Valves

[Reaper27]

Ok so I'm trying to get all of my components and parts either already in the car or in my possession and then I want to get a k24a1 to swap in and just keep it as my daily driver to have some fun with. Since most everything that goes on or in a k20a3 will directly swap over to the a1 I'm just thinking about getting everything on the a3 so it will just swap over. Right now I just got kpro and I'm thinking about doing my head work next. I don't know much about the valve train and am kinda confused about what to get. When I'm done with the car I want to have the a1 supercharged and pushing around 300 whp or so. I'm going for forged valves and I'm wanting to know whether I should get oversized, stock size but high-compression, or what? Sorry if this is stupid or noob question but I checked the search and couldn't really find anything that would answer my questions. Thanks guys

[AKEP]

stock size for the crv valves. you want to run the a1 head, the casting flows more. you can choose what you want to do with those valves but im guessing slightly higher compression with flat valves is what you want to do. springs and retainers too, obviously. you'll need the springs before a cam (stg2+)

[USAF EP3]

Keep in mind if you choose to go oversized valves, do the intake first then the exhaust valves. Also, when going oversized, the valve seats have to be lapped to accept the larger diameter valves. If your seats don't have enough material for this the machine shop doing the work on your head is going to charge you for new seats and installation of new valve seats on top of the valve lapping they need to perform for the new valves.

You will not net major gains from going oversized. Those options are there for those who are searching to extract ever bit of power from their engines. Since you're going forced induction, going flat-faced valves will help you more (about a .2 bump in CR) than going oversized.

[Civic5lug]

Why would you upgrade your valves if you only plan on pushing around 300?

IMO thats super over kill. S2K springs, retainers, keepers and a mild cam.

[AKEP]

Why would you upgrade your valves if you only plan on pushing around 300?

IMO thats super over kill. S2K springs, retainers, keepers and a mild cam.

yeah that

[Reaper27]

I plan on doing at least stage 2 of not stage 3 cams so I was just going to upgrade the entire valve train (cams, springs, retainer, valves, etc). Its going to for power yea but also for smoothness and reliability. So from what you guys are saying to go with the stock size, flat, and a slightly higher compression. So what compression would ya'll recommend?

[USAF EP3]

I plan on doing at least stage 2 of not stage 3 cams so I was just going to upgrade the entire valve train (cams, springs, retainer, valves, etc). Its going to for power yea but also for smoothness and reliability. So from what you guys are saying to go with the stock size, flat, and a slightly higher compression. So what compression would ya'll recommend?

With what you just said here, you won't need a supercharger to make +300 WHP.

We have a member here who made around 275 WHP with a JRSC on a Stock longblock K20A3. He used a meth injection kit and almost broke 300.

A local friend made 242 WHP and ~200 WTQ from a aftermarket built short block (K24A4 w/12.5 CR Wiseco & H-beam rods) and a STOCK K20A2 head.

If you want +300WHP with forced induction you won't need to build the engine much...especially if it's going to be on a K24A1 longblock.

If you still are bent on building the engine, get some 11.5:1 CR pistons, some IPS K2's, S2K valvetrain and you will have a beast of a K24A1. If you still wanted to go FI, the CR on the pistons will still be safe enough to run a small amount of boost (~6-12 psi)

[Reaper27]

With what you just said here, you won't need a supercharger to make +300 WHP.

We have a member here who made around 275 WHP with a JRSC on a Stock longblock K20A3. He used a meth injection kit and almost broke 300.

A local friend made 242 WHP and ~200 WTQ from a aftermarket built short block (K24A4 w/12.5 CR Wiseco & H-beam rods) and a STOCK K20A2 head.

If you want +300WHP with forced induction you won't need to build the engine much...especially if it's going to be on a K24A1 longblock.

If you still are bent on building the engine, get some 11.5:1 CR pistons, some IPS K2's, S2K valvetrain and you will have a beast of a K24A1. If you still wanted to go FI, the CR on the pistons will still be safe enough to run a small amount of boost (~6-12 psi)

This is good to hear. I plan on having everything in the a3 motor including the JRSC and just swapping over to the a1. I would like to still build the motor and have the JRSC just cause I won't the motor to be completely spectacular and for slaps and tickles :-p. So if I build the motor and boost with the SC would forged valves (stock size, higher compression, flat bottom), titanium springs and retainers, and then either stage 2 or stage 3 cams?

[Civic5lug]

I plan on doing at least stage 2 of not stage 3 cams so I was just going to upgrade the entire valve train (cams, springs, retainer, valves, etc). Its going to for power yea but also for smoothness and reliability. So from what you guys are saying to go with the stock size, flat, and a slightly higher compression. So what compression would ya'll recommend?

Stage 3 cams and smoothness......LOLZ

You should study some builds over on k20.org. They've got some MONSTER builds.



With what you just said here, you won't need a supercharger to make +300 WHP.
300WHP ALL MOTOR?!!!!!!
:bs:
unless your pockets are SUPER SUPER deep lol

[USAF EP3]

Stage 3 cams and smoothness......LOLZ

You should study some builds over on k20.org. They've got some MONSTER builds.



300WHP ALL MOTOR?!!!!!!
:bs:
unless your pockets are SUPER SUPER deep lol

What do you mean deep pockets?

My current build I'm shooting for 300. Now I do have to mention I have about $10k dumped into it and still have a bit more to go to finish it. If $10k is what you mean by deep pockets, lol.

It's not cheap, no, but some of the better quality cams labeled as "Stage 3" are capable of producing 300 WHP N/A. BUT you will need the supporting mods done to the rest of the engine. Full blown port and polish on the head, oversized intake valves, high CR pistons, etc.

When he mentioned that, maybe I just assumed that he would go the route I originally started. Forgive me if it came out as misguided advice.

Yes, it gets expensive quick I would know, lol. I don't realise how much I have spent until I look back and count the pennies.

[Reaper27]

As far as stage 3 and smoothness haha I meant like smoothness as in motor operation not idle. But yea I don't really want to spend 10k on just the motor to make 300whp. I would rather just build the motor a little and boost. I figured I could just go ahead and redo the entire valve train instead of just parts of it.

[USAF EP3]

As far as stage 3 and smoothness haha I meant like smoothness as in motor operation not idle. But yea I don't really want to spend 10k on just the motor to make 300whp. I would rather just build the motor a little and boost. I figured I could just go ahead and redo the entire valve train instead of just parts of it.

Don't waste your money on the valvetrain then. Your focus is not where it should be if that's what your goal is.

Build the block, leave the head stock and boost it, whether it'd be by supercharger or turbo. This will be the most efficient and reliable way to reach your HP goal. Good luck with your build.

[Ba82Ep3]

K24a1 valves are the same as k20a3. They even interchange into a k20a2.

I wanna state that aftermarket forged this and that isnt going to guarantee an excellent build. NA Stg3 cams arent going to work so well with a JRSC. And forged pistons arent really gonna be your best choice if youre gonna daily drive the car.

Instead of wasting $ on valvetrain you would be better off port matching the TB and manifold... and then your JRSC inlet once you got that. Spend $ on upgrades that will make the best out of your build... instead of just slapping a bunch of parts together. An engine works best when paired with high quality parts that seamlessly work together to efficiently make power.

JMO tho.

[USAF EP3]

Maybe you need some better guidance....

Here's what I would do if I were in your position:

K24A1 Longblock
Exhaust roller rockers all the way around (VTEC cam killer setup)
K20A2 camshafts (VTEC cam killer setup)
K24A2 pistons
JRSC
3.8 SC pulley (or smaller of your choice depends on how much boost)
650cc injectors (don't quote me you might need more)

With this setup you will make more than enough power, I can't guarantee 300 WHP but you will be pretty damn close if not right on it. If I could do it over again I would've done it this way and not dumped so much money into an N/A build, lol.