Opinions and fact.

[flatcat19]

So then Mike...Out of the pistons you've shown...The Z20E appears to be the option to run in a long-rod 1.8. Or would it give it too high of a compression for a street application when used with my peanut head?

 

There are pistons that look like those Z20E's right now on eBay. The dish on those Z20S pistons looks way deeper than the L18's.

 

L16 block

L18 crank

L16 rods

Z20E pistons?

A-87 C/C head

 

Yay or nay?

[Guest kamakazi620]

So then Mike...Out of the pistons you've shown...The Z20E appears to be the option to run in a long-rod 1.8. Or would it give it too high of a compression for a street application when used with my peanut head?

 

There are pistons that look like those Z20E's right now on eBay. The dish on those Z20S pistons looks way deeper than the L18's.

 

L16 block

L18 crank

L16 rods

Z20E pistons?

A-87 C/C head

 

Yay or nay?

I say get the L16 bore it and run the L18 pistons and A87 I LOVE my L16 it's a mystery motor (No one knows whats been done to it and it HAULS ASS!!!)

[flatcat19]

I say get the L16 bore it and run the L18 pistons and A87 I LOVE my L16 it's a mystery motor (No one knows whats been done to it and it HAULS ASS!!!)

 

You run yours with the L16 crank and rods?

[Laecaon]

You run yours with the L16 crank and rods?

 

He doesnt know. Why open it if it works well. Block says L16. That is what he knows.

 

 

Judging by what your combination it looks similar to this build

 

Long rod L18

flattop Z20S pistons and peanut chamber head for 9.7:1 CR, better rod/stroke ratio for higher RPM.

Parts: L18 crank, L18 block, L16 rods, Z20S pistons

s/2+r+p: 207.66mm

piston deck height: -0.29 (below deck)

[flatcat19]

He doesnt know. Why open it if it works well. Block says L16. That is what he knows.

 

 

Judging by what your combination it looks similar to this build

 

 

 

All for the fact that Z20S pistons are made of unobtainium. That's why I was asking Mike about the Z20E pistons as a substitute for the Z20S'.

I'm a little ways away from starting the engine build, but want to be armed with a solid game plan before I start buying parts and committing.

[datzenmike]

So then Mike...Out of the pistons you've shown...The Z20E appears to be the option to run in a long-rod 1.8. Or would it give it too high of a compression for a street application when used with my peanut head?

 

There are pistons that look like those Z20E's right now on eBay. The dish on those Z20S pistons looks way deeper than the L18's.

 

L16 block

L18 crank

L16 rods

Z20E pistons?

A-87 C/C head

 

Yay or nay?

 

Half the stroke + rod length + piston pin height must add up to (close but not much over) the block deck height or the piston will rise above the block and hit the head or not come up high enough and leave a gap which increases the combustion chamber and drastically lowers the compression.

 

The block height to shoot for on an L16/18 is 207.85mm

 

1/2 L18 stroke is ........................ 39mm

L16 rod length is.......................133mm

Z20E pin height is .....................31.75mm

TOTAL.....................................203.75mm I worked out the compression with the closed chamber p nut head and it's.... 7.24. Way too low. You need an extra 4mm to bring the total up.

 

If you want, find the Jason Gray engine specs in the FAQ. All the rod lengths, piston pin height, bore and stroke and more are listed so you can mix n match to build your own motor.

[flatcat19]

Half the stroke + rod length + piston pin height must add up to (close but not much over) the block deck height or the piston will rise above the block and hit the head or not come up high enough and leave a gap which increases the combustion chamber and drastically lowers the compression.

 

The block height to shoot for on an L16/18 is 207.85mm

 

1/2 L18 stroke is ........................ 39mm

L16 rod length is.......................133mm

Z20E pin height is .....................31.75mm

TOTAL.....................................203.75mm I worked out the compression with the closed chamber p nut head and it's.... 7.24. Way too low. You need an extra 4mm to bring the total up.

 

If you want, find the Jason Gray engine specs in the FAQ. All the rod lengths, piston pin height, bore and stroke and more are listed so you can mix n match to build your own motor.

 

I only asked about Z20E pistons, cuz Z20S' don't look like theyre an option. Can't find them anywhere. Guess I need to go do a little more homework...or just stick with an L18.

[dimedriver]

You may want to just look at other pistons. Have you looked at the SR or CA pistons yet? Or possible custom rods to make that short Z20E piston fit? Think DeviousKA once found a DSM piston that was close and had them machined a little to fit into a KA. There are all kinds of options you just have to widen your search.

 

 

Have you measured ether of the blocks yet to see if they are usable with stock pistions?

 

 

-Dime

[datzenmike]

Ther was a flattop L28 piston that is only 1mm overbore on an L18 block. Has the same pin height as the L18.

 

L18 crank and rods, block bored to 86mm, L28 flattop pistons and stock open chamber 45.2cc head would have a compression of 9.18.... not too bad. Doesn't matter if the L18 cylinders are worn out or not, you have to over bore anyway.

 

The 'new' motor will now be 42cc larger than stock. 1811cc

[datsunaholic]

This was my Z20S when I got it. No dish at all, blown head gasket had cleaned #2 piston nicely though...

 

1981 510

 

 

I never took pics of the underside of the heads, but I still have the banana that came off it, which was the original head. I can look next time I get to my storage barn, but I'm fairly certain there's no quench area on it. I believe only the 720 Z20S EFI model had that "feature". A 1982 200SX head went on it. I think! Could have been an '81. 8 plug, was set up for EFI as I had to pull the fuel pump delete plate and install studs. Plus it had 200SX on the JY pull tag. In any case, after changing heads the engine ran great.

 

Info I had heard was that Z20S and Z20Es had different piston pin heights and different rods. If so, that'd make it difficult to mix 'n match. It's like Z20S pistons can't be found and Z20E rods can't be found.

[flatcat19]

Ther was a flattop L28 piston that is only 1mm overbore on an L18 block. Has the same pin height as the L18.

 

L18 crank and rods, block bored to 86mm, L28 flattop pistons and stock open chamber 45.2cc head would have a compression of 9.18.... not too bad.

 

What's the compression(L28 pistons, L18 crank, rods, block) with using a closed chamber head?

[drewbar]

Wow. I'm learning much from this post. Nice one.

 

Spamming is not allowed.... mod

[Laecaon]

Wow. I'm learning much from this post. Nice one. (the best spinner)

 

Wow, super classy. Cant even tell if that is a blog or just spam. Considering it's your first post it seems like spam...

[datzenmike]

Taking no chances.

[Laecaon]

Taking no chances.

 

ah man, I could have used that opportunity to use the REPORT button! then I would be cool. :lol:

[flatcat19]

Wow. I'm learning much from this post. Nice one.

 

Spamming is not allowed.... mod

 

[datzenmike]

Long gone.

[flatcat19]

So Mike...any figure on the L18 block-bored to 86mm, rods, and crank w/L28 pistons with my A87 peanut compression ratio?

 

Or hey...teach me the equation to start figuring this shit out on my out! :P

[datzenmike]

I didn't post that???

 

9.85 I think.

[flatcat19]

Pump super compatible?

[DanielC]

Volume of a cylinder. Pi x r^2 x h. Pi=3.14159. r is the radius of the cylinder, half of its diameter. you multiply the radius times itself. h is the height of the cylinder, the stroke.

 

L-16 engine. 83 MM bore 73.7 MM stroke. One half of 83 MM is 41.5 MM. 41.5 x 41.5 = 1722.25

1722.25 x 3.14159 = 5410.6033 sq mm. 5410.6033 x 73.7 = 398761.46 cubic mm. divide by 1000, to convert cubic mm to cubic cc and you get 398.76146 cubic centimeters that times 4, gives you 1595.0458 cc, the approximate displacement of a L-16 engine.

 

For figuring out the compression ratio, we need the displacement of one cylinder. In this case, 398.8 CC (rounded up)

Lets say the cylinder head chamber is 45 CC.

The volume of the cylinder and head chamber is 443.8 CC, at bottom dead center. At Top dead center, the volume is 45 CC. You divide 443.8, BDC total volume by 45, TDC total volume, and you get 9.86222.

 

9.8622 is the compression ratio of this engine.

 

I know I ignored gasket thickness, deck height of the piston, piston dish, and or crown. You will have to calculate, or measure these.

 

Here is the tool you use to measure the cylinder head volume. It is called a buret.

 

Here is another picture with some plastic plates to use to seal off the head to measure the chamber.

 

To measure the head volume, you do a valve job, so you know the valves seal. You then put a very thin film of Vasoline around the combustion chamber, and then use four bolts to hold the plastic plate onto the bottom of the cylinder head. The plastic plate has a small hole drilled at one edge of the combustion chamber. You then set the head on a bench, and block it so the small hole is at the highest point in the combustion chamber.

 

You then fill the buret above the zero mark with ATF, and let the air bubbles float to the top. Then you open the petcock on the bottom, and dump some ATF until the level is exactly at the zero mark. Now, you fill the cylinder head chamber right up to the bottom of the hole in the plastic plate you bolted on the cylinder head.

The level of the fluid left in the buret will tell you the chamber size, in CC.

[flatcat19]

Volume of a cylinder. Pi x r^2 x h. Pi=3.14159. r is the radius of the cylinder, half of its diameter. you multiply the radius times itself. h is the height of the cylinder, the stroke.

 

L-16 engine. 83 MM bore 73.7 MM stroke. One half of 83 MM is 41.5 MM. 41.5 x 41.5 = 1722.25

1722.25 x 3.14159 = 5410.6033 sq mm. 5410.6033 x 73.7 = 398761.46 cubic mm. divide by 1000, to convert cubic mm to cubic cc and you get 398.76146 cubic centimeters that times 4, gives you 1595.0458 cc, the approximate displacement of a L-16 engine.

 

For figuring out the compression ratio, we need the displacement of one cylinder. In this case, 398.8 CC (rounded up)

Lets say the cylinder head chamber is 45 CC.

The volume of the cylinder and head chamber is 443.8 CC, at bottom dead center. At Top dead center, the volume is 45 CC. You divide 443.8, BDC total volume by 45, TDC total volume, and you get 9.86222.

 

9.8622 is the compression ratio of this engine.

 

I know I ignored gasket thickness, deck height of the piston, piston dish, and or crown. You will have to calculate, or measure these.

 

Here is the tool you use to measure the cylinder head volume. It is called a burette.

 

Here is another picture with some plastic plates to use to seal off the head to measure the chamber.

 

To measure the head volume, you do a valve job, so you know the valves seal. You then put a very thin film of Vasoline around the combustion chamber, and then use four bolts to hold the plastic plate onto the bottom of the cylinder head. The plastic plate has a small hole drilled at one edge of the combustion chamber. You then set the head on a bench, and block it so the small hole is at the highest point in the combustion chamber.

 

You then fill the burette above the zero mark with ATF, and let the air bubbles float to the top. Then you open the petcock on the bottom, and dump some ATF until the level is exactly at the zero mark. Now, you fill the cylinder head chamber right up to the bottom of the hole in the plastic plate you bolted on the cylinder head.

The level of the fluid left in the burette will tell you the chamber size, in CC.

 

Good stuff. Thnx for that.

[dimedriver]

Where did you get your burette from?

 

 

-Dime

[datzenmike]

cc heads for free

[DanielC]

I got it here.

http://www.nurnberg.com/

This is in Portland, Oregon.

 

You might try to ask a high school, or college chemistry instructor where they get lab supplies from.

 

I have found out that the correct spelling is "buret" not "burette".

 

That might help with a google search, should you choose not to use the large syringe method to CC your heads.