Zed Head

I think that many of the vacuum advance canisters that come with rebuilt distributors don't have as much advance as the factory units. They seem to have settled on a mid-range advance so that they can use one part for many applications. If you get on to a parts store site you'll see that they use the same distributor and canister for the whole range of 280ZX years. Probably worthwhile to check first. The vacuum advance canister may not match the distributor part number. If the distributor is on the engine and you have a timing light, you can check the full vacuum advance by setting initial timing to a low number (so that the mark will still be on the scale), like 0 or 5, then attaching the vacuum advance hose directly to the intake manifold (not ported vacuum). Timing will jump to the maximum vacuum advance. Do the math and you'll know what you have. If you have a dial-back light, you don't need to reset initial/static timing. Or if you want to know even more, you can connect a gauged vacuum source to determine when the advance starts and when it is full. You might need to adjust the idle speed down if you try this to make sure you're not getting some mechanical also, when the idle speed increases. I've also found that several of my 280Z distributors have more mechanical advance than they are supposed to. It's common to see 10.5 and 11 degree weights in a 280Z distributor. 21 and 22 degrees. Just something to be aware of.

Whatever it is, it looks like it's been broken for quite a while. The other half of the fuse holder and its plastic base are gone. I notice many mentions of "heat glass" in the various wiring schematics. Is that Datsun-speak for fuse? Maybe one of the heat glass parts offers a clue. Since it's been broken, even with a wire attached, it may not have had any function. Probably a red herring.

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Could be that you have a weak battery and an alternator that is not charging. I would check voltage at the battery with the engine off, then with it on. The simplest test to see if the alternator is charging. It may be that he accidentally disconnected the L wire to your voltage regulator. No L, no charge. Whatever the reason, if you determine the alternator is not charging, make sure the VR has what it needs to work right before you replace either the VR or the alt. What does your ammeter show before and after the engine is running? Another tool to use, if you don't have a handheld voltmeter, although not as accurate.

Somebody took the cover off of a the shunt used on cars with ammeters a while ago and I remember being surprised to see that there was a fuse inside. Maybe it's an early model shunt? I would guess that it's just coincidence, and that one or more of the "couple other things" that your friend worked on might be the problem. The obvious question is - if he puts it back in, does the car behave normally? You didn't really indicate if everything was okay until he removed the mystery part. Also - what did he do with the wire that was attached? Maybe it wasn't a "ground" but it's powered and killing your battery via short circuit. In general, and your friend should know this, you should not remove parts until you understand what they do. Especially if there are wires connected. Also, in general, do one thing at a time. Confirm that no problems have been created, then move on to the next project. Now you have the classic " I did five things at once and one of them created a problem" problem.

The K&N phenomenon is pretty interesting. K&N started in the world of dirt bikes, I believe, where it's not uncommon to dump your bike in a stream, completely wetting the air filter. They developed an oil-soaked gauze, or copied it from the old automotive technology. Bikes also used oil-soaked foam but they didn't flow well. Paper would just get ruined. They've done a fantastic marketing job to grow in to other areas. I remember reading dirt bike magazine articles about how the collection of dirt on the outside of the filter element actually increased the filtering effectiveness. Most tests show that the K&N filters flow a tiny bit more air but filter out a lot less dirt. It's really old technology with a lot of marketing behind it.

The EFI harness is essentially separate from the main harness. It can be unplugged and disconnected without cutting any wires. The three main connection points are at the intake manifold, at the ECU (along with the EFI relay), and at the battery. Just start disconnecting and peeling it off until it's free. Then you can sell the whole collection of parts to someone who's switching to EFI from carbs.

The switches are ID'ed in the FSM. Second the heat suggestion on the cog housing, It will soften the o-ring rubber and open the clearance. You can also tap it in a hair with a soft mallet or block of wood to break it loose, before twisting it out, or levering it out via the notch with a screwdriver.

-N3600 looks like the 280Z fan. Not sure which sits furthest back. There's a 280ZX fan blade also. Looks like they're about $72 everywhere. Might as well go to your local Nissan dealer if you want a new blade. http://www.carpartsmanual.com/datsuns30/DatsunZIndex/Engine280Z/WaterPumpFan/tabid/1625/Default.aspx http://www.carpartsmanual.com/datsuns30/DatsunZIndex/Engine240Z260Z/WaterPumpFan/tabid/1591/Default.aspx http://www.courtesyparts.com/blade-fan-p-272967.html

Kind of looks like the guy who wrote the eBay copy didn't actually build the car, or oversee the build. It has a blowthrough turbo with a Holley carb, which he doesn't really describe at all, and he says it had a "frame off restoration". It was only driven to break the engine in. The usual exaggerations also. 500 miles on a brand new engine, with a turbo and nitrous, and he's already claiming that it's "just an awesome reliable ride to cruise around in". Cars like these really need quarter mile times, track times, or dynamometer numbers to show performance, or they might as well just have an empty block with the external shiny parts bolted on. Who knows who put that engine together. The first fill of the nitrous bottle might be hilarious.

I am fairly certain that I tried to turn those adjustment screws and they wouldn't budge. I've also tried to turn the adjustment screws in my oil pressure gauge and they wouldn't move either. The only adjustment I've been able to make on any gauge is on my voltmeter. I wonder if Nissan didn't use some kind of threadlocker on them, since they should only need adjusting one time. Maybe a drop of acetone or MEK on the screw would break them free, or some heat from a soldering iron. A future project maybe, for a spare meter.

My 76 tach shows a steady 200 RPM too high, when compared to my meter. It's a Fluke 115, I use DC hertz to measure, then do some math. I've had my tach dash jump around and misbehave with a new ignition module,even though the engine ran fine. An extra condenser on the negative wire brought it back to life. The tachs seem sensitive to noise. They don't need much "signal" to work, there's actually a 2,300 ohm resistor inline with the coil, on the 76. Your 240Z tach uses the positive side though but may still be sensitive. Maybe a new condenser or an extra on the circuit would help damp some noise.

At least you got to drive it for a little while. I get the impression that the guy is kind of a BS'er. This quote just goes against all that I've ever seen about the L series heads - " built hundreds of heads without worrying about matching rockers to the cam and centering the wipe pattern with no problems to date". On the valve seals, if he didn't use the little straws to protect the seals during installation, he could have cut them. Maybe another internet myth. Also noticed that he talked to you like he rebuilds the heads himself, but the eBay site says thet they're rebuilt by a professional machine shop. Same company, but different stories. He even told you hundreds, but says dozens below. The Datsun Parts LLC disclosure is at the bottom of the eBay ad. "*THESE ARE REBUILT AT A PROFESSIONAL MACHINE SHOP THAT HAS SEVERAL YEARS REBUILT DATSUN HEADS. I HAVE SOLD DOZENS OF THESE WITH PERFECT EBAY FEEDBACK. **" http://www.ebay.com/itm/Datsun-Z-240Z-260Z-280Z-ZX-Rebuilt-N47-Cylinder-Engine-Motor-Head-1976-1980-/151491312445?pt=Motors_Car_Truck_Parts_Accessories&hash=item234595fb3d&vxp=mtr Sorry, hope I don't kill your interaction. Send a PM if you want to keep things quiet for a while and I'll edit this down.

Same comments we're making over here. Validation! I guess if you don't need the cash right away, it's an investment of time to wait for the "right" buyer. Like lurking out in the weeds for the right trophy animal to wander by. Bagged him...$80,000!

Details on the L24 "enhancements" would be interesting. You could probably sell the engines and the car separately more easily. There are a few members in your area that might have some ideas for a local sale. Put ATL GA in the title.

I'm not saying that those rocker arms are bad. Just that they appear to be pulled from a collection of odd rockers. I'm pretty sure also, that I can see the typical shiny line in the middle of the contact pad that used rockers get. DPLLC probably just shipped a batch of collected rocker arms off to Delta for refinishing and pulls from the collection when a head is "rebuilt". He just messed up on lash pad selection.

Look at the pictures and you'll see that design isn't the same. Not small differences. Even someone carving their own arms from a chunk of wood to be used for forming the sand mold would get them closer than that.

I just noticed that the rocker arms appear to be from different sources. One would assume that the rough casting shape would be the same for a common manufacturer but you can see that the portion of the casting on the inside of the wear/rubbing/contact pad is different on several of the arms. Less material. The shape of the "foot" that sits on the lash pad is different also for the ones that have the different contact pad seat. Kind of fits the impression I've had of DPLLC that he collects parts, used and new, from various places, then assembles engines and heads from his collection. Not trying to pile on, just noting. Maybe a little ammo for you to use when talking to Al (the owner, apparently). Interesting also that the cam actually wore some of the casting after it fell off of the pad. The wear pad is supposed to be harder than the casting, apparently, so probably no extra cam damage. Good luck.

Actually, I was almost remembering the wrapped rail. That's what it was. Wrong "not stock" memory. Maybe your FPR got stuck and overpressurized the rail for a moment. Although, having taken an FPR apart, I'm not sure how that could happen. Good luck. I hate the smell of raw gas.

Hey, since the cam and rocker arms took so much abuse but still survived, could you share the names of the companies that made them? ITM and Paraut are typical rocker arm companies. I have a thread on Hybridz collecting info about rocker arms, just because they, or the cams. seem to fail so often. You have dodged the bullet, so far.

Bummer that you have to deal with more problems but lucky that you found it early. I think that you might have some nomenclature/naming a little off. What you're calling the "lash pad" is normally called the rubbing pad. The "bucket shims" are the lash pads. There's a sentence in my Honsowetz How to Modify book that says "The only sure way to determine correct lash-pad thickness is to check the cam-lobe wipe pattern". Page 70. Trial and error. I've seen it described that if the valve stems are all trimmed to the same length out of the head that you only have to do one. But I've also seen that some builders leave random valve lengths in the head so each requires a different lash pad. On the rocker arms, since they're been wearing on half the pad you'll need to carefully check that there's not a discontinuity in the middle of the pad. Worn and unworn. On the oil usage - if DPLLC installed a high lift cam it may be pushing the retainers ( I think that's the part) down in to the valve seals, damaging them. Page 63 of said book says that 0.460" (11.7 mm) valve lift is the maximum. Rocker arm ratio is ~1.5 I believe (although others have measured differently), if you have cam specs. ~7.80 mm (0.307") max Or you could look at a seal. There's a Ford valve seal out there that people use with high lift cams. DP might have used stock seals with a high lift cam. Doesn't really look like he knows a lot. Thanks for sharing though. You should get back to him with what you found and see if he tells you "tough luck" or offers help. At least he should pay for the lash pads and new seals. That would be good to know.

Can't tell whose car is what, but if you have full time vacuum on the advance canister, you could see 32 at idle, which will drop to 32 minus max vacuum advance (the 16 djwarner saw) when you open the throttle. Most people run ported vacuum to the vacuum advance canister. Or disconnect the vacuum hose when checking timing. 16 initial isn't unreasonable. That would give 34 total at open throttle, high RPM, with 18 degree (not uncommon) weights.

More likely that the inner lining would get damaged during installation. They're multilayer. But you already knew that. I was just pointing out the possibility of the leak starting in a not obvious location. Another thought is one of the fittings on your fuel rail. Brass fittings in aluminum might loosen a little over many heat cycles. Just brainstorming...

When my old injector hoses failed they cracked lengthwise internally. I smelled gas, stopped and opened the hood, and a very thin stream of fuel squirted out on to the sidewalk. A tightening with a screwdriver got me home, but that fuel traveled quite a way from its origin.

Wow, that's a big change in pressure. Pretty good example of why valve lash is the very first thing in the Engine Tuneup chapter. You can get low compression also, if the intake valve doesn't open soon enough. It's the air that pulled in on the intake stroke being pressurized that causes the cylinder pressure. Less air to compress = lower pressure. So your adjustment caused the front three to pull more air through the front carb. I know very little about carb tuning. Very little. It's like more vacuum.