oversize valves worth it?

Discussion in '2.3L (N/A & Turbo) Tech' started by mr_woodster, Nov 27, 2003.


  1. mr_woodster

    mr_woodster Active Member

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  2. Lx89Stang05

    Lx89Stang05 Founding Member

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    thats a big help since these heads on the tubos dont flow good, a good port job with nice valves will work good.

    __________________
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  3. muh'stang

    muh'stang If I were rich, I'd make sure all the scoops on my

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    the idea came to me the idea day while on a ricer board, I said to them: "reduce the base circle of the came lobe significantly and replace youre valves with oversized ones that are the right length longer then the stock ones so they roll on the modified cam properly"
    In theory, it sounds like it would work.
  4. mr_woodster

    mr_woodster Active Member

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    anyone know what the stock valve sizes are? Also the flow numbers of a head/valve stock , verse ported with bigger valves? one more thing, if i want to use an aftermarket grind for my cam, would i need to use the old solid followers, or can i get a roller cam for a 2.3 custom grinded?
  5. bhuff30

    bhuff30 Founding Member

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    oversized valves are great, but not unless you have the matching work. You need to unshroud the valves, or you only shroud them more by installing larger valves. in short, unless your head is ported and unshrouded, it won't be worth the effort or cost.
  6. Lx89Stang05

    Lx89Stang05 Founding Member

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    turbo heads have
    Intake valves 1.73
    Exhaust valves 1.49
  7. mr_woodster

    mr_woodster Active Member

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    thanks guys for the info, thats great stuff! Should i get the machined (valve seats done, etc) before i further* unshroud, so so i knew what im looking at as far as the max radius of the port? Also , looking at this kit, comes with dual springs and stuff, would u guys (anyone who has delt with this issue) recommend this setup? i have heard of better spring rate springs, but not a dual setup like featured. the benifits seem obvious, better reliablitly at high rpm, using duo-springs to prevent valve float. I could be way off, but it seems like a good idea, what are your thoughts?
  8. GTPhreak

    GTPhreak Founding Member

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  9. mr_woodster

    mr_woodster Active Member

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  10. GTPhreak

    GTPhreak Founding Member

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    yeah its my site, but that is ispy malik's head. he posts on here sometimes, but the motor isn't built/installed yet
  11. mr_woodster

    mr_woodster Active Member

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    anyone? stinger .... 140 , svo1? has anyone done this here besides me ( me wanting too that is)...just looking for some knowledge able feed back ( i have reicieved plenty about matching un shrouding and such thanks guys!) ...so the more the merrier :p
  12. 140cilx

    140cilx Founding Member

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    you want input from someone stupid?

    Sure.

    I only have one buddy w/ the oversized valves whose head I've worked on. I'd go that route if you did all that bhuff said. This head I mentioned is awesome, should be installed anytime now and he'll hopefull dyno so we can see improvements. Many argue that it's not really worth it since the stock valves handle all the limited head is capable of anyway.

    I'd do my porting first though, so that if you accidentally touch the valve seat, they will address that anyway when they do the valve job and remove your flaw. If I was doing it after they did the valve job I'd be a little more nervous. And actually, I've done it both way's.

    When they do the 3 angle or 5 angle for the big valve install, rest assured it will blend in nicely w/ the work you'd do unshrouding the valve and opening up the short side and you shouldn't have to go in again and clean anything up.

    The valve springs doubled like you mentioned is nice, but only if you are gonna go beyond the stock computer rev limit w/ something tunable. Stock springs are fine and won't float well beyond the 6.25k redline. For minimal parasitic drag, if you are staying with the stock computer, I'd just continue to use the stock springs. AND for me, I don't like solid lifters, I don't like adjusting tappet's and I don't like shimming. I like the oil pressure keeping everything in spec so I don't have to plan on checking them every 10k miles. That's just me.
  13. mr_woodster

    mr_woodster Active Member

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    so would i hafta use solid lifters in order to do this setup? I've aske about the durablity of stock springs about the rev limiter, i wasnt sure how safe it was. My plans are to raise the limiter to about 7k , i dont think ill be pulling to a 7k redline, but i want to use it as a buffer zone when/if i use a nitrous setup. Unless im mistaken (very well could be ;o) ) when u hit the revlimiter it starts to cut fuel pressure...and running lean and melting pistions with nitrous isnt my idea of fun ;O) anyone who wants to clarrify some of these details , do so !
    thanks again
  14. 140cilx

    140cilx Founding Member

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    the answer I got to your question is every set of stock springs might be a bit different than their brethren. I never had people telling me that they experienced valve float beginning at 7,500 rpm or anything specific.

    I know a local guy that raced his carb'd n/a 2.3 flattrack and ran it at 10,000 rpm on stock springs every race the entire race for a season and a half before breaking his crank.

    On my nitrous I'm just using a little plug in pill from msd that shut's off the nitrous at 6k. It'll operate in a window like 2500 to 6000. pretty common, $50.
  15. Stinger

    Stinger Founding Member

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    You do realize you will probably have 500-600 bucks minimum in the head if you want to do this right? IMO the money is better spent elsewhere. I can think of much easier ways to gain power. IMO this mod is best left to the guys looking to sqeeze the last 20hp out of their nearly maxed out setup.

    Of course, that is only my opinion...you can do whatever you want...it's your money :shrug:

    You don't have to use solid lifters, you don't have to use double springs (although I don't see why not if you have them). You don't have to do anything special except have the head machined properly for the bigger valve seats and have them installed.

    You can have a roller cam reground, get a custom slider cam, roller cam, whatever you want...

    Stinger
  16. Turbobob

    Turbobob Founding Member

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    Gotta chime in

    OK I gotta chime in with my set up. I've done the big valve install into an oval port head and can see a big difference from the stock set up. I had the valves cut into the head before I unshrouded so I knew how far I had to go. My springs are not dual but show now trouble at all at high rpm. I also have the 60mm throttle body and let me tell you mister.....RESPONSE!!! would be an understatement. I chose this setup mainly 'cause I wanted more flow and throttle response. Well it worked. I can run less boost but get the same power as before. The airflow math has changed of course , but if you realize everything you've done and change accordingly , it's all good.
    Needless to say I Love It!! :banana: :banana: :banana:
  17. mr_woodster

    mr_woodster Active Member

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    if i go with just the valves (same sizes, just not the extra stuff) plus a valvejob i would have ~200 into the head, unless im missing something?
  18. Turbobob

    Turbobob Founding Member

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    200

    Yes that's about right. I allready had an A237 cam and roller followers so it was about thaty much to do the valves in.
  19. mr_woodster

    mr_woodster Active Member

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    well tomorrow im ording my valves, i think my setup will be a fully ported head, new valves, roller rockers/ranger cam. that should take care of the head for the most part. im thinking if i want to have a custom cam someday , i wont hafta pull the head. Right now just setting things up in such a way that upgrades will mostly be accessable/external things that are (more) easily changed out, without having to pull the head, or the entire motor....though it is sooo much fun ;o)
  20. mightypoof

    mightypoof Founding Member

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    My head as the machine shop right now getting the large valve conversion done.... I am pretty dam excited too....

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