Opinions and fact.

[flatcat19]

So...I scored quite a few things today...And upon receiving what I did, I go back to something I'm sure we've all heard before. "One man's trash is another man's treasure." I really hope this isn't all my trash to pass on to someone else.

 

I bought a pile of parts today, for $30. Owner told me it was a disassembled, complete L18 w/an A87 closed chamber head. "Everything is there. It's just all torn down."

So I piled everything into my truck, and took off. Upon closer inspection, I came to find out that it is NOT COMPLETE. I knew it wouldn't be. But this also raises quite a few questions in my mind. I'll post those after the show 'n' tell.

 

Of the missing parts, I'll direct those in the questions I have.

 

So now, I have a pretty much complete L18 short block. And that raises a few questions in it's own right.

1.> Which would be more beneficial? L16 w/L18 pistons? L18 internals stuffed into L16 block? Or build L18 stock, or with something else?

2.> Who has done any of the listed options? How did you feel about them?

 

Now the head: It's missing rocker arms, rocker arm springs, and the little groove washers? that sit on top of the valve springs. It's also missing the cam gear.

1.> Can I disassemble a different head (W58 or 210) and use the cam gear, arms, arm springs, and washers to work on the A87?

2.> Is there something else I'm overlooking on building a head that I might be missing?

 

I know I need to have the rocker arms refinished. I already plan on new valve springs, retainers, and maybe a light porting/cleaning. I would love to get a cam. But don't know which, or when that will happen.

 

If it means anything, I have in my possession...the L16/210 that's in my truck now; The L18 I just showed you; and I can get my hands on a spare L16 block. I don't have carb(s) YET. I'm not looking for a monster fast truck. Good streetable, reliable fun. Any insight and help would be great. Thanks guys.

[Laecaon]

I dont thing the l18 pistons fit in the L16. The L16 block and L18 block have the same outside dimensions but the bore and stroke are different, of course. Build a L18. I would take a L18 any day to replace my L16.

[flatcat19]

I dont thing the l18 pistons fit in the L16. The L16 block and L18 block have the same outside dimensions but the bore and stroke are different, of course. Build a L18. I would take a L18 any day to replace my L16.

 

To fit L18 pistons is only a 2mm overbore...and from my searching...L18 pistons in L16 on L16 rods w/closed-chamber head results in right around 9.5 to 1 compression. And I've read all sorts of people saying they've put the L18 pistons, rods, and crank into the L16...but not a single person gave any feedback on their set-up. That's what I'm wanting to find out. I want to know what other peoples' experiences are with these set-ups.

 

Maybe someone can correct me on my compression number. (Mike?) And while I'm at it...would the bore/stroke ratio be off by going L18 pistons in an L16?

 

And after much more research...I'm missing a ton of stuff from the head. Crap!

 

I'd say I'll post some boobs for good answers...but we all know where that ended last time I helped out with the boobie brigade. :P

[DISLEXICDIME]

Out of all the l series I have owned my l18 was myh fave

[datzenmike]

An L16 bored to 85mm with L18 stock 4.36 dish pistons and closed chamber head would have a compression of.... 9.1

 

Bore stroke ratio would change for sure, but so what? You would have a 1678cc motor. Basically an L17

 

If you are boring the L16 to 85mm why not use the L18 crank and rods and have an L18?. Using the closed chamber you would have a compression of 8.9

 

All the missing valve train parts can be swapped onto the A-87 head from any L head.

[flatcat19]

An L16 bored to 85mm with L18 stock 4.36 dish pistons and closed chamber head would have a compression of.... 9.1

 

Bore stroke ratio would change for sure, but so what? You would have a 1678cc motor. Basically an L17

 

If you are boring the L16 to 85mm why not use the L18 crank and rods and have an L18?. Using the closed chamber you would have a compression of 8.9

 

All the missing valve train parts can be swapped onto the A-87 head from any L head.

 

Mike to the rescue!!!

 

Mike, it seems to me the drop in compression by using the L18 internals in the L16 block isn't really worth it. Am I missing something? I know it's only by .2, but still. Balance would even stay the same between the two combos. Would this combo be a bit more torquey? Or is having an L18 just that much better?

 

And I just noticed, in the 2nd picture, the oil filter points up. Is that normal on the 18s? I didn't even notice til just now.

Thanks for the answers guys.

[dimedriver]

The stock L16(210) head has a very small but open combustion chamber. The peanuts are just a little larger. It is thought that the L16 head was the same head used on the smaller L13 not sold in the US.

 

This is why your seeing the drop in compression from the L16 head to your closed chamber.

 

-Dime

[flatcat19]

The stock L16(210) head has a very small but open combustion chamber. The peanuts are just a little larger. It is thought that the L16 head was the same head used on the smaller L13 not sold in the US.

 

This is why your seeing the drop in compression from the L16 head to your closed chamber.

 

-Dime

 

Um...the drop in quoted compression was L18 pistons in L16 block with L16 internals vs. L16 block with all L18 internals.

No one said anything about the 210 head in this equation. No where.

Thanks though.

 

[MicroMachinery]

(Hey, I think he was trying to help you)

 

I'd stick with the L18 for higher rev capability. For only $30, it still sounds like a good deal(people charge twice that for a stripped A87 head) Just find the few parts you need(which should be easy) and maybe get a good set of SU's, you're golden.

 

If you have a few extra bucks, balance the rotating assembly, throw some ARP hardware in there, then rev it to the moon, Alice!

 

Another tip: Any time you transport an aluminum head like that, it's wise to stick a piece of cardboard underneath it, so as to not mar up the sealing surface. That aluminum is really soft, and very easily gouged up sliding around in the bed of your pickup.

[flatcat19]

(Hey, I think he was trying to help you)

 

Another tip: Any time you transport an aluminum head like that, it's wise to stick a piece of cardboard underneath it, so as to not mar up the sealing surface. That aluminum is really soft, and very easily gouged up sliding around in the bed of your pickup.

 

It was in a canvas bag, in the cab of the truck during transport. It was the only part being protected during this journey. It may be my first Datsun, but not my first rodeo. But thanks.

 

And I am oh-so-aware of the 210 being the poor man's head. My aim on this purchase was just the A87 head. And that is why every question I layed on the table involved that exact head. It is what I'm going to run. Owner wouldn't let me buy them separately. He finally said he would sell me the head for the same price...and that I'd be getting a free motor with it. Golden.

[datzenmike]

The shorter rod L16 would rev the highest I would think but is the smallest displacement. The L18 had longer stroke and displacement for more torque. All things considered I would go with the larger L18, but that's me.

[Dime Dave]

There is no replacement for displacement!

 

And don't worry about the L18 not turning some RPM's. Typically the shorter the stroke, the higher an engine will potentially rev. But that said, I've run L20B race engines to over 8K regularly. IMO I'd build the L18 and forget about the L16.

 

And if you want more displacement use stock L28 pistons (86mm bore, .040" overbore on a stock L18). Early 280Z pistons have a 10.9cc dish, later are flat tops. If you are changing cams, the flat top pistons may need valve pockets added depending on how wild the cam duration and lift are. 290 duration with .600" lift will definately needs valve pockets.

 

Generally if an engine is under square (stroke bigger than bore) it is a considered a low RPM (torque) engine. Think KA24, Z22 & 24 and even the L20B to a degree. SR20 is square (86mm x 86mm) and these are considered to be good revving engines. Both the L16 & L18 are over square engines and they have no issues with RPM.

 

Now another factor that effects RPM range is the rod to stroke ratio. Most race engines are around 1.8 - 2.0 ratios. Generally good street engines are 1.6 to 1.8. The L16 is near race engine territory at 1.80 (133.0mm / 73.7mm) and the L18 is 1.67 (130.0mm / 78.0mm). The L20B is 1.70 (145.9mm / 86mm) and just for comparison, the later Z22 is 1.56 (145.9mm /92.0mm).

 

The bore-stroke realtionship has more effect on RPM ability than rod/stroke ratio. Of course you still have to get fuel/air in and exhaust out. Bad exhaust, small carb(s), limited cam timing and/or lift, bad ports will all restrict RPM, that is why I say RPM potential. If you have a carb that functions well to 4000 RPM, don't expect to create an engine that turns 7K by overboring it or adding a cam or header. Compression is about the only thing that if raised, creates HP without needing to alter other parts (cam, carbs, exhaust, porting) but it comes at the risk of getting fuel with enough octane. A 15:1 compression will be fine on 116 octane race fuel, but the engine will not live on 87 octane pump gas.

 

I guess what I am saying is don't expect an engine to rev past stock RPM's unless you've added the parts needed top get more fuel/air in and the increased exhaust out.

 

And remember when it come to displacement, it is all about size. Yes, bigger is better!

[DanielC]

I think I recall some discussion about building a long rod L-18, using an 1-18 crankshaft, and block, L-16 connecting rods, and pistons with a short pin to top height to make up the difference.

[datzenmike]

I think I recall some discussion about building a long rod L-18, using an 1-18 crankshaft, and block, L-16 connecting rods, and pistons with a short pin to top height to make up the difference.

 

L18 block bored to 85mm and crank, L16 rods, Z20S pistons.

 

The dish is unknown but I think similar to the L20B because of the assumed Z20 head used. If a p nut head used the compression would be 8.3 ... maybe higher if the dish is smaller. The trouble with the L16 rods is that the piston does not reach the top of the block so this space .33mm adds up to almost 2cc of space added to the combustion chamber.

 

1.7 rod/stroke ratio. (very slight increase) Big bore 85mm X 78mm (very over square)

[The Stig]

"L18 block bored to 85mm and crank, L16 rods, Z20S pistons."

 

I had that set-up with twin 45mm DCOE's in my 510 back in the eighties, but I don't think they were Z20 pistons. I cant say for sure, but I think they were aftermarket for an L20B

A friend of my Dad's built it, but it was noticably WAY better than my mild port, polish and cammed L18 (admittedly the PL610 it was in was somewhat heavier than my PL510)

A 5.0 mustang couldnt touch me to 90MPH where I would hit redline in 4th gear. I regret having sold that car every time I think of it....:mellow: the body had been restored with all OE factory panels, back when they were still available. Wonder if it still lives?

[flatcat19]

Now another factor that effects RPM range is the rod to stroke ratio. Most race engines are around 1.8 - 2.0 ratios. Generally good street engines are 1.6 to 1.8. The L16 is near race engine territory at 1.80 (133.0mm / 73.7mm) and the L18 is 1.67 (130.0mm / 78.0mm). The L20B is 1.70 (145.9mm / 86mm) and just for comparison, the later Z22 is 1.56 (145.9mm /92.0mm).

 

This is why I asked about just using the L18 pistons in the L16 block.

 

And if you want more displacement use stock L28 pistons (86mm bore, .040" overbore on a stock L18). Early 280Z pistons have a 10.9cc dish, later are flat tops. If you are changing cams, the flat top pistons may need valve pockets added depending on how wild the cam duration and lift are. 290 duration with .600" lift will definately needs valve pockets.

 

 

What's the compression by using the L28 flat tops in the L18 block, with L18 crank and rods? Too much to get away with pump 92?

 

NOW...Last question. If I just decide to rebuild with what I got, Should I use L18 guts in the L18 block, or the 16 block? I have no idea why this guy tore the 18 apart, but I'm guessing something went askew. At least with the 16 I know what I'll be getting into.

[flatcat19]

"L18 block bored to 85mm and crank, L16 rods, Z20S pistons."

 

I had that set-up with twin 45mm DCOE's in my 510 back in the eighties, but I don't think they were Z20 pistons. I cant say for sure, but I think they were aftermarket for an L20B

A friend of my Dad's built it, but it was noticably WAY better than my mild port, polish and cammed L18 (admittedly the PL610 it was in was somewhat heavier than my PL510)

A 5.0 mustang couldnt touch me to 90MPH where I would hit redline in 4th gear. I regret having sold that car every time I think of it....:mellow: the body had been restored with all OE factory panels, back when they were still available. Wonder if it still lives?

 

Knowing which pistons you used might totally change my direction. There is no suitable information on the so-called "Z20S" pistons. Jason Grey doesn't give any info on them. Jason Grey's notes also say 9.7 CR, where as DatzenMike says less...And given Mikes track record, I think I trust his answer also. Especially considering I can't find "Z20S" pistons on any website anywhere.

[datzenmike]

NOW...Last question. If I just decide to rebuild with what I got, Should I use L18 guts in the L18 block, or the 16 block? I have no idea why this guy tore the 18 apart, but I'm guessing something went askew. At least with the 16 I know what I'll be getting into.

 

The L18 cylinders may be worn past where the stock pistons and new rings can be used. You would have to bore to the next oversize and new pistons or... bore the L16 block and run the old l18 pistons.

[datzenmike]

Knowing which pistons you used might totally change my direction. There is no suitable information on the so-called "Z20S" pistons. Jason Grey doesn't give any info on them. Jason Grey's notes also say 9.7 CR, where as DatzenMike says less...And given Mikes track record, I think I trust his answer also. Especially considering I can't find "Z20S" pistons on any website anywhere.

 

JG quotes a 45cc combustion chamber on the Z series head. There are Z heads with this but it must be on the Z20S motor. I have measured 2 of each of the following heads: 20E, Z22 and Z24, and found the combustion chamber to be 57cc. So there are two different sizes.

 

Since the Z20E and the Z20S are basically an L20B block. If the Z20E flatops with the larger 57cc head (that I have measured) gives an 8.5 compression... then the Z20E cannot have a dish or it would be even lower. I have to assume that the Z20S uses the JG 45cc head and some undetermined dish (probably around the same size as the L20B.

 

BTW the 720 has a Mileage Option motor that is a Z20S and yes it has a 9 compression. It gets this by (I believe) using Z20E flattops and a Z20S 45cc head.

[datsunaholic]

Mike, I've had both a Z22E and Z20S head side by side. They were identical in every way. The only one I haven't checked is the Z20 4-plug head, but the only difference I know of is the spark plug holes aren't machined out.

 

I do know the Z24 heads are very different.

 

On my Z20S, the only "dish" the pistons have is the valve recesses. BUT... they are .020 oversize so they've been replaced.

[blue72]

One note: If you do go ahead and pull the rocker arms from another L series engine to put on this one, it'd be a good idea to have them resurfaced first. They wear to the individual cam lobes and having them resurfaced lets them bed in like new again.

[flatcat19]

One note: If you do go ahead and pull the rocker arms from another L series engine to put on this one, it'd be a good idea to have them resurfaced first. They wear to the individual cam lobes and having them resurfaced lets them bed in like new again.

 

I already mentioned that in the first post. Thnx though. I've been doing my homework. I only got a C+ on it...but it's been done.

 

Do people actually read these posts? Or do they see an opportunity to interject their .02?

 

I don't mean to be a dick, but really? That's twice in one thread, directed at me. :blink:

[Laecaon]

Do people actually read these posts? Or do they see an opportunity to interject their .02?

 

Patience. Everyone fails to read something. I know I read that line, but forgot about it over the day. And are they inserting their .02 or are they really just trying to be helpful? There is a lot of content in this thread, and your line about resurfacing the rockers, well appears to be an afterthought and because of that I tend not to think of it til, well after.

 

But really patience, it makes the world go smoother, like new oil in a motor. The guy was just trying to help.

[flatcat19]

Patience. Everyone fails to read something. I know I read that line, but forgot about it over the day. And are they inserting their .02 or are they really just trying to be helpful? There is a lot of content in this thread, and your line about resurfacing the rockers, well appears to be an afterthought and because of that I tend not to think of it til, well after.

 

But really patience, it makes the world go smoother, like new oil. The guy was just trying to help.

 

Touche. But if we're all just repeating ourselves...My main interest in this purchase was the head alone...the motor is really just the after thought. Since I have it, may as well see what I can get out of it. Right?

 

But with my main focus, in my head, is building this head-I already plan on every aspect of this head to be tits. That includes mild port, new seats, springs, washers, rocker arms, yada, yada, yada.

 

Like I said...I don't mean to be a dick. Really. Maybe it's just me, that if I'm not armed with the entire conversation; I stay out of it.

 

A loaded gun is more dangerous than an empty one. Minds are very much the same.

 

And on a final note...GET BETTER EDDIE!!!

[datzenmike]

Mike, I've had both a Z22E and Z20S head side by side. They were identical in every way. The only one I haven't checked is the Z20 4-plug head, but the only difference I know of is the spark plug holes aren't machined out.

 

I do know the Z24 heads are very different.

 

On my Z20S, the only "dish" the pistons have is the valve recesses. BUT... they are .020 oversize so they've been replaced.

 

I have two Z20E (200sx)4 plug heads, 2 Z22 truck, and several Z24. I cc'd them all twice, and gt 57cc on all. The Z24 was only different in the intake port shape.

 

The Z20E had flattops with valve reliefs. Paired with a 57cc head it works out to about 8.5 compression.

 

Z20E piston

 

Z20S piston

 

I have a picture of a supposed Z20S piston and it is dished. So it must run a much smaller Z head combustion chamber.

 

Z20/22/24 head with 57cc chamber. Note it is perfectly round

 

Z20 head from a Mileage Option 720 with 45cc chamber and 9:1 compression. Note top and bottom quench areas

 

I think the smaller head and the dished Z20S pistons go together to make an 8.5 compression motor. The 9.0 compression Mileage Option motor is the small head and the flattop pistons. I've worked out the math and if fits.