Honda / Acura K20a K24a Engine Forum banner

1 - 10 of 10 Posts

·
Registered
Joined
·
10 Posts
Discussion Starter · #1 · (Edited)
Hi everyone, new to the forum and K series in general. I've played with H22s forever and other random stuff here and there but I've been thinking a K swap might be in my future. I purchased a 1961 MG Midget shell originally for an EV build but I ended up also buying a completely running 73 so EV stuff will be done with that later. I was planning on getting a K24z3 and mate it with a zf BMW transmission, get a custom driveshaft made, LSD differential for the rear end, upgraded axels just to get it off the ground. From what I've read the z3 has a tricky immobilizer system in place but I was thinking since I have a bare bones shell can't I just use the stock engine harness, ecu, and internal harness without issue? The midget is so small that I don't foresee any issues with wire length, and I'm assuming I just have to get a key coded for the ignition I'll end up getting. Am I underestimating this, or is it possibly that simple?

Goals:
HP: 200, 400+ with turbo later
Purpose: Race car? No specific purpose just wanna make it.
Budget: $8K-$10K

MG Midget diagram:
104335


A few pictures of what I'm working with...
104350


104351


104352
 

·
Arouse the DAMPFHAMMER!
Joined
·
7,722 Posts
Welcome @WinterT to K20a.org.

I was planning on getting a K24z3 and mate it with a zf BMW transmission, get a custom driveshaft made, LSD differential for the rear end, upgraded axels just to get it off the ground
That's a nice and achievable goal. There are a few ZF RWD projects, also a Double Clutch one, with an K-series from Honda. I just wonder if the midget can stand the torque (brakes, coils/springs, steering, ...)? Anyway, some further information:

K20a2 in an mg midget | Honda / Acura K20a K24a Engine Forum
The Midget Register :: MG Midget K Series Conversion 2 | FAQs Considerations of the Conversion Process - Not a Honda K-series, but the same chassis
K swapped MGB | Honda / Acura K20a K24a Engine Forum

 

·
Registered
Joined
·
10 Posts
Discussion Starter · #3 ·
Welcome @WinterT to K20a.org.

That's a nice and achievable goal. There are a few ZF RWD projects, also a Double Clutch one, with an K-series from Honda. I just wonder if the midget can stand the torque (brakes, coils/springs, steering, ...)? Anyway, some further information:
I was actually thinking of upgrading at least the rear brakes with a "kit" I saw. It's an upgrade plate that bolts on and uses Nissan Sentra brake calipers that fit on a midget. I also considered using an eclectic power steering column from something like a Prius but I may just keep it as is for road feel. Don't know about the suspension though, that's something outside of my normal knowledge base so I need to study up on the options.

Thanks for the info, I've come across a couple of them in researching but still all good stuff.
 

·
Registered
Joined
·
10 Posts
Discussion Starter · #4 ·
So slight change of plans...I came across an 03 Accord for a good price and ended up picking it up. So K24a4 instead of the original K24z3 I had in mind. The motor also has 250K on it so I will need some sort of refresh done I presume even though it runs perfectly fine. Any suggestions on what to focus on would be much appreciated.
 

·
Arouse the DAMPFHAMMER!
Joined
·
7,722 Posts
Any suggestions on what to focus on would be much appreciated.
The K24A4 is an eco VTEC engine. There are two options:
  • keep it complete stock longblock-wise and adapt header and IM for the chassis. Here you need a tuning access to the ECU.
  • or add an K20A2 head to add reasonable power potential, but this would mean the pistons has to be swapped too because of the deck height of it. Piston to valve contact can easily occur.
 

·
Registered
Joined
·
10 Posts
Discussion Starter · #6 ·
  • keep it complete stock longblock-wise and adapt header and IM for the chassis. Here you need a tuning access to the ECU.
I was under the impression that a K24a4 could handle upwards of 300-400WHP with stock internals and a properly tuned turbo setup. That being the case I think I could leave it there, especially since the car weighs like 1500lb. I was also thinking of using an S2K IM as it faces forward (relative to how the engine will be placed) but any IM that faces forward would work in theory. Header I will have to sort out though. I am taking some inspiration from This build (kinda found it after I bought my shell) but his MGB is slightly larger overall so I may have some issues here and there.

Midget:
Weight 1600 lbs
Length 11' 5"
Width 4' 5"
Height 4' 5/8"
Ground Clearance 5"

MGB:
Weight 2140 lbs
Length 12' 9 3/4"
Width 4' 11.9"
Height 4' 1 1/4"
Ground Clearance 5"

  • or add an K20A2 head to add reasonable power potential, but this would mean the pistons has to be swapped too because of the deck height of it. Piston to valve contact can easily occur.
I did read that to do the K20/K24 I'd need to swap the pistons but I wasn't sure what pistons and/or rods would fit and not cause the contact issue. All I see is people mentioning aftermarket pistons which would indicate every piston aside from stock ones has no clearance issue.
 

·
Arouse the DAMPFHAMMER!
Joined
·
7,722 Posts
I was under the impression that a K24a4 could handle upwards of 300-400WHP with stock internals and a properly tuned turbo setup.
It does, we have several members having exactly this.

I did read that to do the K20/K24 I'd need to swap the pistons but I wasn't sure what pistons and/or rods would fit and not cause the contact issue
Yes, the PtV clearance is the issue, because the K24A3 and A4 have different combustion chamber and valve timing design for better combustion efficiency. Deep valve pockets are not supporting a faster combustion, so they don't have it.
 

·
Registered
Joined
·
10 Posts
Discussion Starter · #8 ·
I'll be taking the engine apart to do general maintenance. Gaskets, timing chain, tensioner, getting the block milled/decked, etc. Might also upgrade the oil pump if everything is apart. So if it can handle my hp target without swapping the internals (save the head studs) I'll leave it be I think.
 

·
Registered
Joined
·
10 Posts
Discussion Starter · #9 ·
Managed to pick up the E46 zf transmission I was looking for from a local junk yard. Next on my list is the adapter plate and an intake manifold. I don't think there is a way for me to avoid paying more than I want to for the adapter plate since it is specific to my application and is a critical component but maybe I can cheap out on the IM. There are not a lot of options from what I have seen for a RWD K24 IM (for less than $500).

Would I be able to cut a stock one right at the plenum, flip it, and weld it back together? Or cut two (k24 runners and something with a large plenum) and merge them together, presuming this would have some advantage?
 

·
Registered
Joined
·
13 Posts
Cutting the IM at the plenum is an option. Other option is to use S2000 IM with an adapter plate but still need to grind of the water passage on the IM. Last option is to use a "flippable" IM like Skunk2 ultra.

I'm probably going with option 1 myself.
 
1 - 10 of 10 Posts
Top