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Discussion Starter · #1 ·
im currently putting together a motor and am not sure what +plus size valves i want to use for intake, im going to use supertech titanium valves with double behives1021 ,ti retainers and drag cartel street cams , the head will be ported
should i use +1, +1.5, +2, +2.5 for intake valves ( ill be using standard ex)

other list of engine mods

fullblown intake manifold
74mm throttle body
bc 102mm crank
saenz ti rods
je pistons 89mm 12.5:1
acl bearings
darton sleaves
dc/atpower/daileyeng dry oil sump
kpro hondata
rdx fuel injectors
radium engineering fuel rail
s2000 fuel pump
plm swap header
3inch exhaust
takeda intake
 

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97 civic HX K24a
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im currently putting together a motor and am not sure what +plus size valves i want to use for intake, im going to use supertech titanium valves with double behives1021 ,ti retainers and drag cartel street cams , the head will be ported
should i use +1, +1.5, +2, +2.5 for intake valves ( ill be using standard ex)

other list of engine mods

fullblown intake manifold
74mm throttle body
bc 102mm crank
saenz ti rods
je pistons 89mm 12.5:1
acl bearings
darton sleaves
dc/atpower/daileyeng dry oil sump
kpro hondata
rdx fuel injectors
radium engineering fuel rail
s2000 fuel pump
plm swap header
3inch exhaust
takeda intake
You may want more injector than rdx for your build. 89mm 12.5:1 with a ported head AND OS valves will want a lot of fuel. I would get 1000s to be honest. How much power are your shooting for ? Lots of 300whp motors on oem sized intake valves.
 

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Discussion Starter · #3 ·
You may want more injector than rdx for your build. 89mm 12.5:1 with a ported head AND OS valves will want a lot of fuel. I would get 1000s to be honest. How much power are your shooting for ? Lots of 300whp motors on oem sized intake valves.
would get 1000s to be honest. ya i was kinda thinking that as well , that was going to be my next question...
-How much power are your shooting for as much as i can make off canadian 94 chevron, no other magic fairy juice though
 

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Is the S2000 fuel pump capable of supporting the fuel needs? Fuel pumps are not expensive, it would not hurt to have something that can push more fuel.

I think the PLM headers are decent headers for the money. In the case of a build like the one you are putting together, I would suggest getting a custom header. Something from ASP, DTR, or Hytech will really pull power out of this set up. A good investment I think for a custom badass NA build. You know what I mean?
 

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going much bigger in combination with big cams might get you into trouble with valve to valve clearance.
Dan Webster in the UK build a 92mm 87mm bore stroker with the clockwise crank and 27mm compression height pistons, ITBs and +1mm valves, actually of the F series engine, and got just over 300 crank HP.

I had a 93mm K20 block stroker having the bores worn out within 5000km. The short rod to stroke ratio did not help at all. Lot of torque, flat top end.

With this stroker crank, I‘d consider getting pistons with a lower compression height allowing for slightly longer rods and with it a better rod to stroke ratio.


These pistons are available in 86.5mm / 87mm / 87.5mm / 89mm. Buys you 3mm rod length.
 

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going much bigger in combination with big cams might get you into trouble with valve to valve clearance.
Dan Webster in the UK build a 92mm 87mm bore stroker with the clockwise crank and 27mm compression height pistons, ITBs and +1mm valves, actually of the F series engine, and got just over 300 crank HP.

I had a 93mm K20 block stroker having the bores worn out within 5000km. The short rod to stroke ratio did not help at all. Lot of torque, flat top end.

With this stroker crank, I‘d consider getting pistons with a lower compression height allowing for slightly longer rods and with it a better rod to stroke ratio.


These pistons are available in 86.5mm / 87mm / 87.5mm / 89mm. Buys you 3mm rod length.
@Lotus
If the OP uses a 92mm stroke crankshaft, would running flat faced valves be a safe way to increase the compression? Would running the flat faced valves intrude on the safety margin between valve and piston contact?

From what I have read, when running flat faced valves one can increase the compression ratio by 0.4 points. I am sure the actual compression gains would vary from engine to engine, and one of those factors would be if the block's piston rings are new. One my next engine build I have interest in running flat faced valves that have the same weight as typical dome shaped valves and I want to start at a 11.7 compression piston.
 

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The tightest spot is usually the edge of the valve, but then they are concave. At least for the Mahle forged pistons, the angle of the valve pocket and the angle of the valve are identical at 26° and 25°.
For a flat faced valve, you'll get the same clearance as for a concave valve.
The point I don't get is how a flat faced valve can be as light as the otherwise identical hollow valve.

If you want higher compression, get a higher compression piston. My Mahle piston was shipped as 12.8:1 to start with. I then had it machined and the intake valve pocket deepened by 1mm for about 11.5:CR.
Both intake valve pocket machining, the critical bit, and dome machining were "OKed" upfront by Mahle in Germany. The engine shop that did the piston work and block boring shipped one of my pistons to Mahle Germany to check upfront if this is OK. Any deeper and the pockets gets too close to the top ring groove. These pistons come from Mahle Motorsport in the USA.





As my calculations on the dome volume, it is a complex shape, were slightly off, I had to further flat sand off some aluminium to get to the desired dome volume. As the dome milling already created a flat reference plane and weights were still very uniform this was very easy to do by hand with weigh control
I based my removal on weight as I have a precise laboratory balance. The pistons were very uniform to start with with a weight difference of less than 200mg straight out of the box.
Pins were very uniform, too. My former supertech pistons were much less uniform. I had to machine both pistons and pins and match them in pairs to equalise the weights. Pins were off by more than 1 g to start with. Mahle pins deviated by less than 100mg across all 4 pins! The quality is literally an order of magnitude better.

 

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Thank you for that bit of information. Impressive the custom work on the piston.

The point I was trying to make and now it really is not a point lol... was I want to find a flat faced valve that weights less than a standard OEM dome shaped valve. Yes if both valves are made of the exact same material the dome shaped valve will always be lighter.

I have never built a custom engine like yourself and I want to build on soon. Thank you for sharing Lotus.
 

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im currently putting together a motor and am not sure what +plus size valves i want to use for intake, im going to use supertech titanium valves with double behives1021 ,ti retainers and drag cartel street cams , the head will be ported
should i use +1, +1.5, +2, +2.5 for intake valves ( ill be using standard ex)

other list of engine mods

fullblown intake manifold
74mm throttle body
bc 102mm crank
saenz ti rods
je pistons 89mm 12.5:1
acl bearings
darton sleaves
dc/atpower/daileyeng dry oil sump
kpro hondata
rdx fuel injectors
radium engineering fuel rail
s2000 fuel pump
plm swap header
3inch exhaust
takeda intake
Don't use very large oversized valves for your setup, especially if use very big cams.
Ex side let it stock.
In side Max + 1mm.
Over 1mm will loose midrange torque.
13.5CR + recommend bigger 37mm+ valves..
 
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