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

[Trev0rN0t]

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

[datzenmike]

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...

[demo243]

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. 

 

 

[Trev0rN0t]

Gents,

 

Thanks a ton Mike & Demo in my research I quickly found out it would become an expensive nightmare, maybe posted this premature. Just for the Kennedy adapter it was a couple thousand bucks. Then yes ignition I couldn’t mind much on that. 

 

Everything points to either the 240z KA24D not the E’s or L20B like Mike suggested. We then moved on to thinking about a Chevy 350, because I just finished that swap a few year ago. Note to those listening don’t let your kids go off to college and allow them to buy 914s from their boss and a V6 block. Because a.) they will spend their student loans on speed parts and b.) skip class, get a hotel valet job pickup extra shifts and work on cars instead of getting educated. Truly a “valuable” lesson, from a “poor mans” Porsche If you get my drift haha.

 

Update though we’ve pulled the tired 1.6l found a really really good deal on a brand new performance cam, headers, and some used Webber side drafts. So we are just going to rebuild that and sell that rebuilt engine in hopes I can fund and find a KA24 or L20B.Or maybe just drive it make it a good little runner. 

 

Couple additional Questions? 

 

Electronic Ignition? For 1.6L what’s the best setup out there? 

 

Cheap speed parts or tips for our L16? 

 

What are guys getting out of the L20B? I want a daily driver with say 150-200hp what are my best opitions. 

 

If someone has a L20B for a good price please message me. I live in Utah but work for FedEx, so locations and transport can be arranged. Fluids must be drained though and palletized.

 

 

 

[Trev0rN0t]

On 10/13/2018 at 11:35 AM, demo243 said:

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. 

 

 

 

[Trev0rN0t]

Thank Mike! Great Stuff here while I’m deciding between doing either the L20b and KA24. 

[datzenmike]

4 minutes ago, Trev0rN0t said:

Couple additional Questions? 

 

Electronic Ignition? For 1.6L what’s the best setup out there? 

 

Cheap speed parts or tips for our L16? 

 

What are guys getting out of the L20B? I want a daily driver with say 150-200hp what are my best opitions. 

 

 

 

The later '79 and '80 L20B distributors were EI matchbox and drop right into an L16. You need the matching coil to get the most out of this system.  Hotter spark and no points to replace/adjust ever again.

 

Anything bolt on after market to an L20B will fit the L16. Cam, carbs, exhaust... With a lot of $ and work you can get up around 100 hp. The L20B does that already.

 

To double the L20Bs HP is beyond incredibly expensive. Get an SR.

[Stoffregen Motorsports]

150 HP = $2500

You can achieve this with a more or less stock L20B, a mildly ported head, cam, valve springs, 10:1 CR, good header (not cheap shorty header), a recurved single point distributor and a single downdraft Weber DGV.

 

200 HP = $4500 or more

You'll need a full port job on the head with big valves, a big cam, 10:1 CR, plus the good header and recurved distributor, but now you'll need dual side draft carbs (preferably Mikuni/Solex 44's or Weber DCOE 45's). The head build will cost $1000-$1500. The carbs and manifold will cost about that too, but could be more depending on the setup. Early Solex 44's on a BRE or Nissan Comp manifold will run into the thousands of dollars. Later Mikuni 44's on a Mikuni manifold can be had for around $1000. Cannon manifolds are even less and used Webers are cheap in comparison the Solex carbs.

 

Bigger motors make easy horsepower, but now you're talking about a custom engine which requires a different block, rods and custom pistons.

 

If it were my car (truck, whatever...), I would get a KA24E 12 valve out of a truck. Simple and easy 150-170 HP.

[alexg89]

On 10/13/2018 at 1:35 PM, demo243 said:

 

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

 

 

 

As i thumbed through this.. i noticed you have the PCV on the back of the timing cover plumbed into the valve cover vent.. Is there no issue doing this? figured you would need to have it vented.?

[demo243]

21 hours ago, alexg89 said:

As i thumbed through this.. i noticed you have the PCV on the back of the timing cover plumbed into the valve cover vent.. Is there no issue doing this? figured you would need to have it

They T together under the intake manifold and then are run to a catch can on the fire wall.

 

Ran the same set up on my L20b.

 

 

[alexg89]

5 minutes ago, demo243 said:

They T together under the intake manifold and then are run to a catch can on the fire wall.

 

Ran the same set up on my L20b.

 

 

Awesome

I will be doing the same then if it works.. Thank you for letting me know !

[Stoffregen Motorsports]

I built a PCV system on my '65 Austin Healey Sprite with a single PHH44 Mikuni. Reason? To help pull a vacuum through the crankcase and eliminate oil leaks.

 

Does it work? Yes. Would a Datsun need it for that reason? Probably not.

[reza]

Carb a KA24E, very simple. 
L-series matchbox preferably 
distributor oil drive from any L series

Here is a picture of my KA24e 510 with custom intake, running duel SU 240z carbs. I drilled out the head and ran a mechanical fuel pump

[Stoffregen Motorsports]

That's pretty cool. Everything looks like it could pass for vintage, except the oil cap.

 

You have to wonder why they cast the fuel pump boss into the head on a KA. Surely, by then , all of the KA motors were injected...?