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KA24DE Carb Swap HELP - Grandpa's Garage???

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Hello,

 

Just recently purchased my first Datsun a 72 521, beyond stoked to begin this project. Currently has the original 1.9L Engine but I just so happened to have a 1999 Nissan Altima I recently changed the timing belt and did a valve job on but the client couldn't pay and we came to an agreement and the car is mine now.

 

The Datsun is currently at my Grandpa's along with the engine, we came to an agreement Grandpa would do the engine swap etc. The catch is Grandpa wants to convert the KA24DE to Carburetor and I was hoping to get some direction. Solid mechanic skills but really looking for some direction or even a bump to another article that outlines exactly these steps. I assume the issues ill be running into will be high fuel pressure, Vacuum, and Ignition. Grandpa and I would probably figure it out, but why experience the frustration when I've got the best Datsun mechanics all in one place.

 

Please no haters do not need to be told to leave it to EFI done my fair share of EFI swaps and mods want to stay true to the era and Grandpa doesn't do EFI. Half of this is about the time spent with my Grandpa so that is reason enough.

 

Much Appreciated

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The '70-'72 used an L16 or 1.6 liter engine. It may have been swapped to an L18 or L20B?

 

 

Some things to consider....

 

1/ This is a FWD engine. Besides the engine mounts, what RWD. What transmission will you use? Won't bolt to the 521 transmission and it wouldn't handle almost 3 X the power anyway.

 

2/ The KA24DE uses a CAS. (crank angle sensor on the side of the head) It needs the EFI set up to help the ECU generate a spark and an ignition advance curve. I can't think of a points or EI distributor that will replace it.

 

3/ You will have to make an intake manifold for a carburetor.

 

4/ The fuel pump is high pressure (around 38 PSI) and will need replacing with a 3.5 PSI one

 

5/ needs an electric cooling fan for the radiator.

 

 

If this was a truck KA it's already RWD and has a 2wd 5 speed available. The intake has a throttle body injection on it and only needs a flat aluminum adapter plate made to mount a carburetor. Although it has a CAS, it's on the side of the timing cover and an earlier distributor will mount to it. Has it's own cooling fan.

 

 

You might reconsider this move. This engine is 'doing it the hard way'. Not hating just saying...

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Its doable (my 510 is proof) your best off with the rwd KA24DE from either the 240sx or the frontier. I dont know anyone who has converted a FWD KA to a RWD setup. I recall reading a few threads about it but nobody ever did the FWD to RWD conversion. 

 

As Datzenmike said there are 3 main issues converting a KA to carbs.

 

1) Timing - The truck KAs are very similar to the L series engines and I believe you can just use a L series distributor (but youll need to do some more research to confirm that...) The 240sx KAs the distributor runs of the cams and wont work. Some people have hacked together an L series distributor to make it work... but your best bet at that point is to go with a crank triggered ignition such as megajolt, gives you much more ability to tune it and will be rock steady.

 

2) Carb manifold - they are out there, but not easy to find. Ive got two, one from Ed Pink which is supposedly the Nissan Motorsports one, and a second cast one from EWL (Edwin.... something... saw him on the facebook ratsun group a while back). I liked the look of the cast one and used that. both of those are for sidedrafts (Mikuni or Weber). So you'll need to track one of those down or make your own. You can buy flanges for both the KA side and the sidedraft side of the manifold and then will just need to connect the two.

 

3) Fuel - not a big deal, just run a carter low pressure fuel pump, toss a regulator on it to be safe and to dial in the pressure.

 

You may or may not need to run an electric fan, but might as well for ease of use.

 

There is a 620 floating around that was using a downdraft carb on a KA, was all over instagram not sure if he is on here- I think it was farmerjoe?

 

Here is a link to my KA build -Starts about half way down this page

 

https://ratsun.net/topic/46032-red-71-4dr-carbed-ka24de/?page=20

 

The short answer is though, I would avoid using the FWD KA or start doing some research. 

 

 

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