Attached: 1970 Oct Road and Track Datsun 240z.pdfEarly Article of Automatic 240z in NA

 

Hi Kats,

I saw the pistons you sold on Yahoo auctions. I like to look at Z432 /s20 parts for sale on there from time to time, its great to get an understanding of what makes up (and the difference) of the S20 and its related/surrounding parts. It is a great piece of engineering from my point of view. Lucky to have seen a couple in the flesh, S20 that is.

Hi everyone, thanks so much for your inputs .Those inputs make this thread attractive so much . I really appreciate it , as usual .

Recently I have been writing about various kinds of cars , today I am back on route , Datsun 240Z vs Fairlady Z432 .

I want to say , both are great great cars , each cars has each fantastic things .

About their engines , here are some comparisons .

” Stock specification “

  L24 150 ps , 21kgm / S20 160 ps , 19 kgm

” L24 Racing specification “

  200 ps , 24.5 kgm (71 Monte / Safari )

  250 ps , 25.5 kgm (73 RAC , 2498 cc )

“ S20 Racing specification “

  200 ps , ( 69 JAF Grand Prix ) GTR

  253 ps , 21.9 kgm ( 71 mid ) GTR

  265 ps , ( 72 Fuji Masters ) GTR

Wonderful engines they are , Nissan is not a manufacture like Ferrari or Porsche, but I think Nissan did great ! 

An interesting interview of Nissan works rally team manager Mr. Namba and Mr . Wakabayashi after winning of 1971 Safari rally  he said

“ we dropped its engine power like a normal car , range 2000-6500 rpm , compression ratio 8.0 ( usually 9.5 for racing) . We assumed average octan 93 , field elevation 0-3200 meters for the race. High-tuned engine is not good for this race , we used standard head gasket , we shaped inside of dome .

Also carburetor setup is the key , this rally has various field elevations from zero to 3200 meters , that made us feel challenging.

With the assumed octan 93 ,

we finally settled down setting them at 1800 meters , that was Nairobi “ ...

I am so amazed by reading this interview, what a fascinating they were !

And a clever thing is , they filled up their 510 rally cars with six different kinds of fuel before sending back them to Japan ( maybe this was common for rally team ? ) after winning of the 1970 Safari rally. They thought quality of gas was not the same , they needed to know what was the average quality so that making trouble free engine .

They analyzed and tested those fuel , then they had got the plan for the 1971 Safari rally.

Also an interesting interview for the three ex Prince Murayama engineers is so much fun to read , they did so hard on their racing S20 engine . I will write about it later .

• Citation 

Nissan graph June 1971 

DATSUN 510 & 240Z ( Grand Prix Shuppan )

SKYLINE 2000 GTR MEMORIAL 

( Yaesu Shuppan )

Kats

 

 

 

Thanks for the great info Kats!

I am hoping you can help translate the 73 RAC specs.

 

For rows 1 to 4, it seems

1. Valve Architecture = SOHC

2. Displacement= 2498cc

3. Bore = 84.8
    Stroke= 73.7

4. Compression Ratio= 11.0

 

What are the last 5 rows?

 

5. Horse power= ~250
     ???
     RPM = 8000

6. ??
    ??
    ??
    ??

7. Cam Duration
    ??
    ??

8. ??
    ??

9. ??

10. ??

THANKS!

 

 

 

 

 

Hi Blue , I added notes , I hope you get it .

This data must be a " typical " for works rally cars, each car has each set up I think . 

Kats

Edited December 14, 20195 yr by kats

Datsun 240Z and Fairlady Z432

Kats

Photo from the early 70's in a city near where I live. Similar side decal like yours. Very vintage.

SOLEX 44 TYPE 2 , arrived , I am so happy about this set . Jet setting is like this , 

Main 160 / Air.  200 / pilot 60 / pump 30 .

Going to be coupled with Option “ 8L “ camshafts 300 degrees , valve lift 10mm . Also race piston compression ratio 10-11 . 

I am thinking using these optional parts into my spare S20 , but sometimes I tend to think the other way , going to put these into my Z432’s engine. 
If I do that , it would not be easy work for me getting it back to normal. Modified car’s value is lowered in most case , will it be applicable to my Z432 if I put these options into its engine ? To  Use genuine optional parts ,  does it make any difference ? 
( I would think it would have not hurt it’s value if my Z432 would have installed  genuine optional parts at the dealer before the delivery in 1970 , and well documented about those extra ) 

Kats

Edited December 23, 20195 yr by kats

On 12/3/2019 at 12:55 PM, Gav240z said:

I am also a fan of the Type Q/Type 2 Mikuni 44's... but local legend has it that they don't stay in tune. Apparently the magnesium/alloy composite they are means that as they heat up they distort and create vacuum leaks, leading to poor tunability... At least that's what a local guru (who I trust knows more about them than me says). Have you heard of similar?

By the way is there any difference between the Z432-R option ones and the U20 Roadster versions?

Hi Gavin , I have heard of the issue from the seller , yes the material of the metal is the cause of imperfections of type 2 . It was made of Zinc and it is easy to twist or bend its flange if there is enough heat or if tightening torque of the securing nuts is too much .

About heat , S20 has cross flow configuration , so the impact of the heat is not so serious than that of Lseries , U20 or other turn flow engine .
And it is heavier than aluminum.

Racing model 50 and later type 3 changed their body to aluminum . Molding technology had improved , cost matter might be acceptable for Mikuni . 
 

The seller said U20 and S20 race option are different in fueling system ,some  tiny holes are specifically made for each models. U20 44’s has bigger idle port to help street ability four cylinder ,  2 litter engine. 
 

S20 race option 44’s was designed for more racing use , those tiny holes don’t think about below 3000 rpm . What am I going to do with 8L camshafts? Definitely not street use !

Kats

Here are some shots with type 3 , 40 mm .

 

Edited December 24, 20195 yr by kats

Hey Kats,

Like you, I always liked the look of the Type Q carbs. I think they have a nice aesthetic appeal. I would use them on your hot rod S20 build, but leave your Z432 as original as possible. It's beautiful as it is.

Many owners of U20 Roadsters remove the Type Q's for later carbs, which I think is a shame. I like to see the original carbs on a U20 motor. But not many people think the way I do when it comes to that level of originality with the old Roadsters. Very hard to find a good original car here, many have been messed about with over the years.

I say "put the 44mm on the spare S20"  Make it your special race engine and keep the Z432 original.  I'm drooling.  Merry Christmas!

44mm is a big carb for a 2litre engine.