Z22 engine information

[mojojojo78]

 I am in need of some technical help with a Z22 rods and pistons.

So from what I can find is that 81-83 720's had different rods and pistons than the 82-83 200SX both with the Z22 engine.

The 720 had rods with a center to center length of 145.9mm while the 200SX were 149.5mm. The 720 piston pin to top of piston was 35.5mm and the 200SX was 32.1mm.

Both used the same block and crank as far as I was able to find. I have the 720 style rods and pistons in my car.

I would like to know what the difference in the setups are. Does one create less compression than the other? I know I can't mix the pistons and rods, but can I use either setup as long as the rods and pistons match?

[datzenmike]

The Z22 was used in the '81-'82 720 and all used the earlier L20B rod that was 149.5mm long and a piston pin height of 35.5mm. Add to 1/2 the stroke this amounted to 227.4mm just 0.05mm below the block deck of 227.45.

 

This combination was also used in the early S110 200sx from 07 '81 through 12 '81. Starting in 01'82 through 08 '83 the rod was lengthened to 149.5mm and the pin height reduced to 32.1mm and when added to 1/2 the stroke this amounted to 227.6mm or 0.15mm above the block deck of 227.45mm

 

If the pistons have identical dish volume the difference in compression would be negligible. The early Z22 dish is 9.32c but I don't know the later piston dish. I would strongly doubt it's that much difference as this directly affects emissions and at this time makers were very concerned with pollution.

 

The reason may simply have been to use longer rods. As you know longer rods have less side loading on the pistons so less internal friction and probably slighter better mileage.

 

 

Yes as long as the rods and pistons are kept together you can use either. I see very little advantage from going to all this trouble, it will run and perform the same.

[mojojojo78]

Thanks for that information Mike. I am just trying to see what all my options are right now. Some parts are easier to find than others.

[datzenmike]

 Well with a 720 or early 200sx Z22 if you can buy some KA24E pistons they will fit the Z22 rods and by over boring to 89mm this produces a 2.3 liter 'big bore' engine. Usually an L head is put on for better breathing but the Z22 head would work and this would be a tame 8.4 compression. You could have the deck milled 1mm at the same time and this would bring the compression up to a hair over 9 to 1. There's lots of things you can do.