Hi everyone,
Can someone please help me with this question ? I'm building a A13 engine from a 74 b210 ( tall block ). My question is. Will the 73mm pistons from a A12 engine fit in my A13 engine ? I know the pistons from the A13 is also 73mm. But can I use the A12 pistons with my A13 rods !

Short answer, NO. The pin diameter is larger on A13, A14, and A15 engines than it is for the A12. Check the Tech Wiki for more details.

73mm bore piston used the 17.5mm piston pin diameter:

•A10
•1971-1973 A12 (1200)
•1974-up A12
•1974 A13 (tall block engine)

This is what I found in the Tech Wiki. I have the 74 tall block A13. So is this info. wrong then ?

Same piston

Quote: Yes, Nissan Competition sold the same flattop piston for use in A12 or in 1974 A13 engine.

12010-H2361 73MM/2.874" PISTON
[This is the factory stock GX piston]

Both A12 and 1974 A13 are 73 mm diameter, pin height 32.5 mm, pin diameter 17.45 mm. The A13 rod differs from the A14 rod.

The part numbers are not the same for A12 and 1974 A13 piston. I would guess the dish on the A13 piston is larger, so as to keep the same compression ratio. So using the 1971 A12 piston may bump up the compression to 9.5:1 and using the 1972-1973 A12 piston to 9.0:1. Still good for regular gasoline.

This topic explains what I thought were oddball parts, tech wiki shows a different part number for the A13 rod, I had a box full of rods some of which were 133mm and some of those had smaller pin diameter but I can't remember if they were indeed 17.5 but after reading this they would have to be. The taller block requires the 133mm rod but the A12/A13 piston would require a 17.5mm pin so that explains what I thought were odd ball rods.

Tom

Thank you all for the info. Now I can get the block going. I also got the valve calibration for my 300 American Racing cam.Later I will post a pic of a head block that I bought that has celica valves, big ports, shaved, double springs etc, etc even though I have a concern with some spacers that are under the valve trane to raise it up. Never seen that before, but pics coming soon. Thanks again

Oh, remember that swapping pistons will require the engine to be re-balanced.

Oh, remember that changing pistons will require the engine to be re-balanced.

Will do. Thanks DD !