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SR20DET motor + L24/L28 transmission = Motion?


altrock182

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I've done some research on the combo.. I can't see where it's ever been done. However, The transmissions behind an L28, KA24, and SR20 are supposed to be nearly identical minus the bellhousings.

 

Does anybody see any reason why an L28 transmission could not be bolted to an SR20DET, with an SR20 bellhousing and SR20 clutch? I'm not worried about durability, as the L28 trans *should* hold up to 300hp+ L28ETs. I am not planning on building a high hp SR20, at most 10psi of boost with stock ECU. It shouldn't see 250rwhp.(and if I add it up right 240rwtq).

 

I have seen where an SR20 transmission has been successfully bolted to an L28ET, I believe the only modification was a slight grinding on the order of a few thousandths somewhere, but i don't remember the details.

 

I have also seen where the KA24DE transmissions will bolt to an SR20DET, and the other way around with no modifications.

 

As far as I can tell, my idea SHOULD work. If not, let me know!

 

Thanks,

John.

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KA and SR transmissions are the same, its the bell housing that is different.

 

Don't confuse HP to an engines strength, its the torque that kills a transmission.

 

People have put KA transmission onto a L28, by swapping on the L28 bell housing on to the KA transmission. Now think about it.

 

Only reason why I see it justifiable to swap on a L28 transmission onto a SR, is because of there not being any SR/KA transmissions local. You are working backwards.

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I am wanting to use the same transmission to save money and also so I don't have to fab transmission mounts or shorten the driveline.

 

I noted that the trans shouldn't see more than about 240 ft-lbs of torque with my plans, which it should hold up to. I don't plan on auto-crossing or offroading or any of that silly business. It's simply a daily driver, and won't see alot of hard driving.

 

One more reason, I have the 3.36 gears and live in oregon - it's rare to find a road to drive much faster than 55-60 on.. I wouldn't have a use for 5th gear without putting a lower geared differential in.

 

In any case, the idea is to save money by not having to buy the transmission. This is, of course, assuming I can find a bellhousing and clutch for the SR for cheap enough to justify it, or buy a whole motor/trans combo and sell the transmission.

 

My question was more towards whether is was physically possible / practical, not whether it would hold up to the power or if there was a better transmission to use for more money.

 

Thanks,

John.

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Let me start over.. and just ask a very simple question so I don't get arguements over whether it's the best route to go or not; simply is it practical(NOT more practical than something else), or should I say "Easily enough done"

 

CAN an L28 transmission be bolted to an SR motor and bellhousing? Is there anything I should be worried about? Does anyone that knows whether it will work or not have anything to contribute? Does anyone that has an idea of whether it will work or not have anything to contribute?

 

Assume that an SR transmission will not work for my application no matter what. Neither will a KA. Only an L28 transmission will work. Assuming that, if you still have a response then I will be very interested in hearing from you. I hate to sound like a ---- but this is the answer I'm looking for, not "No you're wrong don't do it because xxx"

 

Thanks,

John

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Ok i will take a shot at actually answering your question. the problems i see with the swap your talking about is the 2nd shift fork and the counter shaft bearing.

 

To do the swap from ka tranny mated to the L6 bellhousing you have to bore out the countershaft bearing hole and you have to bore out the 2nd shift rod hole to 5/8. So when you go the other way the countershaft bearing is going to be to small for the bellhousing. Granted its an easy fix with a bearing swap but the bearing isnt cheap and you have to order it from nissan and it runs like 50 or 60 bucks if im not mistaken. Now on the 2nd shift rod your rod is going to be to small for the hole in the bellhousing. now you could make a bushing and put it in the bellhousing to make it work but unless you have a machine shop yourself, your spending more money again.

 

So to answere your question the answere is yes it can be done but your going to end up spending probably around $100-$150 in parts and having stuff machined. so why not just get the sr tranny that can be had for cheaper. I know i can find ka24de trannys all day long for 100 bucks.

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Ok i will take a shot at actually answering your question. the problems i see with the swap your talking about is the 2nd shift fork and the counter shaft bearing.

 

To do the swap from ka tranny mated to the L6 bellhousing you have to bore out the countershaft bearing hole and you have to bore out the 2nd shift rod hole to 5/8. So when you go the other way the countershaft bearing is going to be to small for the bellhousing. Granted its an easy fix with a bearing swap but the bearing isnt cheap and you have to order it from nissan and it runs like 50 or 60 bucks if im not mistaken. Now on the 2nd shift rod your rod is going to be to small for the hole in the bellhousing. now you could make a bushing and put it in the bellhousing to make it work but unless you have a machine shop yourself, your spending more money again.

 

So to answere your question the answere is yes it can be done but your going to end up spending probably around $100-$150 in parts and having stuff machined. so why not just get the sr tranny that can be had for cheaper. I know i can find ka24de trannys all day long for 100 bucks.

 

You are thinking about swapping a KA/SR tranny onto a L28. Doing it the opposite, you will have to fill it in, Or jam a brass bushing into the bell housing to tighten up the countershaft. I'm not sure as to which would work best, because I haven't do it before.

 

The fork won't be an issue, because Everything in front of the transmission has to match the bellhousing (SR bell housing)

 

So~, you will need a SR bell housing, flywheel, clutch kit, fork; L28 transmission. then swap bell housings.

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You are thinking about swapping a KA/SR tranny onto a L28. Doing it the opposite, you will have to fill it in, Or jam a brass bushing into the bell housing to tighten up the countershaft. I'm not sure as to which would work best, because I haven't do it before.

 

The fork won't be an issue, because Everything in front of the transmission has to match the bellhousing (SR bell housing)

 

So~, you will need a SR bell housing, flywheel, clutch kit, fork; L28 transmission. then swap bell housings.

 

I wouldnt put a bushing in the countershaft bearing hole i would just swap the bearings and put the larger ka/sr countershaft bearing onto the l28 transmission. You would have to put a bushing into the shift rod hole though.

 

Sorry not sure if your agreeing with me or if your trying to say it wont work. I just stated what is neccessary to do the ka to l28 swap first and then worked backwards from there.

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Lol I shouldn't be reading when I'm half asleep :P.

 

Yes, reading what you wrote, after getting some sleep. I agree :P

 

I'm in the same position as altrock182, but my reason is...

<======== location.

 

I just ended up cutting my L28 bell housing in half, rotating the piece cut by 10-15 degrees and welding it back on.

 

Reason why I cut in half instead of cutting the flange is because of the bulge for the started.

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Would I be correct in assuming the bearing you are talking about is circled in red, and the bushing that needs to be put in would go in the blue circle? Or would I have to have three bushings, one for each of the 3 smaller holes? Of course if I had a trans and bellhousing to play with I could probably see exactly what needed to happen.

 

This is the only picture I could find that has a good view of the inside of an SR bellhousing, the KA just happens to be next to it.

 

9gld3t.jpg

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on the shift fork im not sure which one it is.

 

Since you are using the SR bell housing, everything in front/inside of the bell housing should be all SR. Its not the fork that you should worry about in respect to the TOB engaging the pressure plate, Its the TOB collar, usually comes with a clutch kit with the bearing pressed on.

 

So just order a clutch kit for an SR, or use the stock one, and you'll be fine.

Not sure on the bushing part. You will know, when you test fit the bell housing on the transmission. I think that part is going to be too much of a hassle because the bushing/spacer (whatever you want to call it) will be so thin. But if you press in a thicker one into the housing and then bore/drill it out, it won't be so bad.

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ive done the swap. it is possible, but more cost efficiently done by just using the sr tranny if you do an sr swap. the money you save by using the tranny you have and drive shaft will more than likely be eaten up by machine shop costs. when i was weighing out the costs of using the stock components it was cheaper by a couple hundred dollars to use the sr stuff. same would with the ka setup if you went that route.

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ive done the swap. it is possible, but more cost efficiently done by just using the sr tranny if you do an sr swap. the money you save by using the tranny you have and drive shaft will more than likely be eaten up by machine shop costs. when i was weighing out the costs of using the stock components it was cheaper by a couple hundred dollars to use the sr stuff. same would with the ka setup if you went that route.

 

since he wants to use the L28 transmission, he wouldn't need to get a custom driveshaft. He just needs to mount the transmisson to the tranny mount, in then tunnel, then put the engine mount where the tranny mount dictates where everything is positioned.

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I am in the process of doing this swap.... Infact i just picked up my modified bellhousings today from the shop...

 

The bearing and shaft holes are the ones that need fiddling with.

 

The SR bellhousing has a larger bearing hole than the l28. HOWEVER, the inside diameter of the two different bearings are the same. Therefore, just use the SR bearing, the L28 shaft will fit on/in properly.

 

The only other thing to contend with then is the fork hole. It is 16mm instead of 14mm, so you will need a 16mm outer diameter, 14mm inside diameter spacer to wedge in there. The other 2 holes, not circled in the picture above, do not need altering.

 

THAT IS IT!!!

 

 

 

One more thing.... WHY?! Seriously, the drive shaft will cost you MAX $150 to have it shortened and balanced with new cv's and the dust cover taken off and the SR gearbox is TONS stronger than the L28. My N/A L28 is punching 180rwhp, 240rwnm and i've been through 4 gearboxes in 18 months. The Z gearboxes are just getting old. The NEWEST Z gearboxes are 30years old.... Their at the end of their servicable life in my opinion.

 

The SR gearbox is an UPGRADE, and the SR gearboxes are about half the price of an L28 gearbox.... (well in AUS anyway)...

 

So whilst, YES, you can do it, and it wont be difficult (see above), i just dont understand why you would want to do it when it will be far easier in the long run to just make a new driveshaft and tranny mount.

 

If you have a 240 with the tranny mount that bolts upwards, then all you do is turn the original mount around, and drill two new holes ~5mm further back on the mount, and your tranny will bolt straight in (the Z tranny mounts fit on the SR20 gearboxes). If you have a 260, where the tranny mounts are parralel with the gearbox tunnel, simply cut the centre section of the tanny mount out and re-weld it 35mm further back. Viola, tranny mount lines up.

 

Another thing. Why not put the SR20 as far back in the engine bay as possible for weight distribution? Friend is doing this, the tranny mounts (SR20 box) are basically the same procedure as i just described, and the tail shaft just has to be shortened the correct amount.

 

 

 

PICS. (see attachments)

side by side comparison gearbox bellhousings

260Z gearbox mount modification

240Z gearbox mount modification

 

 

Useful link:

How to install an SR20 gearbox into a 240Z

http://home.comcast.net/~zheimsothtn/transmission.htm

9gld3t_thumb.jpg

SSPX0054_thumb.jpg

72Xmber4_thumb.jpg

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Haha, yeah it sure is :D

 

That pic is going to my mechanic on wednesday when he fabs up the same thing for me :P You said it was your first welding piece ever, but i have no welder so they are doing it for me.

 

Seriously, that looks fine to me. Make it a bit tidier on the welds and joins perhaps and it would be what i am hopeing to have on my car. I don't know why the guys were bagging on you. I have that thread bookmarked in my "Z gearbox Swap" folder :)

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Haha, yeah it sure is :D

 

That pic is going to my mechanic on wednesday when he fabs up the same thing for me :P You said it was your first welding piece ever, but i have no welder so they are doing it for me.

 

Seriously, that looks fine to me. Make it a bit tidier on the welds and joins perhaps and it would be what i am hopeing to have on my car. I don't know why the guys were bagging on you. I have that thread bookmarked in my "Z gearbox Swap" folder :)

 

LOL glad i can be of some help. The origonal thread was actually over at Zcar wasnt it? I guess i did post a picture of it here though. The way i made that was i cut it into the 3 pieces and then bolted them all up to the transmison and the tunnel and then i just tacked everything in place. Took it all out and then welede it all together.

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