Z22 block, what do I have?

[wayno]

OK, I bought this last sunday, I might not have spent my money the best way I could have, but it is spent. Is this a fuel injected piston? It came with what looks like a early 200SX EFI setup. Is there a differance in the piston tops, carb verses efi? Looks like I am going to have to rebuild this block as the #4 piston is loose as it can be, the guy told me that the bottom end was good, but it's hard to beleave that that piston did not make some kind of noise. So I am going to punch this out and am needing advice on what to buy, I have a W53 head with 260Z valves at the machine shop being rebuilt at this time which has been ported to match the dual SU manifold, what should I buy for pistons ect. I plan on running regular gas and have been with my L20b and the head in the shop, it ran just fine for 10 years, except for wearing out. :lol:

 

[datzenmike]

Hmmm it does look like my Z22(S) from a 720.

 

2nd from the left:

 

Also this picture is supposed to be Z22E pistons...

[wayno]

My pistons look like the second from the left as you said Datzenmike, but they also look like the second photo you posted below the first photo, so it could be a fuel injected engine, this is going to be my first L/LZ block rebuild, in the past I have been lucky to buy lower mileage blocks and just put rebuilt heads on them, and they have been fine, not sucking oil, ect. So I would like to put together an engine that will run on regular gas, but still have some guts, I am sticking with a stock L20b cam, but it still breaths with the bigger 260Z valves. My L20b block has what looks like the first piston on the left in the first photo, is that style my best choice? I will still be running dual SUs. There are a lot of guys here that have put together this block combination, I guess my question is, what is the best piston for what I am going to put together and not have knocking problems.

 

 

[datzenmike]

I was in a hurry last night... but if you look at yours and the bottom picture I posted you can see that both 'eyebrows' connect at the middle but the second piston from the left (Z22S) just barely touch.

 

So I would say that yours are EFI pistons. Later Z22E (efi) pistons have a pin height that is different from the Z22S (carb) pistons.

[Sealik]

Here's my Z22(S) pistons.....block was then bored....and...

 

 

replaced with Z24 pistons

 

[wayno]

Sealik, did you have to take a lot out to fit Z24 pistons? The Z24 pistons are carbarated type, correct? What's your compression ratio? The machinist told me I don't want more than 9 to 1, does this sound right, what piston should I use with the Z22E block I am going to have rebuilt? wayno

[Sealik]

Sealik, did you have to take a lot out to fit Z24 pistons? The Z24 pistons are carbarated type, correct? What's your compression ratio? The machinist told me I don't want more than 9 to 1, does this sound right, what piston should I use with the Z22E block I am going to have rebuilt? wayno

 

87 mill to 89....so 1 mill off the sides.

I believe my CR will be 8.9 with the U67 Head....yes they are (carbed) Z24 NPR pistons.

Not sure of your pin height....or connecting rod length on the Z22E....or...what your compression would be with your W53.

Mike will chime in... :D

Should go to a higher lift cam though...breath a little better.....don't have to increase duration much at all

[wayno]

87 mill to 89....so 1 mill off the sides.

I believe my CR will be 8.9 with the U67 Head....yes they are (carbed) Z24 NPR pistons.

Not sure of your pin height....or connecting rod length on the Z22E....or...what your compression would be with your W53.

Mike will chime in... :D

Should go to a higher lift cam though...breath a little better.....don't have to increase duration much at all

 

I have huge valves in the head, as it is, the machinist had to custom fit the seats in because they have to be trimed to fit together, they overlap each other. How many thousands is 1 mill? A mill. seems like a lot, and I still need to know what type of piston will work with my Z22E rods as I will be running dual SUs and the W53 closed head. Thankyou for helping me guys, I know nothing about this part of datsuns, except it is an engine, I know that. :lol: wayno

[Sealik]

1 millimeter = 0.0393700787 inches

 

The Z22S (truck) block is more desirable to bore to 89 mil than the L20B.....not sure about the Z22E

[datzenmike]

Doug are you sure these aren't the Z24 pistons already fitted???

 

[Sealik]

Doug are you sure these aren't the Z24 pistons already fitted???

 

 

 

Good question....but....that's what I found when I pulled the Z22 head.... :)

I doubt anything was changed prior.....????

I got more pics somewhere

[datzenmike]

... and I still need to know what type of piston will work with my Z22E rods

 

You will have to measure from the center line of the big hole to the center line of the piston pin hole. Just take the bottom cap off and stand it up on a flat surface and measure up to the middle of the pin hole and let me know.

 

The Z22E came with two rod lengths and I need to know the length of the ones you have. They could be 145.9mm (same as the L20B/Z22S) or they could be 149.5mm long rods.

[Sealik]

Ooooppps... :D

Wrong pic.....those are Z24 pistons in my 85.

:)

[wayno]

You will have to measure from the center line of the big hole to the center line of the piston pin hole. Just take the bottom cap off and stand it up on a flat surface and measure up to the middle of the pin hole and let me know.

 

The Z22E came with two rod lengths and I need to know the length of the ones you have. They could be 145.9mm (same as the L20B/Z22S) or they could be 149.5mm long rods.

 

OK, I will get back to you on the measurement, it might be a couple weeks, I have a lot on my plate. wayno

[wayno]

I found some time today to pull one of the pistons from the block, it seems that the wrist pins are pressed in so I was unable to remove the piston from the rod. I would guess that I have the 145.9mm rods, what do you think?

[datzenmike]

Yeah L20B/Z22S rods. (same thing)

 

OK Z22 block bored to 89mm, and Z22 crank. L20B (or your rods) with KA24E pistons on them. The KA pistons are shorter than the Z22 pistons by about 1.5mm and won't reach the top of the block. The larger bore and the negative deck height is canceled out by the KA pistons having only 2.8cc dish. The compression with an open chamber head is 9.83. Using a closed chamber head will up this to 10.44!

 

The above but with Z24 pistons and closed chamber head gives a much more manageable 8.8 compression.

[wayno]

This is what I found when I took the head gasket off, is this what is called a siamesed block?

[Sealik]

Yeah L20B/Z22S rods. (same thing)

 

OK Z22 block bored to 89mm, and Z22 crank. L20B (or your rods) with KA24E pistons on them. The KA pistons are shorter than the Z22 pistons by about 1.5mm and won't reach the top of the block. The larger bore and the negative deck height is canceled out by the KA pistons having only 2.8cc dish. The compression with an open chamber head is 9.83. Using a closed chamber head will up this to 10.44!

 

The above but with Z24 pistons and closed chamber head gives a much more manageable 8.8 compression.

 

 

Mike.......and the CR with an open chamber (U67) head/Z24 pistons...?

Figured that combo was around 8.8-8.9...?

[datzenmike]

Z24 pistons and open chamber head is 8.43

[datzenmike]

This is what I found when I took the head gasket off, is this what is called a siamesed block?

 

 

 

I would say so. I had/have a Z24 with the same drilled holes between the cylinders. It's for coolant flow past the hottest area around the rings.

[wayno]

Since I have this siamesed block with the extra coolant passages, is it a good idea to bore it out 89mm to fit Z24 pistons or is it no big deal on a Z22 block, I just looked at this thread again and seen that Sealik bored his block(siamesed also) out to 89mm, I really don't want overheating issues. So if everything is fine to bore this block out to 89mm, I use Z24 pistons, the Z22 crank and rods, or do I use my L20b crank and rods? This will give me a 8.8 to 1 compression ratio with my W53 head with the big valves, correct? Z22E verses L20b, are the cranks and rods exactly the same, or is one made better than the other?

[datzenmike]

Since I have this siamesed block with the extra coolant passages, is it a good idea to bore it out 89mm to fit Z24 pistons or is it no big deal on a Z22 block, I just looked at this thread again and seen that Sealik bored his block(siamesed also) out to 89mm, I really don't want overheating issues. So if everything is fine to bore this block out to 89mm, I use Z24 pistons, the Z22 crank and rods, or do I use my L20b crank and rods? This will give me a 8.8 to 1 compression ratio with my W53 head with the big valves, correct? Z22E verses L20b, are the cranks and rods exactly the same, or is one made better than the other?

 

1mm removed is only 0.039", nothing really.

 

Use the Z22 crank. (not the L20B) Use the 145.9mm rods you have. They are the same part number and exactly the same as the Z22E (early) rods. Same.

 

With Z24 pistons a closed chamber head (peanut) is 8.86 compression. With an open chamber it would be 8.43 so either will work well.

[wayno]

I talked to the machine shop guy today and now I am confused,:unsure: he says that 1 mm is about 40 thousands, so that means the hole is being bored out 80 thousands, that seems like a awful lot to me, 1 mm on each side is X 2 = 80 thousands, or am I still confused, and I just don't understand how it works? I looked up the word "siamese", that was a waste of time, because the guy told me that it meant that there wasn't any cooling passages between the cylinders, I am sooo confused, the guy is known in the racing community, he builds race engines, he is "AC Nutter Racing", seems like he would know what he is talking about. Anyway, can this block with the water cooling passages between the cylinders be bored safely for the Z24 pistons? If so then that is what I am going to have done, 8.86 to 1 sounds great as AC told me nothing higher than 9 to 1 Someone here was talking about a japanese cam that was better than the US L20b cam, it was sold in the japanese market, is there a part number for this cam, can I buy this cam anywhere? Or should I just go with the L20b cam? Is there anything else I should know/need to know before I start dumping money into this block assuming it's not rejected because of other issues. Thankyou for all your help guys. :thumbup:

[datzenmike]

It's the diameter. To go from 87mm to 89mm looks like 2mm but really there are two sides to the cylinder and only 1mm is removed all the way around. Yes 1mm is just short of 0.040" and no big deal. The cylinders are submerged in coolant and only the very top where maximum compression and cylinder temperatures are reached get really hot. This is why there is a small hole at the very top to cool this area. On the Z series engine coolant flows generally from the block and up into the head from the drivers side to the pass side and out the 4 intake runners. With an L head, coolant flows up into the head and to the front driver's side and out.

 

Siamese in this case means they are joined by a web of casting. Siamesed cylinders are considered desirable because the cylinder wall are supposed to be thicker.