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Location:
Adelaide
Registered:
May 2003
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Valve sizing (4A upsize)
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Thu, 03 March 2005 07:01
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After being inspired by the famous documentary Super Size Me i am trying to figure out a valve conversion for my little 4A. Been searching around for a while and came up with 7M valves being somewhat larger than the 4A ones, but cant find out how much larger.
Does anyone have some valves and a vernier caliper lying around? Im after diameters and length on the following valves:
4A
7M
1JZ
3S
That should do for now, unless anyone wants to contribute some more. I dont have any 4A valves around as they are all in Canberra, so i cant quite start off. Sorry.
Thanks
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: Valve sizing (4A upsize)
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Thu, 03 March 2005 07:08
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how much bigger are the formula atlantic valves? how big can you go before you lose out from cylinder wall shrouding?
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Location:
Adelaide
Registered:
May 2003
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Club Member
Location:
sydney
Registered:
May 2002
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Re: Valve sizing (4A upsize)
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Thu, 03 March 2005 07:31
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arent the 7M stems too long?? you should be able to pick up SS ones to whatever spec you want but they are not cheapish
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Location:
Adelaide
Registered:
May 2003
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Re: Valve sizing (4A upsize)
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Thu, 03 March 2005 07:41
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Yeah, i was thinking nitrided valves taken from another car. The 4A 20v nitrided valves were only $15ish each from memory, which is quite reasonable. But they dont make any 16v ones that i found, and not oversize either. 
Wouldnt mind Ti valves, with chromo springs for weight saving, but sadly $$$
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Location:
Eastern Sydney
Registered:
May 2002
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Re: Valve sizing (4A upsize)
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Thu, 03 March 2005 11:21
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do you really need to change them though,in all seriousness? the TRD AE92 100kw race spec engines were making ~195Hp with the std valves.
I've seen plenty of japanese built 4AG's making 200hp+ with std valves as well. they're plenty big enough. you're better off spending your cash on putting decent cams in and upping the compression.
from what I've been reading;to make power out of a 4AG,you need big cams (min. 288deg dur,10mm lift),big compression (over 11.5:1,pref. 12:1),big revs (9k),and quad throttles. that's the formula.
big port and 20v heads you don't need to touch bar dag removal,small ports you open up if you want to go over about 180hp.
Justin...
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Location:
Adelaide
Registered:
May 2003
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Re: Valve sizing (4A upsize)
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Thu, 03 March 2005 11:54
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You havnt noticed my project build have you?
Im already running 308* 9.1mm lift cams, with a quad throttled smallport intake. I am searching for a new set of Wiseco 12:1 pistons, which seem remarkably hard to find.
This engine is aiming for somewhat more than most have, and hence why i was considering larger valves. Its also so others can have a reference for the valve sizes.
Im already at 190ish fly hp, and thats without any porting of the head at all and still running on a stock smallport bottom end.
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Location:
East Maitland NSW
Registered:
December 2004
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Re: Valve sizing (4A upsize)
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Thu, 03 March 2005 12:01
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Read this it may help you
www.billzilla.org/agemods.htm
hope this has the info you need
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: Valve sizing (4A upsize)
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Thu, 03 March 2005 12:05
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so what will give you a greater (unshrouded) circumferential area when the valve is half open? 1mm lift, or 1mm diameter?
is there any reason not to run 10 or even 11mm lift (i have 11mm lift in my crappy 4K  )
have you thought about increasing the opening of the valve seat without actually increasing the valve head size? i made my valve seat openings about 1.5-2mm larger diameter but left valve head at original size.. dodgy dremel grinding but something else to think about. mow much non-seat area is there on the valve seats already? how much is needed for the venturi?
if you are keen to do it, don't worry about what people say.. you will find it either does work, or it doesn't.
if you are chasing 200+hp then i hope you are seriously looking at a strict weight reduction program.. the higher you rev, the bigger the parasitic losses and thrashing becomes... just think of the beams 3SGE and follow that mould 
i am keen to hear how your bigger valves go!
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Location:
Adelaide
Registered:
May 2003
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Re: Valve sizing (4A upsize)
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Thu, 03 March 2005 12:11
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There isnt much room around to increase the seat size sadly, i have thought about that before. I will try on the dead head i have down here though, maybe ill port up all four cylinders differently to compare the differences.
I will eventually be running 11.2mm lift on 315* cams, but i didnt want to run those for the current engine revision. The cams that are in there are ones which were made up ages ago for another customer which they never picked up and so i bought them cheap. They are roughly the old TTA spec when they couldnt change to shim under bucket for certain classes.
As for the 4K there is so much more room on the valve/piston clearance than the 4A and i think even the stock cams run about 8 or 9mm lift.
And dont worry about the weight, ill be reducing the weight on a whole lot, i wish i could reduce the weight of the valve train a bit more, but sadly the most i can realistically do is the springs and solid alloy shims. Sucks to not have an unlimited budget
Hopefully the pistons and rods will reduce weight in that department enough.
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Location:
Brisbane / Gold Coast
Registered:
May 2002
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Re: Valve sizing (4A upsize)
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Thu, 03 March 2005 12:13
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| oldcorollas wrote on Thu, 03 March 2005 18:08 |
how much bigger are the formula atlantic valves? how big can you go before you lose out from cylinder wall shrouding?
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Formula Atlantic inlet valves are 32mm, though it's possible to go to 32.5mm.
No point in larger valves in a stock-ish 4AGE, they're plenty big enough as-is.
Better off spending money on something that'll make it go better, not worse.
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: Valve sizing (4A upsize)
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Thu, 03 March 2005 12:18
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| Bill Sherwood wrote on Thu, 03 March 2005 23:13 |
| oldcorollas wrote on Thu, 03 March 2005 18:08 |
how much bigger are the formula atlantic valves? how big can you go before you lose out from cylinder wall shrouding?
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Formula Atlantic inlet valves are 32mm, though it's possible to go to 32.5mm.
No point in larger valves in a stock-ish 4AGE, they're plenty big enough as-is.
Better off spending money on something that'll make it go better, not worse.
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i was just asking for a reference point... and how stock is stockish when we start talking over 300deg cams? heh heh...
Bill, whats your opinion on sayyy... 2mm larger valve head with stock seat, vs 2mm larger seat opening (as a general rule?).
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Location:
Eastern Sydney
Registered:
May 2002
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Re: Valve sizing (4A upsize)
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Thu, 03 March 2005 12:57
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old corollas: you can open the throats up a little,but I doubt you'de be able to get away with 2mm,or even 1 realistically,without forcing the valve to seat on it's outermost edge,which is risking burnout. some of that meat is there for heat dissipation,it needs to remain.
a good throating job is a must on any head rebuild. you want to get the radius where the port ends and the seat starts to be as smooth a transition as you can,but not at the complete expense of reliability.
Takai: no,I haven't looked at your project,this is the first time I've looked in this area of the forum in about two years.
I'm collecting parts atm for my own engine,which I'm hoping to make about 180-190hp with.
I'll be using a big port head with 288deg cams with 10mm lift,shim under buckets,and 12:1 compression. bottom end will be a mixture of small port and 101 20v. throttles will be either gutted 45mm OER carbs or the 101 20v 43mm ones I have on hand.
depends on how easily I get my hands on a manifold when I go over to japan again later this year.
Justin...
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Location:
Adelaide
Registered:
May 2003
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Re: Valve sizing (4A upsize)
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Thu, 03 March 2005 13:04
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Im running the 20v 43mm silvertop quads bored out to 45mm and fitted with blacktop butterflies. T3 in the US is makign a stock manifold for that conversion.
Also i think stewart is asking a theoretical question rather than a 4A specific one.
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: Valve sizing (4A upsize)
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Thu, 03 March 2005 13:18
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| takai wrote on Fri, 04 March 2005 00:04 |
Also i think stewart is asking a theoretical question rather than a 4A specific one.
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yes and no, i have plans up my long sleeves
it will be interesting to see how my valve seats have lasted after about 20K miles of hard use with the exhaust seats ground back to just before the sealing surface.... i was concerned the reduced area would result in excessive shape change of the seat, but i haven't had nasty noises yet....... yet.....
at least the 4A path is reasonably well trodden.. but that doesn't mean that everything has been worked out
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Location:
Adelaide
Registered:
May 2003
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Re: Valve sizing (4A upsize)
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Thu, 03 March 2005 13:22
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So true, i think i might just have to get a set of 7M valves to play with.
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Location:
Brisbane / Gold Coast
Registered:
May 2002
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Re: Valve sizing (4A upsize)
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Thu, 03 March 2005 22:46
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Dunno, Stewart.
Not a good idea though I think.
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I supported Toymods
Location:
melbourne
Registered:
June 2002
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Registered:
July 2002
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Re: Valve sizing (4A upsize)
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Fri, 04 March 2005 09:17
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Check out 3SFE and 5SFE valves.....
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Location:
NSW, East Coast
Registered:
July 2003
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Re: Valve sizing (4A upsize)
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Fri, 04 March 2005 22:30
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Im not going to coment too much on this subject as i know very little, but i remember reading somewhere that 3sge valves are 1mm (or there about's) bigger and fit without to much trouble.
Cheers
Steve
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I supported Toymods
Location:
sydney.au
Registered:
August 2002
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