Where can i find L18 Flattops?

[edakotaford]

i've been trying to do some research on this, and am not having terribly awesome luck... 280zx non-turbo pistons people say work, with boring your block to 86mm (1mm difference from L18 block) does anyone know the compression on this? or if stock L18 rods will work with them? are there any other nissan flattop pistons that i can put in it?

[hang_510]

head CC is requied.

what head?

 

 

http://www.ozdat.com/ozdatonline/enginedesign/

ALL values must be correct.

 

or wait and mike will do it for you (hes a math nerd!)

[datzenmike]

Overboring a stock L18 to 86mm and running flattop pistons will give you an 1811cc motor and a compression of 9.18 with an open chamber head and 9.85 with closed chamber head.

[hang_510]

BAM!

[edakotaford]

about how much could i shave my head to up my compression? running an A87 hi comp head.

[ppeters914]

Depends on current block and head heights. Measure or have 'em measured. If the heads have already been shaved, should cc the combustion chambers to correctly calculate CR....right, Mike?

 

Why is everyone so fixated on and/or determined to run sky high CR's?

[edakotaford]

high revings i guess. haha. trying to build an awesome L setup for my wagon!

[ppeters914]

First, define "high revings" and "awesome L setup". And for what purpose? Not trying to ping on ya, just curious.

 

For a regular, street-driven car with occasional racing (auto-x, stoplight, etc), you're rarely going to be at high rpms, so why build/spend $$$ for the maybe ten-percent time it hits 6k or higher? You're gonna get good at replacing clutches if you have to rev to 3k to get the car moving. :rolleyes:

[edakotaford]

because it's awesome, mate. why do people have hobbies anyway? because they're things they enjoy doing ;) and if you do it right the first time, you shouldn't have to go back and replace everything as it breaks down... ;)

[datzenmike]

You've all seen on TV when gas fumes are allowed to burn along a floor and the flame travels a few feet a second out in the open. Well when the gas and air molecules are compressed closer together, the flame will jump across to the next molecule faster. The more you compress gas and air the more powerful the bang. Same energy released but over a shorter time. In an engine you want maximum cylinder pressure at about 17 degrees after top dead center where the most work can be transferred to the piston as it is just starting to accelerate down the cylinder. A low compression motor will exert a lower pressure over a longer burn time with some of it wasted chasing the rapidly descending piston.

 

A high compression motor is more efficient at converting energy to motion but the elevated combustion temperatures convert more nitrogen to oxides of nitrogen. :angry:

[edakotaford]

what do you mean in that last part, mike?

[datzenmike]

Oxides of nitrogen are a contributor to smog haze, acid rain and ground level ozone. All bad.

[edakotaford]

eeeeeeeeeek. :/

[jonesy510]

wow thats really interesting thanx mike!!!

[hang_510]

what do you mean in that last part, mike?

hes full of hot gasses, waiting to escape his tailpipe!

[edakotaford]

now where can i buy 81-83 280zx pistons online? just 4 of them!

[hang_510]

now where can i buy 81-83 280zx pistons online? just 4 of them!

how many??? 4 or 81-83? :P

 

IIRC rockauto listed some pistons as singles (maybe not these???)

 

ebay? where someone has 5...