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K-Swap an E30? Please select maximum of 3 responses...

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Discussion Starter · #1 ·
Hello! My name is Travis. I have been an all euro driveway for the past 8-10 years, but I have also gotten rather bored with the power trains that are available and reasonable for swaps...so here I am and wanted to introduce myself and my new project.

I live outside of Seattle in the PNW and have acquired a 1991 E30 BMW 318i (sedan). "Benny" is RWD, 5 spd (G240), and is currently fitted with an M42 (I-4) with a 4.10 open rear diff. My thoughts are to get smart on the K20 vs K24 swap for this platform and to acquire an E36 or E46 5 spd (ZF) transmission since KPower and TFWorks make adapter plates for the K series to the BMW ZF trans. The ZF trans allows for my driveshaft and rear diff to stay put and only need an updated version later but keeps functionality and costs down initially. I do understand that the S2K trans "is the business" and all that, but not in my immediate budget. Ideally, I'm thinking that I can keep the parts to less than $5-6k, with a known expense for most of the swap kits are likely $1500-$6000 also...so all in the budget of around $15000 would get my reliable, DD, fun, with potential power/turbo, and restore some portions of the car as well (interior, wheels/tires, body seals, wrap, tint, etc).

Looking forward to integrating into this group more down the road, as I know NOTHING about k-series motors or what is swappable between them or which block/head to start with and which to avoid. I am most likely going NA, but love the idea of turbo down the road (unless project funds or "deals that fall from the sky" happen).

All the best,

Travis
 

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Welcome to the forum and thank you for registering.

If it were me, I would source an entire S2000 AP1 (F20C1) 2.0L (2000-2002) complete swap providing I could find a low mileage one. Since this is not about me and is about you I will give you sound advice.

The K20 was designed for a low drivetrain loss FWD install. The K24 is the same, however with the extra TQ from the larger displacement will be easier to power the RWD set up. The amount of low end power will make the DD much funner to drive, will have better throttle response, and you will not have to rev the piss out of it to get it going. If you are planning on getting the chassis weight near a Miata, I would do a K20 with a carbon driveshaft, stage 2 cams, RRC or RBC intake manifold, custom header, and lightweight wheels.

Assuming you are buying a used engine, I would take the head off for a performance rebuild. This way all of the exhaust soot can be removed from the valves, exhaust ports, and you can bring the head back to new so the valves seal 100% correctly. While this is happening, it will help stop oil from leaking past the valve guides (happens on older motors), stop oil leaks from the valve seals, valve cover, spark plug seals, and you will actually make more power than if you did not do the performance rebuild.

While the head is off you can further inspect pistons for side to side movement and clean the tops off, install ARP head studs, install new head gasket, update the timing assembly including replacing the timing chain tensioner, and install a new oil pump & water pump.

May sound like alot of things. Though refreshing and engine is a way to invest money into the engine, it is your money, and if you install a used engine without refreshing and it craps the bed after a short time, again it will be your money fixing or replacing the engine again.
 

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Discussion Starter · #4 ·
Hi Travis!

Where do you plan to source your motor from?
Thanks for the reply!

I had originally been looking at local sources around Seattle and Portland for used JDM K24A2 motors, but they are much more limited in inventory than similar sources on eBay. However, it seems that the majority of this forum is rather iffy on eBay being a source for much in the way of the K-series swap.

Any thoughts or direction that you would offer?

Best,
Travis
 

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Discussion Starter · #5 ·
Welcome to the forum and thank you for registering.

If it were me, I would source an entire S2000 AP1 (F20C1) 2.0L (2000-2002) complete swap providing I could find a low mileage one. Since this is not about me and is about you I will give you sound advice.

The K20 was designed for a low drivetrain loss FWD install. The K24 is the same, however with the extra TQ from the larger displacement will be easier to power the RWD set up. The amount of low end power will make the DD much funner to drive, will have better throttle response, and you will not have to rev the piss out of it to get it going. If you are planning on getting the chassis weight near a Miata, I would do a K20 with a carbon driveshaft, stage 2 cams, RRC or RBC intake manifold, custom header, and lightweight wheels.

Assuming you are buying a used engine, I would take the head off for a performance rebuild. This way all of the exhaust soot can be removed from the valves, exhaust ports, and you can bring the head back to new so the valves seal 100% correctly. While this is happening, it will help stop oil from leaking past the valve guides (happens on older motors), stop oil leaks from the valve seals, valve cover, spark plug seals, and you will actually make more power than if you did not do the performance rebuild.

While the head is off you can further inspect pistons for side to side movement and clean the tops off, install ARP head studs, install new head gasket, update the timing assembly including replacing the timing chain tensioner, and install a new oil pump & water pump.

May sound like alot of things. Though refreshing and engine is a way to invest money into the engine, it is your money, and if you install a used engine without refreshing and it craps the bed after a short time, again it will be your money fixing or replacing the engine again.
Holy smokes! That's good information! So first off, I would certainly do the head-off refresh since it's relatively cheap insurance to do such things. What is a "moderate" DD build to consider while doing the refresh? Let's say 280-300 WHP is a goal for this DD; would a set of cams, 50* gear, KPro, head refresh, and quality manifolds get me to that point? Also, how would it affect MPG? After all, this is a fun, DD that I may take to the Auto-X days in the summertime for shits and gigs...

Thanks so much for the reply!

Best,
Travis
 

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2002 DC5 Type S
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Holy smokes! That's good information! So first off, I would certainly do the head-off refresh since it's relatively cheap insurance to do such things. What is a "moderate" DD build to consider while doing the refresh? Let's say 280-300 WHP is a goal for this DD; would a set of cams, 50* gear, KPro, head refresh, and quality manifolds get me to that point? Also, how would it affect MPG? After all, this is a fun, DD that I may take to the Auto-X days in the summertime for shits and gigs...

Thanks so much for the reply!

Best,
Travis
All-motor


Supercharging a stock k20 or k24 getting 300whp is much easier than building all motor power.
 

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Discussion Starter · #7 ·
All-motor


Supercharging a stock k20 or k24 getting 300whp is much easier than building all motor power.
Interesting! However, I'm comfortable with owning a turbo car, but Honda has always prided themselves on high compression NA motors yes? Would I be decreasing the reliability of a DD-capable car if I go with Forced Induction on a K20 or K24?
 

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Interesting! However, I'm comfortable with owning a turbo car, but Honda has always prided themselves on high compression NA motors yes? Would I be decreasing the reliability of a DD-capable car if I go with Forced Induction on a K20 or K24?
depends on how much you get on it, how high your rev it, type of oil, cooling system, and maintenance up keep.

I would boost a K20, some would boost the K24. The k20 has a higher rod ratio because the rods are longer and the pistons have to travel less up and down. The lower the rod ratio, the greater the side forces exerted by the pistons against the cylinder walls. This increases wear on the piston skirts and cylinder walls, and creates a higher level of vibration inside the engine. The increase in friction can also elevate coolant and oil temperatures.
 

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"Any thoughts or direction that you would offer?"

Im a die hard Pick and Pull fan, take that with a grain of salt tho,as my car isnt running yet
 

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Discussion Starter · #10 ·
depends on how much you get on it, how high your rev it, type of oil, cooling system, and maintenance up keep.

I would boost a K20, some would boost the K24. The k20 has a higher rod ratio because the rods are longer and the pistons have to travel less up and down. The lower the rod ratio, the greater the side forces exerted by the pistons against the cylinder walls. This increases wear on the piston skirts and cylinder walls, and creates a higher level of vibration inside the engine. The increase in friction can also elevate coolant and oil temperatures.
This makes sense, but one thing that is swaying my input is the pre-fabbed swap kits being made are essentially starting with K24s in mind when doing this swap. Also wouldn't I want the additional torque from the K24 for the RWD drivetrain?
 

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This makes sense, but one thing that is swaying my input is the pre-fabbed swap kits being made are essentially starting with K24s in mind when doing this swap. Also wouldn't I want the additional torque from the K24 for the RWD drivetrain?
yes the extra TQ would be helpful on throttle input. once under boost i do not think that will come into play. The turbo K20 will make plenty of power to drive the rear drivetrain
 
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