73 vs. earlier motors

[Smokey]

OK, here is a newb question. Other than the carbs, what differences are there between a late '73 240Z and the earlier motors? Had they started putting emmisions controls on the motor yet, or did they wait for the 260?

[Mudge]

I'm going to guess 74 is when emissions hit, because that is how the American cars were. There were smog provisions like PCV and stuff, but 74 is when performance started sliding, and also the I believe 5mph front bumper law (or was it 2.5mph).

[Smokey]

So what you are saying is the '73's just had the dreaded flat tops, but the actual motor was the same. Reason I am asking, is I have found a 73 240 with converted carbs. I just don't want to have less performance out of the motor right off the bat.

[Bambikiller240]

There were/are emission controls including fuel tank venting system, a PCV valve, a "smog pump", and the dreaded Flat-Top carbs on late 1972 - 73 240Z's. The 73's also had the charcoal canister added, which I believe was part of the fuel/venting system. The "redline" on the tachometer was set at 5,00 RPM for the 73's (not sure about the late 72's) vs the 7,000 RPM redline on earlier motors.

"Smog Control" systems have been on 240Z's since 1970, but they got more and more restrictive/sophisticated as the years went by. On a street only motor (with round top carbs replacing the flat-tops), I doubt you could tell the HP difference between a 70/71 motor and a late 72/73 motor.

70 - 72's had the thin bumpers that bend like they are made of nothing. These are the ones most people like (visually) and a good example of why the "crashworthy" bumpers became required by law. 73's had the 2.5 mph bumpers as standard equipment. 74's had the 5 mph bumpers standard.

[Dan Baldwin]

'73 240Zs had a lower-compression cylinder head, stamped "E88", but different from the '71 or '72 E88 heads (or the '74 E88, which had a larger exhaust valve). Hence, '73 240Zs had lower compression, like 8.3:1 vs. 9.1:1 for the '72 E88.

The '73 front bumper stuck out further than the earlier ones, black plastic doodads filled the gap to the body. They went to the bigger/uglier 280Z style bumpers midway through the '74 260Z model year, so some 260Zs look like 240s, and some look like 280s.

[CoastGuardZ]

You know everything I've ever read says that it was 1973 was when the new emission laws hit.

for example... I had a 72 1/2 620 pickup with the 1.6L in it. It's said that Datsun released the first year 620 like this because the 1.6 wasn't set up/ ready for the emission sytems yet. In 1973 the 620 came with the choked up 2.0L. Also to mention the 1.6 had 92hp. My old 86 Sentra 1.6L, same block but with cross flow head had 69hp. Emissions and Performance do not Mix obviously!

My 2 cents

Nate:cross-eye

[2ManyZs]

The emissions laws got more stringent in 73, but all the Z's had smog pumps and some type of emission control on them.

[Daniel]

If yours has the round carbs,your good to go.The 73 did have more emissions but not like unleaded only filler at the tank and such.Mine's a 73 with 280 and round tops.If emissions are the largest concern and all else is well with the car ---GET IT!! Also I think the 73 is the only year witha backlit heater control panel.Isn't that right guys? Daniel

[Smokey]

I've managed to talk the guy down a 1000 dollars off his original asking price. It does have the round top SU's . He has been running it on unleaded since 83 when he bought it (Cali car). Gonna take it to the resident Z expert here in town (Rock Vest) and see if he thinks it is a good car, and worth what seller is asking.

If that don't work out, then I have a lead on a '70 that has been restored. It has very little rust (gas lid, and one floor pan), but is not currently registered, or inspected. That will make a test drive kinda difficult.

Thanks for all the informative posts guys. What you have said is pretty much what my research has brought up. I feel comfortable with the 73 now. It is a very nice car, all original--even the paint--128K miles.

[Mr Camouflage]

The 73 has other advantages over the 70 in other areas. Something about the diff being repositioned so the drive shafts are on less of an angle, some other stuff i cant remember at the moment also.

[Victor Laury]

Gonna take it to the resident Z expert here in town (Rock Vest) and see if he thinks it is a good car, and worth what seller is asking.

Rock Vest! The Rock Vest? Roadster Racer Rock Vest? That would be the local expert, no matter how big an area "local" means.

[2ManyZs]

I thought the same thing Victor, shame we all couldn't have someone like that to look at our cars.

Haven't heard his name in a while though or seen it in any race results. Has he retired from racing?