Zed Head

I'm humbled. I got a twofer. The lights are so bright.

Thanks for those pictures Tomzern and site. Those are the first I've actually seen, and they do look like the way a factory would do it, crude but effective. My thorough side though, sees that one block is from Europe and the other from SE Asia. Tasmania. Australia. I wonder if the US models are the same. Curious enough to get me to remove a head some day if I ever find a Maxima in the wrecking yards. Those who think the Maxima head is of high value should read up on "quench". It's not a major power booster, and some people think that Nissan didn't get it quite right. The bigger valve is worth something for sure. The cam profile would be worth knowing too. I'm not sure the true added-value matches the mystique though. And there are some odd theories proposed out there about how smaller valves increase performance due to air flow velocity increase. Anyway, a person can't go wrong saving these old L engine parts either way.

It's either a new start,with all that he's learned from past mistakes, or he's hiding from his old company's bad reputation. Datsun Parts is now California Datsun. http://www.californiadatsun.com/engine/cylinder-heads/ He is putting his face out there though - http://www.californiadatsun.com/contact-owner-al-allen-of-california-datsun-inc.html And two pages of only excellent reviews - http://www.californiadatsun.com/testimonials/

I'm basically playing devil's advocate I guess. I would like to see an actual factory block with factory-notched bores. I just haven't seen it in all of the 5+ years I've been on the forums, and all of the old posts I've read from way back in that time. I get that an L28 head on an L24 bore would need it. Can't see that a Maxima L24E head on a Maxima L24 block would. The valves are the same size as 260Z valves (looked them all up on OReilly auto Parts). Only the exhaust valve, the smaller valve, is bigger in the Maxima head than in L24 heads. So, it's not a valve size thing, it would have to be a combustion chamber shape and valve seat placement issue. But I think that is determined by the cam, and rocker arms, which are the same. My logic center just can't find a reason that the Maxima N47 head isn't a straight bolt-on, and there doesn't seem to be any evidence, despite all of those Maxima engines out there. Maybe Tomzern has the first one. Considering the bigger valve (one) and the slight bump in CR, it's surprising that more people haven't just swapped the complete L24E engine in to their 240Z's. Looks like it has the carb manifold mounting holes. Anyway, let's see how this plays out. Tomzern, where's your camera?

The question remains though as to what you have. You might have an L28 N47 head on an L24 block, that somebody notched to make it work. There's a whole other recent thread on this forum about that. It's fairly common, to get the bigger valves. We'll know more when you figure out what head you have.

Have to disagree. The nicks seen could be from worn valve guides with a close tolerance. Machining the block is actual money spent by the company that could be avoided. Potential money savings in high production automotive factories is one of the most powerful force you'll ever find. Pennies matter.

Here's another informative thread with all the pictures you need, I think. http://forums.hybridz.org/topic/96188-my-200-l28-surprise/

Here's a side-by-side of the MN47 from that Hybridz link and my N42, which has the same "open" chamber shape as the L28 N47. You can see the "quench' area on the MN47.

Here's an interesting thread - http://forums.hybridz.org/topic/62691-l6-heads-pics-and-descriptions/

That's interesting. I've never seen that mentioned for the factory stock Maxima L24E. I may have missed it though. I didn't think that Nissan did any valve relief on their blocks. There's rumor about the 260Z but many people think the "reliefs" are actually from the valves nicking the bore edge. From a manufacturing perspective, it's a lot of work for not much benefit. Best to just design the head so that it works right, and the Maxima head was only used on the L24E. I can't imagine being the engineer that has to explain that every block needs extra machining because the valves will hit otherwise. Just doesn't make sense.

The "M"N47 head is from an L24 engine. Same bore and stroke as the 240Z L24. It's not the same as the N47 head from the L28. Nissan screwed up when they named the head used on the L24E engine. Unless we're saying that the Nissan Maxima and Laurel C32 L24E blocks were relieved for valve clearance.

Aren't we getting diverted here? He has an L24E head for an L24 bore. When he's done it will be like putting flat-top pistons in the L24E. Shouldn't need any notches. As madkaw says it should be a bolt-on. Using the 39cc numbers I get 9.8 CR for the combo.

I mounted the piece in a vise and used a hack saw. Cut, cut, rotate.

I got lucky and it died in my driveway. It would crank the engine fine for a few turns but not start then slow down then make that noise like it's about to give up. Let it sit a few seconds and I could do it again. I put a meter on the battery and it was 12.7, 11, 11, 9, 9, 9, 9, 9, 6, 6, stop. Cleaned the battery terminals, cables are new, same thing every time. One side benefit though was I thought it might be my starter so I installed a gear reduction starter that I had as a spare. It just gave more 9's but now I get the airplane engine sound when starting. Problem wasn't solved until I installed my spare battery. Which is old and will probably die soon also. I think this might have been the actual problem that caused me to replace my EFI relay. Although the EFI relay still tests bad, and I did get a week or two more before the battery gave out. Weird how problems happen in bunches.

I paid a $1000 for a 280Z that didn't run because it had never been wrecked, the body was in good shape, and the interior was decent. I hate body work, but love engine work and had planned to swap a V8 eventually. I wanted something to work on, not something that was done. You've posted twice but haven't said what you hope to get from the car. That's the key to the conundrum. Not unexpected though, since the Z's tend to unearth incomprehensible desire. State what you're hoping for, if you can, and we can give some clues on how to get it.

Here's some pictures. You can see the threaded base on the rod that stops travel of the breaker plate actuating arm. How people adjust maximum advance if they remove the epoxy plug on the canister.

I feel like I should thread this for future problem solvers. It actually happens. My engine was running weirdly, with a very light constant on-off surging at highway cruising speeds, and adjusting fuel mix with my coolant circuit potentiometer didn't have any effect. So I took the distributor out to see if I might have a broken spring letting timing fluctuate. Also checked the vacuum diaphragm and found it was blown. Not completely but enough that you could blow some air through it. The cam, weights, and springs were fine. I'd guess that the vacuum would pull the diaphragm, advancing timing, then the hole would open and it would lose it. Or something like that. Put a another distributor in (I like to test my spare parts when I get a chance) with a good diaphragm and it's super smooth now. I pressed on the lever to the diaphragm after I pulled it off and must have destroyed the remainder, It made a crunchy noise and resistance to breath disappeared. Just one of my recent odd old 280Z problems. Along with EFI relay solenoid going bad, and battery crapping out, even though it shows a full charge.

1 and 3 took me out of classiczcar to a youtube page. I had to back up to get back to classiczcar. 4 opened a new youtube tab, but kept the classiczcar tab open. 2 played the video in classiczcar. Don't know if you were looking for feedback or not but that's what happened. I think that I have Chrome set up to open new tabs instead of new windows. So how does a person embed a video? I like it, except when it's Miley Cyrus butchering an old classic.

Just looked in the Rebuild Book and there is a section on placing the seals. But it's part of the whole process of installing the crankshaft and caps. So you won't be able to follow it precisely but it may give some ideas.

Get the 260Z and put some 240Z emblems on it. The major downside to the 260 is the 6. It just doesn't look right.

Isn't this described in the How To Rebuild book? With some other tips about added sealant on the corners for insurance.

Curious - who's doing the work? I looked back but didn't find anything. Is there a Seattle shop that knows how to work on these old engines? Of course, what you had done isn't super-complicated, but still, some knowledge required.

You have a lathe? Niiiccceeee.....

There's a guy on zcar.com who wrecked his old Z and his seat belts snapped. Busted up his nose on the steering wheel. Seat belt replacement should really be a topic of discussion. The material degrades in the sun with little visible sign that it's weakened.

Looks like he has Z car envy - " IF YOU ARE LOOKING FOR A Z-CAR, GO AND LOOK FOR A Z-CAR AND DO NOT COMPARE THIS ONE WITH A Z WHEN YOU CALL!"