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How To: Convert an open 25 spline clip-in R180 to bolt-in for a 510

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EDIT:  FInally hosted on youtube the infamous R180 bolt-in conversion video by Icehouse and Hainz!

 

 

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This info is already out there, but when I searched all the write-ups were from other forums. So here it is for y'all at Ratsun! Please let me know if there is anything I should add...


How to :
Convert a 25 spline clip-in axle R180 to bolt in axle (for a 510)
1. Procure a 25 spline clip in R180. I got mine from a 1987 200SX CA20E (4 cyl.) [Hot Tip- All N/A 4cyl S12’s have a 4.11:1 ratio.] Removal from the donor car is straightforward, so I won’t get into it. If the CV axles don’t want to come out you are not using a big enough hammer or pry bar.

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2. Blow up your R160. Also relatively straightforward, or you can skip this step and go right to step 3.
3. We need to remove the threaded buttons from the side gears in the old diff. Take off the cover. Do something with the oil/ chunks of old spider gear.
Next remove the 5 bolts on each side of the diff. These are the bearing races for the center section. They might be stuck so gently (or violently) whack one of the ears to rotate the part and break the seal of grime and paint.
4. The diff carrier should now fall right out. Be careful if you have good parts to reuse like the ring gear.

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5. Locate the small pin that holds the large cross shaft. This needs to be punched out with a small punch (preferred method), or a small screwdriver. If you are able to I suggest not removing this pin entirely, push it just enough to allow the large shaft to fall out.

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6. Now remove the side gears. Lay them one at a time on top of a vice and knock out the threaded buttons. I used a socket as a punch for this operation.
You now have the parts required to convert your new diff.

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Repeat steps 3-5 with much more care on the new diff. You should have learned from any mistakes you made on the old diff, and the second one will go more quickly. Be sure to note the orientation of all the gears in the new diff. You want to put it back together EXACTLY how it came apart. I used a white-out pen to make some marks. Also be sure to maintain the relationship of any washers behind the gears. Do not mix these up. You may want to remove the ring gear at this time to facilitate welding, but I do not believe this is required.
7. Now you must remove the C-clips from the new side gears. I used a screwdriver and some needle nose pliers. Be very careful, these can fly out with great force.
8. Tap or press the threaded buttons from the old gears onto the new gears. Be sure they are straight and pressed as far in as possible
9. Reassemble the center section. Place all the gears and their respective shims in the proper orientation. Push the big cross pin back in. If you were careful on step 5 the retaining pin is ready to be punched back into its place. If you punched it all the way out you are on your own.

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10. Take the reassembled carrier to your friend and his TIG so it can be welded up. You may skip this step if desired.

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11. Reinstall the carrier inside the case, being sure to use loctite and tighten all bolts in a cris-cross pattern.

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12. If you haven’t already now is the time to clean and paint the complete r180.

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13. Fill with gear oil.

 

14. Cut off the dust shields on each R160 side stub axle before you attempt to install them.  You can also use Z car R180 axles with no modification if they are available to you.

You are now ready to bolt this bad boy maybe welded 4.11:1 R180 into your 510 and go tear it up!

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Post it here it can only help :)

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Do i HAVE TO disassemble the new diff to place the threaded buttons or can i just groove em in?

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Yes you will need to tear down the new diff to install the buttons.

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I just got an r180 off a 86 200sx with a z20 does anyone know how to check gear ratio on diffs?

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I just got an r180 off a 86 200sx with a z20 does anyone know how to check gear ratio on diffs?

 

Either turn the halfshafts and count the driveline rotations or crack it open and count gear teeth. I think some versions have their gears stamped with the ratio.

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Either turn the halfshafts and count the driveline rotations or crack it open and count gear teeth. I think some versions have their gears stamped with the ratio.

Thanks for the reply I have to take it apart to make it fit my 510 so I will count the teeth or look for a stamp

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So I ended up getting 2 diffs the stamp on on is s37:9 6 10 7 and the other one is 39:11 hp 2: 3 2 ...... Is the first number the ratio? or do I have to do some sort of calculation to find the gear ratio???? And which one would be better to use ?I'm running a 13b street port with a dellorto 48dhla sidedraft

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So I ended up getting 2 diffs the stamp on on is s37:9 6 10 7 and the other one is 39:11 hp 2: 3 2 ...... Is the first number the ratio? or do I have to do some sort of calculation to find the gear ratio???? And which one would be better to use ?I'm running a 13b street port with a dellorto 48dhla sidedraft

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37:9 and 39:11 are the numbers of ring gear teeth: pinon gear teeth. You just divide, 39:11 is a 3.54:1 ratio diff and 37:9 is the 4.11:1.  For a high revving rotary I would for sure go with the 4:11, it will allow your engine to rev faster.  Unless you are building a rotary hyper-miler and in that case go 3.54 it will give better economy.

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37:9 and 39:11 are the numbers of ring gear teeth: pinon gear teeth. You just divide, 39:11 is a 3.54:1 ratio diff and 37:9 is the 4.11:1. For a high revving rotary I would for sure go with the 4:11, it will allow your engine to rev faster. Unless you are building a rotary hyper-miler and in that case go 3.54 it will give better economy.

Sweet man thanks for that info I first I thought I just moved the semi colon over and that was my ratio 4.11 it is thanks man

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Sweet man thanks for that info I first I thought I just moved the semi colon over and that was my ratio 4.11 it is thanks man

 

The semi-colon is the ratio. 37:9 is 37 to 9 which reduces (by dividing the number preceding the semi-colon by the number following the semi-colon) to 4.11:1. So the other ratio you have is 39:11 or 39 to 11 or 39 divide by 11 or 3.54:1

 

 

When there isnt a stamp, you can count the teeth on each gear (which are the numbers listed in the ratio). One gear has 37 teeth where the other gear has 9 teeth. 

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Now I managed to remove the pin holding the cross but the cross won't come out do I have to punch that out as well??

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It should slide out, you might have to motivate it a little. ;)

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I found out what I was doing wrong that cross is tapered on one side and I was motivating it in the wrong direction but luckily it was the old diff got it swapped and welded now time to reassemble great job on the right up man even a newb like me who has never done any diff work got it pretty easy thanks

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Cool I'm glad you got it!  I didn't realize that cross shaft is tapered hmmm....  Good thing this process requires tearing down an old diff to learn on :)

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thanks again for the great right up finally got it installed and im super pleased 4.11 gears are great and the welded diff make corners fun.... and here is a picture of the damaged I did to the cross shaft at first I was tapping it from where the cross shaft has no hole and got it super stuck ,so in my case the correct way for both my diffs was to tap from the side that has the hole for the pin in it thanks again babybooey great write up

IMG_1273_zpsb0488d46.jpg

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thanks again for the great right up finally got it installed and im super pleased 4.11 gears are great and the welded diff make corners fun.... and here is a picture of the damaged I did to the cross shaft at first I was tapping it from where the cross shaft has no hole and got it super stuck ,so in my case the correct way for both my diffs was to tap from the side that has the hole for the pin in it thanks again babybooey great write up

IMG_1273_zpsb0488d46.jpg

 

Glad to know all went well boom death :thumbup: . Looking forward to doing mine this weekend, hope all goes well. Will try to post pics, any recommendations??

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Glad to know all went well boom death :thumbup: . Looking forward to doing mine this weekend, hope all goes well. Will try to post pics, any recommendations??

this write up is pretty good just follow it step by step…. and the differential that i got had a round plate where the drive shaft meets the diff so it wouldn't clear on reassembly so i had to swap out it out with the old square one so it can clear the sub frame and good luck man 

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I'm glad this is helping people :)  Take your time and pictures along the way.  I recommend that it is roughly a 2 beer job, one during and one after ;)

 

I was able to fit the round pinion flange through the stock hole in the 510 crossmember / subframe by loosening up the crossmember mounting bolts.  I may have even dropped one side with the help of a floor jack... can't remember now, but it worked.

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so i tried making the conversion this weekend and ran into a little trouble, any one have any idea on how to get this collar pin out? or anything else i can do with it? 

 

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510boy you should be able to hammer that pin out with a punch of some kind.  I just used a crappy old screwdriver that was the right size.

 

P1030896.jpg

 

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510boy you should be able to hammer that pin out with a punch of some kind.  I just used a crappy old screwdriver that was the right size.

 

P1030896.jpg

hmmm this one is different, it only goes in one way it doesnt go right thru. as if it needs to get pulled out not pushed, or is it just me?

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