Differances between a Z20 and Z24 block?

[Spades]

So, I was thinking about building up the Z20 engine I swapped out when I put my built Z24 in. I am wondering what the differences are on the internals.

 

Does anyone know how different the two blocks are? I am wondering if it is as simple as taking that block, boring it out, and using a crank, rods, and pistons from a Z24, or if the blocks are completely different and the Z20 cannot be stroked out.

 

I was thinking if I could get forged parts for a Z24 and bore the Z20 over, I would get a new L20B cylinder head, and build it into a naps-L hybrid.

 

Anyone know the differences between the Z20 and the Z24 block?

[hang_510]

using a crank, rods, and pistons from a Z24, or if the blocks are completely different and the Z20 cannot be stroked out.

 

Anyone know the differences between the Z20 and the Z24 block?

:no: :(

but i can send all the timing bits for an LZ24 build (w/the seat ;) )

 

 

the stroke diff is 10mm between the 2 cranks.

 

probably not gonna work. Z24 crank in a L20 block... it took A LOT of work to stuff it in.

[datzenmike]

The Z24 is 2cm taller at the very top than the L20B/Z22/Z22. . The crank has longer throws that will not fit in the Z20 or Z22 block. From the center of the crank to the top of the block is 247.45mm. The L20B/Z20/Z22 motor is 227.45mm or 2 cm difference. So if you were to trim the Z24 crank throws and grind some clearances in the block and manage to fit the Z24 crank/rods/pistons, they would extend out of the top of the Z20 block by over 3/4"!

 

You could bore the Z20 from 85mm to 87mm or remove 1mm from the cylinder and drop a Z22 crank/rods/pistons in and make a Z22 motor but trying to use the Z24 stuff isn't worth the bother. It is do-able, but.....

[Spades]

thanks so much for the help Mike! So if I bore the Z20 over, I can drop in Z22 pistons, and rods and crank from a Z22...does the bottom of the block have to be machined to fit? or only the Z24 crank needing the block clearance?

 

Cause if I can just buy some Z22 rods,pistons, and crank, then drop a L20B head, timing cover, ect, that would make for a nice motor...

[datzenmike]

thanks so much for the help Mike! So if I bore the Z20 over, I can drop in Z22 pistons, and rods and crank from a Z22...does the bottom of the block have to be machined to fit? or only the Z24 crank needing the block clearance?

 

Cause if I can just buy some Z22 rods,pistons, and crank, then drop a L20B head, timing cover, ect, that would make for a nice motor...

 

The L20B and Z20 are basically the same motor but with different heads. Same 85mm bore and 86mm stroke. Cranks/piston/rod assemblies could be swapped from one to the other.

 

The Z22 block is basically the same as the L20B and the Z20 motor but has a larger 87mm bore. So boring an L20B or Z20 block 2mm (1 mm all the way round the cylinder increases the bore by 2mm) from '85 to '87 will in a way turn it into a Z22 block.

 

Add to this, the Z22 crank has a longer stroke of 92mm which is 6mm longer than the 86mm on the L20B/Z20 crank.

[Spades]

ok, but can a Z22 crank clear everything in a z20 engine or will I need to have anything machined out?

 

or will I have pistons tapping a L20 head?

 

my thoughts were boring out the Z20, dropping a Z22 crank, and topping it with a ported/polished L20B head with timing cover and parts needed to make the L20B head possible.

[datzenmike]

The L20B/Z20/Z22 motor is 227.45mm...

 

The Z22, Z20 and L20B are all the same block height so what ever will fit in one will fit in the others. For example:

 

Z22 total stroke is 92mm, that's top to bottom, half that from the crank center line to the center of the rod throw is 46mm. add to this the Z22 rod length of 145.9mm and the Z22 piston pin height of 35.5mm you get a total of 46 + 145.9 + 35.5 = 227.4 which will easily fit the 227.45mm tall Z22/Z20/L20B blocks..... but I digress.

 

Yes absolutely you can bore the Z20 out to fit Z22 pistons/rods and crank and make it into a Z22.

[510six]

You can also use VG30 pistons they have the same pin height as a Z20 piston, but are a 2mm overbore.

[datzenmike]

That should work and will make the Z20E about 2055cc liter displacement. A long way from a Z22 though. Also the compression would be above 11.6 with open chamber L head.

[LenRobertson]

I've gotta quit reading any post with Z20 or Z22 in the title. First I learn my Z20 rods/pistons can go into my L20b, and I'll have a cool "long rod" L. Now you're telling me I can get Z22 innards to make the leftover Z20 block into a Z22. That sounds like fun, but then I need another car for the extra engine. Where will it end?

 

Len

[hang_510]

never seen the top of a Z20 block...

 

any issues bolting the L head to it???

the Z22 block needs a few coolant holes added to mate a L head correctly.

 

 

...then I need another car for the extra engine. Where will it end?

why do you want it too???

[510six]

That should work and will make the Z20E about 2055cc liter displacement. A long way from a Z22 though. Also the compression would be above 11.6 with open chamber L head.

 

 

My first 3 liter L series stroker motor was with 100k core motor VG30e pistons, the compression with an N42 head worked out to 10.1 to 1. 80 10 lb bottles of nitrous were run through this motor in a year with no ill effects, this was with crappy CA 91 oct.