Zed Head

Is the frequency of the sound a clue? There are some things that would have a consistent frequency; the four bolts to the hub, the four scallops if you have an early 240Z, four lug nuts, spokes on a mag wheel, the ribs on a vented rotor, etc Don't even know what kind of wheels you have or how fast you were going so it's hard to guess. Also, no offense, but how did the brakes start grinding after just 15,000 miles and what was grinding? Might be a clue. I found that one of my rotors had the inner dust shield (the actual formed in and machined ridge on the rotor) completely worn off from a pebble or some hard object that had been stuck there. Either that or the PO had ground it off for some reason. Must have made some noise.

If the tops of the valves aren't ground square you should be able to rotate the valve and the wear pattern will follow the rotation, from side to side anyway. The valves can (do, I think) rotate during usage so that would be a problem if it was the case. You'd want to replace the valve or regrind the tip. The other possibility is that the valve guides aren't square to the came anymore. An off-center reaming could do that I suppose. A new valve guide should fix it. These are just guesses based on my limited knowledge of how these parts fit. Rotate the valve and see what you get. It should tell you something.

A good paint job is 90% surface preparation. If the paint doesn't stick, but has fully cured/hardened, it's most likely not the paint but something on the surface that was painted. It could be something as simple as the fabric softener on that freshly washed rag you wiped the surface down with to be sure it was super-clean. Or the lubricating oil from your air compressor if you used an air hose to blow the dust off. Or residue from that carb cleaner that looks like it all evaporated. You should follow the instructions to the T and don't add anything more. No cleaning solvents of your own, no extra wipes with a rag, no tweaking the formulation for a faster cure. There are chemists out there who spent years developing those formulations and procedures to make it all seem so easy.

Went back and looked at the valve work on the other thread. Looks like a lot of machine work on those bigger valve heads. And the seats look bronzish in color. That's where the problems with lash usually come from, sunken valves due to seat wear. Seems like a Datsun guy would have recommended new seats. Nobody has mentioned keeping the rockers matched with the cam lobes, but I'd assume you did that, based on your other meticulous work. On the wear lines - I've seen rocker arms with very visible wear lines, that can't be felt at all. Most builders use feel rather than sight to determine wear. I think the lines are visible pretty quickly once in use. Don't know enough to say if your guy's on the right path with keeping the seats and modifying valves or if he's way out in uncharted territory. It's interesting work though. Good luck.

All solid (no hydraulics) valve trains should always make some noise. You should recheck your valve lash and make sure it hasn't disappeared. If you lose valve lash a valve can stay open and be damaged. Check it before the ride, even during.

You never really said how the machinist fixed the incorrect machine work n the #4 intake valve seat. I would guess that he might have shimmed it, since welding and remachining would be very expensive. And the fact you set lash, but it closed up again is a concern. Have you rechecked lash again? Don't assume that things can't keep getting worse. Finally, people that are very confident and say that they have tons of experience and don't make mistakes make me nervous. Just saying. even the pros can get things wrong sometimes. Could be that your guy's fix on the #4 valve seat didn't work.

Works fine on my system. Windows 7, Chrome, old Compag desktop. The picture shows an arrow pointing at a rocker arm wear pad and a cam lobe. This probably is where the typical, normal, noise happens. I've pondered where that wear line on the rocker arm wear pad comes from and I'm pretty sure that it's where the pad drops back down (up) on to the cam lobe after it loses contact with the lobe as the high point goes by. Basically, the rocker arm jumps off the top of the lobe then falls back, clicking every time, and work-hardening that narrow line of contact. Same vein, but not really relevant - notice that many cam lobes are brown and unworn on the base circle. That's from the mousetrap springs holding the rocker arm down so it doesn't rattle. On the base circle there is no contact with the rocker arm wear pad. One easy quick way to get an idea of proper valve lash settings on an old engine. If it's shiny it may have been a while since lash was adjusted. Maybe, it's just a clue. Also, and I've seen this discussed before, sometimes the rocker arm wear pad is not ground on the same plane as the rocker arm lash pad contact surface. So the rocker arm will twist around its own axis as it one wear surface overpowers the other. The lobe wear surface probably wins until it gets around to the base circle, then the lash pad surface wins. This can probably cause some noise. For a fairly primitive looking piece, the wear surfaces probably need very precise and accurate work done to get a quiet valve train.

That wasn't my intent. Rossi just had some great pictures in his thread. I actually used Google to try and find some less controversial pictures, but there's not a lot out there. I would spend a little more time trying to figure out where the oil burning is coming from. Depending on which rings he used and how he finished the cylinders it could be that the engine is just not broken in yet. The oil scraper rings aren't seated. The compression test doesn't tell you anything about the oil rings. On the oil pressure - you haven't given any numbers. You just said uneven. Before going crazy,maybe install a mechanical gauge directly on the side of the engine and see what it says. The oil pressure gauge in the car is electromechanical and can fail at the gauge itself or the sender. Could be that oil pressure is fine, and the engine will wear-in over time and be fine.

Your latest video requires a sign-in. You might try disabling each cylinder to see if you can narrow it down. I don't know if piston slap noise is combustion dependent, rocker noise probably isn't, but since you don't know for sure it might give a clue. Remove plug wires, one at a time. Make sure you ground them to the block though, some ignition systems don't like to have their spark path jammed. If you really wanted to go deeper, you could remove sets of rocker arms. Lots of work but if its rocker arm noise, it will tell the story. If the piston is down, you remove the arms with a screwdriver, by prying the valve down. It's described in the How To Modify book. I've done it on a head off the block. Pretty easy. Easier than removing the head, and looking for something that has no identity.

Here are some threads with pictures: Post #10 - http://www.classiczcars.com/topic/47101-cam-wear/ Here's another (sorry Rossi. And Al) - http://www.classiczcars.com/topic/50485-rocker-geometry-woes/page-1

You said that you lost lash on one valve. Maybe the valve seat wasn't seated in the head and it dropped in as the engine ran. Not good, but not disastrous unless you burned the valve when you had no lash. Just a thought. I know also, that valve lash is lost over time in general as valve seats and valve faces wear. I'd imagine that some tightening of lash is normal during break-in. Would depend on what wears more, valve and seat or the cam lobs and rocker wear pads.

That's life. Most people have to pay for past actions, mistakes or not. If you want to be proactive, reply to the members here who had problems and show that those errors are gone. There are at least two. And by the way, there are at least two engine build vendors that get good reviews on this forum on a fairly regular basis. So it is possible to build a good reputation. Good luck.

There should be a plate on the driver's side door jamb that has a date stamped, like 1/76. That's a clue, plus each year has some small differences. If you post a picture, it could probably be figured out. Or look at pictures of 280Z's on Google or on this site.

I was joking, sort of. Purpose determines value. For your stated purpose though, that car looks like an excellent choice. If it's been maintained and driven, it's probably dependable. It's the "ran when parked " cars that sat for 10 years that have the problems.

It looks in great shape. You could start a completely new forum on "worth". It could be a philosophy forum. Or a money forum. Or a time plus skill forum. An emotion forum. Family forum. The transmission swap isn't that hard. If you have the time and skill. And the extra money. And it makes you feel good, and your family is okay with you spending time away, on the car. Some would say it's not right to change an original car, but that can be debated.

I must have read this before the edit because I saw the part about "last I checked". So the question would be do the points look fine, and are they gapped correctly, now. The part about somehow the points got off makes you wonder how they did that. The first, basic, thing that most people would do is to check for spark. You can do that with a spark plug wire and a bolt, or by removing the main wire from the distributor cap. You don't even need any tools. By turning the engine or by opening and closing the points by hand. You can also check for power to the coil with the key on, if you have a meter, to be sure that you haven't been misdirected by the points. It might not be the points at all.

He was just pointing out a potential problem. Probably depends on if you use a thick wall or thin wall socket. Fairly easy concept to understand though, the socket won't fit in the bolt head well if it's too big. Apparently your isn't.

This isn't really a drifting site. Not even many, if any, 300ZX owning members. Send a PM to the Zociety guy or post in his thread, or on his web site. Might get some recommendations there. http://www.classiczcars.com/topic/51665-zociety/

Depends on which part it is. I've seen the plastic gears on the removable assembly be screwed up. But the gear in the transmission tail shaft housing is plastic also, I believe. It is replaceable but requires removing the transmission. $14.85. Part #65. http://www.carpartsmanual.com/datsunS30/DatsunZIndex/PowerTrain/TransmissionGears/5Speed/tabid/1708/Default.aspx http://www.courtesyparts.com/gear-speed-p-344016.html Make sure they know what they're doing. If your gear assembly (part #59, talked about in Post #6 above) wasn't clocked correctly, the gears could lose contact. It would look broken but just require a slight rotation. If they just watch to see if things rotate from the outside they may not understand about the offset of the gear shaft.

I would build some rollers for the back wheels, pipe the exhaust system outside, and use it as a driving simulator. Win, win, win.

Common to any old fuel tank. Small amounts of moisture will find their way in even with good sealing. The light volatile portion of the fuel finds its way out. You're left with goo and rust. You'll probably have to drop the tank to get it fixed right. Lots of people try to get it done on the car but they usually have recurring fuel supply problems.

Buy a can of Fogging Spray and do the intake system and cylinders. It prevent surface rust on cylinder walls and valve/valve seat surfaces. http://www.autozone.com/fuel-and-engine-cleaners-additives/fogging-oil-and-fuel-stabilizer/sta-bil-fogging-oil/94416_0_0/

Tire size has an effect also. You can tell if it's an offset or a ratio problem by the numbers. If it's the same number off over a wide range, like 3 mph at all speeds, then moelk's fix will work. If it's off more the faster you go then it's a ratio problem and you'll need a different gear. Might have to live with it since the gear ratio choices are limited.

I've seen engines dropped with the cross member. Considering how light our cars are I wonder if wouldn't be easier to lift the car and slide the engine and cross member underneath.

I have a 76 with factory AC. When I got it the temperature control cable (or rod, that's how I think of it since it's solid) was kinked from somebody forcing it in the past. So it didn't move the full range. The kink was behind the panel so you couldn't see it until the panel was removed. After fixing that I'm pretty sure it moved the full range. In other words, it seemed to work right. But I've modified it since then. My thermostatic control capillary was dead so the system went from no heat to full heat within about 1/8 of the lever's range. I installed a Honda control valve (CO wrote a thread on it - thanks!) which works great except that it also only need a small (tiny) amount of movement to flow lots of hot coolant. Way more than needed. Had to redrill some holes and fabricate some new actuators to get more fine control. My AC cooling doesn't work either, the system needs maintenance. Somebody needs to find a modern system that can be plumbed in to our cars, with heated conditioned air for the windshield and through the top vents, like today's cars do. There's got to be something out there.