New World Datsuns...

There's a green test mule in Tri Cities...

I'm asking because I happen to have a Z20 engine here with all the L20B to assemble it.

Arguing with my self about putting that together or removing the pistons and using those in the L18 I have with L16 rods on an L18 crank. Either option would use a W53 C/C head.

I'd throw my vote behind the Z20 for the extra torque.

Is it a Z20 from a truck or a car?

Having driven my L19 build, and been in a bone stock L20 car, go for the displacement.

I would agree with Jacob.
I look at it this way, how many people do you know that drive their car/truck around at a steady 5000rpms plus, a circle track guy is the only one I know and them engines are lucky to last a season if they are a winner or better example would be if they do well, if a cop hears an engine at them type of RPMs he is going to think racing and you will get at the very least stopped even if your not breaking any laws.
Maybe some will say that one can rev an L16 near redline all day long, well I have seen 2 L16 blocks with holes in the side of them, I consider them boat anchors and there is nothing sporty about them except for the sound they make driving them like that.
I consider the best upgrade I ever made to my 1971 Datsun 521 was to go from an L16 to an L20b, it would go up a mountain road behind my friends Dodge diesel without issues, if I wanted to get up that same hill with the L16 I had to get it going and not slow down for anything as it had no torque, and on the freeway it is a night and day difference.
Going from the L20b to the LZ23 was a great upgrade also, but I determined that by how much torque I gained, as I pull a loaded trailer everyday I work, and it was much nicer to drive with the LZ23.

The only replacement for displacement is forced induction.

wayno wrote: ↑Sat Jan 19, 2019 1:22 pm Is it a Z20 from a truck or a car?

That I am not clear on. My guess is car because of dipsticks location, front. There is a hole in the rear with a plug for the dipsticks to go there too.

All say displacement, but if waynos engine gets 8 miles to the gallon...there really is no reason to be driving a Datsun, eh?

Really, all I would need for this 20 then is a strong enough transmission.

I guess I asked the wrong question, does it have flat top pistons or do they have some dish in them?
I seriously doubt it will get less than a normal mileage for a Datsun.

They are flat tops.

I would have passed on this motor if it wasn't.

Well that is the same thing I have, that would put the compression ratio at around 10.8 to 1, you will likely have to have the distributor modified to burn pump gas, but the W53 head on the Z20 block should rev high/smooth from what I have read.
I had a Nova with a high compression engine when I was a kid, it was the funnest car I have ever owned/drove in my life, but that was back in the late 70s when gas was still gas.

I would think he can probably figure out how to locate some pure gas .

LZ20 flat top pistons and long rods with L20b bottom end and U60 head was by far the best L motor I've ever built. Had the most torque, the most revs, ran 3 years hard before I blew it up. Ends up being about 2.1 liters and roughly 10-11.75:1 compression depending on what you do.

HRH wrote: ↑Sun Jan 20, 2019 4:11 pm LZ20 flat top pistons and long rods with L20b bottom end and U60 head was by far the best L motor I've ever built. Had the most torque, the most revs, ran 3 years hard before I blew it up. Ends up being about 2.1 liters and roughly 10-11.75:1 compression depending on what you do.

What gas did you use for this engine you had?

I used pump gas, no vacuum advance on distributor or it would ping.

Your compression numbers seem high. Last time i did the math on this, a while ago, I could have sworn it was closer to 10:1

I would stay at max 9.5 CR unless you have bigger cams to drop the Dynamic compression ratio.

At 9.4 I had to run a tad rich and adjust my dizzy to get it to run on Chevron Premium. It would take 76 Premium too, but all else would ping. I could get high 20s on the freeway. This was with a U67, so open head.

A closed chamber might help with the quench area...

I remember warning Adam about Jessie's motor. That was in the 10s and they had to run octane booster to keep it from pinging.

That was the LZ20

I also shaved the head .030.

It had a U60 casting head, I think it was semi-closed, can't remember.

Laecaon wrote: ↑Sun Jan 20, 2019 5:45 pm I would stay at max 9.5 CR unless you have bigger cams to drop the Dynamic compression ratio.

At 9.4 I had to run a tad rich and adjust my dizzy to get it to run on Chevron Premium. It would take 76 Premium too, but all else would ping. I could get high 20s on the freeway. This was with a U67, so open head.

A closed chamber might help with the quench area...

I remember warning Adam about Jessie's motor. That was in the 10s and they had to run octane booster to keep it from pinging.

Jess' motor had a U67 head. It also had those SUs that were running super rich.

I do plan on having an mild/mid Isky cam with all the bits on a W53. May ask the machine shop to unshroud the valves a little to help lower CR ever so slightly.

If I can get things around 9.7 to 1 I think k it should be fine.
9.7 was the math I came up with last time.e I figured it out.