260z - Rebuilding L26 engine? Drivetrain?

[jezzza]

Hi all,

 

So ive just bought my 260z, and know absolutely nothing about them, and a little overwhelmed venturing into this project

I do have mechanical knowledge from previous builds, but mainly to do with EFI and turbos. I do have a 1L N/A carby van though which I tinker with haha

But this time around ive decided to go against what I know most about, and go down the N/A carby route!

 

So have decided in rebuilding the original motor and keep the car more "classic" spec.. and learn a thing or two along the way

 

My plans for the rebuild are:

Original block, freshened up with new piston and rings

I want to run a cam, but no idea where to start or what to even consider.. any help?

Im investing in a triple carb setup up, Mikuni or Weber - thinking 40mm

Should I be looking at a different head for the L26? P90, E88 or something.. I don't know the difference!

 

Does ignition need to be upgraded? I definitely do no want to run mechanical dizzy (if it has one!)

 

The car will be used for a weekend/street car. Not looking for huge amount of power, but would like something a bit more powerful than stock!

 

As for drivetrain, im planning to run a stock 260z box with stock diff.. or should these be looked at?

Is a 280z diff stronger?

 

Any help would be appreciated!

[steve260z]

I ran the Schneider stage 2 cam in that engine. I'd suggest that cam but its the only one I tried.

Check out MSA for the cams. Google Datsun L series heads and compare the volume. The 260 already has

low compression so you certainly don't want to increase the cylinder head volume. Don't you already have an E88 on there?

[hagdog]

Congrats on your new (old) 260Z!

 

I'm in the middle of getting my 260Z on the road. I have the engine partially assembled. I purchased a reconditioned N42 head for it.

 

You had many questions. Most of your answers can be found on this and other forums. But there are so many enthusiasts that the wealth of info can be hard to sift through. I'll try to save you some time.

 

I found that performance cams are relatively inexpenisve. However, the cam is only part of the expense. Inexpensive cams are re-grinds. Billet or new cams are not inexpensive. The re-grind requires a new lash cap set for maybe $100. You may need new lash caps even if the cam is not a re-grind. Just make sure to measure accurately and only buy one set... The higher lift of a performance cam will crush the stock springs. For new springs add $200-300.

 

So, think about what a "performance" cam will do. The main difference is that it will shift the hp/torque curve. With triple carbs you can get some good HP at the upper end of RPM. But, your low end torque will not be a significant gain over a 2-roundtop carb setup. Is the curve shift worth $500 or more?

 

For a head, the N42 is a good deal. It increases the compression ratio which, of course, is important for a NA engine. The P90 flows best but has a lower CR than the N42. The P79 and P90 are best for forced induction. To sum it up, swapping an N42 for an E88 should result in better CR and exhaust flow.

 

For the diff, you are looking at the R180 in the 260Z vs the R200 in the 280Z. The R180 will handle whatever your NA engine can muster. And, it is lighter than the R200. The more important issue is if you are looking for LSD. There are more options for LSD for the R200. It is my understanding that the R200 short-nose can replace an R180 with no modifications. Using the long-nose from a ZX model is more involved. But, that diff will handle the higher torque of a forced induction setup.

 

Check these links out:

Z engine calculator This does not include L26. But, the L28 numbers are proportionally equivalent.

Head comparison

 

BTW, I got an L28 engine with 240Z round-tops and a 5-speed tranny on Craigslist for $500. I bought the setup to get the 5-speed for a tranny swap from the original slush box. Naturally, I am also replacing the 260Z flat tops with the round tops. Triple Mikuni's, on the other hand, go for $800-1200. Again, what is your budget? 240Z carbs might not be a bad option. Then again, rebuilding 2 SU's costs around $600.

 

So many choices. Enjoy your angst. When you're done, enjoy your Z!

Edited May 3, 2014 by hagdog

[jezzza]

Thanks for the replies!

 

I have been looking at this forum and several others for a while now, trying to build my knowledge, but as you say, it is very difficult sorting through exact threads I want (without reading them all)

 

So a stock L26 head is a E88?

What is a N42 off?

So if I don't want to decrease my CR, want a head to lfow better than E88 but not going force induction, then N42 is the one?!

edit: found a really good thread in regards to heads: http://www.viczcar.com/forum/index.php?topic=6012.0

So looks like I already have the N42 head.. my 260z is a 1977.. late model? Guess Ill find out when I strip it down (square exh ports)

 

I want to get the most out of the engine without going stupidly high compression ratios or forced induction (or forging my engine)

I don't mind paying the money for a triple carby setup, as this is what ive wanted for a while! Looks and sounds awesome haha!

The money doesn't phase me too much.. the planned RB26 and RB25 are now for sale, so it will fund this engine quite easily

 

Do any of the cams have numbers? ie 274/274*?

Edited May 5, 2014 by jezzza

[NewZed]

The cams have letters on the back, and the heads have numbers and letters at the bottom front of the head.  No need to look for square ports.

[jezzza]

Too easy! Cheers!