Can you use 79-83 280zx pistons in a 75 280z?

[Gorp]

I'm having trouble finding .020 pistons and while I was waiting for some to come back in stock I was looking through "How to rebuild your Nissan & datsun OHC engine". The pistons in a 79-83 in a look to be the same as a 75 other than the rings, but I could be wrong. Will ITM RY6140-020 pistons fit? I have a n42 block and head. Thanks

[Zed Head]

ZX pistons are flat top pistons and your 75 pistons are dished.  But many people use the flat tops to raise the compression ratio for a bit more power.  I think it would end up about 10:1.  So yes they would work, you'll just end up with a higher CR.

[Gorp]

27 minutes ago, Zed Head said:

ZX pistons are flat top pistons and your 75 pistons are dished.  But many people use the flat tops to raise the compression ratio for a bit more power.  I think it would end up about 10:1.  So yes they would work, you'll just end up with a higher CR.

Were all zx pistons flat top? I think it was just the F54 motors with P79 heads. The ITM RY6140-020 that I was looking at were dished

[Zed Head]

1980 (maybe 1981) to 1983 were flat tops.  That was the range of the P79 heads, approximately.  1979 was definitely the N47 head and dished pistons.  Check your information source, there is a lot of bad information out there.

eBay shows that those are dished.  So they would be like your stock pistons.  If the picture is correct.  Those are turbo pistons though so the top ring is set farther down the piston, I think, to protect it from excess heat.  They would work but not be exactly the same.

https://www.ebay.com/itm/283805353930

eBay has a bunch but the seller sites are hard to search.

[Zed Head]

Here are standard pistons for what you have.

https://www.ebay.com/itm/172502490849?fits=Make%3ADatsun&epid=77048862&hash=item2829f31ee1:g:FxEAAOSw9KNiFsAL

[Zed Head]

.040" over flat tops.

https://www.ebay.com/itm/165387446201?fits=Model%3A280ZX|Make%3ADatsun&epid=75271992&_trkparms=ispr%3D1&hash=item2681dc27b9:g:8OMAAOSwvkJiMhTi&amdata=enc%3AAQAGAAABIKiiCdDNms8s1aN21U%2Bmm7wiO1Yzt1v6lTAirumB82Fef3JCgqY6kRipL4DKdXgD0FAq7G4lB4Z1PC9drVf527H8gPvzl6v6C%2BMUGWburvcIMlBPo59ZzQ4aq61o5WqQa%2Fw0Qs324QvLl4dptZyuitjGtNYhI3m2nNzBGdSccVhTMZ3fCXLQekspzg9XfkQ3on4sShcbRXe9trCxUy%2BMgjbVkA9czun4vcV%2BD%2FY1rSRju4gT8T50LkSkcSpHOoeP3e9KYDMOU%2FrQwQrvlIkqIH6V9JHYb54tFE5ExVHvU41Ss5S0qVSH6hJioh0OZsJpfCF4T0CARtU9rFKWm3pDVSHvfCN0Mf8zaWbTxWukvgCJsSSTApzPTx79KySUALI%2BFA%3D%3D|tkp%3ABFBMutDWz_Zf

[Gorp]

14 minutes ago, Zed Head said:

1980 (maybe 1981) to 1983 were flat tops.  That was the range of the P79 heads, approximately.  1979 was definitely the N47 head and dished pistons.  Check your information source, there is a lot of bad information out there.

eBay shows that those are dished.  So they would be like your stock pistons.  If the picture is correct.  Those are turbo pistons though so the top ring is set farther down the piston, I think, to protect it from excess heat.  They would work but not be exactly the same.

https://www.ebay.com/itm/283805353930

eBay has a bunch but the seller sites are hard to search.

Yeah I was just basing it on what I read here https://datsunzgarage.us/engine/. Thanks for the help, I really appreciate it

[dutchzcarguy]

6 hours ago, Zed Head said:

1979 was definitely the N47 head and dished pistons.  Check your information source, there is a lot of bad information out there.

In Europe we had the N42 Head in the 1979 280zx.. original..

 

[Zed Head]

The OP is in Austin.

I've read about the N42 heads over there.  They were still running carburetors right?

[Gorp]

I meant to say 81-83 in the title, not 79-83.

[texasz]

Welcome to the group @Gorp.  I'm in the Austin area also.  There's a local club you may want to check out if you have not already, Capitol Z of Texas.

[dutchzcarguy]

18 hours ago, Zed Head said:

I've read about the N42 heads over there.  They were still running carburetors right?

Eh..? No?  Not on 280zx's.. but i think you refering to the 260z that were still build for europe from 1974 till the 280zx came in 1979!  Then Yes! There were still carbs then on the 260z's (So the 260z's were here for sale from 1974 till 1978 between 240z and 280zx.. the 280z was never delivered official in europe.. all 280z are grey import.)

What the head number was on 260z i don't know for sure but the E88 comes to mind, no idea if there were N42's on 260z's? 

On the 1979 280zx there was a N42 head. You can read about it in my restoration of a 1979 2+2 slickroof datsun 280zx thread i think..