Help needed for the L6 ignorant

[Guest JAMIE T]

I just got a '71 240Z. The engine, I beleive, is stock. It has only a header that is 6-2-1 without a muffler. The car is kinda quick(but I am used to my 6spd Z28, pretty darn quick) I am eventually(maybe) going to install the Northstar Cadillac into this car as the Ferrari replica project is a long ways off. I am also about to get an '83 280ZX non turbo, but it is a 2+2 5spd car. That car is very rusted. I understand the 2+2 cars share some parts with the turbo cars(i.e., good 5spd, R200 rear, CV shafts, and the good brakes) My question is, if I put the L28 engine in th 240Z with the header and the stock carbs, along with the 5spd and other goodies, would I make a substantial improvement in power? Are the stock '71 carbs SU's? Are they any good? I am only considering this because I am getting this ZX for a very good deal, and it might be a way to ward off the Hondas, and Mitsu's, without a major engine swap. I want to keep it carbed for simplicity, and a clean under hood compartment. The ZX has been owned by my bro's inlaws since new, and has been taken very good care of(except for the rust, but you can't really prevent that on these things). Thanks guys.

 

Jamie

Deathstar

[Drax240z]

Hmm, yes the 71 carbs were the desireable Su's.

 

I'm not sure about this, but depending on the head on your 71, and the pistons on the 83, I think the combonation of the two would be good. Likely your 71 has the E31 head, and the 83 had flat top pistons. All you really have to do is get larger valves put in the E31, and slap them together. I believe you'll end up at about 9.8:1 compression.

 

I'm not sure what the 2+2 had for a tranny or diff, but the 5 speed/3.90:1 combo into 240z's is said to be a really nice upgrade in both quickness and cruising.

 

I think you could make a nice driver out of the 240z, and save the northstar for the deathstar.

[Guest norm[T12SDSUD]]

Hey Jamie, years before I built my 2.9L stroker motor for my 71 240Z I used to race my 2.4L with the stock E31 head and a mild cam.

That car would turn 9.45 thru the 1/8 mile and a 14.7 in the 1/4 mile.That's more than enough to blow away 90% of the Honda's on the road today.

That car only had a mild 262/272 .450" lift Crane cam, dual K&N filters, Header,stock Dual SU's and a 3.9 rear gear.

 

You really wont be that much faster with the stock 2.8L motor as it has a milder stock cam and lower compression ratio then the stock 2.4L and without a cam change and harmonic balancer swap the 2.8L cannot be revved up to 7000 rpm like the 2.4L.The 2.8L will have more lowend torque which will give it a more powerful feel, but it will be weaker above 5500 rpm.

 

Oh yeah, as far as the question of the stock SU carbs being any good goes, they were good enough to power my 2.9L to a 12.9 1/4 mile.

 

Enjoy your Z!

 

Later,norm

[jimzdat]

Jamie-I know that my 76 2+2 has(had) a R200 in it-3.54 ratio-I'm not sure if they cahnged that for the ZX.

As far as the carbs go; yes the stock 71 had the SU "style" carbs (made by Hitachi if I recall)-and there were a few differences even then-3 or 4 screw dashpots, adjustment knob differences, etc.

 

I just recently bought a 260 that had earlier carbs on an L28, and they had a serious vac leak due to worn throttle shafts-If you want to increase the drivability level, and don't mind dropping a few bucks-look into having Scott Bruning (http://www.ztherapy.com) do a "rebush" on them-at $175, it's cheaper than the full service, and it fixes the biggest problem with them-I had it done to mine, and it made a world of difference-I can actually get the thing to idle now

Drax, he might be lucky enough to get the E31, but I wouldnt bet on it-they only had something like a 9 month production run-most of the ones I've seen were on 70 models-but if it is-it is the one you want to use