're not getting. If you raise the back end high enough you might be able to remove it without losing your fluid.

Started a new thread! Good luck grannyknot. http://www.classiczcars.com/topic/51321-internet-expertise-exemplified-by-a-conversation-about-zinc/

Rather than fill grannyknot's thread with more stuff, I figured I'd just reply here to patcon's comment. Just not a fan of people who defend their positions too zealously with little but the internet to support it. From here, #35 - http://www.classiczcars.com/topic/51243-cam-wear/page-2 You have to go back to posts 16 and 17, two pages from Chickenman of links pulled from the internet with commentary, then read my reasonable post 18, then Chickenman's dismissive tone in post 19, to see how it starts...... Deleted some stuff.... Still... tuning out the bad vibes..

Mike did address this before. Apparently the forum software doesn't have that option. You either get no edit notification at all, or one for any edit, any time. I'm spoiled by other forums and have developed the habit of posting then immediately fixing my errors before anyone sees them. We even have a WYSIWYG box on the More Reply Options page here on classiczcars.com. Lazy on my part, just excusing my own errors.

I did see that, and thought about adding that link. I just don't know who DA Lubricants of Indiana is. Or where Brad Penn oil comes from, besides Pennsylvania. More Google leads to DA. http://www.dalube.com/ Price isn't bad - https://classiccarmotoroil.com/products.php 15W-40 seems a little high viscosity and kind of limited. That's the same weight as Rotella and the diesel oils. Hmmm... Don't know. Guess I'm looking for the do-all product from a big name manufacturer, cheap. I can dream. At this point the Valvoline VR-1 10W-30 looks like the best option for me, up here where it's often cold. http://www.amazon.com/Valvoline-VV205-6PK-10W-30-Racing-Motor/dp/B00DJ4FMK2/ref=sr_1_2?ie=UTF8&qid=1429225750&sr=8-2&keywords=valvoline+vr-1+oil

That was me. I knew somebody would get me. I was being ironical, I think. Just a small item on the list for the next web site revision.

It's your tone. Needs work. And too much verbiage to make a simple point. So no, after seeing the tone, then all of the words, I didn't read all of your posts. I tuned out and moved on.

The big EDITED banner at the bottom of an edited post bothers me so much that I now leave all of my small mistakes in the post. Is this wrong? Can't even edit within seconds, without the banner.

I would also read, a lot, before buying anything. There are many threads on this forum about seal kits that don't work right. Most of us, that are now happy with out seals, are using Kia Sportage seals, either from a wrecking yard or through the internet or Kia dealer. You can waste a lot of money if you don't research what you're buying first. Also, in that vein, there will probably be a time when your engine doesn't run quite right. You'll be tempted to make a quick diagnosis and buy more replacement parts, like fuel pumps, AFM's, ignition modules, EFI relays, etc. Don't do that without testing first. One purchase you could make today, that will pay off in the long run, is a decent multimeter. In a few months you'll be an expert in primitive EFI systems.

Thanks. It's the detergents that would be the issue, I suppose. Sludge. Browsing through all of the various oil container labels, and ad copy, and internet information, it's surprising that none of the companies can paint a clear picture of what someone with an old, pre-catalytic converter car can use to keep their old car engine in safe condition. Seems like there's an opportunity here. Not to mention all of the old cars with catalytic converters, What are they supposed to do? Valvoline seems to get closest with their VR-1 but even they can't simply address the basics of everyday use. Still called a racing oil, with just an insinuation that it's appropriate for daily usage. Pennzoil doesn't even have a link to their racing oil on the Pennzoil web site. http://www.valvoline.com/pdf/vr1_racing.pdf Somebody needs to just produce an "old car oil" and supply information about how they address the cam wear issue. With zero hype. That would be awesome.

Nice. I kind of wish mine was the dark green, although my stealth brown probably saves me some traffic stops. The intake snorkel in the engine bay is stock. It's a dry spot. The air is moving and getting replaced in there anyway, so still "cold". If you park it outside, beware of leaking seals. They're probably dried and shrunk by now and various areas will drip and fill up with water without your knowledge. Spare tire well, under the seats, down by the ECU and fuse box, down the back of the firewall. Don't jump the car on a dead battery, then use the alt. to charge the battery. it's a good way to overload the alternator and damage it. If the engine was started last year, You probably don't need to do much to the engine before restarting. But the fuel tank could need some work. The hydraulics, noth brake and clutch, might be on the edge due to moisture buildup. don't be surprised if they work for a while, then fail. The heater hoses are probably on the edge too. Same thing. Drive it for a little while before modding. You'll probably change your mind about some of the things you're planning to change. It can take some time to work all of the little bugs out.

"Bar car"? Pickup car? That's a lot of oil. Just stopped by the auto parts stores, OReilly and Baxter are side by side, to check out oils. Three big names in diesel oils, Motorcraft, Delo, and Rotella, all had notes on the bottle about how they were formulated for with low ash for the latest emissions devices, one even said catalysts. Could be that ZDDP is leaving the diesel oils too. May not be the cheap option anymore. Baxters had the whole selection of racing oils, except for Brad Penn and Pennzoil. The VR-1 was $6.29 per quart, the others ranged up to $12. Redline's synthetic oil said right on the label - not for break-in, only after 3000 miles. Kind of implying that you need that ZDDP in there for a few thousand miles, at least. So maybe the whole deal is to get any roughness at all smoothed away before the ZDDP isn't necessary. Which would make sense since roughness would have extreme pressure and ZDDP is also defined as an extreme pressure additive. Although I think it was originally added for oxidative stability. If I remember right.

Are there brand names on the paste and the ZDDP oil supplement? Curious as to what the pros send out with their cams. Did Schneider send recommendations on oils also?

I've seen the rough finish on new cams. I wonder what it is though, a coating, or the actual finish from grinding? Anyway, here's some good data on materials and other rocker arm specs. - http://www.rhdjapan.com/kameari-l-type-rocker-arms-set-l6.html

A note from the past, and a thought: the first Nissan rocker arms for this application were chrome plated. Very, very smooth, I assume. So, surface roughness of any kind may not be desirable. The roughness for cylinders is more to get the two surfaces, cylinder and ring, matched for sealing purposes, not long-term wear. I think. And since you have fresh metal now, assuming that the ZDDP basics are correct, you should treat that new rocker pad surface with ZDDP-containing break-in oil or break-in paste. To rebuild that critical "anti-wear" layer. The ZDDP action is at the molecular level, much, much finer than any roughness level you could decide to shoot for. I'd go for a super smooth surface with ZDDP-containing paste and oil for break-in. Of reputable brand. Based on the stuff I just packed n to my brain over the last few days.