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Discussion Starter · #1 ·
Installing Toda cams and valve springs in a K24A and ran into an issue. Toda says that stock retainers are fine but they appear to be small and looks pretty sketchy.

Installed to test and left is Toda valve spring with stock retainer and right is stock spring and retainer.

It looks wrong to me...has anyone else run into this issue?
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This is for a gravel rally Civic

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Discussion Starter · #9 · (Edited)
Thanks all...it appears the K24A OEM is a single spring with a smaller diameter retainer. Any recommendation on aftermarket retainers or just run a OEM part number 14765-PRB-A01 with 14781-PRB-A02 locks? I likely need to change the spring seat too.

BTW...ditching the JRSC and just going NA since all we need is 240whp for gravel.

Andrew
 

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Discussion Starter · #13 ·
Thanks all...it appears the K24A OEM is a single spring with a smaller diameter retainer. Any recommendation on aftermarket retainers or just run a OEM part number 14765-PRB-A01 with 14781-PRB-A02 locks? I likely need to change the spring seat too.

BTW...ditching the JRSC and just going NA since all we need is 240whp for gravel.

Andrew
Following up on this as it seems that Acura/Honda is out of stock on new 14781-PRB-A02 locks, and backordered indefinitely. Therefore, I will likely need to run aftermarket retainers and locks and leaning toward SuperTech steel retainers and matching locks. Does anyone know if this will change the valve height/seat pressure as compared to the stock dual spring set up?
 

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Discussion Starter · #15 ·
Height is dictated by the valve and not the spring.
Seat pressure will be higher with the Toda springs compared to stock, but likely lighter than Supertech double springs.

The K24 will extend its powerband with the JRSC even at very low boost. It‘ll climb to wherever you set the limiter. do you have any class restrictions?
Which Toda did you get?

My CT-E SC (also Eaton MP62) does not work well with the Toda A3 on my K20 build. It severely lacks torque independed of VTC angle and boost is low. It likely suffers blow-through. For next season, I drop in the k20a2 stock cams or go back to NA and the RBC intake manifold.
I am removing the blower and just going N/A since we were only using 3lbs of boost, didn't seem worth the weight and heat. No class rules, but anything over 250whp in a 2200lb fwd car on gravel is pointless.

I went with Toda C's
 

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Discussion Starter · #17 ·
Toda C on a K24 should make a very nice NA engine. Did you fit forged pistons and steel rods or are you running a stock bottom end? If the latter, don't overdo it with the rev limit.

a 3 PSI it won't generate a lot of heat, but the VE won't drop no mater how high you rev the engine. It is a very nice combo despite the low boost. It will easily get you over 250wHp. I am not so sure on Toda C plus supercharging. So overall sounds like a good idea to start off as NA first.
Rev limited is set at 7800...bottom end is stock and only internal change is cams and fixed 35 VTC gear. Car is tuned via AEM ecu.
 

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Discussion Starter · #19 ·
Jeff Cooper in the UK got about 280 crank HP and 214 lbs ft out of his K24 NA with cams and RBC intake and 330bhp and 222lbs ft torque with the JRSC.
It just did not last long reving it to 8k with a stock bottom end.

Gains with the SC were mainly up to 5000 and post 7000 rpm.






Check out his videos. He build a dry sumped K20 caterham on ITBs and the like.
Thanks - I did lose the previous motor (overheated but that may have been from something else), maybe spinning it too high? I think there's not much to gain after 7600 anyway, just top speed with the short gearing.
 

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Discussion Starter · #27 ·
PRB 02-04 K20a2


The 05-06 K20z1 Retainers may be flat. If the image is needed I can provide.
Thanks - I ordered SuperTech steel retainers and locks since the OEM locks on not available from Honda, according to my parts folks. They only had 20 available. I assumed that the SuperTech locks won't work with the OEM K20A2 retainers.
 

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Discussion Starter · #31 ·
Quick update - new Supertech retainers, seats, seals and locks in place and Toda springs are much happier....but there appears to be valve to piston interference with the new Toda C's. Cams spin freely, pistons spin freely but once we put the timing chain on it spins a bit and then binds...spins the other way and then binds again. The goal was to not open the motor and just drop new cams and springs in. The Toda C's have 12.5mm EX and 13mm IN lift....is that too much for a k24a or is something off indexing wise?
 

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Discussion Starter · #34 ·
Update - Finally got everything sorted and installed. Tuned on the dyno last night and netted 190TQ and 233HP at the wheels on 91 octane, VTC hit about 28/29 but is physically limited at 30. We played with the VTEC engagement between 4k-5k and 5K seemed to the smoothest point. It seems to top out at about 6700rpm and assume this is due to my 2.5" exhaust system...with a 3" exhaust system it should keep running to 7000+
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Discussion Starter · #36 ·
I had 2.5" exhaust systems on 290 hp engines for tuning, the difference is just a few lbft in quantity compared to 3" pipings, has nothing to to with what we see here. Something blocks, much more serious I assume. Could be from not optimal tune, a rare valve issue (floating, lash, ...) up to an non well sealing engine or just a simple fuel injector issue and something in the path of alternation of load. Much more serious as just a simple too small piping. Just my two cents.

I am open to check your calibration/WOT log for a second response for you. Do you have header design parameters for validation as well as the exhaust setup for me?
Thanks for the insight. I would think the limit with just cams, header and intake would be 240-250whp on a stock k24A bottom end and head, no? Tune shouldn't be an issue, my tuner has a long history with Honda's, work(ed) for Singer Porsche tuning their cars and tunes on a daily basis. I can see if I get the WOT logs, if you're interested. If there's an issue I'd like to solve before the next rally.

Andrew
 
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