ok, probably a few silly questions but not getting too much help with info, so I'll try again here.

I have 72 240.

1) motor block is stamped 'L26' not 'L24" so im thinking its 2.6litre block right? yes?no?

found a ATK ENGINES tag on the block, so im pretty sure i have a rebuilt crate motor here.

2) head is e88, i've been schooled with the differences in various e88 heads, so i think i have that straight.

3) su carbs, three bolt round tops.

so what im thinking is someone has replaced the motor, and probably kept the original intake set-up.

I just finished a major tune-up. everything from points,condens. to dwell timing, ignit timing, valve gap adjustment.

seems to be running WAY better now. no real issues exept for carbs need some tlc, gonna do that tomorrow.

what i'm worried about is, I've set everything to my manual specs for a 72' 240.

because of the different block stamping, should i use 260 tune specs, are they any different??ie: valve gaps, timing, etc.?

also, does this l26 with e88 head and old su's differ in power from the l24? if so, good? bad?

need someone to give me a bunch of info here, soory to be a pest.

ok, probably a few silly questions but not getting too much help with info, so I'll try again here.

I have 72 240.

1) motor block is stamped 'L26' not 'L24" so im thinking its 2.6litre block right? yes?no?

found a ATK ENGINES tag on the block, so im pretty sure i have a rebuilt crate motor here.

2) head is e88, i've been schooled with the differences in various e88 heads, so i think i have that straight.

3) su carbs, three bolt round tops.

so what im thinking is someone has replaced the motor, and probably kept the original intake set-up.

I just finished a major tune-up. everything from points,condens. to dwell timing, ignit timing, valve gap adjustment.

seems to be running WAY better now. no real issues exept for carbs need some tlc, gonna do that tomorrow.

what i'm worried about is, I've set everything to my manual specs for a 72' 240.

because of the different block stamping, should i use 260 tune specs, are they any different??ie: valve gaps, timing, etc.?

also, does this l26 with e88 head and old su's differ in power from the l24? if so, good? bad?

need someone to give me a bunch of info here, soory to be a pest.

I just answered your other thread regarding the L26 vs. L24 in your other thread.

Regarding your tune-up questions. Valve gap is the same. The factory timing for the 260 was very much predicated on emission control. That train has long left the station in this case and I would use 240 timing as a starting point and because of its modifications tweak it by performance from there.

I can't see why your L26 shouldn't have more power than the L24. In effect you have a stroked '70-72 L24 and not a smog-choked '74 260.

Chris

You can confirm the engine replacement by checking the engine # with the vehicle data tag that is on the strut tower in the engine bay.

But from what you've posted, it sounds as though it has been replaced. There was a time there when obtaining a rebuilt 240 engine wasn't available and you had to do with a 260 and then later a 280.

It isn't bad unless you were hoping to compete for a gold medallion.

E

There is a good read about SU carb tuning on http://datsungarage.com/engine

Sounds like you might be using emision carbs. I dont know what the differance internally. Good luck with tuning;)

PS: The block is a 2.6. Im asuming they changed the block and head, then you should have the E88 with the larger valves. If its still the std 240 head it will have smaller valves.

E88's used on the 240Z's had the same valve size as the E31 42mm intake / 33 mm exhaust.

The 88 used on the 260z had only the larger 35mm exhaust valave.

N42 used on the 75 280Z's had both the larger 35mm exhaust valve and the larger 44 mm intake valve

FWIW,

Carl B.

ok, probably a few silly questions but not getting too much help with info, so I'll try again here.

I have 72 240.

1) motor block is stamped 'L26' not 'L24" so im thinking its 2.6litre block right? yes?no?

found a ATK ENGINES tag on the block, so im pretty sure i have a rebuilt crate motor here.

2) head is e88, i've been schooled with the differences in various e88 heads, so i think i have that straight.

3) su carbs, three bolt round tops.

so what im thinking is someone has replaced the motor, and probably kept the original intake set-up.

I just finished a major tune-up. everything from points,condens. to dwell timing, ignit timing, valve gap adjustment.

seems to be running WAY better now. no real issues exept for carbs need some tlc, gonna do that tomorrow.

what i'm worried about is, I've set everything to my manual specs for a 72' 240.

because of the different block stamping, should i use 260 tune specs, are they any different??ie: valve gaps, timing, etc.?

also, does this l26 with e88 head and old su's differ in power from the l24? if so, good? bad?

need someone to give me a bunch of info here, soory to be a pest.

Valve lash is the same.

Sounds like someone put in a 260Z longblock and attached the '72 carbs to it. There's a very good chance that if the back of your cam is stamped with a "C" it is a 260Z E88 head. If that is the case, go off of 260Z timing specs. The reason for this being that the combustion chamber shape and cam profile slightly differs from the L24 and thus needs a different advance curve. Since the 260Z head is open-chambered, I would expect it to require a bit more advance than a '72 L24.

THAT would make total sense. thanks for the info, exactly what i was looking for.

I actually set the timing to 240 spec, but before i did, i noticed that that the timing was already advanced a bit more than i thought it should be.

since setting it to spec it runs great, but was thinking it could use a bit more advance since it would stumble just a little bit.

tomorrow, I'll look for that cam letter and see if it is indeed there. i suspect i will find it. if so, i'll give er a little more advance and see if its any better.

I did notice that the cam is embossed 'japan' so im confident it is original datsun

when you say the back of the cam, what place should i be looking for? do you mean on the end near timing chain?

Valve lash is the same.

Sounds like someone put in a 260Z longblock and attached the '72 carbs to it. There's a very good chance that if the back of your cam is stamped with a "C" it is a 260Z E88 head. If that is the case, go off of 260Z timing specs. The reason for this being that the combustion chamber shape and cam profile slightly differs from the L24 and thus needs a different advance curve. Since the 260Z head is open-chambered, I would expect it to require a bit more advance than a '72 L24.

Regarding where to find the cam mark, here is a perfect example from Blue's Tech Tips: http://atlanticz.ca/zclub/techtips/cam/index.htm

thats a perfect pic.

do you know if it is legible without pulling the cam?

Ive already replaced the valve cover, so kinda want to know how long to book for surgery.

also, thanks for including that chart. that's a bonus.

You should be able to see it by employing some optical trickery. If you don't have a small mirror handy, grab your wife's/girlfriend's make-up mirror. You'll have to be discrete.

This tool comes in handy sometimes: http://www.northernautotools.com/specialty-tools/engine/fan-clutch/performance-tool-w1259-telescoping-mirror-large.html

my wife is a red head, i dont go there.

i better go buy one.

thanks for everything

Not a problem. Enjoy!