Royce

A used 240 motor doesn't have a lot going for it, especially if it has been removed from a car. It is easiest to sell if the new owner can drive it and see how it runs. In my opinion, once it is taken out it is basically a core. I mean, I wouldn't go through all the work to put it in my car just to find out there is a problem and then take it out again. I would rather take it appart and check it over first and at least replace the bearings and the rings. A 240Z motor is most valuable with the matching serial number 240Z car. Second most valuable place is with a racer that is restricted to original engine specifications. But a motor is expensive to ship so it limits you to mostly local sales. If someone is going to swap to a different non-original motor they may as well go with a 280Z, 280ZX or 280ZX turbo motor. It is hard to beat cubic inches or turbo if you want a little more bang for the buck. I just recently gave away a L24 because I had it for sale for several years and got no takers. But there are a lot of Z's here in California. So where you are they may have more value!? The bottom line is if you have time you have a better chance of finding someone that will pay what you think it is worth. This is just my opinion! Sorry, I probably didn't help much.

Well I noticed the font color was different but didn't realize it was a link. Thanks!

DatsunZGuy, How about some contact information???

Zsled, Remember, that is $5 for a L24 or L28 with modified bottom end, head, and carbs. You are not talking about your basic rebuilt engine here. They can build you a standard L24 - L28 for less, it just depends on the condition of the parts they are starting with and whay you want to have done to them! A little machine work here and there and some upgraded parts can add up really quick. Sure a small block V8 might be cheaper in some respects, but if you get out of the standard build it will add up quick too! Besides, small block V8's are still in new production and race developement. The L6 hasn't been for a few decades, not to the same degree anyway! Hope it makes sense! Derk, Sorry, no clue what Britney has to do with this!?

Sounds interesting, how about some pictures?

I think either motor would range between $4k & $6k depending on what you have done, condition of head/block/etc. they start with and if you are going to give up your original motor or not. If you build your L28 right you could be in the range. My 2.9L Rebello motor, built in 1990, is basically a smaller bore version of there current 3L motor. Mine is a N42 L28 block with L24 rods and custom pistons. It has my E88 head with 280Z vavles and some machine work. These days they usually start with the F54 block and will use a N42 head if you don't supply one. I have never put my engine or car on a dyno but I am sure it is not there. I put in a stock cam with my stock intake, exhaust, and all the smog equipement (remeber this was 10 years ago). It has a lot of torque but needs some other modifications to get the power. I have talked to two members from North California that have purchases Rebello L28 motors recently who could probably tell you more.

It sounds like the gas tank vent lines might be crimped somewhere. There are several vent lines so I am surprised this would happen, but maybe someone has removed some of the vents in the past. It is common for the vent lines to deteriorate over time and cause gas smell to get into the passenger compartment. If someone plugged a couple of the lines and left only one, and now that one is damaged that could cause your problem. All the vent lines are routed to a vapor tank in the hatch area behind the passenger side interior plastic quarter panel. You could start here but it would be best to get a manual and check out the fuel system, specifically around the gas tank to see a diagram of the fuel tank vent hoses. I remember my friend had this problem with his VW bug and it would actually crush the tank slightly from the vacuum. Hmm, I suppose you may have problems if your fuel vapor return lines, that run from the carb fuel rail back to the gas tank may be plugged up. This is easy to test by removing the return line at the tank. I cannot remember how high the return line inlet goes up once in the tank so you might want to do this will fuel level is low. Disconnect the return line at the carb fuel rail. Blow compressed air back through the line and see if you get good air pressure out the other end. In order for gas to get removed from the tank by the fuel pump it needs to have a way to replace the space with air. Hope it helps!

If you are racing you should run the breather to a catch can w/ breather. Otherwise you could use just a breather but as lan240 says if there is a worn o-ring, gasket or seal somewhere on your firewall you can end up smelling fumes in your passenger compartment. I have also heard that having the fumes drawn out by vacuum from the carbs helps keep the oil cleaner. This theory suggests that you are getting vapor contaminants out of the engine. This may be true but I don't know if it is significant. Of course if you have that many vapor contaminants in your engine you may be due for a rebuild anyway. Hope it helps!

I think this person is confusing flat top pistons with flat top carbs. However, if someone wants to show their car in a stock category and has a '73 240 or 260Z at least they can get a spare set of carbs cheap. Because they are probably going to need all the spares they can get to keep the thing running. Then again, all it takes is one person to figure them out and win a race with them and everyone would probably start buying them up! My friend has a '73 with them and it still runs well. I don't think I would stay with them because there is not as much info or parts available. Especially if engine modifications are planned.

Oops!!! Sorry, I looked over you info too quickly and mistook the info as 240, 280, and 280ZX specs, instead of 240,260, and 280Z/ZX! I realize E30,E31 and P79,P90 have better combustion chamber design but I think this is further proof that you can do quite well on a budget when starting with the N42 head! My bad! Thanks for the quick correction!

Zsled, Depends on whether you want to win or just have fun at autocross. It is hard to beat cubic inches when it comes to making more power! I don't autocross (yet) but I would (and did) go the L28 route. But make sure and keep you L24 if it is the original motor for you car. Turbo's and tripple carbs would likely put you in a modified class that would require many $$$ of suspension and other modifications and developement to make the car competitive. Besides, as Dan said tripple carbs are not necessarily needed to get more performance. You can go a long way with SUs. From what I have heard Rebello Racing builds a 200HP L24 SCCA ITS spec motor using relatively stock bottom end and carbs and mild head work. For the same money they can build you a 250-275HP L28 using modified SU carbs, L28 block, and modified head (using 280ZX intake and exhaust valves). I do not work for Rebello or have any affiliation, they are just well know local Z motor builder that I had build my motor many years ago. Dan, I think that makes a good case for the N42! Any L6 head could use a cam and a little polish and port. With the N42 you do that and add the 280ZX intake valves and there you go! Thanks for the info! Mudge, Well that is almost a second off the R/T test times when the cars were new, ~16.6 if I remember correctly. Although, with modern tires you might be able to make that difference. It is hard to compare without knowing you entire setup. Engine spec, exhaust, intake, trans, diff, tires. Have fun!

I voted for "All the time", although occasional drives would be more like it. With two young ones around neither of us drive it as much as we would like. Plus at 5'4" she has a bit of a time reaching the peddles. She would like it a bit more if I actually cleaned the inside once in a while and if it had more than just the stock radio! She doesn't know that's why I leave it the way it is! (kidding!)

It would kinda fit under the Tech Documents, open, or misc. forums. Maybe, he could ad a historical reference forum for these topics? And maybe a new discussion should be started since this is drifting away from the E-30 topic.

Yes, I too would love to learn more about the non-USA Z cars from a non-USA perspective! I enjoy all the different personalities on this and other sites. Hey, if we were all the same with the same opinion life would be boring! And everyone would be driving Z's!!! Maybe that would be too much of a good thing! Nah!

Sure Bambikiller240, you Carl guys stick together!!! ;-) Actually, I agree to your statement exactly. Carl Beck worked in a US Datsun dealership and has a great amount of US Z knowledge. But like anyone his comments may be a little biased to his own experiences. Most of the information on Zhome was contributed by Z folks from around the world. I am certain he would be very happy to have more information on the different Z markets! HS30-H, Thanks for the info on the E30 head. I had heard it is not necessarily a good choice for the L24 - L28 because it has smaller valves than even the early L24 heads. Of course vavle sizes can always be changed, and often are. Sure Carl Beck or zhome.com can take your affectionate punches. He enjoy's talking Z as much as anyone and I am sure if he has argured with you about anything Z it was in the interested of learning more and challenging you to the point of disproving some other information he was convinced by another was fact! I post things on this site and other Z forums that I think are ture. I certainly don't want to send anyone down the wrong directions and apprieciate it when I am corrected! Go for it, challenge him, them, it, us! Take care!

Sure it will work in a 240, 260, 280Z, 280ZX or anything that currently takes an R160, R180, R190 or R200. From what I have heard the trick is getting the right output axles so that you can attach your Z/ZX half shafts or CV joints. Example, If you have the 4 bolt flange type diff now you would need Datsun 510 R160 flanges to bolt up to your R180 or R200 half shafts. Hope that makes sense!? Also, the bolt holes on the back of the R160 and R180's are smaller than the R200. So you should be okay here to swap with a R180 but if you swap with a larger diff you would need to modify or change your rear diff mount, mustache bar for us first generation Z folks. I have read that a LSD diff is stronger than the comparable open diff. And that a LSD R160 would be stronger than a open R180 diff. So which Subaru's come with 3.9 or 4.11 LSD??? Hope it helps!

All L6 Z/ZX heads have round intake ports. The N47 & P79 have round exhaust ports as well. It has been said that the square ports are more productive to flow but I have never seen any dyno results to say how much of a difference, if any, it makes. I have seen "the quest for the best Z/ZX cylinder head" conversation come up many times on many different forums. I have some questions that I have not seen discussed... What are the different int/exh valve sizes for the various US marked Z/ZX L6 heads (E31, 240Z E88, N42, P90)? I have heard often talk about putting 280Z or ZX valves in E31 or E88 heads. Does it require machining the head to use these larger valves? (What I mean is sometimes you can increase the valve sizes by just grinding the valve seat and not actually machining the head and putting in larger seats.) What about larger than 280Z/ZX valves in any L6 head. Has anyone done this? I would expect that all the above has been done but it may be helpful in determining how cost effective it is to modify different stock Z L6 heads. As a Z car person on a budget the best head to me is the one that gives the best bang for the buck. I have often thought if you have a head in good shape that is the best place to start. From there you can modify it to meet your performance goals. I have heard that the E31 and P90's have the "best" combustion chamber design. Sure you could put larger valves in a E31 but I would have a hard time justifying the work it would take to get a P90 head to work well on a non-Turbo Z motor. Of course to take advantage of head work mods (big cams and large valves) you also need higher than stock compression or you could actually see less power output. What do you folks think?

I have seen 34 years! Took my first ride in a Z when I was 2 years old. My father borrowed his friends brand new yellow '70 240Z and took the family for a ride. Those were the days, Mom and Dad up front and three kids in the back. I bought my silver 240Z from the original owner when I was 20.

My car weighs about 2400lbs (+/- 20) with a full tank of gas and No driver. I have heard people talk about the early series I 240Z's being a little lighter but I think it is very slight and mostly a myth. I think all the 240s are going to be pretty close. The '73 has larger front bumper mounts but not much more that would make it heavier. I didn't mean to imply the early US 240Zs weighed significantly less than the later US 240Zs. The US 240Z is significantly lighter than US 260Z (late model) & US 280Z. This is because of the larger bumpers, larger radiator support/radiator, heavier exhaust, larger diff, door internals, and many smaller things. Probably good for 300+ lbs!?

Oops, just read my post. The first line should read that in the US the '72 is considered by many to be the best out of the box. I didn't mean to imply that the US '72 was best 240Z around the world, I cannot speak for 240Z's in other parts of the world. Sorry!

For clubs you have ZONC, Z owners of North California, but from what I can tell us Sacramento locals are the only ones having monthly meetings. There is also zdriver.com which is very active and I think centralized in the South bay area. I went with Revolution wheels on my Z, see my photo link, because they reminded me of the older period American muscle car wheels and were not as common as the minilite style 8 spoke wheels. I am a bay area native and grew up in Redwood City. I also am a closet Mustang fan. I still miss my fathers black '65 GT conv.(4-spd, black top with red pony interior) and his '67 Shelby Mustang GT500. He sold them both before the American muscle cars started going up! Isn't your car a '65 (judging by the louvers in the rear quarter windows) or does that only appy to the Shelby GT350R cars!? Welcome to the club!

I think from the factory the US market '72 is considered by many to be the best 240Z. But at this point many have integrated the improvements into the other years. So by this time there probably isn't as much of a difference but it helps to know what to look for. Reason being that '70 - '71 had a weaker transmission design and the diff mount location caused more stress on the half shaft joints. There were other things (like reclining seats, better rear window defroster, etc.) but those are the big ones. The '73 has the same stronger trans and diff location (moved back about 1") as the '72 but the cylinder head and carbs were redesigned to try to met tougher smog standards. Most '73 these days have been converted from the problematic '73 flat top carbs to the earlier '70 - '72 round top SU style carbs or the weber DGV downdraft carbs. I have seen some cars still running fine with the flat tops but it is harder to find help and parts for them. They probably due better in the California climate than somewhere else were there are more extreme seasonal changes. The Weber DGV's aren't bad either but again harder to find support from the Z community if you have problems. The 240Z is very popular because- it is the first design, it is physically lighter, in the US it has less smog so power is equal if not a little better. Also, the US cars had smaller bumpers which some people prefer to the larger bumpers of the later cars. The 260 & 280's do have some improvements to interior and such that make it a little more comforatable car. I like the 240 because it is simple and raw! I remember driving my sisters '84 300ZX Turbo 50th Anniversary car and thinking what a boat it was. Even with it's adjustable suspension turned all the way stiff. Hope that helps!

I had mentioned pulling the motor and installing the motor and trans together. When I have done this it was because I had the motor out. When installing it by myself had a problem getting the motor and trans lined up. It is a lot of extra work if you only have the trans out. But I would still do this before using the long bolt idea. It is best easy to do if you have a load-leveling device for your engine hoist. -Drain fluids from engine, radiator and trans. -Disconnect fuel, water and vacuum hoses. -Disconnect ignition & alternator wires, throttle linkage and choke cables. -Remove hood. With hood open go to one side and remove bottom bolt and loosen top bolt (where hood is attached to the hinge. Then on other side with hood resting on your shoulder remove bottom bolt and loosen top bolt. Now you can slowly let hood come down (make sure it doesn't go down onto a fender). Then remove the two bolts and remove hood. When you put it all back together don't tighten the bolts with it open. You need to close it and push down on the center at the front to make sure you have proper alignment. -Remove radiator. -Jack up the rear of the car and put on stands. -Attach the engine hoist to the engine and lift enough to remove slack in chain/straps. -Undo motor mounts and trans mount bolts. -Adjust the load leveler so that the tranny starts coming down. You need to work the height of the engine hoist and load lever until you get a good angle to start moving the hoist forward until you can get them both out. I just wanted to give an idea what is involved. As with any procedure it will take longer the first time but will get easier with practice. But hopefully you won’t need a lot of practice! Hope it helps!

Yes, I think the N42 is a good replacement choice if for no other reason then because you can find one more easily and probably less expensive than an E31. The larger valves is a nice bonus, but I wouldn't change heads just for the larger vavles unless you had another good reason to change. Any of the E31, E88, or N42 heads look even better on a L28 with flat top pistons!