2.4 or 2.8

Nick Hedges

Club Member
Hi all,
I am about to get my 2.4 engine rebuilt, however before I do this would it be better to get a 2.8 and build that. I am not looking for mega power but I am going to swap the carbs for efi , sportier cam and some head work along with coil pack etc as I want an elemant of reliability. I am thinking, due to the extra capacity it may cost less to get the same and possible more tractable power using a 2.8 over a 2.4.
I would appreciate some advise as I sure there are plenty on the forum that know fat more than me about these engines. Thank you.
 

candy red

Club Member
Hi all,
I am about to get my 2.4 engine rebuilt, however before I do this would it be better to get a 2.8 and build that. I am not looking for mega power but I am going to swap the carbs for efi , sportier cam and some head work along with coil pack etc as I want an elemant of reliability. I am thinking, due to the extra capacity it may cost less to get the same and possible more tractable power using a 2.8 over a 2.4.
I would appreciate some advise as I sure there are plenty on the forum that know fat more than me about these engines. Thank you.
I might be wrong but I think you’ve already answered your own questions looks like 2.8 not going to give you serious power without spending serious money JB will be along soon to advise 🤓
 

jonbills

Membership Secretary
Site Administrator
I agree, costs to build a 2.8 are the same as a 2.4, so you might as well have the extra capacity if you're not looking for originality.
costs do start to mount up with head work, but it all depends what you have done.
 

Rob Gaskin

Treasurer
Staff member
Site Administrator
I think you'd be better going with the 2.8. That already gives more power and has bigger valves.
Some 2.8 engines have dished pistons which you don't want, so bear that in mind during the rebuild.
 

Robotsan

Club Member
I think you'd be better going with the 2.8. That already gives more power and has bigger valves.
Some 2.8 engines have dished pistons which you don't want, so bear that in mind during the rebuild.

Sorry to butt in, but how do you know if your L28 has dished pistons? And why is it bad?
 

Nick Hedges

Club Member
Hi all, thank you for your input, looks like a 2.8 may be the way to go. I am not worried about originality as the car is being converted to RHD and from auto to manual.
Just got to find one now.

Many thanks
Nick
 

Rob Gaskin

Treasurer
Staff member
Site Administrator
Sorry to butt in, but how do you know if your L28 has dished pistons? And why is it bad?
Dished pistons give a lower compression ratio.

I don't know exactly which engines they were in but early 2.8s I gather. Have a look into the plug hole?

When I first got into Zs I stripped my 2.4 engine down because it was knackered. I had it bored oversize (from 83 to 86mm).

This was the time when unleaded fuel was just being used here and there was a lot of scaremongering about pre-ignition etc.

Being naive about these engines I bought dished pistons thinking it would run better.

I then decided to have the engine modified and built by a specialist - he was horrified about my piston choice and had them machined flat (with valve cut-outs). The stroke was increased to compensate - another story. The engine was superb.
 

Robotsan

Club Member
Dished pistons lower the compression.

Your car’s L28 will have dished pistons. Standard issue for the 280Z’s N42 block L28.

Dished pistons give a lower compression ratio.

I don't know exactly which engines they were in but early 2.8s I gather. Have a look into the plug hole?

When I first got into Zs I stripped my 2.4 engine down because it was knackered. I had it bored oversize (from 83 to 86mm).

This was the time when unleaded fuel was just being used here and there was a lot of scaremongering about pre-ignition etc.

Being naive about these engines I bought dished pistons thinking it would run better.

I then decided to have the engine modified and built by a specialist - he was horrified about my piston choice and had them machined flat (with valve cut-outs). The stroke was increased to compensate - another story. The engine was superb.

Ahh ok. Does that mean the early L28s are lower powered than later then? Or just not as easy to increase power (without changing the pistons)?
 
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