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Angela

5 Speed swap in a 521 Specs etc?

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Hello all. I've got a question I can't seem to find answers to despite searching.  I've done a successful 5 speed swap in my 510 wagon a few years back so this type of project isn't new but I'm getting varied advice so thought I'd ask the esteemed experts here.

 

Thanks to COVID-19 & being furloughed from my job for the last few months, I've spent as much time as possible working on my Datsuns & doing all the stuff I never have time for. Treated my rusty floor pans & Installed sound deadener & a carpet kit in my 521, replaced, refurbished & fixed my rear tail light buckets, trim & lights, painted & freshened up some random stuff, rebuilt an L20B, acquired a 5 speed transmission, replaced tires, got my rims & valve cover powder coated, pinstriped my NOS Datsun stamped hubcaps, finally installed my Datsun stamped side mirrors ,& fixed my headlight switch issue & other random stuff.

 

...All loving little projects that are keeping me somewhat sane in the midst of so much B.S. in the world. Enough about that...now to my question...

 

I plan to install the L20B & 5 speed (from a '77 or '79? 620 I think it came from...it's NOT a dogleg) in the next week or two.

 

I've got modified transmission mount (thanks to ]2eDeYe)

 

Question: How much do I have to shorten/modify my 521 driveline? Will I have to cut out my transmission tunnel much?

 

I've been told that a 510 wagon driveline will bolt up without any mods & work fine..BUT from rough measurements I took from the individual pieces...

 

The current 4 speed is about 26.5 inches long

The 5 speed is about 31.5 inches long

The 521 driveline is about 56.5 inches long

The 510 wagon driveline in 56 inches long.

 

I'm not great at measuring or math but it seems to me that there's going to be about an extra 4.5 inches that needs to be dealt with. Does this sound right? I assume some of this length will be taken up when all parts are mounted up together but I'm not sure it'll be enough.

 

Any thoughts or advice/links would be most appreciated.

 

I'll be happy to post oics once I'm all done tinkering...& spend the time figuring out how you guys do that here nowadays 😉

 

Thanks y'all.

 

Angela

 

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The difference between a stock 521 4 speed and a 71B 5 speed is 5.5"

 

A stock 510 goon driveshaft is 48 7/8". This is between the center lines of the front and rear U joints so measure this way on your 521 and see what you get.

 

I think the tunnel has a long narrow hole with a cover plate over it that has the dust boot. It can be removed and re positioned to fit. I may be wrong it's been a long time. Either way I replaced the same 4 speed in my car with a 71B 5 speed and the hole was fine.

 

 

I was looking at my post and saw DATCHICKS UNITE (wtf?) so I took a closer look at the poster... Hi Angela!!

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On 7/15/2020 at 8:23 PM, datzenmike said:

The difference between a stock 521 4 speed and a 71B 5 speed is 5.5"

 

A stock 510 goon driveshaft is 48 7/8". This is between the center lines of the front and rear U joints so measure this way on your 521 and see what you get.

 

I think the tunnel has a long narrow hole with a cover plate over it that has the dust boot. It can be removed and re positioned to fit. I may be wrong it's been a long time. Either way I replaced the same 4 speed in my car with a 71B 5 speed and the hole was fine.

 

 

I was looking at my post and saw DATCHICKS UNITE (wtf?) so I took a closer look at the poster... Hi Angela!!

 

Hey there amigo! WE SPOKE FOR A MOMENT OR TWO AT THE LAST CANBY EVENT. I WAS SUPER GLAD TO MEET YOU & CHAT.THANK YOU FOR YOUR TIME.

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I kept the two piece drive line in both of the 521 trucks I put a long shaft 5 speed in.  I just had the front half of the drive shaft shortened, and the whole drive shaft rebalanced.    Driveshaft balance is very important.  The drive shaft on a 521 turns around 4,000 RPM at 60 MPH.

The speedometer cable can go over the top of the transmission, and reach the speedometer pinion on the right side of the five speed transmission.

I cut a slightly oval hole farther back on the plate that covers the hole in the cab for the transmission, put the boot in that hole, and welded a round piece on metal in the original hole of the plate.

This page

https://ratsun.net/topic/30606-my-ratsun-datsun-521-now-with-l-20-b-and-a-five-speed/page/21/

has some discussion on putting a 1980 720 five speed transmission in Ratsun, my white 521.   It shows how I tightened the mainshaft nut, and the reverse idler nut inside the 720 five transmission.

 

This page

https://ratsun.net/topic/49698-my-dragon-datsun-521/page/10/

shows the changes I made on the plate that the shifter goes through.

 

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Thank you for your help on this. I really really appreciate it. I think I've got it worked out & have a plan to proceed with thanks to you guys. One question though...in order for my speedometer to read correctly (+/-) which colored pinion do I need? Advice on sourcing one?

Thanks again as always. More oics soon(ish)😉

20200718_201928.jpg

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 I used a red speedometer pinion in both of my 521 trucks that I put five speed transmissions in.

The bad news, I do not think pinion holder from your stock four speed transmission will work.  I do believe the pinion holder from 620 trucks will work, the 620 four speed transmissions were very similar to the five speed transmissions.

DatzenMike will be the expert on this.

 

If at all possible try to get the correct speedometer pinion in the transmission before you put the transmission in the truck.   The speedometer ends up above the crossmember, and is a little difficult to change, and if the truck is level, transmission oil will run out of the speedometer pinion hole when the pinion is removed.

 

The reverse light switch is the farthest forward on the five speed.  Just make two short jumper wires with one end matching the truck's harness, and the other end matching the switch wires.  I think the reverse light switch wires are red with a black strip.  There are two more switches on the stock 521 four speed transmission, one is for third gear, the other is for neutral, and both of those two switches are used for the crude emission controls 521 trucks had.

 

Electrical diagram to help with reverse light switch.

521wires.jpg

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437 gears have a purple gear, red gear is 411, never seen a purple one in a 71B but I have not been looking, your stock gear in your 4 speed will not likely work, don't know if transfer case speedo gears are the same as transmission speedo gears.

I actually had to modify a 3.3 gear(yellow) that Crash I think sent me, so that may be an option if you can find a purple one and for some reason it doesn't work, it appears you are using a 1977-79 5 speed(I re-read your first post), that may already have the proper speedo gear in it, I believe they came with 4.3 or 4.1 gears in them, your 521 came with 4.3 gears in the rear, so unless they have been changed you might be just fine already.

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  71B  4 and 5 speed pinion sleeves are interchangeable. Pre 1980 sleeves don't fit post 1980 transmissions but can be modified. If your current speedometer is accurate, pull the pinion sleeve out of it and see what color gear is on the end. Use the same color or number of teeth in the 5 speed. The 510 used a  YELLOW 16, BLACK 17 or BLUE 18 tooth depending of differential ration and tires. I'm guessing the goon has a 3.90? probably Blue.

 

'77 or '79 truck? Well that means the possibility of two differentials. So 20 RED for the 4.375 or WHITE 19 tooth for the optional '79 4.11.

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That chart is for a Z car which have different tire diameters. Over 1 inch diameter. I used a calculator on line to see the new gear ratio on a 4.375 differential with a larger Z car tire and it was 4.18 which is damn close to your chart

 

All standard transmission trucks were 4.375 except '79 which had a 4.11 but optional 4.375 (or the other way round) so only two gears to choose from. Red 20 tooth or White 19 tooth.

 

A 4.11 will go faster than a 4.375 at the same RPMs so you run fewer teeth so the speedometer spins faster.

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6 hours ago, datzenmike said:

  71B  4 and 5 speed pinion sleeves are interchangeable. Pre 1980 sleeves don't fit post 1980 transmissions but can be modified. If your current speedometer is accurate, pull the pinion sleeve out of it and see what color gear is on the end. Use the same color or number of teeth in the 5 speed. The 510 used a  YELLOW 16, BLACK 17 or BLUE 18 tooth depending of differential ration and tires. I'm guessing the goon has a 3.90? probably Blue.

 

'77 or '79 truck? Well that means the possibility of two differentials. So 20 RED for the 4.375 or WHITE 19 tooth for the optional '79 4.11.

 

Thank you all so much for chiming in. Mike, you commented about the 510 pinions...just wanted to make sure to clarify I'm putting the 5 speed in my 521 (same info between the two or?). Not sure of the gearing in my truck. I'll see what's currently in there & hopefully it'll all work without having to source a different one. I remember having to do this when I put the 5 speed in my wagon. I had a couple spare pinions of different colors but think I gave them to folks in need since then. Can't remember what colors they were though as it's been awhile. 

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Oh man, too much sun. Sorry Angela the 521 you have would be a BLACK 17 tooth for a 4.375 differential and 6:00 X 14 tire, or should be. It's for a 63 series transmission and won't fit the 71B. You'll have to pop it out and confirm the tooth count then get the same from a 71B.

 

If you have changed the tire size (diameter) I have to ask, is your speedometer accurate, because now is the time to alter the speedometer pinion to account for this. For example if reading  50 when actually going 52.5 because the tire is larger that's 5% too fast. If you step down from a 17 tooth to a 16 tooth 17/16= 6.25% this reduces your error to 1.25MPH at 100 MPH. Just a thought.

 

 

 

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I have two 521 trucks with 4.375 rear axle ratios, and both have 5 speeds in them.   In Ratsun, I used the the engine, transmission and red speedometer pinion from a 1980 720.

In Dragon, I had a 17 tooth black speedometer pinion.  I took it for a test drive, on the freeway, and with my cell phone indicating 55 or 60, the speedometers was indicating over 80.

I swapped a red speedometer pinion into Dragon and the speedometer read pretty close to my cell phone.

The last piece of this puzzle. Ratsun has a 205/70 -14, tire on the rear, and Dragon has a worn 215/70-14 tire.

 

My plan it to take Dragon to a measured 5 mile piece of freeway, and check the odometer in the truck, and see how far the odometer read off the 5 miles.

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So, 5 speed is in, L20B swapped, S.U's installed & engine sounds great. Still working on exhaust & other little details. It's still over at my Datsun buddy's place for now so no real pics to share yet but I have a question for all who've done a tranny swap...

 

What did you do for the transmission tunnel plate? Cut a new hole & patch the old one? Does anyone make custom tunnel plates that look good mounted on top of carpet?

 

Any advice & especially pics will be appreciated!

 

Thanks guys!

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It's been a while... Doesn't the 521 have a screw on cover plate with dust boot hole. This covers a slot on the tunnel floor??? Can't remember. Just relocate the cover plate farther back??.

 

I had the same basic 4 speed in my 710 and the 71B shifter fit the old hole close enough.

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1 hour ago, Crashtd420 said:

I could have sworn I heard someone say to flip that cover plate 180 but I could be wrong....


Not wrong DanielC did that with his.  

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Look at my Dragon thread, near the last page.   I cut a new hole, slightly oval,  and welded a patch in the old hole.

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On 7/19/2020 at 4:34 PM, wayno said:

I don't know where you got RED for 4.37 gears Mike, this is the chart I have.

Speedometer-Pinions-page-001.jpg

Tire diameter can change a lot.  When I buy tires for my trucks I buy tires that are as close to OEM diameter as I can find.  I use this a lot for finding different tire sizes that are close in diameter.

 

Tire Size Comparison

Here are different type of drivelines and how to measure them.

 

figure1.jpg

 

figure2.jpg

 

figure3.jpg

 

figure4.jpg

 

figure5.jpg

 

Pick which one meets your drive line scenario.

 

I have purchased several parts from this eBay seller all good.

 

The Z Connexion

 

Edited by Charlie69

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On 9/21/2020 at 1:36 PM, Angela said:

What did you do for the transmission tunnel plate? Cut a new hole & patch the old one? Does anyone make custom tunnel plates that look good mounted on top of carpet?

 

Any advice & especially pics will be appreciated!

 

Thanks guys!

 

I have looked at these trans tunnel plates (I have a 521, a 620 parts truck & a 1980 720 parts truck, all manual), the basic shape of that plate is the same, but they moved the shifter hole to suit the changes in transmissions over the years.  I have all three plates, but will have to look again!  Will post back here!  I will eventually put the 77k original mile 1980 720 L20B & 5speed in my 521, but likely not until Winter sets in! 😁

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Thanks for the input guys. I did try to orient the plate 180° but because of the contour, it wasn't gonna sit right. My buddy ended up cutting a new hole in the existing plate & patching the old one. It's "okay" for now but I'd really like to find a solution that's a little nicer looking. If anybody out there is fabricating something more stock-looking or smoothed out so it doesn't look so "cut 'n paste" I'd love to know about it. DanielC, I still need to dig through all your wonderful posts on Dragon to find what you did to yours.

20200920_144626.jpg

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I believe that is what DanielC did and so did I, but I used a 720 console to cover everything in my work truck as it has a longshaft 5spd, my 521 kingcab I made a short shaft and the shift lever came out the stock hole so the plate didn't have to be modified.

As I recall that plate is supposed to be covered by the carpet.

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6 minutes ago, wayno said:

I believe that is what DanielC did and so did I, but I used a 720 console to cover everything in my work truck as it has a longshaft 5spd, my 521 kingcab I made a short shaft and the shift lever came out the stock hole so the plate didn't have to be modified.

As I recall that plate is supposed to be covered by the carpet.

I thought about covering it with my new carpet kit I just installed but since my truck had an original plastic snap in mat that the shifter plate sat on top of, I figured that's how it came from the factory. I have never seen any examples of a 521 with the shifter plate under the carpet or mat. I suppose there are several custom variations that could be done but I think I am a fan of the plate on top of carpet. I have a metal 520 dash top I just painted in flat black that I plan to install next so it kinda ties things together. I just love this truck so much. My 510 wagon gets jealous sometimes I think 🤔 😆

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When I bought my first 521 the rubber shift lever boot was connected to the round hole in the plate and the carpet hole fit snugly around the base of the boot, I have never thought of doing it the way you did yours, I believe stock they came with a vinyl mat and the plate was not on top of the vinyl.

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