#61831, "How much boost can stock 420 valves take?" Dec-08-03 02:43 AM by ZadensDSM
just wondering what everyones opinions are on this matter.... im rebuilding the head but wondering if the 250 bux spent on stainless valves is necessary or even worth it?
hahn runs on stock valves dont they?
i will be turbo in future, and i'd rather not take the head apart again unless i must, so i'm asking now.... if they are in good shape now and can handle it, why upgrade?
thanks, any and all opinions are welcome
not sure about the setup yet, but it will be a 20g or more capable turbo.... im aiming for 12's (and yes i realise this is quite a task at hand, but im getting there)
#61840, "RE: How much boost can stock 420 valves take?" In response to Reply # 1
IMO I would just get a stock valve job done. Replace the valve guide seals etc while you have the thing off. Other than that, Hahn does use the stock head valvetrain other than I believe valve springs. You should be fine with all the stock stuff. Just freshen it up a bit.
If I am wrong on the HRC's valve springs I apologoize, but I think that I am right.
#61843, "RE: How much boost can stock 420 valves take?" In response to Reply # 0
Well I have 15 psi and valves never float. Now the pistons holding up is another story... something is messed up, but not where near the head. I have done 20psi pulls and the valves seam to work just fine.
-Danny
" We cannot appeal to the conscience of the world when our own conscience is asleep. " Carl von Ossiet
#61845, "RE: How much boost can stock 420 valves take?" In response to Reply # 3
Originally posted by 98RsT Well I have 15 psi and valves never float. Now the pistons holding up is another story... something is messed up, but not where near the head. I have done 20psi pulls and the valves seam to work just fine.
Float is not cause by valves it's cause by the lack of seat pressure which is generated by stiff springs but I've had bent valves on a NA so I would say that SS valves and some aftermarket valve springs are a needed. HRC is good but I cannot comment on their good fortune with a stock head.
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Originally posted by YourInMyMirror95GS dick teaser's should be rounded up and shot in the forehead
Originally posted by etx Good luck man! Project 'STFU Brian your talon is dead meat' should be on it's feet soon!
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#61858, "RE: How much boost can stock 420 valves take?" In response to Reply # 4 Dec-09-03 02:36 AM by ZadensDSM
ok, basically it boils down to this.. this is what i have pt rockers and lifters crower stage 2 cams upper engine gasket set in the process of ordering crower springs and retainers and valve stem seals
i need cam gears and i was going to replace the valves (not messing with the valve guides themselves, unless i absolutely must)
i know its kind of stupid to do everything BUT the valves, but im on a budget and a time limit which is the only reason i posted for info about it
it has to be done between christmas and new years (i have one week off of work and it is my daily driver) and i cant afford both valves and cam gears right now..... so i guess the new q is crane cam gears or stainless valves? thanks for the info guys, i appreciate it
#61869, "RE: How much boost can stock 420 valves take?" In response to Reply # 5
dont buy the retainers its a waste of money.
you have 3 choices on valves rev SI and ferrea in about that order
You can have it cheap, fast or good. Pick any two.
If you want it cheap and fast, it's not going to be good. If you want it cheap and good, it's not going to be fast. If you want it good and fast, it's not going to be cheap.
#61870, "RE: How much boost can stock 420 valves take?" In response to Reply # 6
do the valves
cam gears can be installed ina mere few hours maybe 8 with the motor intact..
Bill
You can have it cheap, fast or good. Pick any two.
If you want it cheap and fast, it's not going to be good. If you want it cheap and good, it's not going to be fast. If you want it good and fast, it's not going to be cheap.
#61878, "RE: How much boost can stock 420 valves take?" In response to Reply # 8
The only things that you would really need to worry about under really high boost is your valve springs. You would want stiffer ones. Also, replace your valve guides and valve stem seals.
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#61924, "RE: How much boost can stock 420 valves take?" In response to Reply # 9
ok, a couple of things im almost positive my gasket kit didnt come with valve stem seals, and they even told me that it wouldnt be included in the kit
second, you guys say dont buy the retainers.... now, lets say i had a redline of closer to 8k, would i need them then? thats why i planned to buy them
now, im leaning towards buying a used head..... it will greatly benefit me, as i can get everything together as i get time to do it and then swap them out and adjust timing over a weekend or something
#61975, "RE: How much boost can stock 420 valves take?" In response to Reply # 10
Originally posted by ZadensDSM ok, a couple of things im almost positive my gasket kit didnt come with valve stem seals, and they even told me that it wouldnt be included in the kit second, you guys say dont buy the retainers.... now, lets say i had a redline of closer to 8k, would i need them then? thats why i planned to buy them now, im leaning towards buying a used head..... it will greatly benefit me, as i can get everything together as i get time to do it and then swap them out and adjust timing over a weekend or something once again thanks guys you rock still open for opinions and suggestions btw
No, the gasket kit does not come with the valve guide seals. A retainer is a retainer, no need to really buy them..I feel the stock vavles are just fine, for whatever you want to run. If you are melting the stock valves, then something needs to be tuned a bit better Some say the SS valves have a bit better thermal conductivity, but who really knows about that...Utilizing the stock redline RPM, a good valve seat grind, new guide seals, and maybe some upgraded springs if you really want to. A very slight deck job done to the head surface to be sure its flat and clean, and that really is all that needs to be done, esp if you are on a budget. People here have run over 20 psi of boost on a fully stock head, without one single issue...its all about the tuning.
13.5 @108 MPH-2.2 60ft(stupid FWD!) S16G @ 18 PSI/FMIC/Running on MegaSquirt II (Now with sequential fuel injection) My webpage: http://eclipsed4evr.home.comcast.net -1998 Mitsubishi Eclipse RS-T- "Toy" -1992 Plymouth Laser Turbo AWD(SOLD) -2000 Honda CR-V(daily)
#61990, "RE: How much boost can stock 420 valves take?" In response to Reply # 12
i have NEVER replaced my valves, and i dont think you can throw enough boost at them to make them the "weak link". if you bend them or otherwise harm them, either they were faulty or something else was wrong. that being said, if you have the head off already...and you have the MONEY(that being the most important part) id say, why not go ahead and upgrade them? if $$$ isnt the issue, might as well replace/upgrade everything you possibly can the first time round. i replaced my lifters,rockers,cams and had a 5-angle valve job done the last time i tore mine apart. might as well while its easy. 1999 Black C5 1997 Silver RS Wiseco 8.8:1 Pistons(back to low compression!) Eagle Rods T3/T4 Turbo Custom FMIC Greddy Exhaust 390's Most current 1/8th mile time: 8.3@90mph 2.015 60'(Nitto Drag radials, i suck)
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Some say the SS valves have a bit better thermal conductivity, but who really knows about that...Utilizing the stock redline RPM, a good valve seat grind, new guide seals, and maybe some upgraded springs if you really want to. A very slight deck job done to the head surface to be sure its flat and clean, and that really is all that needs to be done, esp if you are on a budget. People here have run over 20 psi of boost on a fully stock head, without one single issue...its all about the tuning.
