Jump to content

Swapping the H190 Input Flange for 521


DatEz

Recommended Posts

Hi folks,

 

I am about to buy an H190 LSD from a guy who had it imported from Japan, however, I am worried about the input flange. I am currently swapping in an sr20det into my 521, so I will need to have a custom drive shaft made eventually. My dilemma is that I would prefer to keep the driveshaft flange the stock flange so I can swap out the LSD to the Stock diff if I please, BUT the H190 flange is not only a different shape, but also has different lengths between the holes than my stock diff.

 

I read the thread titled "521 3rd member swap" but I got lost on how he got the LSD to fit. From what I understood, the 521 input flange will not fit the H190, so am I missing something? Is there a way to swap the input flange on the diff to the 521 flange? I'm confused on how he was able to apply the 720 flange?

 

If all else fails, I will just have the custom driveshaft fitted to the flange the H190 comes with, but like I said, it wouldn't be my preference to do, and it would also cost me more money.

Link to comment
  • Replies 26
  • Created
  • Last Reply

Top Posters In This Topic

Top Posters In This Topic

I found an H190 LSD in a 1993 hardbody a long time ago, at first I didn't believe it was an H190, there happened to be a 620 right across the row from the hardbody, so I pulled out the 620 pumpkin and I put the hardbody LSD into the 620 axle housing and slid in the axle, I could hardly believe it fit.

So the LSD had this huge flange on it like a late 720 4X4 has with the C200 axle, I looked at the 620 flange, it was the size I needed, so just to make sure it was not possible I removed the flanges from each pumpkin and put them side by side, they looked exactly the same to me except for where the driveline bolted on, so I inserted the 620 flange into the hardbody LSD and it fit perfect, I have that LSD in my 521 kingcab diesel truck now with, as far as I know it still has that 620 flange on it and it doesn't leak gear lube either.

The transmission yoke is a different thing, I have only dealt with 720 transmissions.

Link to comment

I also bought one of those LSDs (and I'm also planning on installing an SR20DET). Where in CA are you? 

 

I know what you mean about the flange. Not only does it appear to be a larger bolt pattern for larger bolts, it also appears to be longer. I haven't really looked at it much, but I'd guess you could remove it and put your flange on it and do your best to retorque the nut just enough to get it tight but not too tight to change the gear mesh. 

 

But really, I think I'll be redoing the shaft, anyway, since I'll need to shorten it for the SR20 transmission (unless I get a KA). The larger bolt pattern with larger holes (from what I recall), may be a benefit and allow the use of a larger U-joint. 

Link to comment

So Wayno, you installed a 620 flange on to the LSD and it fit the same bolt pattern as your stock 521 driveshaft? Did you have to lengthen or shorten the driveshaft at all, or was it plug and play after putting the 620 flange on the new pumpkin?

Link to comment

2wheel-lee I am located in Torrance, CA. I also got the s13 driveshaft with my swap, and I measured the bolt pattern on that and it matches the LSD, however, since I haven't received the LSD yet, from the looks of it, the center ring on the driveshaft might be too big. If I end up needing to make the custom driveshaft, Im wondering if I can grind down the protruding ring to have a flush fitting on the driveshaft and lsd. Anyone know if that would affect them negatively?

Link to comment

I wonder if either of those LSDs are ones that I sold ?

 

Here is what I had to do to put mine into my 620:

 

If they were from me (eBay ID duax_machine), they are car LSDs, that had ball bearing axles.

They will work just fine in the older trucks by changing the input flange.

But they do require the iron carrier, as it would take a bunch of machine work to get them to fit the aluminum carrier.

 

I had to use a 3mm ring gear spacer to use the 4.6 gear set I wanted, as these came out of a housing with a 3.7-ish gears.

 

I addresses the larger ring gear holes in the LSD, by making spacers, but I really doubt if it was necessary, as I've seen quite a few S15 Silvia LSDs installed in 240SXs with the same problem, without spacers, and never seen one instance of any ill effects.

 

The other issue I found is the trucks have tapered roller bearings on the axles, and rely on the axles holding them in place.

The stock open diff had a thrust block in the center that the axles bumped up against.

The car H190 LSDs don't.

To take care of this, I machined a spacer that would slide into the center of the LSD, that was the same length as the block thickness.

Typically, the blocks are .902" +/- .001" long, so the spacer has to be that length.

 

To install, I first installed one axle, then took the spacer, glued it to the end of the other axle with a dab of silicone.

When it set up, I slid that axle into place with the spacer on the end.

Worked great.

 

Other notes on those late model H190s coming out of Japan, is that they are set up rather soft.

That is they have 2 outer plates next to 2 inner plates lessening the locking power.

For performance, pull the LSD apart, and rearrange the plates so they are evenly staggered, 1 inner, 1 outer, 1 inner, 1 outer.

 

Also, a solid pinion spacer can be made from the spacer from a 240sx (about $10 from Nissan), but will have to be custom fitted.

 

Also, these take the same internal parts as the R200 Nismo LSD.

I replaced my spring plates with outer plates from an old R200 Nismo unit to gain even more locking power.

By removing the spring plates, the rear end acts like an open diff with no power being transmitted through it.

Make rolling the truck around much easier, and more well mannered when parking, or going slow. 

But when I get on the gas, it locks up hard !

 

DSC07892.jpg

  • Like 1
Link to comment

G-Duax, I am buying mine from AFRacer on here, he had an ad up about a month ago. I actually think he was reaching out to you about some questions I had for the LSD upgrade to my truck. I will be quite honest, I have never worked on a differential before, so I am not very familiar with everything you were saying up there. But if you don't mind, I have a question that I would like you to answer:

 

Will the H190 LSD differential work well if I just bolt it into place and attach a custom driveshaft? He told me it has 3.7 gears in it which was good for the sr20 swap. He also mentioned that you said its out of an automatic Cedric 430. I don't trust myself to mess with the differential since its so expensive, I wouldn't want to mess it up. Should I just forget the idea of installing that LSD and just go welded diff on the stock 521 diff?

Link to comment

All I did was remove the hardbody flange and install the 620 flange, I then later(over a year later) installed it in my 521 kingcab, but my 521 kingcab cab is sitting on a 1981/1982 Datsun 720 diesel frame, it was put it in,  I connected the driveline, put LSD fluid in it and drove it, maybe I got lucky, and it doesn't leak fluid out of the front either.

The flange that was on it was connected to the hardbody driveline, it was different, I do not recall for sure how it was different now, but it would not have worked on my driveline, that is why I changed it.

That said I must also mention that the axle housing did not have the orange LSD sticker on it either, someone else put that LSD in that truck before it got to the wrecking yard, it didn't look right to me when I looked at it, I kept going back to that truck and looking at that axle trying to figure out what was wrong about it under that truck, and when I turned the wheel and the other side turned the same way I figured it was welded up, imagine my surprise/the look on my face when I dropped that pumpkin out and seen an LSD, I really thought it was not an H190, that is why I put it in the 620 rear end housing and slide in the axle, I just didn't believe it was an H190 LSD, it cost me $99.00 and I left with a big smile on my face.

So Wayno, you installed a 620 flange on to the LSD and it fit the same bolt pattern as your stock 521 driveshaft? Did you have to lengthen or shorten the driveshaft at all, or was it plug and play after putting the 620 flange on the new pumpkin?

Link to comment

DatEz, I wouldn't put a welded diff in anything...

You can just bolt that unit in, as long as you add the spacer.

I can make a spacer for you.

 

I would also just change the flange, so no custom driveshaft would be required.

That's what I did to mine.

Link to comment

I was talking about 2 different spacers.

One, if you were going to change gears.

You are not, so forget about that one.

 

You do need the one that goes between the axles, that has to be .902" long.

This one keeps the axles pressed tight against the bearings that the truck uses.

Link to comment

Ah! I see, sorry for the mix up. I kept referring back to your original comment with the details and I was digging myself deeper.

 

I would like to order a spacer from you if you don't mind G-Duax. As for the installation of the spacer, why cant I install it into the LSD before I put the pumpkin on the rear end?

Link to comment

... why cant I install it into the LSD before I put the pumpkin on the rear end?

 

You can, but you will probably have to put a lot of grease on it to hold it in place, in the center of the LSD, unless you are careful to not tilt it to one side while installing the carrier.

 

My carrier was already in when I discovered the mis-match between the car & truck thing.

So I just pulled one axle, and stuck it in place with silicone.

 

$35 for the spacer machined, and shipped to your door.

Link to comment

Thanks 69srl311 for that part of the question, as that's what I was thinking, and thanks to G-Duax for answering. 

 

So on the cars, the driveshaft ends are touching each other?

 

Since DatEz and I are in the same situation, and we're in close proximity, how much would you charge for two spacers shipped to the same address?

Link to comment

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
×
×
  • Create New...

Important Information

By using this site, you agree to our Terms of Use.