What are the differences between a 240 z and a 78 280 z(x)?

[cdk4219]

What are the diferences between the models, and can you put an LS1 in the 78? Where do these cars commonly rust out?

[j260z]

weight. as the cars developed they became heavier eg. bigger engines, crash bumpers, sturdier frames. the basic dimensions are the same so you could put an LS1 in any z from 70-78 but it's not just a walk in the park. the cars commonly rust out around the battery tray, behind the front wheels on the fender, the floor and the frame rails just behind the front wheels. most of these questions have been answered many times before and can be found using the search function. that being said, welcome to hybrid z.

[rreford]

here is an e-mail I saved from years back on estimated weight differences in the 240 vs. 280 discussion

 

From: Donn Vickrey

Subject: <z> Reconciling the weight of a '70 240 to a '78 280

 

A number of people have asked what caused the weight increase from the

240 to the 280. Magazine articles attribute the weight gain to

bumpers, emissions devices, and luxury items. It appears that the car

gained weight every year, except '77-'78 when the car's weight

decreased by approximately 90 lbs. (according to Car and Driver).

What follows is a mixture of (1) data from magazine articles, (2)

personal observations (i.e., I, or someone else on the list weighed

them), and (3) educated guesses. Each source of data is listed below

with a number of 1-3 corresponding to the data type. When more than

one source of data is available, personal obserbvations are given

first priority below due to reliability.

 

Curb weight, '70 240Z (per Road & Track) 2,355

Air conditioning (2) 50

Bumpers (2) 40

Wheels and tires (3) (see a below) 45

R200 differential (1) 25

5-Speed transmission (3)(see b below) 15

Flywheel (3) 10

Stronger clutch components (3) 10

Suspension components (3) (see c below) 20

Additional soundproofing (3) 5

Upgraded interior pieces (3) 10

Catalytic converter (1) 25

Engine, stronger internal components (3)(see d below) 50

Miscellaneous underhood components (3) (see e below) 15

Larger gas tank (3) 5

Stronger frame, unibody (plug figure) 100

-----

Curb weight, '78 280Z (per Car & Driver) 2,780

=====

 

a. Wheels increased in width from 4.5" to 5.5" from '70-'78. If each

wheel/tire weighed 50 lbs. (a conservative, low estimate) then the

increase in weight will be approximately 1/4.5 X 50 X 4, or

approximately 45 lbs.

 

b. The car I am reconciling to is a '78 280Z equipped with a 5-speed.

The 5-speed must be slightly heavier due to an additionl gear,

synchros, etc.. It probably also is stronger than the original

4-speed on the 240 due to the increased torque requirements.

 

c. If the car weighs more, it will need heavier springs and other

suspension components. Also, the 240 had no rear anti-sway bar. This

weighs 10 lbs. alone.

 

d. Obviously boring the engine will reduce the weight of the block

minimally. However, add larger/stronger pistons, larger/stronger

valves, a heavier/longer crank, stronger/heavier engine mounts,

heavier/meatier head, and so on, and 38 lbs. seems entirely

reasonable. The figure could be closer to 50 lbs..

 

e. There are a number of underhood componenents that the 240Z did not

have to cope with. Included are fuel injection components, the odd

charcoal cannister, and other emissions equipment.

 

If these observations/guestimates are correct, it is interesting to

note that one could take a 280Z and, after weight reduction efforts,

wind up with a car very close in weight to a '73 240Z (2,450 lbs.),

yet with a larger engine and stronger body. One IZCC member reported

reducing his 280Z to an observed 2,575 lbs., including the A/C and

even larger wheels and tires. The car could have easily been brought

down to 2,500 lbs. without these two items. Given that most 240Z

owners tend to add weight to their cars through larger wheels/tires,

A/C, 5-speed, heavier suspension components, and occassional L28

conversions, in many cases, I wouldn't be surprised to see some

modified 280s and 260s that weigh less than modified 240s.

 

Donn Vickrey

'78 280Z (BSP),'90 300ZXTT (ASP next year???)

IZCC #443, ZCSD #56