Zed Head

A timely post, re the Panama problems. I looked back to where I found a drawing of the thermostat placement and find also that Nissan has a check procedure. Made a copy. It's in the 1972 FSM, page EC-21. I didn't find anything in 1973 though, and the Parts Manual shows it as disappearing in June of 1972. Maybe that's Build date.

Found some old CZC.com threads on the steel Porsche-style, and actual Porsche factory, synchro topic. Haven't figured out if it's just the synchro/baulk ring or if you need the gear/cone that goes with it too. Steel and brass might not be interchangeable. It looks, though, that the gear ratios might tell if you have a Competition transmission. The ratios can be pretty tight 1st to 5th. Might not even be suitable for the way you plan to drive. Here's one example, not sure if they're all like this. 2.906 / 1.902 / 1.308 / 1.0 / 0.864. 2.906 would need something like a 3.9 diff, which would make the .864 5th a 3.37 overall. Compared to a .864 with a 3.54...3.06. Just playing around in your thread. Good luck.

They look like steel on my computer. A brush with some Scocthbrite would remove any tarnish. But they'll be out and on the bench soon anyway. The outer part of the teeth is thicker also in the pictures, both here and my ratsun link. Almost like tops have been machined down. Pretty sure I saw a post from JMortensen about machining Porsche steel synchros to fit the Datsun transmissions. Don't know where Datsun gets their steel synchros. It's an interesting puzzle.

Still weird that your guy couldn't tell steel from brass. Oh well. Note the conversation on the Competition transmissions in that link and the different ratios. John Coffey probably knows what you have there. Might reply if you sent him a message.

Groovy! Looks like steel, not "black fiber" (who coined that term anyway?). Found an old thread with pictures. Edit - modified the link so that it can be opened. something weird gonging on. Change the space between community and ratsun to a . community ratsun.net/topic/51601-5-speed-id-help/page-2

The thing I circled? It shows up in the pre June 1972 diagram. Looks a lot smaller though. #38 http://www.carpartsmanual.com/datsun/Z-1969-1978/engine-240z-260z/manifold/to-jun-72

C'mon Bart, haven't you seen the problems that other people have had. Are you implying that they're all idiots? One good, many bad. It's simple calculation of the odds.

Hot. http://www.weather.com/weather/tenday/l/Panama+City+Panama+PMXX0004:1:PM

A few more pictures showing how the carb heating just might, maybe, who knows, be part of the problem. Even if it's not though, it's so easy to eliminate it as a potential cause. Eliminate the simple stuff and you're left with a better focus. No thermostat in the carb heating line, coupled with attachment to a high velocity return to the water pump inlet, pulling water through the manifolds, could lead to excess heat at the carbs. As noted in the FSM, "deterioration" can occur with too much heating.

They're probably following this thread and don't want to open a new can of worms. He hasn't fixed the most basic problems yet. Getting in to the carbs would just add to the chaos.

I meant the the thermostat in the picture I posted, at the carburetor heating line.

What about proper coolant line connections and the thermostat? Too easy?

Probably means that your brakes need bleeding. The light indicates a pressure imbalance between the front and back brake systems. The thing with the wire connected to it is the pressure switch.

It should read the same. The speedometer drive gears in the transmissions are the same so the cable will be spinning at the same speed. On the other hand though, some 240Z gauges are not the same size as 280Z, I think. Not sure which. But if you can get it in the dash and the cable connected it should be as accurate as the 240Z gauge. Forgot to say, the fonts are probably different. A no-no for the purist.

Tried to find more on the topic and went in a big circle back to myself (!) and others. It's down near the bottom of the page (this is why we need post numbers Mike). And here's the picture and description from the FSM. I would check for that thermostat first, and block the line at the back of the cylinder head. That should give proper flow and control, for cooling and carbs.

Also, it may be that the way you have those hoses connected runs the hot water through the carburetor heating plates. I think that there's supposed to be another thermostat in that line to the carbs, but don't really know the system. But, being in Panama, I think that you could block both of those lines and improve cooling for the engine and avoid overheating the carbs. That might be the whole problem right there, you're overheating the carburetors. Hopefully one of the carb experts will chime in. If I'm off-base feel free to send a torpedo.

It must be tough down there to find someone who knows these cars. You said that the radiator works fine "while running the car". And overheating when stopped is more likely to be an air flow issue. But I do see that you have the coolant hose looped back to the water pump inlet. This will allow the coolant to flow back to the pump without passing through the head or through the radiator. Try blocking that path before doing anything. No guarantees but it's cheap and easy and will help cooling.

I saw a post on another forum a little while ago from a guy who got hit in his Z. His belts looked in good shape but snapped on impact. He bashed his face and nose on his steering wheel and looked pretty messed up. The polymers used in the belts are susceptible to degradation from sunlight. They can look fine but actually be severely weakened. If there are any vendors out there who want to develop a new product, bolt-in replacement belts would be an easy sell, I think. We're all surrounded by SUV's and distracted drivers these days, plus many have grown accustomed to having an air bag in their other cars.

So you do have a small amount of heat buildup. Still doesn't really explain your problem, but might be a factor. Here's something easy to look at that might be significant, especially since you're in Panama and probably don't use your heater - are the heater core coolant lines from the back of the head blocked off or are they looped back to the water pump, from the head? Or are they connected properly to the heater core? Looping the line back to the pump inlet (bypassing the heater core) can cause overheating, in a perfectly fine cooling system. And, still wondering about fuel pressure, and the return lines for your fuel supply system. Important.

Euro gives good advice. Replace the hose too, it's probably aged. The one thing not said, that we're all hoping isn't the case, is a too-tall collar. But, a later clutch kit would use a later clutch fork and slave cylinder, so odds are that's the way to go. You could try cutting the slave cylinder rod down first. It should come out with the rubber boot.

This is good information. Another clue would be what the temperature gauge does while these things happen. Even though they're not accurate, they're still good indicators. Where is the needle when you're "running the car" and where is it when you're "stuck in traffic"? If it's in the same spot, then the cooling system is working. Engine temperature is not changing between driving and stopped. But engine bay temperature might be. What thermostat temperature are you using? Maybe you just need to use the 160 and you have a 180. Here's a question for the carb guys - would measuring fuel flow on the return line be worthwhile? I don't see it in his pictures but I don't really know what I'm looking at. Could be that his guy is running it dead-head style and the insulation is being overpowered at a stop, or he just has low flow for other reasons. If I had carbs I'd probably use that as an overall check of the lines and fllters. Without good fuel flow past the carbs vapor-lock could still be a problem. Also - I attached a picture of what looks like a hose laying on your throttle linkage. Could cause throttle feel issues.

I can't really say. As the guy in the second link notes, the kit synchros were okay for average driving. But stock worn synchros probably are too. The bearings in your eBay kit are Nachi brand which seems reputable and is what comes in factory boxes, I think, so those look okay. But as duragg noted, some of the kit seals were wrong. So, some of the kit parts are probably fine, but you might need others. And, since you only saw problems in one gear, maybe you only really need one synchro. Four worn and one new Nissan synchro might be the way to go. You said 2nd was grinding like crazy but didn't say at what RPM, and only you know if the others were fine. Personally, I found that the fluid used had a big affect also. I tend to collect a bunch of information then put my own plan together. In short, all I'm really saying is that the rebuild kits that are out there aren't known for making people happy. Don't expect a like-new transmission, even if your guy knows what he's doing.

Hope you don't mind but I tend to pile on when this topic comes up. Here's a good thread from Hybridz. duragg is the guy that rebuilt his transmission many times and knows most of the inner workings. Full disclosure, I'm in there as NewZed (unintended multiple identities). http://forums.hybridz.org/topic/113022-syncro-difference-btw-closer-ratio-and-wider-ratio-fs5w71b/ Here's another link where the guy, who seems to know some stuff, was disappointed in the kit parts - http://zhome.com/ZCMnL/tech/240SX5spd/transmission.htm

Browsing around, I find that Courtesy has discounted the synchro prices. Not terrible. http://www.courtesyparts.com/oe-nissan/32604p0100

That's the same not-quite-right kit that's been out there for as long as I've been aware of rebuild kits. Notice that the name/ID of the transmission is wrong, it should be FS5W71B, not 71A. Also notice the two different types of synchros (aka baulk rings, look at the number of teeth if you use the magnifier in the eBay link) in the picture when other places call for 5 synchros of the same type (even though some also call for a different 5th gear synchro). The ones in the kit picture (called out as the actual parts), show two different styles. Plus, too many exclamation marks. And why would you call a baulk ring a "crush ring"? Don't get that. Here's a reference, also look at the other link I posted. Part #45. http://www.carpartsmanual.com/datsun/Z-1969-1978/power-train/transmission-gears/5-speed The Z car trans rebuild market is kind of messed up. I think that some parts shop created a list of parts many years ago, with the wrong trans ID number, and everybody uses it. Kind of weird how that wrong ID follows the various "different" sellers around the internet. Seems like somebody would have the details figured out by now. Don't want to be a buzz-kill. But you'll probably pay more in labor than parts. Just some odd things I've noticed.