sil80drifter

Here is a bearing and piston grade calculator spreadsheet for the KA24E (should be the same for the DE as well). The names and information as to what grades to use comes directly from my 1990 240SX FSM.

Here it is:
http://fiznat.000k2.com/supercoolbea...ka24eandde.xls

Right click and “save as.”
Thanks to fiznat (from NICO) for hosting the file and naming it like it should be named.

When you need to get stock pistons/bearings for the KA, they each have a grade number corresponding to their sizes.
This spreadsheet will help you figure out what grade bearings and pistons you need to get, according to the information stamped on your engine block, ASSUMING THAT THEY ARE ALL STILL IN GOOD SHAPE AND CAN BE REPLACED WITH THE SAME TYPES, WITHOUT ANY MACHINE WORK BEING DONE (aside from honing to get the rings seated well, but this has nothing to do with piston or bearing machining).

What I myself am confused about is that when you order pistons or main/rod bearings, they don’t really give you an option to select the grade. It seems that they will all be the same grade, and in fact most after market OEM sellers do not even list the grade number as a parameter in the listings. All they list is what the sizes are, like stock, 0.02 over, 0.04 over, etc.

SO! Can anyone answer this:

For pistons, what do the grades 0,1,2 correspond to?
For rod bearings, what do the grades 0,1,2 correspond to?
For main bearings, what do the grades 1,2,3,4 correspond to?

Do the piston grade numbers have anything to do with stock size, 0.02 over and 0.04 over?
And the bearing grades for the equivalent of oversized bearings?

How does one order different grades/sized then?

Look at this site where I was planning on ordering my rings/bearings (I’ll keep my pistons they are in good shape):

http://www.hybridka.com/ebearing.htm
http://www.hybridka.com/episton.htm

http://www.importperformanceparts.ne...s-nissan2.html
http://www.importperformanceparts.ne...gs-nissan.html

So how do I know what size I need, based on the grade numbers?
Btw my piston/bearing grades are as follows:
Main bearings (1 to 5): 3 3 1 3 3
Rod bearings (1 to 4): 2 2 2 2
Piston grades (1 to 4): 1 1 2 2

Also, does anyone know which are better, Toga or Topline?

Thanks for your time and hope the worksheet helps whomever needs to select bearings and pistons (once we get this hosting and size correspondence issue squared away.)

sil80

Rambuck

You really need to check a field service manual (FSM). You can get one from the dealer ($100+) or perhaps download one from a Nissan forum or elsewhere on the Internet. I have a gen4 Maxima. My FSM shows a 6 micron diameter gradation (3 micron clearance) for every grade increment. For pistons, the gradations are 10 microns diameter. FYI, 25.4 microns/mil or .0394 mil/micron. Yes, these are very small differences compared to typical "oversized" increments of 250 um (0.010"), 500 um (0.020") or larger. It is useful for polishing and soft honing (< .001") to achieve the tightest specs. A Nissan engine should never need "service" unless it gets mistreated or suffers catastrophic damage. I only just serviced my block after 300,000 miles, and went with .020" oversized pistons. Crank is still decent.

Not too convinced there is a credible difference in bearing quality. Any Multi-layered design should be decent. But you only get the graded standard bearings from Nissan. A STD aftermarket bearing should be fine if you crank is within spec. If it's getting worn like mine, and is just on the edge of spec, then STD+0.001" are available. Anything beyond that would take regrinding to match proper clearance on a typical oversize such as .010" or 0.020 etc. Problem with regrinding cranks is that you remove the surface hardening. Take that away, and the crank won't have much life left in it, and perpetual regrinding becomes necessary, as in many American muscle cars.


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