Oops

Took a photo of one of the buckets that are going in.

Yup, they have eyebrows. Indicate the taller piston?

 

Damn! Mine doesn't have those cut outs.  I'm guessing those are original equipment?  They look unburnt or just super clean.

Below is photo of stock E88 combustion chamber from an earlier 260z.  It seems to have the deeper pocket for the piston.

I wish I cc'd it.  It is now at machine shop getting 1mm shave and valve job. I'll check deck height soon.

The pistons do not have fly cuts however the link below shows 260z pistons with fly cuts and 38.1mm compression height.  I wonder if the odd pistons were for 73 and part of 74?

https://www.uempistons.com/index.php?main_page=product_silvolite_info&cPath=6_25_27&products_id=1533

 

The carpartsmanual site is not clear on dates: http://www.carpartsmanual.com/datsun/Z-1969-1978/engine-240z-260z/piston-crankshaft

 

The 1973 FSM gives a compression ratio of 8.8 to 1 so working backwards the volume of the 1973 E88 is ~49cc.

 

 

Edited December 31, 20177 yr by 240260280

The L24 i was talking about has serial Nr: L24-180723  and came out of a '73 Dutch version 240z.

I believe it's one of the last L24's ??

( Almost sure it's a all Original block..  the car where it came out of was sitting on a junkyard under a enormous pile of junk..for about 25 years...  in the early '10's  that had to go because the yard was no longer to be and they discovered this car... (It's now on a new location) The son of the owner looked at it and was not surprised by it, he bellowed to his dad on a crane:  Shall we throw it in the press or save the engine of it?    It got saved..  the car... sadly no... they did'nt know what they were throwing away....    )

On the pic you see that these are flat tops..  no fly cuts.

Edited December 31, 20177 yr by dutchzcarguy

Glad you found these specs on the 73 Nissan piston Blue. I had noticed the taller piston back in 2012 when I bought some .040 over 73 pistons from my local Nissan parts guy (they were still available). I tried to find out more info, and no one could help.....not even Sam Neves (built Greg Ira’s car) or Dave Rebella. I shaved the pistons .015 inches just to be safe. If the gasket is approximately .055 inches and the piston comes out  .027 inches, you have .028 inches clearance. If that isn’t enough, you either shave the piston or use a thicker head gasket......question is how much (or little clearance) is enough.......anyone got that answer?

 

Edited December 31, 20177 yr by Diseazd

1 minute ago, Diseazd said:

Glad you found these specs on the 73 Nissan piston Blue. I had noticed the taller piston when I bought some .040 over 73 pistons from my local Nissan parts guy (they were still available). I tried to find out more info, and no one could help.....not even Sam Neves (built Greg Ira’s car) or Dave Rebella. I shaved the pistons .015 inches just to be safe. If the gasket is approximately .050 inches and the piston comes out 

 

Thank @Lumens for sharing the TSB's.  Glad to be the messenger. I look forward to meeting in October!

 

Me too Blue.....I’ll buy you a drink!

Lumens.....Here are the 73 pistons shaved and installed. If you decide to have them machined, do it before you install the rings.

22 hours ago, siteunseen said:

Damn! Mine doesn't have those cut outs.  I'm guessing those are original equipment?  They look unburnt or just super clean.

Yes these are original equipment. I purchased them when they were still available.

The person rebuilding the motor wanted me to get these.

This is the later E88 head I plan to use. Back from machine shop with all new OEM valves.

 

Looks nice. No corrosion evidence at water passages...that is a nice head!