Zed Head

You'll probably break some studs and bolts and find stuff that needs repair in the head when you take the engine out to swap parts. Might be better off to buy a complete engine. How did you "spin" the bearing and how do you know? Everyone loves a good story...

Thanks, that clears it up for me. I was looking at it as attached at one of the long ends, not laid down. My perspective was off, if I had seen one out of the engine before I would have known the tab wasn't that long. Kind of surprised that Mallory didn't show more interest since it looks like a failure of their product. Maybe you were talking to the wrong guy.

Thanks for the reply. Maybe my brain is stuck, hopefully it will unstick later if so, but the picture of the shaft and the broken piece in your first post shows a counterclockwise twist. The distributor has two tabs that fit around the one center piece at the end of the oil pump drive shaft. That piece sticks up and it's twisted counterclockwise,looking down on it as it would be in the engine. The only way to do that is if the distributor shaft is twisting ahead of the oil pump shaft. But the oil pump shaft is the driver not the driven. If you held the distributor shaft in place, put the car in gear and rolled it backward you could get the same twist. Sorry if I'm not getting it. I enjoy looking at broken machines too.

I might have this backwards, and it doesn't help that the picture of the end of the dist. drive shaft is upside down but isn't the twist backwards for the scenario where the distributor stops and the pump keeps turning? Shaft turning counterclockwise, broken end pointed up. It looks more like the pump stopped and the distributor kept going. Maybe I'm looking at the wrong end of the shaft, or just thinking backward. I haven't actually had one out. Is it possible that the twist is old damage that finally fatigued and broke?

Don't forget metal fatigue as a possible cause for the tabs breaking. Fatigue doesn't take much force just many many cycles. Could be that the tabs broke off one a time. Since they are advance limiters, you might have had really high advance for a while before they jammed the shaft. BUT it is hard to see how the tabs could get in to a spot to jam the rotating shaft. Jamming the advance mechanism would just lock your timing advance in to one spot. Did you find the tabs actually wedged in somewhere? Seems like they would have done more damage if they were the cause and not an effect. The shaft locking up from galling or some other bearing/bushing type failure might have stopped things so suddenly that inertia broke the advance tabs. Just a possibility.

How about bending up a couple of U shaped brackets, with the bottom of the U flattened, drilling them for the through bolts, and bolting them to the original locations. That area is strong enough and you'll be able to use the original cross-member.

You could put a loop in the hose. Point the loop up so it won't catch on something. Make sure it doesn't rub on anything. Zip-ties work well for holding the loop where you want it. I did this for the outlet on my new pump when I installed it, for a similar reason. The hoses are in metric size. You're right, the outlet is smaller. I can't remember the outlet from the pump, but when you get up to the engine bay, it's 8 mm, which is very close to 5/16", which works great. Probably 12 mm on your inlet hose. I would guess that 3/8" (close to 10 mm) might work on the outlet of the pump.

I've had a clutch slave cylinder go bad within months of installing. I took the replacement apart before installing and found manufacturing grit inside, which I removed with a brake fluid rinse. So some aftermarket parts don't have the greatest QC on the cleaning side. Could explain the master cylinder going bad. It shouldn't leak, and there's no where for the fluid to go except backwards toward the booster. It could also leak down the face of the booster at the mounting surface. I also had a booster go bad after already having replaced the brake master cylinder. It was full of old brake fluid (that dripped on my paint when I was removing it), from the bad master that I had replaced. The car had sat for a few years. The fluid isn't kind to any plastic type materials and probably helped the booster disc fail. So I would say that yes, your master cylinder is bad, and yes that you should replace both. But the 1" master would give you shorter travel on the brake pedal but will require more effort, so you might want to consider that before deciding which master to use. If you get another aftermarket master cylinder take it apart and clean the bore, piston and seals, or flush it out well before installing. Edit - Forgot to say that the hissing sound and the motor dieing are sings of a bad booster. The hissing is intake manifold vacuum escaping and the motor dies because of it. Good point on matching part dimensions (below) before installing.

That was an exhaust manifold mounting stud. They break a lot. There are many Z's driving around right now with that stud broken. It shouldn't hurt to drive it a shop. Bummer, but it was probably already half-broken when you tried to tighten it. They crack and break from metal fatigue after a few tens of thousands of heat cycles.

That brings up one good point about the "bible" - it shows how to take the measurements from the connector at the ECU AND has the chart of temperature versus resistance on the same page. The FSM's are vague and you have to do some figuring and page-flipping to get to the same point. If Cethern has been using the 280Z Electronic Fuel Injection Book then he's already checked the connection when he took the coolant temperature sensor measurement at the ECU connector.

Other causes of running super rich are more common, but it is also a sign of a bad ECU. Some people have fixed theirs by re-flowing the solder connections from the connector to the board.

You got me. I made an assumption (that all fluoropolymers would be fine with brake fluid), and a bad suggestion. I should know better. Sounds like Eurodat has the best resource for figuring out what will work. Interesting thread.

You implied that the Drivetrain.com (Post #3) kit would be fine since your spirited driving days are over. It's cheap and almost complete. The missing bearing and nuts are available from courtesyparts.com (tamo3). I've bought bearings, seals and the countershaft lock nut from them within the last couple of years. You might try courtesyparts.com for the synchros also to be sure. Shows as available on their web site, and even cheaper than I thought. Put it in the cart and look at the red dot. - RING-BAULK :: Nissan Parts, NISMO and Nissan Accessories - Courtesyparts.com You can get part numbers from here, the 71B gear sets are essentially the same up to 83. Datsun 280Z Transmission Gears, Speedometer Pinion (5 Speed-FS5W71B) (From Aug.-'76)

I would be careful on material with the o-ring. Plain old plumbing o-rings might absorb brake fluid and swell (I tested an Ace Hardware o-ring to see if it could be used - it swelled). Viton would be fine if you can find them. I don't know what the typical material used is, and most manufacturers that I've seen don't list it. It's a problem.

The 75 files are 86 MB total. Have you taken any of the resistance measurements shown from page 45 on of the "bible"? The three tools that will help you the most are a multimeter, a timing light and a fuel pressure gauge. Without those, troubleshooting will be difficult.

The problems you described and the actions you took don't really follow, and the description is a little confusing. You said that the pump kept running when you turned the key off then the engine started running rich. But the engine can't run with the key off....? Plus you're on the "changing parts" path, instead of the "test and take measurements" path. Nobody can recommend a new part to change until you've taken a measurement. First, I would download the 1975 FSM and use it instead of the "bible". The "bible" is like using Cliff's Notes, when the original book is right there, and free. Read the Engine Fuel chapter. I would measure fuel pressure and record the resistance of the coolant temperature circuit. Those are two things that can easily cause a rich condition. As far as the pump goes, the wiring diagram is in the Engine Fuel chapter also.

I think that what's bothering some of us is why you aren't worried. Can't figure out why you're so confident, when you can't even get the gasket material off of the head. Maybe you're just okay with problems if they do come up, you'll just take it off and start over. Can't say that I haven't taken some chances like that myself but you seem a little over-sure that all will be well. Looks like an interesting adventure though. Good luck.

I didn't know the internet would turn the link in to an advertisement. I was referring to his comments about quality, in the text on the page - "We've seen a lot of problems with a lot of different less expensive syncro rings for these transmissions. Years ago we decided not to install or sell them anymore. No one likes having to do a job twice because of junk parts. We've never had a single problem with this style. Be wary of less expensive syncro rings." It may be that not all baulk rings are the same. But, as gnosez says, maybe it depends on how you intend to use the transmission. As far as cost, Nissan charges about the same as zspecialties for one ring. But I don't think that Nissan sells a kit, although you can get bearings and seals individually also.

The comment on zspecialties' site about the synchro rings is interesting. Oliver, the owner, might be worth a call or an e-mail. He's been helpful when I've talked to him. Syncro Ring 1st through 4th 70-83: Drivetrain Z - 40124-EPDT - Z Specialties Online Store - If we don't have it in stock, we can get it!

Everything seems consistent. What is there to disbelieve?

Did the head come complete, with cam, rocker arms, etc., from a running engine, with the new steel valve seats already installed and broken in? Or did you remove the valves and replace the seats? Did you keep the rocker arms, valves and assorted pieces in the order that they were taken out? Just curious, since you might have other problems when you try to put it back together. A little bit of heat would probably soften the old gasket material and make it easier to remove. Makes some people nervous but the gasket will soften up well before any damage is done to the head. A heat gun would work if a torch is too scary.

Don't know if it will affect your decision but that is an F54 block, so might have flat-top pistons, if it came from an NA car. If so, with the N42 head, the compression ratio will be higher than the stock L28. Either way, the head did not come with the block, and the "E30" cam did not come with the N42 head, so somebody has put together their own set of parts. That's not a typical L28 engine.

Flat, straight and parallel is more important than clean. Along with the critical dimensions of valve seats, guides, etc. You're focusing on the wrong thing, if you plan to use the engine to make the car move.

That's probably the best picture of the housing out there, I always forget where it is. Eurodat's probably right, it's just an extra transmitter. Measure the resistance from the bullet connector to ground. If it's a transmitter you'll get a number, if it's switch you'll get zero or infinite.

You might have a 76-77 thermostat housing. 76 for sure has four - thermotime switch, coolant temp. sensor (for ECU), coolant temp. indicator (for gauge) and temp. switch for the ignition module (to use the second pickup in the distributor to advance the timing when cold).