240z 5 speed conversion - Nissan : Datsun ZCar forum :Nissan Z Forum: 240Z to 370Z
User Tag List

Reply
 
LinkBack Thread Tools
post #1 of 21 (permalink) Old 04-03-2019, 02:50 PM Thread Starter
Junior Member
 
Join Date: Feb 2018
Posts: 2
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 3 Post(s)
(Thread Starter)
240z 5 speed conversion

I am wanting to convert my 1970 240z from a 4 speed to a 5 speed and understand that a '81-'83 280zx 5 speed is the way to go. Can anyone tell how I can identify the '81-'83 280zx 5 speed (Casting numbers or markings)? I do have a line on a '75 5 speed but understand that is not as desirable?
IronKen is offline  
Sponsored Links
Advertisement
 
post #2 of 21 (permalink) Old 04-03-2019, 05:22 PM
Senior Member
 
Join Date: Jun 2016
Posts: 499
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 106 Post(s)
Quote:
Originally Posted by IronKen View Post
I am wanting to convert my 1970 240z from a 4 speed to a 5 speed and understand that a '81-'83 280zx 5 speed is the way to go. Can anyone tell how I can identify the '81-'83 280zx 5 speed (Casting numbers or markings)? I do have a line on a '75 5 speed but understand that is not as desirable?
The gear ratios are SLIGHTLY different between the Z and ZX transmissions but I really wouldn't fret over it. If you have a 5-speed ready to go, pop it in and you'll be more than happy with it.

1978 280z - stock L28 engine - Dallas, TX
chaseincats is offline  
post #3 of 21 (permalink) Old 04-03-2019, 06:32 PM
Senior Member
 
bificus's Avatar
 
Join Date: Sep 2010
Location: SC
Posts: 1,041
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 52 Post(s)
Garage
Well in the US we didn't get a 5 speed til 77. I have a 78 in my car its more a 4 speed w/overdrive. The key with that ZX 5 speed is it comes with a 3.9 differential. US 240s came with a 3.54 if I recall correctly. So keep that in mind as well as trans tunnel clearance, might need a mod to get to 5th.

1975 280Z F54/N47 MSA 6-1 Header 2.5 Exhaust
bificus is offline  
Sponsored Links
Advertisement
 
post #4 of 21 (permalink) Old 04-03-2019, 08:11 PM
Senior Member
 
Join Date: Mar 2010
Posts: 587
Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 67 Post(s)
Simplest is to use the 77-78 "5 speed". Outside dimensions are exactly the same as the one you have. As mentioned, Datsun just added a 5th overdrive gear inside on an existing shaft in the 77-78 units. So technically it's not a 'true' 5 speed, but they work fine and will give you a little more top end - or slight MPG increase, depending on how you drive.
6shutr is offline  
post #5 of 21 (permalink) Old 04-04-2019, 08:57 AM
Senior Member
 
Join Date: Sep 2015
Location: Central FL
Posts: 852
Mentioned: 0 Post(s)
Tagged: 1 Thread(s)
Quoted: 199 Post(s)
the later 5 speeds have a .75 OD, if you have a 3.54 diff then you are turning about 3k at 80mph. Its a nice setup for highway speeds but the OD cant be engaged at anything under 65 on flat roads least you lug the engine.
Dave M is offline  
post #6 of 21 (permalink) Old 04-04-2019, 11:58 AM
Senior Member
 
Join Date: Jun 2016
Posts: 499
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 106 Post(s)
Quote:
Originally Posted by Dave M View Post
the later 5 speeds have a .75 OD, if you have a 3.54 diff then you are turning about 3k at 80mph. Its a nice setup for highway speeds but the OD cant be engaged at anything under 65 on flat roads least you lug the engine.
I put the car in 5th below 65 daily but I don't get any shakes/signs the engine is having difficulty. Is lugging the engine something that can be not noticeable?

1978 280z - stock L28 engine - Dallas, TX
chaseincats is offline  
post #7 of 21 (permalink) Old 04-04-2019, 02:21 PM
Senior Member
 
Join Date: Sep 2015
Location: Central FL
Posts: 852
Mentioned: 0 Post(s)
Tagged: 1 Thread(s)
Quoted: 199 Post(s)
Quote:
Originally Posted by chaseincats View Post
I put the car in 5th below 65 daily but I don't get any shakes/signs the engine is having difficulty. Is lugging the engine something that can be not noticeable?
If your setup has you going under 2.5k in 5th that is lugging the engine, read that somewhere in one of the owners manuals IIRC.
its not noticeable other than the sluggish nature of accelerating. Generally speaking I don't like the engine to turn less than a minimum of 2.5k under pretty much any driving condition.
Dave M is offline  
post #8 of 21 (permalink) Old 04-04-2019, 02:23 PM
Senior Member
 
Join Date: Jun 2016
Posts: 499
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 106 Post(s)
Quote:
Originally Posted by Dave M View Post
If your setup has you going under 2.5k in 5th that is lugging the engine, read that somewhere in one of the owners manuals IIRC.
its not noticeable other than the sluggish nature of accelerating. Generally speaking I don't like the engine to turn less than a minimum of 2.5k under pretty much any driving condition.
Ah, good to know. I'll change my driving practices then, thanks Dave.

1978 280z - stock L28 engine - Dallas, TX
chaseincats is offline  
post #9 of 21 (permalink) Old 04-04-2019, 03:24 PM
Senior Member
 
Join Date: Sep 2015
Location: Central FL
Posts: 852
Mentioned: 0 Post(s)
Tagged: 1 Thread(s)
Quoted: 199 Post(s)
actually it was don't drive under 2.0k in any of the 1st - 4th, and 2.5k for 5th. I just cant remember where I read that, but I do know on my 3.54 with a .75 OD and stock wheels that its pretty sluggish below 65 mph. I think my 5speed trans came from a ZX with a 3.7 diff but I never bothered to swap the rear ends. I just stay out of 5th unless I am on a free way going 70. You should just check your RPM, you may have a different setup that lets you run lower than 65.
Dave M is offline  
post #10 of 21 (permalink) Old 04-05-2019, 02:14 PM
Member
 
Join Date: Mar 2013
Posts: 97
Mentioned: 0 Post(s)
Tagged: 0 Thread(s)
Quoted: 17 Post(s)
I have a closed ratio 5 speed rebuilt for 850. never ran went to a 350z 6 speed
malibud is offline  
Reply

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Nissan : Datsun ZCar forum :Nissan Z Forum: 240Z to 370Z forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in










Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page



  Similar Threads
Thread Thread Starter Forum Replies Last Post
'73 240Z with '90 Ford 302 V-8 conversion. Blue. 5-speed. $7000 1wdwarrior Cars for Sale: 1970-83 240Z, 260Z, 280Z, 280ZX 1 11-12-2013 06:28 PM
Clutch options, 240Z 5-speed conversion with 2+2 flywheel MX500 70-83 Tech Discussion Forum 5 11-07-2009 09:19 PM
4 speed to 5 speed conversion zbrowner Car Talk Forum 4 09-24-2004 07:33 PM
speed speed speed speed speed speed Unknown User 90-96 Tech Discussion Forum 0 03-14-2001 09:48 AM
78' 5 speed manual vs. 72' 240z 5 speed manual Mouse 70-83 Tech Discussion Forum 5 03-06-2000 11:57 AM

Posting Rules  
You may post new threads
You may post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome
 


Content Relevant URLs by vBSEO 3.6.1