ok, what sort of clearences are you all running on the main and big end bearings ? the manual says up to 3 thou is ok, but my engine builder will not build it unless we get 1.5 thou, i can't get any bearings to give me that clearence, the brown colour coded shell that i got hold of from nissan is the biggest they do before the regrind and that would still make it over 2 thou clearence, does'nt anyone know the sizes of the bearings at all, nissan don't have them listed, it looks like i'll have to have a regrind, but i still need to know the bearing sizes, they list them in colours, but i need to know the measurements, plus nissan only list 1 regrind size for the big ends, any help would be appreciated, thanks.

Info. posted earlier in answer to a similar Question.

"FJ20 Big End bearing sizes
January 23 2008 at 7:48 AM

Bearings are the same as the Nissan 610/180B, L18 engine.
The main journals are 54.942-54.955mm and undersized bearings are 0.25mm or 0.0098" for diameter of 54.692-54.705mm.
Factory bearing clearance is 0.1mm or 0.004".
The big end journals are 49.961-49.974mm diameter.
[Source: Nissan S12 FSM]

Just a little wrinkle....
It appears that you need to check the oil holes and/or grooves on the bearing shells.
They sometimes do not line up correctly with the oil passages drilled in the FJ20 block.
It depends on the manufacturer of the bearings as to what the situation is.
So, my advice is to keep your old shells and compare them with the L18 type you get.
Then you can modify the oil holes to suit if necessary.

It also follows that the undersizes that are available, would be the range for the L18 engine, not just the 0.25mm I quoted from the FJ20 FSM.
There are three undersizes available: -
0.25mm, crank journal diam = 59.692-59.705mm
0.50mm, crank journal diam = 59.442-59.455mm
0.75mm, crank journal diam = 59.192-59.205mm
[Source: Nissan 610 FSM]
There must be a reason why the FJ20 FSM doesn't list the last two undersizes.
Not recommended by the factory perhaps?"

Anyhoo, if you really want such tight bearing clearances, the 610 bearings could be used with a custom grind on the crank to give the desired result.
However, there must be a GOOD REASON why Nissan designed the bearing clearance to be 0.1mm!!!!

Hope this info. helps.

thanks mate, i'll tell my engine builder to have a read.