NewZed

I've put over 20,000 miles each on two old high mileage L28 engines, using a variety of modern oils from Quaker State 20-50W to Pennzoil 10-40W (whatever's on sale) and have not seen any signs of camshaft wear. My valve lash doesn't even change significantly. It seems to me that there might have been a problem in the early days of removing zinc from oil formulations but that the oil manufacturers have since fixed the problem. The whole zinc thing is old news and the high zinc formulations are unecessary. Has anyone seen that using today's oils, today, from a reputable supplier like Pennzoil, Quaker State, Valvoline, etc., without added zinc, will wear out an already broken-in camshaft? How many people spend extra money to get added zinc complex in their oil?

Aren't you supposed to add an NSFW when you post a link like that? I learned more about SE Asia travel through the FAQs on that site than I ever knew before. Pretty informative. Thanks for the education.

You must be getting parts from your doppelganger. Here's an old slave cylinder I took off a 78 280Z.

Rock Auto doesn't make parts, they just resell. Which brand did you buy? Sometimes the good stuff is cheap at Rock Auto. There's a thread or two on this site about which u-joints are stronger, I believe.

To summarize - cracked L6 blocks are common. A crack between 2 and 3 is not common. Someone "rebuilt" the engine without noticing the crack (doesn't it project all the way through to the interior of the cylinder?). What happens if he just runs it as-is? Catastrophe or a slow death?

I'm just passing on the link. No idea who's selling it. Caveat emptor.

I'm not positive but I don't think that you can run two devices from one O2 sensor. Might be part of your problem.

Shipping from Portland to Portrush might be spendy - http://portland.craigslist.org/mlt/pts/3625163741.html

Hot wire the fuel pump for a short test. You might be losing power to the fuel pump. The safeties are bypassed at Start. On the 76, with the AFM fuel pump contacts, typically if it starts then dies after a few seconds, it's because the contacts aren't making contact. They need air passing through the AFM to stay closed. The fuel pump only comes on at Start or when the key is On and the AFM contacts are closed.

Wow, those Accel coils seem to be mysterious and magical. They don't list any specs. for the coils, they're all "Super" and they have instructions like this - "New resistors will smoke initially in operation and get extremely hot. This is normal". http://accel-ignition.com/original-super-coil-points.html http://accel-ignition.com/media/instructions/accel/ACCEL_Instructions_universal_super_coil_140001.pdf You've got a bunch of options. How much do you want to spend and how simple does it need to be? You can probably get a good conversation going on whether or not any distributor-initiated ignition system will handle 8,000 RPM. Let alone a stock (except for balancing, whatever that means) L24 engine with just a different cam. Don't forget to consider tachometer accuracy also, the needle may not be showing true RPM. Revving around at 8,000 RPM does sound like fun though.

Have you measured fuel pressure? Timing? Looked for intake leaks? Can't go wrong with confirming that the basics are right before you get in to the fine details.

7 is colder than the factory recommended 6. As I understand heat range, you want to be hot enough to keep things clean (no carbon fouling), but cool enough to avoid damage. You've got a pretty good coating on your electrodes. Might be better of with the factory 6. I just had my plugs out last night and noticed that #1 porcelain is very white and clean compared to the rest, 3 and 4 seem a little brown and the rest look "normal". This has been common for the only two engines I've had, both with the same N42 intake manifold, one an N42/N42 head/block before and N42/N47 now. Seems like cylinder 1 might be getting extra air, making it a little lean or it runs hot. It's hard to tell which, or how to confirm. The flow imbalance idea seems reasonable, I've often wondered why my idle seems rougher than it should be.

There's not much to the spark initiation portion of the distributor. The only "new" part you'll get with another distributor that might be stopping spark is the pickup coil. Any of the 280Z pickup coils will swap in. You're just guessing and replacing though. You'll probably spend a lot of money and find out that your buddy left a wire disocnnected. Have you even checked for power to the coil?

Click "More Reply Options" at the bottom of the reply window > click "Browse" > choose the image file from your computer, it will take you back to the More Reply Options page > click "Attach This File" > click "Add Reply" to finish.

You have to crawl under the car and stick a long screwdriver up to the latch and release it. It's been described around the various forums. Pretty sure I saw some good stories about it over on classiczcar.com.

Old stock factory FPRs tend to leak down. They're not supposed to though, I think the valve just stops seating right after many years or rust holds them open. I've checked a bunch and found a few that don't leak down for days. I have one on the car now. The Aeromotive FPR design just doesn't hold pressure once the fuel pump shuts off. It regulates fine, just doesn't hold when flow stops. They're aware of the problem (I've emailed the company and received a reply). The other source of pressure leak down is the check valve in the fuel pump. They fail occasionally.

I haven't heard of many cracked L6 blocks, although I would guess it happens. Where is yours cracked and how do you know?

Just a guess. Wouldn't be surprised if it was like the oil pan drain plug. Internet says M16.4 - 1.33. They're also avaialble from Courtey Parts if you've got time to wait. Cheap. http://www.carpartsmanual.com/datsunS30/DatsunZIndex/Engine280Z/FuelTank/FromJul76/tabid/1622/Default.aspx

It's fun to guess, with little information, but if you really want some good ideas you need to add more. "My z sat for 8 months in my garage. Installed 40mm webers H7 models (completely overhualed). Installed rx7 fuel pump (producing 4psi on gauge). Installed 81 280zx distributer. (Replace oil driver and gear)" Did it run before you parked it 8 months ago? What else did you remove when you installed the Webers? and the fuel pump? and the distributor? Assuming it ran well when you parked it, odds are you just made a mistake when you did the distributor work. No reason for your rings to get messed up over 8 months. If you don't reset the distributor to factory specs. then you'll have to work around it and make it work based on principles. You'll probably understand your engine much better if you do things the second way. Or you could just start from scratch. There's a drawing the 1981 Engine Lubrication chapter showing orientation at cylinder #1 TDC. It seems to be the only drawing, for some reason, in the '81 FSM. You can at least check orientation to see how far it's off. As for the loose medal backing plate witch is concerning - maybe a promiscuous, decorated, female military member who practiced the dark arts used to own the car. lol

Have you measured resistance on the 9-8 and 8-6 pins? My first AFM measured high on those pins, 126 and 227 instead of 100 and 180 and the engine would only idle and go full throttle. It just popped back through the intake and bucked in between. Which, in retrospect, was probably a lean condition and 45 psi might have "fixed" it. But then it would have had a rich idle and burned a lot more fuel at full enrichment. The resistor in the coolant temp. circuit might give you a clue. It's pretty easy to do and cheap. Get an audio taper potentiometer they're easier to adjust. If it works you can decide if you want to keep it that way or get a different AFM.

Are you still shifting at 7,000 RPM? And you never said what fluid you were running. Bummer that it's not there yet. I was hoping. Maybe there is no good way to rebuild an old transmission to like-new performance.

Kind of sounds like you might have your timing light lead on the wrong plug wire or your distributor is off. If it starts and idles, you're probably in the ~20 to~ zero degree advance range. Move the timing light lead from plug wire to plug wire until you get a reading in that range then set it to 10, for starters. The cylinder that you're measuring timing on is then your new #1. If you have an adapter on your cylinder pressure gauge you'll get much lower pressure readings. If it runs you probably have much more than 70 psi cylinder true pressure. The gauge volume becomes part of what's being measured and affects the number. Just look at the difference between cylinders, if they're close, don't worry about it.

Look at Post #30 here, BRAAP has some thoughts on timing that might help - http://forums.hybridz.org/topic/95316-braaps-l6-efi-induction-advice-and-tips/page-2 And, from your picture, it looks like you should measure voltage not resistance, then divide by .01 to calculate degrees of advance. It says 0.01 Volts per degree right on the front panel.

One possibility is that you're sucking oil vapor in to the intake system through the crank vent. The PCV system is designed to move air and exhaust byproducts at a variable rate, usually low volume, through a pressure imbalance between the PCV valve and the fresh air supply in the valve cover. If the rings seat well and the valve seals are good there's not much aitr movement at all. You had it set up to pull air down through the valve cover through the crankcase, through the crankcase vent and in to the intake system at full intake manifold vacuum. That's a lot of air. You said that you applied vacuum through the through the valve cover, but it's hard to tell what that means. Might be worth studying the Emissions chapter in the FSM, or blocking the crankcase vent from the intake manifold to see if it gets better. Even if it's not the problem, I don't think that your crankcase venting system is right. It's a giant intake manifold vacuum leak, the way you've described it.

Nissan forgot to put the relief valve in the Component Parts drawing, or didn't think it belonged (they left the PCV valve out also), so the schematics were the next best place to look. Good engineering practice is to make any illustration as descriptive as possible. The drawing is misleading and could be improved. At least they showed it's general shape on EF-30.