Mark Maras

IMO, Tear it down, at least so we can see the guts. It may be that this trans is still usable but if I was going to put money into a trans, I'd prefer one that hadn't eaten and pooped out a bearing. Hard to understand how this tranny wasn't making noise.

Fuel percolation and vapor lock were discussed a few months ago at length. There wasn't a consensus of opinion on either the cause or fix but unwrapped headers seemed to aggravate the problem. Summer and winter gas formulations seemed one of the more likely possibilities. Heated carbs were also not ruled out. As I recall some of the fixes were; The factory heat shield below the carbs seems to be a necessity. Wrapping headers, Some have rerouted the fuel lines away from the valve cover. Some have added an elec. fan from the later Zs. some have installed a vented 280 hood. The list goes on.

Easy to pull the front and back covers off. Whether you do it or not depends on your curiousity. You'll be able to see almost everything inside if you do. Might help with the decision.

That depends on the year. You don't mention the year of your Z. The first few years had little to no electronics. Little to go wrong with points in the dist. The later Zs have had problems as you describe. I believe it's the ECU that's the usual culprit. (I'm not very knowledgeable about engine management systems.) RedBird is about to replace hers to see if she can eliminate her intermittent problems.

This sounds like a temporary fuel starvation problem usually caused by heat. Many Zs, of all years, have had this problem. I would try to duplicate the conditions that cause it with one exception. Leave the hood cracked open allowing heat to escape. The results should tell you if excess heat is the culprit. Another easy thing to try anytime you suspect a lean mixture is pull the choke on a bit and see if it runs better. The choke trick only works if there is a sufficient fuel supply in the floats bowls.

Your patience was rewarded. That's a VERY nice Z. And the bonus of thousands of dollars discounted. Congratulations.

Interesting. I had never considered blending to improve shifting. Thanks

Been thinking about the 2nd gear grinding issue. My first Z had this problem. When I tore it down, I found pristeen synchros. No wear on any part of the assemblies inside or out. Didn't want to do the job again so I bought synchro assys from Nissan and sourced the bearings at a local b. supply co. Put it together and it shifted perfectly. For forty some years I had not come up with the reason for the previous 2nd gear problem until the subject of gear oil came up a few weeks back. The main subject was brass and gear oil compatibility but there was a mention of gear oil affecting the shifting. I'm beginning to believe my original problem could have been cured with a different oil brand. Back then, 1975, I probably used Kendall to refill the trans. I'd like to hear from the members what brands of gear oil (brass compatible) have caused balky shifting or what oils have cured it. Anyone with an opinion?

IMO, I would add one more thing to lumens' procedure. After wire brushing and sanding, I would treat the bare metal with Ospho before painting.

As I recall some members have questioned the quality of aftermarket synchros. There is also the gear oil issue to consider, If you offer up a few kit provider names, I'm pretty sure you'll get a rating review on them from our members.

Pulling both end cases off is pretty straight forward. Be sure not to nick any of the mating surfaces. In the center section there is a specific procedure for loading the balls in the shifting shaft detents. (hope I said that right). I mention it because if you've got the cases off, it isn't very difficult to install new bearings, synchros and be done with it. It can be done on a 4X8 piece of plywood with basic tools. Easiest manual I've ever worked on. Period. Plus, there's that very good feeling of I did it myself. Instead of crap, now I've got to pull it again. Coulda, woulda, shoulda. I say, Go for it.

Gorgeous, I love the color. The paint is great just the way it is. It shows the car is loved and driven. Looking at it puts me in the Way-Back Machine and brings back many memories of those days. I turned 21 in 1970. Beautiful, fast cars and cheap gas.

Be sure to pour enough solvent into the port to submerge the entire valve head. I've always wondered why designers didn't use more bolts to seal sheet metal covers properly. Seems there is never enough. Hmm, It doesn't seem like it would be too difficult to fab. a full length reinforcing plate for both sides. Has anyone tried it?

Rubbing alcohol may have too much water in it. I did a test using water, vs mineral spirits a while back. Started with water and it showed no leaks. Then tried m.s. and it leaked. I think the reason that m.s. worked better is because the valve and seat had trace amounts of oil on them. The water wouldn't seep past the two oily surfaces. IMO any solvent from acetone to xylene will do the job as long as it will mix with oil.

When you're done lapping the valves and have installed the springs, tip the head port side up and pour any solvent you have into the ports. Take a look in the combustion chamber. If the valves are sealed, no solvent will seep past the seats.

When I had driveshaft & u-joint problems. The vibration was much faster than a drum roll. Sounded like a 100 lb. bumblebee. The vibration was a buzz not even close to a drum roll. I agree with ZH. Time to look at the mounts.

IMO, If the rattling, hammering sound, at 60 mph, is more like a buzz, it is probably coming from the drive shaft. It spins about 3 1/2 times faster than the axles. Try to determine if the sound frequency matches axle or drive shaft speed.

I do like it. It blends that Z look in the rear while seducing us with E Type curves in front.

Unfortunately no, but I haven't given up on it yet. On my original visit, I thought someone was home but wouldn't come to the door. Left a note but didn't get a response. After thinking about it , I didn't want to appear pushy. Thought it best to let some time go by and approach it again later. I'm assembling the parts that you and Zup need. One more door to disassemble and I think I'll have them all.

IMO it has to be either air or a bad seal in the MC. If you're SURE the MC didn't run dry at any point during the bleed procedure, I'd remove, disassemble & inspect the MC to make sure the problem isn't internal. You mentioned the MC was new. Was it by any chance new(rebuilt)? There was a recent discussion about foreign matter being found in rebuilt MCs.

I'd replace it. You shouldn't have much trouble sourcing another crankshaft. At the very least, you'll be using the marks on the balancer to set the ignition timing. Worst case scenario, Big, expensive problems at the front of the engine if anything breaks. Also, check your balancer to be sure the bond between the two pieces isn't compromised. They've been known to separate at speed with ugly results.

I'm ready to thank that DIY Hoser up North. He taught me a clever method that seemingly most of the industrialized world already knew. ZH, I'm curious why the method couldn't be used on blocks or manifolds? I must be missing something.

Had to listen to him a couple of times but he said 30 hrs. I think that may be optimistic but after reading a few forums It appears that this method is used by many people in the repair bus. A fellow in the musical instrument repair bus. says steel screws broken off in brass instruments used to be a problem. Now they submerge the brass part in boiling alum and water and the screw disappears. I agree with Zed Head. IF the method works that well and depends on electrolysis, the threads on the stud should be the first to go. Maybe pluck it out in 10 hours. No need to make it disappear. The 30 hr. wait may have more to do with drugs.

This was to good to be true until I Googled the subject. It appears to be true. Apparently this method will remove a ferrous screw, bolt, etc. from any non-ferrous metal. It will still require removing the manifold(s) on a Z but being able to let the bolt dissolve instead of fighting it with implements of destruction is fantastic. Oh yeah, one more thing. This method will also dissolve the stud and anything else that broke off in the stud such as a drill bit, tap or a bolt extractor. Who's going to the first to try it? Alum is avail. in the spice section of WM. I checked my spares hoping? that I had a head with a broken stud. No luck?

I've been curious about the slots for a long time. What was their purpose?