Zed Head

If Courtesy decided to remove even the weak references to the older cars from their site it's probably just a matter of time until they remove all support from the company. Search "280ZX" on their new site and it's not even recognized. Send Courtesy an email. If you've been brand loyal to Nissan, make that point. Tell them that you want full-service not just easy money service. Since they're in the middle of change it might not be too late to get better service instead of worse. customerservice@courtesyparts.com Where's Mike? Is Courtesy a sponsor?

That makes sense. In sum, the essence of my question is "what's the difference between a head that's bent down to flatness using head bolts and a head that's milled to a flat surface". The answer I get is "not much". Especially when you look at how each cylinder has its own fire ring. Full disclosure - I work in R&D, where questioning the status quo is how you justify your job. Of course, better and cheaper is the end goal. Part of cheaper is no wasted effort though. I could be missing something. Open to criticism/discussion. Edited for too many "thoughs".

I may try the test. I ran in to one problem with a head bolt though, it wouldn't thread correctly (the one opposite it was fine). I had already reinstalled the sprocket and chain so didn't want to take it off again. But winter is coming and I will get bored so it will probably happen. I have the starting numbers so why not. I'm not sure that aluminum sitting in its elastic region on the stress-strain curve will relax to flat with no heat-cycling though. It would be odd if it did.

That's the interesting part of the whole question. When the head was bolted on at the factory everything was flat and in-spec. and turned freely, unbent. But when the head is unbolted from the engine, that's when it will warp, due to internal stresses. It certainly wasn't warped sitting on top of the engine, unless the deck was warped also. Then it's planed/milled to flatness, but the cam tower surfaces are still warped. That's the factory way. The second way is to mill top and bottom, and remount the cam and towers. But then your valve guides and valves are slightly akimbo. Seems like to do it "right" you have to remachine every surface, including valve guides and seats. And it f you're not going to do it right, you might as well just bend it back to where it was when it left the factory, using calculated torque values. The whole milling/planing/flattening head thing has always bothered me. You always end up with something that's not quite right.

I'd go with an OEM style with compressible steel fire rings. Nothing fancy. You can spend some time looking at heads and head gaskets and how they work. They're really three gaskets combined in one assembly.

Good point on balancing torques, for even pressure, down the length of the head. Measuring the amount of torque required, with a torque wrench and working down to it, on the center bolts to get to "flat" could give a number to be added to the final torques. And turbo head bolts to allow the increase without overstretching a bolt. Some day I'll probably try it. The main reason I put much effort in to looking at it was because the engine ran fine, and the head gasket showed no signs of leakage, at the cylinders, or at the various fluid passages. Logic says it worked before, why mess with it. I can see planing a blown head gasket head, to be sure you have good sealing surfaces, but this one would seem a waste.

Back when I had stock ignition components I found that the ECU would not fire the injectors if the resistor on the tachometer line was not in place. So the ECU is sensitive to the quality of what is coming through on the blue wire from the coil negative. I wonder if there's a combination of coil and Unilite that would work. It seems like I've seen people with 280Z EFI use the Unilite. I'll have to do some Googling. Maybe it's stock coil + Unilite + EFI that doesn't work.

That's interesting from MSA, but the explanation doesn't quite fit. The ECU doesn't see the distributor trigger mechanism, just the make and break of the coil current, on the negative post. They're different sides of the ignition module. So the problem would be more about the ignition module side of the Unilite. Maybe it doesn't cut it cleanly, so the ECU doesn't get a good sharp signal. Interesting issue. I wonder if a GM HEI module in between could "translate" the Unilite weirdness. Use the Unilite to run a GM HEI module, just like using the ECCS to do the same.

I decided to mess with my old engine parts, and put them back together for easier storage. It's an N42/N42 combination, that ran well, but had leaky valve seals and a coolant leak from the back of the head gasket. After I took the head off I used a long straight level and measured .007" of upward bow in the center of the head. By the FSM, that's out of spec. (.004" maximum) and the bottom should be reground to under .002" warpage. I set the head on the block and rechecked flatness, measuring the gap in the middle. I got .006" this time, which makes sense since the contact points are closer together because my front cover is lower than the deck. The head was only touching on the ends of the block. So then I inserted a single head bolt in the center and with a few easy twists of a wrench, not even using the end of the wrench handle for leverage, was able to reduce the clearance to zero. The head was easily flexed down to good contact, end to end. So, it seems to me, that if there are no surface defects and the "warpage" is gradual, that a person could probably just bolt up an out-of-spec. head and run it. The only concern might be stretching the head gasket as the ends of the head push out when the center comes down. Just wondering. More food for thought. Has anyone out there just said "screw it" and run a warped head, and what were the results?

What year is the car? And which country did it come from? You said 280ZX distributor, but you may not have a ZX. Typicality though, there's a blue wire that would be attached to the coil negative terminal that goes back to the tachometer and the ECU. That's what the ECU uses to know when to fire the injectors. Does the tachometer still work? And you siad that you see spark, but you didn't say when. You can see spark when you turn the key on and off, but still not have spark when the engine is cranking. Describe how you tested for spark and how you know that you don't have injection. Here is a link to many different manuals and diagrams. http://www.classiczcars.com/files/

Yeah, it's probably only worth doing if you live one of the states that won't let you pump your own fuel.

I picked up an unleaded filler neck from the wrecking yard a couple of months ago to see if I could get it installed in my 1976 leaded filler neck, to make it easier to fill at the stations. I racked my brain for a day or two trying to figure out how to get the filler neck mounted inside the gigantic 1976 pipe, but couldn't come up with anything so I set the parts aside. Then the other day my simple-minded brain part took over and I came up with an easy way, using a drill, a tap, three holes, and some screws. The filler neck came from an older Dodge van, I believe, mainly because it was easy to access from under the fender. There's about 10 inches of pipe still attached. I found that even with the extra pipe, the whole assembly could possibly fall in to the tank. It's essentially a straight shot through the giant 1976 pipe, and the later model filler necks are small. With the set screws, even if they loosen I should have time to fix it before it drops. Seems tight though, after 1/2 tank of driving and fuel sloshing, and temperature variations. Haven't even had the gas guys (attendants fill all tanks here in Oregon) try it out yet, but I think that they'll like it. The big hole always made them nervous that the nozzle would fall out. Or things got so splashy that the nozzle safety kicked off. I was going to cut the screws down for a nicer look, but once I got it set, I didn't want to mess with it. Might need some fine-tuning. But if they like, it's not changing. Just food for thought for anyone looking for a solution to that problem.

Maybe it's the rotors then. I've seen the descriptions of material transfer from the pads and how it's important, but my rotors will pick up a light cost of rust, just sitting for a few days outside when it's rainy and moist outside. Not much material on them, just raw metal. Still, Nissan didn't design and cut hundreds of thousands of shims for nothing. Car companies just don't do that. One of those interesting things.

Did the CRC stuff work for you? And did the Pig Squeal deliver you from the bad brake pads?

I think that CO just bought this as a project. No fun to just replace a whole engine. More fun to make bad parts good again.

Rebuilt calipers cost $30 USD here, at OReilly auto. They have rotors also, for $107. Says they'll ship. Looks like shopping at various places will save you the most. Quality is a question though. I had to exchange an OReilly caliper because the piston wouldn't retract enough to get a new pad installed. http://www.oreillyauto.com/site/c/detail/BBR2/9064RGS/01310.oap?year=1972&make=Nissan&model=240Z&vi=5142640&ck=Search_C0062_5142640_2513&pt=C0062&ppt=C0009

I'd replace both calipers also. I had a mismatched set and one grabbed before the other. Different seal materials or something.

I wonder if a bad fuse alone could cause the melting and self-destruction. No short involved, just the fuse developing resistance at a bad junction and building heat from normal current flow. Might be searching for a phantom.

Overheating usually leads to compounding of interacting problems. Excess heat causes excess piston expansion leading to localized heat in the bores and more expansion. The aluminum pistons usually bind up in the bores before things get too too hot. Motorcycles seize all the time from over-heating. I've never seen any discussion of rings losing temper due to overheating. I have seen discussion of crankshaft bearings losing lubrication due to oil-thinning though. Seems like certain engines have certain failure points. As far as block problems due to being aluminum, you really need to know if the bores are sleeved or not. The old Chevy Vegas were known for ruining blocks due to over-heating, but they were still saved by sleeving the bores and rebuilding. I'd find a Hyundai forum to get the details on that engine. But like dj says, the evidence is probably on the cylinder walls.

I have a can of the CRC spray-on material. Goes on red. Sticky. Only worked for a short while, on two different brands of pad, one unknown, the other Beck Arnley. (Sprayed on the back, Iv'e never heard of any treatment for the face of the pad). The Beck-Arnley pads were nice pads. Had a good feel, better than the Posi-Quiets. Dirty though, Still squealed, even with their stick-on shims. Maybe there's something in the water here. Regardless, the factory steel (clean steel, no polymers) hanging shims work great. Not a peep, from backing out of the driveway to all manner of stopping conditions. Just tried the Posi-Quiet system 'cause their ad copy said it would work, and they run cleaner. I'll probably go back to Beck Arnley in the future.

It's interesting that the guy seems to have built a few engines but doesn't seem to be well-known. I've never heard of the shop. Cylinder pressure will give some idea of potential ping problems. That's probably in the future though.

I think that the adjustment holes are for taking up wear. 1 = new parts 2 = worn parts 3 = very worn parts

Forgot to say, I notice that the tape on the top of the engine says "Do not turn over". Does that mean don't turn the engine crankshaft or don't turn the crate? Also see that the camshaft lobs have some wear so it's not a newly ground shaft. Zinc may not be as critical.

More support that a free-flowing exhaust system can have a big affect. You asked about the drop off after 5500. That seems to be typical of the L6 engine, unmodified factory issue. If I understand what I've read in the past, head work and cam profile are needed to extend the range. My stock L28 isn't worth taking over 5000 RPM before shifting to the next gear. You can see your torque dropping dramatically there in the dyno plot. It would be interesting to know what kind of head porting Ritalon did, and if they installed bigger valves. And read up on zinc for the cam break-in. It would be a shame to have break-in problems.

That fuse must have been defective or of poor design or both. A proper fuse of that design typically fails with absolutely no drama. Most people don't even realize it's blown unless they inspect it closely. No smoke, smell, heat, or burn marks. Just a missing filament. And many amps through a dead short will melt the wire insulation. You'll get smoke and smell then. I would check the wire on the back of the fuse box that attach to that fuse terminal. It's probably melty looking. Follow it up in to the harness and you might find the short. It's probably waiting for the right bump.