common issues L20b - 521

[sdsurf]

I did a bit of a search but didn't see if there are any problems associated with what I want to do.

The L20b is a taller motor than the L16. In stock condition (hitachi carb etc), are there any hood clearance problems? with a weber?

 

I assume motor mounts and pan are to be to be used from L-16, anything else? I don't want to hack up the floor so I am going to keep the stock trans. Anything to help freeway driveability here?

 

thanks

 

Hainz?

Mike?

[banzai510(hainz)]

weber carb might hit the hood if with tall aircleaner/or taller carb adapter.

 

there is a 1.75 tall aircleaner. webercarbsdirect has these.

 

I believe youlll use the clutch and throwout bearing/collar set up that came with the L20b. as Trucks L20s use a HEAVY 225mm flywheel set up. Or car L20s use a 200mm setup which is interchangeable with the stock 510521 setup(200mm)

 

also the exhaust it come up about 3/4 ich but I dont think it will be a proplem.

 

Datto510 just did this with his 521,instaling a L20b PM him

[pl521sss]

Don't forget the oil pick up from the L16 that goes with the oil pan

[datto510]

Don't forget the oil pick up from the L16 that goes with the oil pan

 

 

Your gonna want the dipstick too.

[sdsurf]

Which head? pros/cons

 

U67

 

210

 

Closed A87

[ppeters914]

Which head? pros/cons

 

U67

 

210

 

Closed A87

 

Been discussed a zillion times. Partly depends on your end goals.

 

Basic L-head info on The 620 site:

 

http://www.olddatsuns.com/html/tech/head_ID_2.htm

 

Even a n00b like me knows to avoid the 210 (umm, I guess it might be good for MPG. Experts?), which means you're comparing the closed A87 to the open U67.

 

FWIW, I'll be replacing the open W58 smog head on my L20b w/ a closed W53.

[datzenmike]

A 620 L20B motor should fit without changing the oil pan. It's only 2cm or 0.78" taller so not likely a problem.... oval the motor mount holes to let it sit lower. If using an L20B use an L20B head.

 

"Anything to help freeway driveability here?" Then get a 5spd. This makes it MORE drivable on the freeway by dropping the revs a bit. The larger motor can handle it and it will save some gas too. You want any '77-'79 620, 280z or 1980 2wd 720 5speed.

 

What is the length of the stock 521 4spd??? My info is a picture that looks like a long tail 31.5". Doesn't the dogleg drop in?

[datto510]

What is the length of the stock 521 4spd??? My info is a picture that looks like a long tail 31.5". Doesn't the dogleg drop in?

 

 

Pretty sure its in the 28 inch range. The same length as the 77-79 200sx 5 speed.

[datzenmike]

26" then, yeah I have always said so, but a have a small data base for Nissan parts, #, price etc. It also has a pictures of the part and the tranny sure looks like a long. Anyway all other stuff seems to agree so I'll ignore the length. Thanks.

[pl521sss]

A 620 L20B motor should fit without changing the oil pan. It's only 2cm or 0.78" taller so not likely a problem.... oval the motor mount holes to let it sit lower. If using an L20B use an L20B head.

 

 

Ahhh

so only 510 has the clearance issue on L20b oil pan.

521 clears it with no issue.

Just learned something new.

 

I've done L20b on 510 and not on 521 yet.

[ppeters914]

A 620 L20B motor should fit without changing the oil pan.

 

Is this because the oil sump on the 620 L20b oil pan is different than a L20b for other models?

[sdsurf]

1. Can you run an L20b with a stock hitachi carb and air cleaner in a 521 without clearance issues?

 

2. L16 with A87 head and 240z flat top pistons. Is this a good set up?

 

Mike

[Cuts metal like mad]

Ahhh

so only 510 has the clearance issue on L20b oil pan.

521 clears it with no issue.

Just learned something new.

 

I've done L20b on 510 and not on 521 yet.

 

I am pretty sure that the 521 oil pan must be used. It is specific to the 521. I think I gave datto510 BOTH oil pans, but I am pretty sure he used the 521 pan... but we never discussed it after the swap was done.

 

1. Can you run an L20b with a stock hitachi carb and air cleaner in a 521 without clearance issues?

 

2. L16 with A87 head and 240z flat top pistons. Is this a good set up?

 

Mike

 

Thanks for bringing this back up! :lol:

 

1. Yes

2. Its OK, but still gutless. Datto510s truck pulls pretty hard for an L20b. It pulled way harder than my old 510 wagon with an L20b, this could be due to gearing though... or the fact that the motor was rebuilt. Probably both though.

[datzenmike]

You need the 521 L16 oil pan on the L20B to make this work.

 

I swapped a car L20B into my '71 and had no problems. 'Course now I know that the car had a different oil pan but the same flywheel/clutch size as the L16. So I would have had to change the oil pan and the throw out collar was a bull shit luck match!! Beginner's luck.

[banzai510(hainz)]

L16 with flattops /closed chamber head is OK but I wouldnt go out of my way to spend money on a L16 if I could do a L20 .

[datto510]

I am pretty sure that the 521 oil pan must be used. It is specific to the 521. I think I gave datto510 BOTH oil pans, but I am pretty sure he used the 521 pan... but we never discussed it after the swap was done.

 

 

 

Thanks for bringing this back up! :lol:

 

1. Yes

2. Its OK, but still gutless. Datto510s truck pulls pretty hard for an L20b. It pulled way harder than my old 510 wagon with an L20b, this could be due to gearing though... or the fact that the motor was rebuilt. Probably both though.

 

Use the 521 oil pan. I tried using the 510 pan, dosent work- it hits the steering link. I had to pull my motor to swap pans.

[sdsurf]

Yeah I am well aware of the oil pan issues. I have the L20b in my truck already. Mainly I wanted to know if the stock hitachi with stock air cleaner will fit under the hood. I am trying to make the truck as stock as possible but already have the L20b in it.

 

Thanks for all the input!!!

[datto510]

Not sure about the stock aircleaner hitting the hood. The 32/36 is getting pretty close but not hitting even with the tall air filter box. Why on earth would you run a stock carb anyway?:lol:

[whitechef]

I've got an L20B in my 71 521. 4 speed, Stock carb The motor is out of a 75 something or other and had the oil pan changed. I have to put a rag on top of the air cleaner or it rubs on the hood.

Edited November 27, 2009 by whitechef