frankendat Posted October 27, 2019 Report Share Posted October 27, 2019 The engine posted in a craigslist Ad:https://eugene.craigslist.org/pts/d/creswell-80-nissan-4x4/7003427432.html Since this is a 1980 and assuming the engine has not been swapped, the engine in the picture should be a non-efi Z20---right? As I understand it, a head from a L20B can be swapped onto this block (along with L20B intake manifold/carb and an L20B header) and after drilling some coolant holes, this will create a single distributor, frankenmotor with slightly higher compression and larger displacement than a stock L20B. Am I right? Is this swap/modification as simple as it sounds? Quote Link to comment
wayno Posted October 27, 2019 Report Share Posted October 27, 2019 I don't know about the Z20 in the trucks(dished pistons?), but the carbed version in the 1981 car engine I have(Z20S) didn't need any holes drilled in the block, but it had flat top pistons and my compression ratio is 10.8 to 1, it would be lower if I had used an open chamber head. As far as I know both the L20b and the Z20 are 2000cc engines and are exactly the same size, but the Z22 block does need the coolant holes drilled and that would be a larger displacement engine. I wonder if this truck could be a mileage option engine package, I doubt it as it is a 4wd, I would have thought it would be a Z22. Quote Link to comment
datzenmike Posted October 27, 2019 Report Share Posted October 27, 2019 There are two (2) Z20 heads available. One is 57cc and uses flat top pistons for an 8.4 compression used in the A10 HL510 car. The other is head casting number W 04 and is about 46cc combustion chamber and used with flattop pistons in the '83-'86 Mileage Option 720 trucks. The compression is 9 to 1. The 57cc head is also used on the Z22 engine and with the 7cc dished Z22 pistons has a compression of about 8.4..... It can be used on the Z24 engine with its 15cc dished pistons for an 8.3 compression. 57cc Z20/22 on top and 46cc (ish) W 04 head below. It's very subtle but there are two small quench areas on the top and bottom of the W 04 combustion chambers. In the bottom head you can see that the intake valve appears to be closer to the edge of the combustion chamber than the top one. Here's a much better look at the two flattened quench areas. Z20/22 heads have round intake ports with injector notches and a block off plate for the fuel pump. Z24 heads, while the same combustion chamber size, have squarish intake ports and the fuel pump opening is closed. Quote Link to comment
frankendat Posted October 27, 2019 Author Report Share Posted October 27, 2019 Thank you for the replies. Sadly, I am confused. It might be that I am attempting to put a square peg in a round hole. I have been searching for a 1980 720 4x4 with the L20B motor. I found one in Oregon a while back, but lost out to another buyer. The 1980 720 4x4 in the Oregon craigslist link I provided, meets requirements with exception of the L20B. The 1980 720's were offered with the L20B and with a Z motor. I assumed that in 1980, if a Z motor was offered, then it would have been a Z20. (The owner of the truck in the craigslist ad believes the engine is original equipment.) From the photographs in the craigslist ad can the motor be positively identified as a Z20? My aversion to the Z series is the dual distributor setup. But reading on Ratsun has led me to believe that an L20B head/intake/header can be easily transplanted onto a Z20 block. There seems to be a number of performance benefits associated with this swap, but so long as, the Z20 is changed into a single distributor setup and becomes in many aspects an L20B, I would be happy. If I performed this swap, then I would use the 720 bellhousing and a 720 manual transmission. Therefore, as I understand it from reading here, the "tilt" of an L20B would not be an issue. Thank you again for aiding my understanding. Quote Link to comment
datzenmike Posted October 27, 2019 Report Share Posted October 27, 2019 All years of 720 had one or another SD diesel engine available but only 2wd and not as an automatic. Gas engines.... The '80 720 only came with the L20B engine. From '81 through October '82 the Z22 was the only gas engine. From November '82 through '86.5 the Z24 was available. January '83 through '86.5 the Z20 was offered as a 2wd option. There is virtually no visible difference between the Z20, Z22 and Z24 engines. The Z20 and Z22 have a block off plate for a fuel pump just forward of the intake side number one spark plug. The Z24 does not. The engine size is stamped into a flat spot on the block where it meets the head between the two pair of exhausts between #2 and #3 spark plugs. If you use the Z series engine block, and put the L head and intake/exhaust on, it will be tilted to the driver's side by 18 degrees. Not much room on the left with the steering right there and the large brake booster in the way on the intake and carburetor. The carb would be tilted like you were driving with the right tire up on the curb all the time. This is an '81 model year 720. So stock Z22 engine. Quote Link to comment
Crashtd420 Posted October 27, 2019 Report Share Posted October 27, 2019 So what are you actually trying to do? What vehicle do have that you want this for? What is the current motor? Depending on what you plan is I believe a 720 4x4 might not have the speedometer drive in the transmission.. Quote Link to comment
frankendat Posted October 28, 2019 Author Report Share Posted October 28, 2019 DatzenMike - Your knowledge again reigns supreme. The owner of the Datsun truck in the craigslist ad picture I supplied claims it is a 1980. What features did you notice that identified the truck as a 1981? I perform most of my searches through phone calls/internet and sometimes have difficulty correctly identifying what is offered. Quote Link to comment
frankendat Posted October 28, 2019 Author Report Share Posted October 28, 2019 Crashtd420 - Eventually, swap motor, transmission, transfer case, from Datsun into Suzuki LJ20. As this is a long term project, the benefit of having a working 4wd truck, in the interim is preferable to parts collecting. 1 Quote Link to comment
wayno Posted October 28, 2019 Report Share Posted October 28, 2019 (edited) See the holes in the hood, that says to me it is a 1981 with a Z22 in it, the 1980 model has louvers in the hood like on the photo below. Here is a 1980 Datsun 720 4X4 truck I bought for parts, louvers in the hood, it had an L20b. Everything I see in that Craigslist ad you posted says 1981 with a Z22 in it, and that block would need coolant holes drilled in the block to put a L head on it, but it is totally doable, I have done a couple of them LZ blocks, way more power than a L20b or LZ20b would have. Edited October 28, 2019 by wayno Quote Link to comment
datzenmike Posted October 28, 2019 Report Share Posted October 28, 2019 51 minutes ago, frankendat said: DatzenMike - Your knowledge again reigns supreme. The owner of the Datsun truck in the craigslist ad picture I supplied claims it is a 1980. What features did you notice that identified the truck as a 1981? I perform most of my searches through phone calls/internet and sometimes have difficulty correctly identifying what is offered. The '80 truck has a unique hood for only that year. It has louvers oh... there's wayno. The model year starts in June of the previous year so the PO may have seen the build date of anywhere between July and December of '80 and assumed it was an '80 truck. Well then the '81-'82 hood has an opening on each side and a small grill covering. You can see the holes in that picture. Quote Link to comment
Crashtd420 Posted October 28, 2019 Report Share Posted October 28, 2019 9 hours ago, frankendat said: Crashtd420 - Eventually, swap motor, transmission, transfer case, from Datsun into Suzuki LJ20. As this is a long term project, the benefit of having a working 4wd truck, in the interim is preferable to parts collecting. Makes a bit more sense now.... Quote Link to comment
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