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Are there major differences between the F4W63 and F4W71 4 speed transmissions? Is the F4W71 a drop pan transmission? Various unreliable sources claim the F4W71 is the stronger transmission. Is this a legitimate claim? Finally, since I am building an off road/on road machine with focus on reliability, simplicity and economy over power (stock hp or a bit more, through efficiency upgrades is fine)

Anyway, with max horsepower certainly under 130, is transmission strength (when off roading) worth worrying about?

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The 63 and the 71 is the measurement in mm (millimeters) between the mainshaft and the counter shaft inside the transmission. Obviously the same number of gear teeth on a larger diameter gear can be made larger and therefore stronger. In addition the bearings can also be larger to support more power.

 

The F4W63 is certainly adequate for an L20B powered car weighing 2,600- 2,800 lbs..

 

The F4W71B(4 speed) or the FS5W71B (5 speed) are actually a 6 cylinder transmission first used in the 240 z car. Because of this added strength it was also introduced into the '74 620 truck when the displacement rose from 1.6 to 1.8 liters in '74 quickly followed in '75 to 2.0 liters. The 71B is rugged enough for any abuse a 2,750 lb truck with an 1,100 lb load can produce.

 

Only the F4W63 has the removable oil pan on the bottom.

 

You do not want an F4W63 with anything near 130 hp when there are 71B transmissions out there..

 

 

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Thank you for the information. Dang, I was excited with the ease of acquiring the F4W63. Is the 71B a 26in transmission like (or at least close) to the length of the W63? I am building an off road rig, similar to Ratsun member Boxcar. His was a Samurai, mine is an LJ20. He talks of employing a 4 speed drop pan and claims to be pushing more than 130hp in off road vehicle. In your opinion, would the wiser choice have been the 71B?

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All L series 71b transmissions are 31.5" long. There was a 720 variant for the Z series engine that was 26" long but you would need to swap an L series front case onto it. Easier to just shorten the drive shaft.

 

 

 

I have had a few questions asked about this conversion. Thought I'd better respond.
 The L20B was a 1,952 cc (85.0 x 86.0 mm) engine produced from 1974 through 1985. It produces 110 hp (82 kW) in 1974-75 form with 112 lb·ft (152 N·m) of torque as installed in the Datsun 610 and 97 hp (72 kW) in 1977-78 form with 102 lb·ft (138 N·m) of torque as installed in the 200SX.[1] The L20B engine introduced larger-diameter (60 mm) main bearings while retaining a fully counterweighted crankshaft. The U60 crankshaft also ushered in the use of a six-bolt flywheel boss. The block introduced a taller deck height to accommodate the longer stroke and connecting rods. This specification would also be used later in the Z20 and Z22 engine series. The bigger powerplant even helped spawn an important new offering from Datsun's competition department -50mm Solex twin-choke carburetor kits- complete fuel systems that help produce nearly double the power from the ubiquitous L20B. The legendary robustness, the nearly square configuration and the rod-to-stroke ratios possible have made this engine a popular choice among tuners for turbocharging.
The engine used a carburetor but switched to fuel injection (and round instead of square exhaust ports) in some non-USA markets in 1977. Carburetors were used in all US L20B applications for both cars and trucks. There were six versions of the L20B in the US- U60, U67, U95 (used in cars) and U60, U67, B98, 04W, and 05W (used in trucks). In the US, the L20B was used in six different model families -A10, 610, 710, S10, 620, and 720 models- making it the most versatile powerplant in the company's US history

 

 

The L20B was measured in gross hp back then. Today it's net hp so the 110 is really about 95-ish and why the hp numbers changed for the 200sx with the same engine.

 

The L20B was only available in North America through 1980 the first year of the 720 truck.

 

It was never offered in North America with fuel injection, ever. However the '78-'80 L20B did switch to the W58 head with round exhaust ports.

 

The L20B in North America came with A87 (rarely) U67 and W58 heads, that was it. A few Japanese engines were imported with different heads and they were used because it was cheaper than rebuilding them here.

 

It would take more than twin Solex carbs to make double the hp. 

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I have more questions than a 5-year-old in a porn store---- The plan is to install a datsun engine and transmission in a Suzuki LJ20. LJ's are smaller pre Suzuki Samurai's. On the LJ sites are examples of LJ's with different motor swaps, including one with an A series installed. On several sites, including this one, is information regarding installation of an L20B in a Suzuki Samurai. Based on the size constraints of the LJ, it is likely a body lift and/or hood scoop will be necessary. I am prepared for this potential issue.

 

I owned a 78 620 in college and put over 200k on it - Loved that truck. I also got pretty handy working on it, rebuilt the weber carb, replaced the clutch, etc. Anyway, that truck never let me down,  even when it went down, I was able to get it going again, carrying a small cache of tools.  I believe a LJ20 with a weber, electronic ignition and a solid state distributor, would provide a simple reliable daily driver and mountain vehicle with decent power and the ability to achieve 30mpg (hwy). I am open to changing the head, if it would yield an overall efficiency improvement, but stock horsepower (110) should be fine, the small modifications I listed, should give a little more.

 

I recently sold my FJ40 to fund this project.

 

It seems you can spend money for days rebuilding an L20B and transmission. I have found reasonable priced units for sale,  but shipping has been the killer.

 

To add to the confusion today on Facebook Marketplace (8 hours from me) found a carborated Datsun Z motor (claims rebuilt) for $500.

 

My questions:

Are the dimensions of the L28 (size/weight) similar to the L20B?

Are there low profile oil pans/sumps and other space saving tricks for the L28 (Like the space saving tricks for installing an L20B into a 210)

Is working on the L28 similar to the L20B? (The two distributors and eight plugs are scary)

As I understand it,  from reading here  and on the net, the L28 runs a bit more efficient than the L20B, meaning a bit more power, with a bit less gas. Is this correct?

 

This is a wild hare, I am pretty much sold on finding an L20B, but realize it is old tech. My concern is installing an L28 might mean losing reliability or simplicity. 

Thank you

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Thank for squaring me away.

Although it seems Boxcar was inflating the numbers, if I am understanding correctly, an L20B with a weber carb, electronic ignition and solid state distributor should provide at least 100 horsepower (net)

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Seems you have confusion .........

 

Engine in pic is not an L28, but instead a Z24. People are retarded and call these "Z Engines" because they have "Nissan Z" on the valve cover. Reality, the engine is NAPS-Z, which stands for Nissan Anti-Pollution System "Z" (because there was infact Nissan Anti Pollution System "X"). I think Nissan boasted the "Z" nomenclature on the valve cover to piggy back on the legendary Z-cars. 

 

 

Any way, to answer your question -- The NAPS-Z (Z24) in the photo is relatively identical to the L20b in overall size. It has the same engine mounts and will "bolt in" into any vehicle that has an L20b given you have the correct oil pan layout. 

 

The L16, L18, L20b, KA24E, KA24DE, Z20, Z20E, Z22S, Z22, Z24 and Z24i engines are all in the same family and can be interchangeable. They all share the same bellhousing, but early engines (L series) sit at a 12 deg angle compared to the later Z and KA engines. This can be corrected by the bellhousing swap or transmission choice. 

 

 

My best advice.... read more and educate your self. All of this info is HEAVILY documented. Stay away from Facebook idiots and read here and datsun1200.com

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L-28, six cylinder in line.

L-20-B four cylinder in line.

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Edit:

 

That is one fucking ugly engine in the pic.

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6 hours ago, mhub91 said:

. Stay away from Facebook idiots and read here and datsun1200.com

 

True, so true.....

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L series sit 12o to the right of vertical.

Z and KA series about 6o?  left of vertical, barely noticeable.

 

Although the bolt pattern on the transmissions are the same you can't just bolt a Z or KA onto an L series transmission, the mounts just can't handle an 18o miss match. You would need the correct transmission or swap the fronts of the transmissions.

 

The advantage of a Z22 or Z24 is it's increased torque from it's increased stroke and displacement. A Z24 has about 130 ft lbs at 2,800. A real rock crawler. The Z series were designed for low pollution and not much else. They are quite efficient with hemi style cross flow heads with dual plugs but don't lend them selves to performance increases like the L heads do. An L head on a Z series is basically making a larger displacement stroker engine.

 

L and Z series blocks are very similar other than their increased heights. L heads will fit Z blocks by just bolting on parts. I have a Z24 with an L series head on it I'm working on. It's basically a 2.4 stroker engine or L24B with 20% increase in displacement.

 

Pa22yU2.jpg

 

KA blocks, heads and cranks are quite different. Not much you can swap between KA and the other two, nor would you want to. If contemplating a KA, just swap it complete with it's 5 speed.

 

 

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Not inflated, it was the difference between how the engine hp was measured and published. Gross hp was read directly from the engine often with special gasoline, header (no muffler) and no parasitic draw from a drive train, water pump, fan or alternator so they can report a number as high as possible. In the real world people were confused that an engine rated at 110 hp was about as fast as another rated in SAE or net hp at 95. Eventually all makers adopted the lower much more accurate real world number rather that the apples and oranges mixing.

 

My '76 L20B engine tag says 110 hp but my '78 L20B 620 was 93? or near there.  

 

A weber might gain you a few hp on a stock L20B but keep in mind that total hp output is not the best way to measure an engine's potential. We don't often drive around at 5,800 RPM. Often a hp increase moves the engines power peak higher in the RPM range and sacrifices idle quality and low speed torque. If rock crawling at low speeds a good strong idle and torque band at low speeds is ideal.

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Thank you Datzenmike, the information you provide is starting to gel and I am realizing some of my errors in earlier posts. To clarify/double check the transmission information - Although Boxcar talks of employing a 4 speed drop pan (W63) and claims to be pushing more than 130hp in off road vehicle. In your opinion, the wiser choice would have been the 71B?

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Thank you for the information.

To clarify my understanding: Since my goals focus on torque and efficiency (mpg) over top speed/high rpm horsepower ( I still want to be able to comfortably maintain hwy speeds,  but believe that can be accomplished through proper gearing) A stock  Z24 or a Z24 with a U67 head would be superior to a stock L20B. If I went with a Z24 with a U67 head then I would have additional torque and the engine would operate the same as a L20B. (All other things being  equal) If I went with a stock Z24, then I would have the efficiency benefit of the cross flow head but will have the additional complications of a dual distributor dual plug engine. Is this correct? What would be the mpg difference between the two engines? What would be the horsepower/torque difference between the two engines?

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The LJ20 is 1,400 pounds!! An L20B is almost 4 times  larger that the stock engine!!! You'll have zero problems driving highway speeds. Hell an L16 would be 70 hp and 3 times larger and would do the job.

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This is the problem of having 2 or 3 similar posts. They're hard to keep track of.

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I estimate my LJ will be 2000 or a bit more fully outfitted. Yes, I began this investigation by considering an L16,  but for lower rpm torque the L18 seemed better. The L18 and and L20B are so similar in size and my familiarity with the L20B prompted this exploration. Also, in the used market, all three engines are offered at similar prices. Finally,  stock LJ's are very slow and underpowered, most swap in Samurai engines. I believe datsuns are better in terms of reliability and simplicity as opposed to Samurai''s. Do you think my reasoning is flawed?

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I separated the posts by engine and transmission but understand this could have been a mistake. Is it possible to combine threads?

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There is a lot more involved than just slapping an L block head onto the Z22/Z24 block, the blocks need coolant holes drilled in them to match the head, you need all the L block stuff like the oil pan/oil pick up tube, engine mounts, timing chain cover, if using a Z24 block you will need to figure out the timing chain, I don't know if it is as simple as adding links or if one has to change the gears also, and you also need to fill the gap between the head and the top of the timing cover, it appears that D-Mike is using the Z24 timing chain cover, I don't know how that works.

 

Back when I built my LZ23 I used a lot of info from Sealik's thread, they had photos back then, most if not all his photos are gone now, here is my thread about making an LZ block.

 

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Wayno, thank you for the reply, I went through those threads a while back.  Hopefully, along with the virtues of L16 engines, Datzenmike will clarify this statement, made in an earlier post " L heads will fit Z blocks by just bolting on parts."

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If you don't drill the coolant holes in the blocks you will likely blow head gaskets from uneven cooling in the head.

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I read your thread and your reasoning is sound. Also, from your detailed information of your thread and information on this site, I would feel confident to drill the holes in the block. But, if Datzunmike believes the drilling is not necessary, then he has demonstrated the expertise to make his opinion carry significant weight.

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