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1972 automatic 240z

908 Views 9 Replies 4 Participants Last post by  sranco
Hi Guys,

i am brand spanking new to this site. I recently purchased a 1972 240z with only 66 000 original miles, and i am so happy about it i can barely sleep at night, i've wanted one since the first time i saw my uncle pull up at the door with one when i was like 6. Anyways. The car is an automatic and i don't plan on swapping it to a manual trans because my wife hates driving manual and to be honest with you, even though performance is less, i don't really mind driving the auto tranny. Now here are the questions i have, i would still really like to make this car a better perfomer...

keep in mind i love this car, but don't know much about fixing them...

I want to put Weber carbs on the car...is that doable with an automatic?
I read somwhere that an auto trans from a 1984 Maxima would help make the car a little more
spirited? can that be done?

I plan on putting a P90 head in the car, i already have it waiting in my garage, and i will be upgrading to a Pertronix ignition once the weather gets better.

I'm looking forward to hearing what you guys have to say.

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General thinking is to make the car run as well as it possibly can in stock form before you start tinkering. Carbs alone won't get you better performance (unless you're swapping the later EPA 'flattop' ones for the earlier round-tops). Neither, necessarily, will a different head. The L24 was a magnificent motor in its own right and doesn't need a lot of messing with once you really get it dialed in. As far as the auto, Datsun's auto trannies are about as bulletproof as the engines. Enjoy!
Hey 6shutr

I really appreciate the imput, the car already runs pretty well and i totally agree with getting the stock engine dialed in before thinking of anything else. It's great that the trannies last, however my question was about the Maxima transmission being a better performer, i would not be replacing the stock unit because of anything else, other than the fact i want something that performs a little better.

anybody else have some imput?
The three speed auto tranny performs well on its own. I haven't heard of anybody switching them for a Maxima version. If you are thinking of switching over to a pertronix set-up be aware that you will have to buy a single point distributor. I know because I purchased one thinking it would work with the dual point dizzy only to find out it doesn't. Congadulations on your new ride. Have fun!!
3sp automatic
RWD 3N71B 2.458 1.458 1.000 - - - 2.182 240Z, 200SX,510, 710,810,Maxima, 210, 620

Assuming this info is correct (www.datsuns.com) then there is no gearing differences between your AT and the Maxima AT. So, to get better performance you'd need a high stall converter but to what end? It is still a 2.4 automatic.
You should also have the round top carbs (unless flat tops were installed in late production runs). These are fine so no need to go swapping for newer carbs unless your's are worn out (not likely).
The points distributor is also good for your application. The Petronix is a nice upgrade though. Your distributor is probably single point unless someone swapped it out for a dual point (I'm assuming that Nissan didn't put dual-point dizzies in automatics by default). I have dismantled a couple of auto Z's and never seen a dual-point installed.
Swapping on that head won't make much power for you and there is the larger valve clearance issues too. Hang on to that head should you get the bug to build a bigger motor (2.8).
Do a good tune-up and enjoy what you've got.
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As far as I know Nissan put dual point distributors into cars with automatic transmissions. Both of my maintenance manuals Haynes/ and Chilton refer to this. I'm not sure why they did this and I think quite a few people switched them out for single points units as a matter of convienence.
Hey Guys

thanks a lot for your imput.

I will naturally do some research on all this because i do plan on making this car an even better performing one than it already is. I'm sure i'll be using the site a lot.


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oops sorry about the duped pic.
Nice looking car. You should call Ztherapy and order their SU tune-up video. It will make life with and early Z much more enjoyable.
@ Montana240Z

yes that probably would help me a lot, the carbs seem to run a little rich.
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