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Old 12/20/2011, 08:16 AM   #1
crxh22honda
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Default over size valves? are they a good idea or should i just leave them alone

I'm questioning on getting over sized valve. Here is a small part of my build. So someone can help me.
H22a
BisiMoto stage 3 cam
Crower crank 100mm
BisiMoto custom pistons 88.5mm 12.1 to 1

An when I get this figured out ill be sending my head off to RLZ to get PNP

I have brand nw skunk2 STD valves but wondering if there is power gains by going with .5 over n is it worth it an is it safe.

I've read some things now honda-tech but u never know with people on there. Like one thing I've read was v-tec motors don't like them to much. But I didn't see why. An with big cams an high compression its not to safe cause they could hit. But then someone said its just in the tuning. Now I'm just lost.

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Old 12/20/2011, 08:56 AM   #2
Charlie Moua
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Default Re: over size valves? are they a good idea or should i just leave them alone

Quote:
Originally Posted by crxh22honda View Post
I'm questioning on getting over sized valve. Here is a small part of my build. So someone can help me.
H22a
BisiMoto stage 3 cam
Crower crank 100mm
BisiMoto custom pistons 88.5mm 12.1 to 1

An when I get this figured out ill be sending my head off to RLZ to get PNP

I have brand nw skunk2 STD valves but wondering if there is power gains by going with .5 over n is it worth it an is it safe.

I've read some things now honda-tech but u never know with people on there. Like one thing I've read was v-tec motors don't like them to much. But I didn't see why. An with big cams an high compression its not to safe cause they could hit. But then someone said its just in the tuning. Now I'm just lost.

It looks like you have decent compression and cams
honestly if your getting your head done by RLZ, i'd go oversized valves!

if your wondering about whp gain per dollar spent, oversized valves don't provide much.....
but then again, it's all about how much money your willing to pour into your NA setup.

IMHO i think more gains would be beneficial from a good IM or custom if possible.

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Old 12/20/2011, 09:35 AM   #3
crxh22honda
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Default Re: over size valves? are they a good idea or should i just leave them alone

I'm really bad on abbreviation what's IMHO n im...... intake manifold? I Make Hoes Ooooo? I serious don't know them.

Last edited by crxh22honda; 12/20/2011 at 09:38 AM.
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Old 12/20/2011, 09:43 AM   #4
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Default Re: over size valves? are they a good idea or should i just leave them alone

What are the specs on those cams? I know that with the Skunk Pro3 cams and even the Pro2 cams you do NOT want to run oversize valves. I dont think the Bisi stuff is as aggressive so maybe you can get away with it but I know with the Pro3's the valve to valve clearance was about .03" which is very tight and doesnt leave any room for error. It makes me nervous just thinking about how close that stuff gets when its whizzing around at 9k rpms!

You deffinately want to be careful and degree the cams either way you go. You can check valve to valve clearance by assembling the cylinder head, without putting it on the block and wrapping an old timing belt around it so that you can rotate the cams in sync with each other, then measure your clearances with a feeler guage. You can adjust your cam gears and make yourself a little chart so that you know what clearances you have at different settings, that way later on when its all together you will have those specs.

With aftermarket pistons you shouldnt have an issue with clearance on the piston side of things. Even with higher compression the valvepockets typically stay the same, the dome just gets bigger.

For reference my motor is an 89x99 (just a few cc's bigger) at 14:1 compression and I still run stock valves. Partly because of the clearance issue and partly because I dont feel that it would benefit me. The best person to ask this question to though would be Brad himself since the valve size directly affects what he is going to be doing with the port work and both of those aspects have to work together. I think he will have the same opinion as me and thats to keep it stock. I know if the geometry of the head were different however it would be a different story. The angle the valves are placed in the head is a real limiting factor on valve/cam size.


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Old 12/20/2011, 09:44 AM   #5
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Default Re: over size valves? are they a good idea or should i just leave them alone

Quote:
Originally Posted by crxh22honda View Post
I'm really bad on abbreviation what's IMHO n im...... intake manifold? I Make Hoes Ooooo? I serious don't know them.
IMHO = In My Honest Opinion


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Old 12/20/2011, 10:26 AM   #6
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Default Re: over size valves? are they a good idea or should i just leave them alone

This is what BisiMoto site says. .488 valve lift/.470 (272 Dec intake at. 050 lift /270) when they get here ill know more.

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Old 12/21/2011, 01:51 PM   #7
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Default Re: over size valves? are they a good idea or should i just leave them alone

Stick with standard sized valves with Bisimoto Level 3 camshafts. H22 heads have poor valve angle and will have valve to valve clearance issues with large lift camshafts. Also if you are looking for a more serious CNC head porting services Bisimoto can help you out also


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Old 12/21/2011, 07:55 PM   #8
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Default Re: over size valves? are they a good idea or should i just leave them alone

Im really considering you guys. We shall have to talk about it soon when I'm ready.

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Old 12/22/2011, 02:20 PM   #9
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Default Re: over size valves? are they a good idea or should i just leave them alone

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Originally Posted by crxh22honda View Post
Im really considering you guys. We shall have to talk about it soon when I'm ready.
Certainly give us a call or email me at Julio@bisimoto.com for more information and prices for what we can do for you.


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Old 12/22/2011, 03:01 PM   #10
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Default Re: over size valves? are they a good idea or should i just leave them alone

I've tried to find pictures of your guys work. N its just not really out. I know a picture doesn't mean much. But I would kind like to see.

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Old 12/23/2011, 04:24 PM   #11
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Default Re: over size valves? are they a good idea or should i just leave them alone

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Originally Posted by crxh22honda View Post
I've tried to find pictures of your guys work. N its just not really out. I know a picture doesn't mean much. But I would kind like to see.
google image search bisimoto cnc porting.. i've seen several online.


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Old 12/23/2011, 04:24 PM   #12
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Default Re: over size valves? are they a good idea or should i just leave them alone

http://bisimoto.com/store/index.php?...&cPath=5_9_101


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Old 12/23/2011, 07:01 PM   #13
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Default Re: over size valves? are they a good idea or should i just leave them alone

Lol i know the information on it n I've seen the site but. When I did that most of them won't connect cause its a site that's not infuse anymore. N also none of them are h22. N i didn't really see any b series erither.

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Old 12/29/2011, 12:23 AM   #14
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Default Re: over size valves? are they a good idea or should i just leave them alone

I thought I told you to ask me these sort of things so you don't have to spend days doing research. Although I guess it's not so bad that you post about it because Rosko has a much better way of explaining things then I do. And he's got a lot more knowledge then I do.

Anyhoo, keep the stock sized valves. You have many more reasons to keep it stock then to go bigger. Here's a few pros and cons for ya to look at. Hopefully this will make you see you should just keep it with the stock sized valves.

Reasons to keep your stock valve size- You already bought valves so if you bought different ones you just wasted money. You'll feel a lot more comfortable with your motor if you keep the ones you have. Over sized valves don't add as much power as you wish they would.

If you went oversized here would be things that you should expect.- You're valves would be ridiculously close to each other, about a fingernails thickness (of course depending on your cam size, valve size, and who did the timing set up on it.) with them being that close just a small amount of slack in your timing belt could cause them to hit. Just think about how easily your alternator belt tends to flip over on you. Another thing to think about is how strong your valve springs are, not strong enough could cause a small enough amount of valve float to cause them to hit. If you went oversized you would always have that fear and thought in the back of your head that at any given moment your motor could spontaneously blow and all that money you just spent would go right into the shitter.

This is also your first personal motor build that you've ever done, you haven't really gone that far in depth of building it. Yes you know all the parts necessary and you've done all the research to determine what parts are the best to go with for what you want. But have you ever looked at how dangerously close your valves come to touching each other? Just the littlest mistake is all it takes. Setting your cam pulleys off by 1 degree and it's over. They could potentially hit the first time trying to start the car and it would be over before it ever began.

I guess the best piece of advise I have for you is this. You're building a street car, so keep it a street car. You're going to drive this car everyday, so build it for that everyday purpose. You don't need to squeeze every small bit of power that you can out of this.


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Old 12/29/2011, 06:40 AM   #15
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Default Re: over size valves? are they a good idea or should i just leave them alone

This car won't be driven much anymore when its done,ill be looking for tracks n events n if it doesnt come out that much then thats ok. How often is it out anyways. N i want it to last. I dont want to build another car. Its personal.But I am sticking with skunk2 STD valves. Bisimoto springs,retainers,stage 3 cams,PNP,pistons 88.5mm,sleeves,injectors,header,head gasket,dhracing intake manifold(might go with some kinser itb soon see what the deal is)100mm Crower crank, BisiMoto will also be putting it together.


BisiMoto gave me a really really really good deal.I was shocked. N got a group buy on the header.

Last edited by crxh22honda; 12/29/2011 at 06:47 AM.
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