Length of L20B?

[mshort07]

I’m thinking of swapping an L20B into my 68 520. I know it’s been done before and written about it on ratsun, but I never seem to find a thread where people talk about it when it’s finished. Just plans of doing it. Can anyone point me to a thread where it’s followed through. 
 

Anyway, I’m looking for the length of an L20B from the rear edge of the block, where the transmission mounts, to the front edge of the fan.  Can anyone provide me with that length? Thanks

[datzenmike]

The engine mounting points on the 520 frame are in a different position for the J 13. The L series won't just bolt onto them.

[mshort07]

9 minutes ago, datzenmike said:

The engine mounting points on the 520 frame are in a different position for the J 13. The L series won't just bolt onto them.

I read that about the engines. I know I’ll have to do some fab work. I’m more concerned about the length and fit from the firewall to the radiator support. Not looking to relocate the firewall. I can relocate the trans tunnel some. 

[datzenmike]

If not raining tomorrow I'll measure mine. 

[mshort07]

3 minutes ago, datzenmike said:

If not raining tomorrow I'll measure mine. 

Thanks!

[wayno]

It is 2 feet(24 inches), It's going to be tight getting the L20b in there, it can be done with the early type fan like I have.

I did it in my 1966 Datsun 520, as mentioned your going to have to make new engine mounts, if possible it would be best to get the stock mounts off a 521(cut them off), also your going to have to deal with the heater outlets, what I have done is either cut the outlets shorter and put the clamp inside the cab but have the hose make a 90 degree turn when they come out the holes or I cut the outlets even shorter and re-routed the hoses inside the cab about a foot towards the passenger side then out.

Edited December 22, 2019 by wayno

[mshort07]

31 minutes ago, wayno said:

It is 2 feet(24 inches), It's going to be tight getting the L20b in there, it can be done with the early type fan like I have.

I did it in my 1966 Datsun 520, as mentioned your going to have to make new engine mounts, if possible it would be best to get the stock mounts off a 521(cut them off), also your going to have to deal with the heater outlets, what I have done is either cut the outlets shorter and put the clamp inside the cab but have the hose make a 90 degree turn when they come out the holes or I cut the outlets even shorter and re-routed the hoses inside the cab about a foot towards the passenger side then out.

Why get the mounts out of a 521. I thought the 521 has a j15 which is the same block as the 520’s j13 (just a bigger bore)? Are the engine mounts different on the j13 and j15?

 

where is the “thinner” fan blade from? What model car and year is it off of?

What radiator did you use?

Did you have to shorten the drive shaft? I have a line on a L20B with a 5 speed and drive shaft. 

[wayno]

OK, I should have said the 521 with an L16 in it(70-72), but you can make your own mount brackets but it is so much easier to mount the stock type metal brackets on the engine motor mounts, set the engine/transmission in, connect the transmission mount and then set the engine onto the frame and let it take the weight, tack the brackets into position and then remove the engine and weld the brackets into position.

They only put the J13 into the 521 for maybe a year(9/68 thru 9/69???), all the rest of the 521s came with an L16 which is basically the same as the L20b block except the L20b is 3/4" taller.

Edited December 22, 2019 by wayno

[mshort07]

Oh. I see. 
 

what about that thinner fan blade. where is it from? What model car and year is it off of?

What radiator did you use?

Did you have to shorten the drive shaft? 

[wayno]

I use the L16 fan blades if possible as that is the shortest it is ever going to be, but others use electric fans, that is the last route I will ever go, it has to be impossible for me to use a stock type fan before I will go electric.

I have used stock L16 radiators on everything I have owned till recently, I have a 1969 Datsun 521 with a SD25 diesel engine, the truck originally came with a J13, I drove it with basically a J13 radiator for 5/6 years, but when I turbocharged it I had to use a Volvo Wagon radiator as that small radiator just wasn't enough anymore.

I also recently changed from a stock L16 radiator in my 521 work truck, it has an LZ23 in it now, I drove it that way since 1995 when it had an L20b in it until 6/7 years ago when I installed the LZ23, until recently it was fine even with that engine, I had bought an aluminum 3 core radiator from Quik510 on here several years before, when the truck started running hot I changed over to the 3 core and everything was good again.

I don't know about the drive shaft situation, my 520 cab is on a 1986 Nissan 720 chassis/frame, it is a custom truck that is highly modified in every aspect.

 

I suspect if you used a short shaft transmission you could use your stock 520 drive line, but you would have to build a short shaft 5spd, otherwise you will need a custom drive line, keep in mind that all the destroyed transmissions/drive lines I have ever seen were 520 one piece drive lines, but they were getting on it/driving it like they stole it.

 

Edited December 22, 2019 by wayno

[mshort07]

That is modified. Thanks for the info.