Your crazy engine combos?

[Fineline]

I have read in different places 37 to 45 cc. I am using this head for a couple of reasons. Mainly because of the closed chamber design. I removed a small amount of material during the process but not much. Mainly just polished it. Size wasnt as big a consideration. Mainly the heads resistance to detonation. I picked my compression ratio with the thickness of my head gasket.

[kiznook]

MY crazy engine combo!

 

as it sits now my setup is a Z20S bottom end, with an A87 closed chamber head. Assuming the 148.6 connecting rod length (which seems to be completely un-verified) it works out to about 10.83:1 CR. The more I crunch the numbers the more I think I'll end up keeping this setup. I may swap the A87 for a U67 to drop the CR down to around 10:1. Right now it suffers on 91 octane, and is a bitch to tune (DGV).

 

I really want to build a 2.1 longrod, but after looking at the numbers, the ratios on my current setup are pretty decent. BUT my motor needs a rebuild, So I'll be tearing into this spare I have and freshening it up a bit. I'll let you guy's know what I find, it's "supposed" to be "built" but we'll see how it measures out :D then I'll rebuild the Z20S for my "final" powerplant and I'll take measurements to finally put an end to the big WTF over the Z20S numbers.

 

If anyone in the Portland area needs a z22 or z24, I know where there's a few. just let me know

[RacnJsn95]

I need a Z22 :) I'm about 4 hours south of Portland

[Fineline]

Here is my frankenmotor.

 

http://forum.ratsun.net/showthread.php?t=1816

[datzenmike]

I have read in different places 37 to 45 cc. I am using this head for a couple of reasons. Mainly because of the closed chamber design. I removed a small amount of material during the process but not much. Mainly just polished it. Size wasnt as big a consideration. Mainly the heads resistance to detonation. I picked my compression ratio with the thickness of my head gasket.

 

I think the original L16 may have had the smaller chambers, 38ccs I think. Many years ago I put an L16 head from a 68 510 on an L20B and it ran fine. It was temp until I got the other head milled.

[datzenmike]

MY crazy engine combo!

 

as it sits now my setup is a Z20S bottom end, with an A87 closed chamber head. Assuming the 148.6 connecting rod length (which seems to be completely un-verified) it works out to about 10.83:1 CR. The more I crunch the numbers the more I think I'll end up keeping this setup. I may swap the A87 for a U67 to drop the CR down to around 10:1. Right now it suffers on 91 octane, and is a bitch to tune (DGV).

 

I really want to build a 2.1 longrod, but after looking at the numbers, the ratios on my current setup are pretty decent. BUT my motor needs a rebuild, So I'll be tearing into this spare I have and freshening it up a bit. I'll let you guy's know what I find, it's "supposed" to be "built" but we'll see how it measures out :D then I'll rebuild the Z20S for my "final" powerplant and I'll take measurements to finally put an end to the big WTF over the Z20S numbers.

 

If anyone in the Portland area needs a z22 or z24, I know where there's a few. just let me know

 

Kiz, What piston are you using? Have you seen these Z20S pistons? Are they flat tops? I calculate a 10.868 C/R (close to yours) using a flat top piston.

[SHADY280]

wow fineline, i like it alot, how close to running is it. im gonna prolly run the same turbo, but im going cheap on the computer, manifold and injectors. gonna do a 280zx swap kinda thing and make it work ghetto style.

[kiznook]

Kiz, What piston are you using? Have you seen these Z20S pistons? Are they flat tops? I calculate a 10.868 C/R (close to yours) using a flat top piston.

 

yes they are flat tops. We've talked about this before! The big ?? is the rod length, but given the running characteristics, I'd say 10.5-11:1 seems realistic

 

so I popped the U67 off the mystery "built" L20 from the Tuesday project, turd car and what did I see...

 

 

what do you guys think? L28 pistons? Had a regular L20 (85mm) head gasket. Dished, 4 valve reliefs (not including the "custom" additional reliefs :D)

 

time to crunch some more numbers

[SHADY280]

nice pistons, those "additional" valve reliefs make those pistons almost garbage. thats exactly where cracks start. too bad those look good.

[banzai510(hainz)]

I would just grind down the slap marks from the valve hitting and call it good.

Looks like a dished piston to me. I say run it.!!!!!!!

 

photo Left stock L20 11.36 dished piston Photo right is 4cc L18 piston

 

Make a judgment call on yours ,on what u have.

[69FJWagon]

One of the fastest 510s I have driven that is N/A 230hp at the crank, NAPz 2.2 with a fully worked 12 valve KA head with a big cam. Ermish And Rebello hybrid

 

 

 

 

 

 

 

 

[datzenmike]

yes they are flat tops. We've talked about this before! The big ?? is the rod length, but given the running characteristics, I'd say 10.5-11:1 seems realistic

 

so I popped the U67 off the mystery "built" L20 from the Tuesday project, turd car and what did I see...

 

 

what do you guys think? L28 pistons? Had a regular L20 (85mm) head gasket. Dished, 4 valve reliefs (not including the "custom" additional reliefs :D)

 

time to crunch some more numbers

 

Those are NAPS Z series pistons. As you can see the reliefs are cut in such a way that they are useless for an L head. Obviously an L head left it's tracks on those pistons. As Hainz said that's a dished piston very much like the Z22 set I have. The Z20E set I have are flat with tiny valve reliefs like these but flat. The rods are 152.5mm long. Never seen them dished, but they do exist.

 

Looks like a 30 thou. over, set of Z20 pistons. This makes sense in a used L 20B block. It's been over-bored and larger pistons used.

 

CORRECTION: It's not 30 thou over it's more like almost 70 thou over.

[banzai510(hainz)]

Mike are you sure?????

 

I thought the pin height on Napz pistons were different like 1.25 and th Lseries pistons were 1.5 or 1.48 to be exact

If a Napz piston it would never make it all the way to the top unless a Napz crank/rods???????

 

I think they timmed it wrong thats why it hit the piston. Or a SUPER CAM was in there.wheither dished or Domed pistons, if timmed correctly it will not hit.

 

i think it was just a manufactured with it as differnt makers made pistons back in the day. Doesnt look like a nissan piston to me and I dont see any oversize marking on top of the piston.stock size aftermarket pistons, Matter of FACT(CSI Hainz) that could be home made cut valve reliefs

 

 

kiznook

is that a slight crack on the right side of that center headbolt hole?????????where the water passage is??????? magna flux it

[datzenmike]

MY crazy engine combo!

 

as it sits now my setup is a Z20S bottom end, with an A87 closed chamber head. Assuming the 148.6 connecting rod length (which seems to be completely un-verified) it works out to about 10.83:1 CR.

 

Mike are you sure?????

 

I thought the pin height on Napz pistons were different like 1.25 and th Lseries pistons were 1.5 or 1.48 to be exact

If a Napz piston it would never make it all the way to the top unless a Napz crank/rods???????

 

I think they timmed it wrong thats why it hit the piston. Or a SUPER CAM was in there.wheither dished or Domed pistons, if timmed correctly it will not hit.

 

i think it was just a manufactured with it as differnt makers made pistons back in the day. Doesnt look like a nissan piston to me and I dont see any oversize marking on top of the piston.stock size aftermarket pistons, Matter of FACT(CSI Hainz) that could be home made cut valve reliefs

 

 

kiznook

is that a slight crack on the right side of that center headbolt hole?????????where the water passage is??????? magna flux it

 

Hi Hainz,

well he says it's a Z20S bottom end. So either a Z20 or an L20B block bored out to 86.74 which is 0.0685" over or close to 70 thou over.

 

They do look like Z22S pistons I have, but can't be as his bore is under 87mm.

 

I've got Z20E and Z22S pistons and they both have eyebrows in the same position exactly like those Kisnook has, however the Z20E ones are true flat tops with valve reliefs, no dish.

 

CSI Hainz: If home made valve reliefs, it sure isn't for an L series head. They miss by a mile so must be for a NAPS.

 

 

Kiznook: I think you have either a:

Z20S piston 35.56mm and rod 148.6mm OR

Z20E piston 31.75mm and rod 152.5mm

 

Both have a 13cc dish

 

I recalc'd the C/R with the 86.74mm bore and 13cc dish and got 9.081 with a closed chamber and 8.59 with an open one.

[kiznook]

Mike- Sorry for the confusion. THIS IS A DIFFERENT ENGINE. completely seperate from the Z20S that's IN my car.

 

This one is a L20B block that was said to have been bored .040 over.

 

I think I might leave the rings and bearings alone on this one (assuming everything looks okay) unless someone can tell me what rings to buy, or how to figure it out.

 

Hainz- I wouldn't be surprised if it is cracked, didn't really look too closely yet. doesn't make much difference on this one anyway.

 

I also came up with something like 9:1 with l20, l28 pistons, and peanut head. It'll be nice, I've got the a87 for this block, and the u67 for the Z (flat top) block. I'll have a 9:1 and a 10:1 :D

[banzai510(hainz)]

most piston manufactures not ethe oversize on a piston in metric or inches

if nothing on there I say its stock bore.

 

L28 pistons??? I have never acutally seen anybody buy L28 pistons?? Wher do you get these from. Most people want the 280ZX NON turbo cause they are flat and use them in L18s. Flattops in L20s are too much and seen alot of headgasket proplems.

Turbo L20 pistons are 10.9cc dished so not much more than a stock L20 pistons. So Ill let you justfy the cost or let us know where to get this pistons at.

Maybe Datsun freak can explain more on this one.

 

Nissan wants 46$ a apiston for a 280ZX flattop last time I cked 4 yrs ago.

 

I would rering it and rebearing it while you have it out. Just wing it unless the crank and rods are really chewed up

 

 

rule of thumb here

put a closed chamber A87,w53 SSS ,head on a l20

a open chamber U67 on a Napz block

[RacnJsn95]

Well I got my pistons today for my super crazy combo idea. Everything measured up good... I wish I could just figure out the CC of the dish without actually CCing one. The dish size is .130" deep x 2.785" diameter. The compression height is 29.75mm, but I will be taking .8 to 1mm off the top of the dish. .8 off would be a +-0 deck height.

 

 

I think they'll work pretty good... I just need a z22 crank now.

[datzenmike]

Well I got my pistons today for my super crazy combo idea. Everything measured up good... I wish I could just figure out the CC of the dish without actually CCing one. The dish size is .130" deep x 2.785" diameter. The compression height is 29.75mm, but I will be taking .8 to 1mm off the top of the dish. .8 off would be a +-0 deck height.

 

 

I think they'll work pretty good... I just need a z22 crank now.

 

Hey Jason, I worked out your dish volume with the .8mm removed from the top, but it would be more accurate if you could give me the distance across the bottom of the dish. With the numbers you posted it works out to 9.828cc. But as you can see the side is tapered down to the bottom, so it would be a little less. I took some measurements off the screen (very rough) and have trimmed it down to 7.207cc

 

Trimming the top removes about 3cc from the dish.

[datzenmike]

This one is a L20B block that was said to have been bored .040 over.

 

The stock L20B bore is 85mm, this is 86.74 or 0.0685" bigger. So much for 0.040 over.:D

 

most piston manufactures not ethe oversize on a piston in metric or inches

if nothing on there I say its stock bore.

 

Stock what? The L20B and Z20 were 85mm, the L28 was 86mm and the Z22 was 87mm. This one is just a bit smaller than a Z22 piston but larger than an L28. Has to be an oversize, (can you get a 68 thou oversize Nissan piston?) or a custom. They also have valve reliefs like a Z20 or Z22 piston.

[RacnJsn95]

Hey Jason, I worked out your dish volume with the .8mm removed from the top, but it would be more accurate if you could give me the distance across the bottom of the dish.

 

Hey thanks Mike! I attempted to figure it out, but I came up with 13ccs after the cut, but I'm pretty sure that isn't right...

 

The top of the dish diameter is appx. 70.5mm, and the bottom of the dish diameter is appx. 63.5mm.

 

So using the 7.2cc number, I calculated a 10.5x:1 compression ratio.

[banzai510(hainz)]

dont the pistons say on the box the dish measurements?

 

read carefully they list a lower comp piston on this site. the upper is a stock 11.36 the lower is even more dished

 

http://www.kb-silvolite.com/spistons.php?action=Mfg4l&mfg=Nissan&Div=Nissan&l=1952

[RacnJsn95]

The measurements are not in metric units, and it doesn't say anything for cc's on the box. The dish size is .130" deep x 2.785" diameter. The measurements in mm above, are ones that I took with the calipers.

[datzenmike]

Hey thanks Mike! I attempted to figure it out, but I came up with 13ccs after the cut, but I'm pretty sure that isn't right...

 

The top of the dish diameter is appx. 70.5mm, and the bottom of the dish diameter is appx. 63.5mm.

 

So using the 7.2cc number, I calculated a 10.5x:1 compression ratio.

 

Thanks Jason, I'm at work, but will re do it again but expect it will just shave a small amount off or on.

[datzenmike]

Well your measurements are slightly different in mm but now, with the .8mm cut off the top, I get 8.835cc dish. This will lower your comp very slightly.

[pope_face]

Ok, this is probably a stupid question, which is why I'm posting it here rather than in it's own thread, but I read today that a KA head will fit on an L- or Z-Series block... Apparently it can be done in order to get an FI swap onto either block without modifying the stock heads. Can this be done?

 

And, more importantly, if the above is possible, could someone mount an Z-Series, or (specifically) an L-Series head on a KA? I figure if you can swap the head and the block one way, the reverse should be true as well.

 

The only reason I ask is that I want a carb'd engine, but I want to be able to get an auto transmission with more than four speeds... I'm just assuming the KA has five- or six-speed autos available just because it's a newer engine, as opposed to the four speeds available with the L-Series.

 

Anybody have any input?