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Discussion Starter · #1 ·
Is it possible to take the rods out of a tsx engine and put them in a rsx-s engine or is the block not high enough. If the block isn't high enough then how many people have put the k20a2 crank in the k24a2 block with k24a2 rods.
 

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Yes, you would have to destroke to 59.944mm netting a 1.3L if you kept 86mm bore.

To use the K20A2 crank in the K24 block would require a 6.250" rod if you used stock compression height piston.

-Ron
 

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Discussion Starter · #3 ·
so you would have to use that long or shorter right? Where can you get that size? I am more for oversquare and big rod ratios
 

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Discussion Starter · #5 ·
what would happen if just used the stock k24 rods. I know they wouldn't be near the top of the deck. Could you tell me where to get the specs for the k24a2 and k20a2 motors like the deck height, piston compression height, rod length, etc. Thanks
 

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If you used the k24 crank and rods in the k20a2 block,the pistons would stick out of the hole,what is it,about an inch Ron?

This will not work at all... the head wont be able to sit anywhere near flush on the the deck surface of the block.The k24 99mm stroke is WAY too big to use in anything but the k24.If the stroke were 92mm,you could get away with it,but unless you are running a deck plate,you will have a horrible rod ratio.There is no reason to plate a k20 block when you can start with the taller deck of the k24.
 

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k24 cranks do fit in a k20a block. And it's not WAY TO BIG for k20. You would have to use a shorter rod to make it work.
 

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edo said:
Yes, you would have to destroke to 59.944mm netting a 1.3L if you kept 86mm bore.

To use the K20A2 crank in the K24 block would require a 6.250" rod if you used stock compression height piston.

-Ron
do you know if the block will need to be notched or is it a direct bolt in..on my old b seris motor we had to notch the block on the bottom of the sleeve for the rods to clear..
 

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fearless_dsm said:
If you used the k24 crank and rods in the k20a2 block,the pistons would stick out of the hole,what is it,about an inch Ron?

This will not work at all... the head wont be able to sit anywhere near flush on the the deck surface of the block.The k24 99mm stroke is WAY too big to use in anything but the k24.If the stroke were 92mm,you could get away with it,but unless you are running a deck plate,you will have a horrible rod ratio.There is no reason to plate a k20 block when you can start with the taller deck of the k24.
what about useing a deck plate on a k24??is there anyone that can make a longer chain and head bolts??
 

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k20ahondas said:
k24 cranks do fit in a k20a block. And it's not WAY TO BIG for k20. You would have to use a shorter rod to make it work.
The shorter rod-bigger stroke isnt always a good idea. I had a B16 stroked and bored to a 2.1L with no deckplate. This gave a severe rod angle and was actually trying to "push" the pistons out the side of my block. There was significant wear on the lower cylinder walls which I assumed to be caused by the oil actually being squished out from the force of the rod/piston.

To the original question, the k20 crank in the K24 would work with custom rods. This is something I have been looking into for a while.
 

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Discussion Starter · #11 ·
you all got it backwards, I wanted a k20 crank in a k24. Also do you know where I can get those specs?
 

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curryitr said:
you all got it backwards, I wanted a k20 crank in a k24. Also do you know where I can get those specs?
what kind of rod do you want to run in a K24 block with an 86mm crank?
 

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curryitr said:
you all got it backwards, I wanted a k20 crank in a k24. Also do you know where I can get those specs?
K24 block height-- 9.114"
compression height-- 1.181"
Stock K20a Stroke-- 3.386"
(taken from wiseco.com)

Basically-- Rod length = block height - comp. height - (stroke/2)

So you would basically want a rod that was 6.240" Edo said a 6.250" rod, so I am not sure why my numbers are a 100th off, but thats what I get.
 

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One of the blocks we measured 9.120". Pistons should be made with appropriate compression height to compensate for block variances, as well as material removed by decking the block. Up to 0.005" is typical to get the deck flat. We like the 6.250" rod because it works in so many applications. With an 86mm crank in the K24 block, the pistons will be proud of the deck between 0.004 - 0.009" at 1.181" compression height (dependent upon final block height after decking). This works really well since we have 0.030" gasket thickness and an additional 0.010" of quench in the combustion chamber.

-Ron
 

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edo said:
One of the blocks we measured 9.120". Pistons should be made with appropriate compression height to compensate for block variances, as well as material removed by decking the block. Up to 0.005" is typical to get the deck flat. We like the 6.250" rod because it works in so many applications. With an 86mm crank in the K24 block, the pistons will be proud of the deck between 0.004 - 0.009" at 1.181" compression height (dependent upon final block height after decking). This works really well since we have 0.030" gasket thickness and an additional 0.010" of quench in the combustion chamber.

-Ron
That would make sense. I just pulled the numbers off of the wiseco site so thats where the difference was. I will find out what my K24 measures out to be and adjust my calculations to that before I move on with my de-stroker project.
 

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curryitr said:
where can I buy a 6.250" rod? Does anybody have dynos or a thread about doing this?
I havent seen any rods commercially available in this size, you will probably end up with something that is custom made.

Unless, edo knows about some shelf rods in that size...
 

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I am sure that someone out there is doing it, or something similar to it.

I plan to use this engine platform when I switch from all-motor to turbo. I dont think that you will sacrafice reliability, but only time will tell.

I know that at 8500 rpm with the k24 stroke the piston speed would be 5522 fpm.
With the K20 stroke piston speed would drop to 4796 fpm at the same rpm. On the negative side, you will lose quit a bit of displacement keeping the stock bore. Displacement goes from 2354cc to 2045cc...about a .3L change.
 

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Discussion Starter · #20 ·
Well hopefully some companies will make more parts for stuff such as this in the next couple of years. It doesn't really bother me to lose displacement, I just want a reliable high performance motor.
 
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