upper timing mark

[yankabilly]

there are 3 marks on the top gear with numbers "1 2 3" factory setting are the # 2 hole... well on to the question...the other marks are for when you shave the head right?? what i'm after is this #1 hole is it advanced or retarded and how meany degrees ???same for the #3 hole advanced or retarded and how meany degrees???

thank you

[72240z]

The pegs are to compensate for chain stretch but can def help with a shaved head or aggressive cam. #2 position is 0 degrees and I believe #3 is 4 degrees advanced, #1 4 degrees retarded.

[yankabilly]

so if i was running a cam that makes its hp/tq at say 5200 rpm (z20) and i timed it to the #3 hole it would move my hp/tq lower in the rpms (z24i 4wheel drive) ????

my setup is z24 bottom end and z20e head and cam

[72240z]

Yes advancing the timing should move the tq curve lower. Which is probably more desirable for a 4x4 z24i.

[banzai510(hainz)]

My boook says

#1) 0deg,#2) 4deg ,#3)8 deg on stock sprocket.

[Sealik]

I have my 4x4 (Z24) set at No 3 position....noticeable improvement at lower RPMs climbing hills

[datsunaholic]

Each mark is 4 degrees different.

 

On a L16 and L18, mark 1 is the stock zero degree mark. On an L20B, mark 2 is the zero mark, so mark 1 is -4 degrees and mark 3 is +4 degrees. The reason for the difference is that the L20B has a taller block and longer chain, but it's not EXACTLY a perfect chain link difference.

 

Since there are 40 teeth on the sprocket, moving the chain one tooth is 9 degrees.

[yankabilly]

thanks for the info guys

[datzenmike]

....my setup is z24 bottom end and z20e head and cam

 

The Z20E head is the same as the Z24 except for the intake port shape and early ones had only single plug. Even as the same combustion chamber size.

[yankabilly]

mike i posted this in another thread here it is again for you

if you look at this pic you can see the space between the valve and the side of the combustion chamber......3mm smaller...

z24 top and z20e bottom .......

[yankabilly]

link to thread http://community.rat...opic/47187-z24/

[datzenmike]

Ha ha I can't keep track of all my pictures. Thanks for this one.

 

The bottom head is from a 720 Mileage Option Z20S (carb) motor. The Z20E looks identical to the Z22 head. The difference between the Z20S and the Z20E is about 12cc. I have at least two Z20E heads and they are the same combustion chamber size as the Z22 and Z24.

[datsunaholic]

Mike, I will note that while I don't have pics, I had both a Z22E (1982 200SX) head and a Z20S (1981 510) head side by side (the Z20S was a banana) and they were identical in every way. The Z22E head went on the Z20S. Same casting, same valves, same combustion chambers. In fact the only difference was the Z22E head had a plate where the fuel pump would go and bolts instead of studs, since no pump went there on an EFI engine.

[yankabilly]

Mike, I will note that while I don't have pics, I had both a Z22E (1982 200SX) head and a Z20S (1981 510) head side by side (the Z20S was a banana) and they were identical in every way. The Z22E head went on the Z20S. Same casting, same valves, same combustion chambers. In fact the only difference was the Z22E head had a plate where the fuel pump would go and bolts instead of studs, since no pump went there on an EFI engine.

thank you , i took this head off of an mpfi motor...i have the intake hell i have the whole motor and automatic trans too

[yankabilly]

what do you guys know about the cam difference between z20/22/24?????

[datzenmike]

Mike, I will note that while I don't have pics, I had both a Z22E (1982 200SX) head and a Z20S (1981 510) head side by side (the Z20S was a banana) and they were identical in every way. The Z22E head went on the Z20S. Same casting, same valves, same combustion chambers. In fact the only difference was the Z22E head had a plate where the fuel pump would go and bolts instead of studs, since no pump went there on an EFI engine.

 

 

OK here's what I have and have cc'd. Did them all twice to average the results. (they were all the same)

 

'80 and an '81 200sx Z20E head...... 57cc

two Z22 720 truck heads.................. 57cc

two Z24 heads.................................. 57cc

 

There is a Z20(S) used in the 720 truck. It's basically a Z20E 200sx motor with flattops but with a smaller combustion chamber with 9 to 1 compression. I worked out the combustion chamber to be about 45cc, similar to the open L series.

 

I haven't seen a Z20S from an HL510 or a Z22E from a 200sx, BUT, if you say they are the same I bet they are the 45cc small chamber head. I say this because the pistons in the HL510 are dished... if used with a 57cc head the compression would be in the 7s.

[datsunaholic]

The pistons in the same Z20S that banana head came off of has valve reliefs and nothing else. No dish.

 

[yankabilly]

hold on i'll get pic of the z20e i have ....maybe somebody put an z20s in it before i ever saw it ...it has been around since 1981 i'll post it after i get dressed .......maybe your right mike.....we also have an z22 head but its bolted to a running motor or i would post pic of it too

[yankabilly]

banana head .....someone explain this please

[datzenmike]

Warped.

 

 

 

 

The pistons in the same Z20S that banana head came off of has valve reliefs and nothing else. No dish.

 

 

Oh no. Any chance this motor was swapped in Doug? If flattops it would need a 57cc head to give a normal 8.5 to 1 compression. I have a picture of a Z20S piston (supposedly) from a 510 and it is quite dished.

[yankabilly]

ok heres pic of the z20e i got my head off

and one of the whole block

i used the good cam so you could see better

[datsunaholic]

Swap? Always a possibility with cars with 263,000 miles on them, which is what the odometer read when I got it. The story I got from the prior owner was the he had the original engine rebuilt (then the original 263,000 mile radiator cracked, his daughter didn't notice the pegged temp gauge, and hence one banana head).. The pistons aren't standard, they are 020 or 040 overbores. But most sources say the Z20E and Z20S used different rods so putting a Z20E piston in a Z20S would screw up the deck height. I've had a couple NAPS-Z engines apart and every one of the Z20 engines had pistons like that though. I didn't open up the last one I had.

 

All I can say is, after I changed the head that engine ran great. For the 6 months I had it before the car got rear-ended by an Explorer on the freeway.