Yad

Hello guys I just bought a rb25det for cheap. I have a ka tranny laying round. I was wondering if any of you have done it before and what do I need to make it work. Thanks in advance!

S14rebuild

Do able yes.....why waste the time and $?? It cost you more to make the ka trans work with the rb25, then u could by a rb25 transmission. Not to mention how much stronger the rb25 transmission is over the ka one. This is a prime example of going the correct direction the first time, and not cheaping out.

Either way if u can afford an rb25 swap, you can afford the right transmission

Yad

Thanks for the feedback! I was wondering if it was possible. I have a 2 ka trannies 1 in the car with the ka bolted in and one spare. Here its really hard to find rb trans since theres no rb cars with them in Puerto Rico the only option is getting one from the states or japan . I'm looking for one rb tranns in Florida since the shipping would be a lil bit forgiving to send it to PR but I dont know any shops in FL that have them in stock. I'm going the ka route since I can find them locally.

any info for the swap would be appreciate it like what flywheel clutch kit do I need to make it work

S14rebuild

You would need someone to make you a custom bellhousing, driveshaft, transmount etc. There is no off the shelf kit, because like i said before, doing this would be pointless.

You need to just find a rb25 transmission for it...... thats your best and cheapest option

Yad

From what i found out on the Internet the ka will bolt up but 2 bolts wont line up and the shifter would be a inch further back (in s14. Not sure about s13)

I heard that people doing the rb20 BH to ka trans since since both trans have the same or similar internals.

S14rebuild

Rb20/sr/ka are pretty much identical internally, rb25 diffrent beast

Bout 90% the ka trans will not bolt up directly to an rb25


Again u sourcing a rb20 bellhousing to swap on a ka trans is pointless when u can just get an rb25 transmission.....
.

Yad

Have anyone done this? What do i need for clutch ka or rb?

240sx-venezuela

Almost all Bolts of a ka tranny match perfectly with rb or vice versa, but a ka transmission behind a rb won't last with some abuse, as for the clutch you can use ka rb20 or rb25 flywheel, if you choose rb flywheel you can go with clutch disk and pressure plate from a Z33, also known as white bunny clutch, i has more surface area and hold more power.

tylerdurden

I ran the KA trans with RB25,,,,need a custom starter plate in order to use the KA starter, also had to drill out a couple of the transmission bolt holes on the bell housing to bolt up them up. You will also need to modify the transmission cross mount by welding an additional metal plate to line up with the bolt holes on the chassis...this part all depends on what engine mounts you are running.

I should have purchased a mount kit, but when I did the swap the kits were not readily available like they are now. I actually had to have someone fab some mounts for me by hacking up the crossmember and welding on mounting points. made custom urethane mounts in order to use the stock mounts on the engine.

Changing everything up now piece by piece using an RB25 trans...PM if you haven't done anything yet and still want to use the KA trans...I still have the bracket and starter....but the other members are right. Save the money and later on the time by doing it right the first time.

I did not have a choice because my swap was done in the 90's and I did not have the luxury of all the kits that are currently out.

GL

S14rebuild

Kingtal0n

They make an RB25 transmission that has all of the ka/sr internals and fits the stock 240sx chassis perfectly. The transmission comes from a Laurel I think. I used to have an RB25 with that 5-speed on it, just like an SR transmission same crossmember etc...