L20 Block...N70 Head What the ???

[justaZcarguy]

Ok, pardon my Stoopidness :stupid:

Just decided to check the numbers on the block and head (due to Beandips' question on it....) and yes, I never have lookied into the number, which is what I usually do first, go figure...

SO, have been told that Nissan made a "racing" motor that was an L20 and also the Fairlady had the same engine block in it as well (according to the tech guys at Beaverton Nissan).

So it's over to you guys, the true professionals.

L20 Block and N70 head....

Has great power but the carbs suk. (Flat tops)

Help! Need info.

(now I really need to put those round tops on....)

Thanks all, have a safe weekend!

Brian.

[justaZcarguy]

Make that a Y70 head!!!!

Sorry:stupid:

[2ManyZs]

Ok, let's see if I get this right. :cross-eye

L-20 block is the 2 litre block that was offered in the Fairladys. PS-30 cars?

Y-70 head was a head offered in New Zealand/Australia.

According to info on the Datsun Garage web site they may have been a higher compression head than what we had here in the US at the time and possibly made to run leaded gas.

Hmm, wonder where this came from originally?

I think I'm correct on this, but I'll need corroboration on which model or models had the L-20 as original equipment.

Perhaps we can get Alan to post from his research collection the differences in the heads used between the Japanese home market cars and the export cars that were sent to Aus/NZ and the UK. I'm curious as to how many different ones were used and if there were any that were exported to more than one market. We have a good idea of which ones were installed on US spec cars, just wondering aloud if there were a differetn set of heads for home market, US market and European market cars or did they consolidate them?

We know this much. Between the L-24, L-26, and L-28 in the US there were 7 different heads used.

E-31, E-88, N-42, N-47, P-79, P-90, P-90A

There was also an E-30 on the L-20 Fairlady version as well.

Aus/NZ had three types of heads used: Y-70, E-80, and the E-88.

So how many other heads are there?

[dohc]

I know a lot of the other nissans got the different heads here in Aus. I've seen all of those head at the junk yard, including an N42 on a late model 260Z 2+2? but mostly just the E88 as expected.

I've never heard of the L20 six outside of Japan? Was it released anywhere else? I think you've got the list almost complete 2manyZ, any others would be home market variants only I think?

Alan! We need your help again.

R.

[justaZcarguy]

No luck on my research with the Y70 head so I am sooooo waiting for Alans wiZdom on this...

I do have a N42 on a L28 block that is peppy, this is the triple Michuni set up...(on my '74 260). Needs TLC tho. I have established that the L20 is a Fairlady block. I bought this car from a guy who had no idea of the history of this engine, it runs well and has great power. For some reason they put the flat tops on and that needs to be switched to the round tops, I have a pair of round tops and need the linkage...

Beandip stopped over today and I had him verify that it IS a Y70 head and I have not lost my mind. At least not all the way:cross-eye .

I appreciate all info as I am out of options at this point...

Thanks again for the conversation today Beandip, it was cool. That gold portfolio is excellent!

Everyone have a great Sunday!

[HS30-H]

Sorry to be AWOL while you were scratching your heads on this. I have been out working on a job that took me away from home for a couple of days.

First of all, the "Tech." guys at Beaverton Nissan need to go and bone up on their history a little. I think they are getting confused with the "S20" ( the Twin Cam 2 litre six fitted to the 432 and 432-R, as well as the GT-R models of the C10 and C110 Skylines ). The "S20" is a whole engine type, and not just an engine block. The "L20" is an engine block as well as an engine type ( thanks for the confusion - Nissan ) and was fitted to a list of Japanese domestic model types and variants that would drop off the end of this page its so long.

Anyway, the L20 block and "Y70" head combination is something of a nail I'm afraid ( sorry ). It was a fairly late incarnation of Low Emissions L-series sixes, and this one probably did not come from an S30 Z originally - its more likely to be a late-ish Skyline engine that has been modded to fit into the Z chassis. You quite often see this kind of "make do and mend" modification on unloved or run-on-a-budget cars in Japan. Depending on what model of Nissan it was originally fitted to, it would or would not need a Sump / Oil Pickup / Dipstick conversion for the Z chassis-fit.

More bad news is that this engine is not particularly desirable, and has unusually thin and spindly Con-Rods that are prone to break ( eek! ). Taking the L20 Crank out and installing it in an L24 Block would make a good bore / stroke ratio that would rev to kingdom come if you could make it breathe properly and stop the valves from bouncing. I have seen and heard an L28 block / L20 Crank combination racing in Japan, and it sounded wonderful. Now there's a thought...........

Sorry to give you what might seem bad news - but its better if you hear the truth before you start making plans for this engine.

And just to nip this one in the bud before it gets set in stone; when talking about the S30-series Z, the L20 was offered on the very first Domestic incarnations of Fairlady Z and Fairlady Z-L. They came with the E30 head first. The Fairlady Z432 and Z432-R ( "PS30" and "PS30-SB" ) were also launched at the same time as the Z and Z-L ( late 1969 ) and were fitted with the S20 Twin Cam 2-litre. This creates lots of confusion outside Japan, as people talk about "Fairladies" as though they were just one model. You have to remember that Japan had a bigger choice of Z than everybody else got. In fact, by October 1971 you could buy six different variants of Z in Japan................

Carchaeology. Fun isn't it?

Alan T.

[justaZcarguy]

Hey, good or bad news, at least now I know and learned a bit in the process!! The bummer is that this motor seems fresh, has GREAT compression and power, I think that I will switch over to the round tops from the flats and call it good. It's bound to get better from the need-to-be half choked flat tops that are current, I just need the linkage and cleaner housing. Then I can concentrate to the L28 / N42 with the triple michunis that came in a 260 parts car that I purchased. The engine is fast but to me seems like overkill, I enjoy a stock Z just fine and the dependability seems better, but fast is fun too... :classic:

The carbs need to be tuned on the L28, it runs but really rough with a crappy exhaust since the car sat in a field for close to a year... (some people need to be beat with a '75 Pinto battery cable...) Apparently the engine has hemispherical pistions, and a radical cam, I have no idea on head specs, con-rods, bla, bla, bla. I can see however Mallory dual point ign., header and the triple michunis with the Muchini intake. About two years ago I was in the car with the previous owner and it SCREAMED, it is / was fast. Currently the centerforce clutch is out so it's tough to tell...The story is that Anton (previous owner now off to do the enlistment thing) bought it from a guy in Texas that built it to race. Wish I could talk to him to see exactly what the history is, my x-ray glasses are in the shop

Well thanks again for the info Alan, it's been fun and I've gotten the chance to talk to a bunch of great people so it has been a great experience, too bad the news wasn't exactly great but it's still a Z so I'll take it!!

Have a great Sunday all...Any feedback good or bad is welcome on this L28 / N42 engine, I hope to get pics for ya all next week downloaded...

And Alan, I wish I had 1% of your knowledge, I think we should clone him so we all have an "Alan" at our disposal...:classic:

Votes? Sorry Alan this will only hurt a little, and we promise you won't look like a sheep!

[HS30-H]

They already cloned me - where do you think Pee Wee Herman came from?