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Discussion Starter · #1 ·
I was very interested in koop's idea, so I also looked into it. And negotiated a minimum order of 50 at $30each. That's only 8 other people after subtracting my brother and I! I decided on 41mm because it's the largest that can be machined into the factory 40mm seat. So if your're running a NF head you just need to get the seats machined. Another mod to go with Koop's ti retainers is light weight lifters available at $15ea. Also here's a list of necessary parts and prices to switch to 7mm stems.
7mm guild $5.40ea
7mm keeper $1ea
7mm stem seal $1.26ea
7mm Steel retainers $ 4.25ea or for a little more buy ti's from Koop!!
Let me know if this sounds good. :wink:
 

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41mm stainless intake,correct? I might be in, depends on finances, plus, then i still gotta get inconel exhausts, so $300 in valves is a deal right :eek: .
and what are these lightweight lifters. I've never heard about em'.
 

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Discussion Starter · #3 ·
The lifters are 8 grams each lighter. When combined with the ti retainers, one would expect a lot quieter and smoother running valve train!
I'm still looking around for a exhaust valve deal. Javad iirc posted inconnel 35mm valves at $35 each. 41/35 head would make a nice package!! Getting the intake valves at 150 and ti retainers from Koop really helps keep the cost down.
 

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For those contemplating the 41mm SS 7mm stem, I need to verify what upper retainer they use. If it is the 20v unit, score. If its a modified 10v unit, score (which in talking with Myke about them, it looks that is the case). If it is something else, not sure....
 

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ok, the 7mm stem/41mm head SS valve should need a different retainer/lock combo (because of the different stem obviously), that would be fine with me since I'm still buying the 8mm stem retainers already, I'll still stick with 8mm stem 35mm head, inconel exhaust valves. I'm assuming rusty can make the retainers for the 7mm stem,right? those would be basically the 12v keepers, correct?
just so i get this all straight before i end up with enough bits to build three w12 valvetrains :D

also, where would abtain these lightweight lifters?
 

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Well, Myke and I talked about the retainers more. After looking at some parts and Myke saying that the retainer is factory and you can use the 309AD lifter with it (ie, the lifter from the 10v/10vt), I'm thinking that the 7mm retainer for the 41mm valves are 7A/3B/AAN/PL/9A retainers. Those engines all use 7mm stems with dual valve springs as well as the 309AD lifter.

Also, a friend did some math a while ago about reducing mass in the valve train and how much power it freed up. Just removing a gram here or there really adds up due to the accelerations and such that happen in an engine...
 

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Discussion Starter · #8 ·
:bump:
 

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hey all, i found my dad's scale buried under some junk and decided to weigh some of my bit's and pieces of stock valvetrain from my old 4kq engine (that's engine code JT, correct?)
all these things are bone stock, never been altered
38mm intake valve--------72 grams (all carbon build up cleaned off)
33mm exhaust valve------70.5 grams (ditto on the carbon thing :wink: )
lifter that's been in oil-----68.5 grams (don't ask why it was sitting in oil)
lifter that was bone dry---67.7 grams
valve retainer--------------18 grams
valve keepers-------------2.5 grams

now, about those light weight lifters, I seem to be a bit confused. they are lighter than which factory lifters? sorry for my incompetence :(

eric, can you weigh one of those Ti retainers? and does anybody have any 40mm stainless intake and 35mm inconel valves for comparison?
 

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Discussion Starter · #10 ·
The lifter are 8 grams lighter than stock so just over 10% and fit 10v and 20v.

The valves are oversize Stainless 41mm Intake valve with 7mm stem necked down to 6.5mm for hyd lifter. They also weigh 10 grams less than std 40mm 8mm stem valve. Higher flow than std. valve. Black nitride treatment reduces friction, improves heat dissipation and Valve guide wear.

The ti retainers weigh 9 grams

So the valve, retainer and lifter reduce the valvetrain weight by 26 grams per valve! 130 grams on the intake side alone of the 10v pretty impressive in my book.

HTH
 

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sweetness! I do love real numbers 8)
 

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cuatrokoop said:
Well, Myke and I talked about the retainers more. After looking at some parts and Myke saying that the retainer is factory and you can use the 309AD lifter with it (ie, the lifter from the 10v/10vt), I'm thinking that the 7mm retainer for the 41mm valves are 7A/3B/AAN/PL/9A retainers. Those engines all use 7mm stems with dual valve springs as well as the 309AD lifter.
are you sure that this would work? i need to know so i can get five retainers for the 20v 7mm stem from rusty. it shouldn't be a big deal to make just five right? he said if i want to get these things, to hurry cause he's moving and won't be able to make them any more.

oh yeah, in order to get the 41mm/7mm stem valves we still have to get another 7 people right? if we can't get enough people interested, then none of this stuff will do me any good except for the stock style replacement retainer in Ti.
 

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Discussion Starter · #13 ·
Yeah that's the problem. I thought there was like 15 interested people so I found a similiar deal with a small min. order but now no one seems interested. Den, me and you are not enough and eric (Koop) is out because I sold him a set of 40mm intakes valves before getting this together. But yes everything would work fine and I would have set it up so all necessary items came with it, unless someone found a better price on them and wanted to purchase it themselves.

Sorry I did try :(
 

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We are moving yes, but not until May. Doing any outside projects starting basically May 1 will be absolutely out of the question (possibly sooner than that). Finals, FSAE competition, graduation, moving, and I think the EIT (aka FE) exam is that month as well.

Rusty'll be working for Polaris (ATV's) as an engineer.

I'll be, well, not sure yet, still looking.

Our other roommate who is also graduating, not sure where he will be as his S.O. will still be in school for a year. He and I have applied to some of the same companies, so we may end up as neighbors. Gee, I bet we wouldn't be in a garage playing with the cars when we got home from work ever... :D

Any way you look at it, we won't have access to the sorts of machines that we do right now.

Also, I did not get the 7A head stripped completely yet, so we don't have CNC files for them yet. And, the first 20 8mm retainers are now finished, looked at one today ;-) That means I should have my 10vt head assembled in the next week or two, depending on machine shop turn-around time.
 

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well, i guess i'll just have to stick with the regular old 8mm stem/40mm head :( , bummer, oh well i guess it'll work :wink:
 

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Ya, should be good for *only* 400-450hp or so...bummer :(

:wink:
 

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haha, the other thing i didn't think about, call it blind interest i guess, is that what happens when i need the next set of valves. I would be hoping that these 7mm stem valves become a common thing, other wise I'm SOL on the next valve job :( . maybe i'll just reconsider going 40mm intake with 35mm exhaust.
where do i get the seats from? the 35mm exhaust. 40mm eurospec has the 40mm for a ridiculous $5 and some change.
man, I must be stupid........ :p
 

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That is the wrong length stem...You need a 91.9mm for the intake. 90.8mm is correct for the exhaust. Also, I'll bet the exhaust valves are NOT sodium filled for that price. The factory did not make 35mm exhausts in sodium AFAIK. Factory sodium filled 33mm valves are $58/ea from WorldPac.
 

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well, I had my dad check with his supplier on the soduim filled 33mm valves and he can get em for $50 each, so if anyone wants to save some dough, lemme know.
8)
 

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Discussion Starter · #20 ·
Those 5 dollar valves aren't those for mechanical lifter heads being 98mm's long. I'm sure we'd have heard about that stuff from Javad since he use to work there. Kind of wondering if it's a miss print 5.89 because other around it are 15.89, either way they'd have to honor it right?
 
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