# big valves?



## riceatingrabbit (Aug 20, 2005)

I'm building an 8v to drop into my golf and replace the high milage one thats in it. I'm looking for a little more power but i understand that 8vs are not powerhouses... I have a bottom end thats bored out 1mm over with a fresh rebuild and i'm lookiing at the head department now...
I was thinking i'd just rebuild a gti head and slap a mild cam in it and call it a day...but...I've got all the free machine work i want...so i'm curious about how big of a valve i can sqeeze into an 8v hydro head, and where i can get the valves themselves...
so has anyone done this? is it worth the extra time for the power gain? or should i just stick with the gti head?
my overall goal is a nice streeable 8v that i can drive everyday...


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## Mk1Racer (Apr 16, 1999)

*Re: big valves? (riceatingrabbit)*

You can go from 40/33 to 41/34, but I'm not sure where to get the valves. Not sure if it's going to gain you that much in a street motor either.


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## twicepardoned (May 2, 2006)

You can get the valves from USRT or Techtonics I think.


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## ABA Scirocco (May 30, 2001)

*Re: big valves? (Mk1Racer)*


_Quote, originally posted by *Mk1Racer* »_You can go from 40/33 to 41/34, but I'm not sure where to get the valves. Not sure if it's going to gain you that much in a street motor either.

41/34 mm valves can be used with the existing valve seats, if you replace the valve seat you can go another millimeter larger 42/35.
For 41/34mm valves, do a Google search on "supertech performance valves", these are the same valves Techtonics sell, they're very nice nitrided one piece stainless steel valves http://****************.com/smile/emthup.gif, the stems are 7mm diameter, stock on most 8v heads is 8mm, so you'd need to change the guides, retainers and keepers in order to use these valves (use ABA guides, retainers and keepers).


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## girdwood (Mar 10, 2004)

*Re: big valves? (ABA Scirocco)*

Any particular reason you mention ABA components? Is that cause they are made for 7mm, or is there a trick you are subtly mentioning?


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## ABA Scirocco (May 30, 2001)

*Re: big valves? (rollercoasterracer)*

ABA stuff because I know for certain that everything fits. ABA valve guides because they're 7mm I.D. and the right length for an 8v hydro head, ABA retainers because they're 7mm triple grove retainers, I'm not sure but I think VR6 retainers would work too.


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## girdwood (Mar 10, 2004)

*Re: big valves? (ABA Scirocco)*

http://****************.com/smile/emthup.gif Thanks!


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## Auto Pilot (Nov 29, 2001)

*Re: big valves? (rollercoasterracer)*

If you are going to do all the work and replace everything anyways ... why not switch over to solid lifters? more choices for cams too http://****************.com/smile/emthup.gif


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## eurotrashrabbit (Oct 25, 2001)

*Re: big valves? (riceatingrabbit)*

41in/34ex biggest valve using a standard seat Tectonics $25 a valve nitrided


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## ABA Scirocco (May 30, 2001)

*Re: big valves? (eurotrashrabbit)*

Those are 100% identical to the Supertech valves I refered to earlier, if you shop around a bit, you can get them for about $18 each. Whether you get them from Techtonics or elsewhere, they're very nice valves http://****************.com/smile/emthup.gif 


_Modified by ABA Scirocco at 9:58 PM 10-19-2006_


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## Auto Pilot (Nov 29, 2001)

*Re: big valves? (ABA Scirocco)*


_Quote, originally posted by *ABA Scirocco* »_Those are 100% identical to the Supertech valves I refered to earlier, if you shop around a bit, you can get them for about $18 each. Whether you get them from Techtonics or elsewhere, they're very nice valves http://****************.com/smile/emthup.gif 

_Modified by ABA Scirocco at 9:58 PM 10-19-2006_

ABA Scirocco is completely correct. Look around and save some money
These are my valves
http://forums.vwvortex.com/zerothread?id=2601656
These are my valves


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## Monster8V (Dec 23, 2000)

*Re: big valves? (eurotrashrabbit)*


_Quote, originally posted by *eurotrashrabbit* »_41in/34ex biggest valve using a standard seat Tectonics $25 a valve nitrided 










I have 42mm intake, 36mm exhaust valves in my solid lifter 8v.








7mm valve stems. TT 306 cam. P&P of course.


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## Auto Pilot (Nov 29, 2001)

*Re: big valves? (Monster8V)*


_Quote, originally posted by *Monster8V* »_

I have 42mm intake, 36mm exhaust valves in my solid lifter 8v.








7mm valve stems. TT 306 cam. P&P of course. 

how did you fit that size of valve in there? do you have one side of the valve flatted slightly to clear the other? I just measured my head and I do not have the clearance with my supertech valves in there. it is only ~2.8mm
And you definitely did not fit those valves in there using the stock sized seat like eurotrashrabbit had mentioned


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## Mk1Racer (Apr 16, 1999)

*Re: big valves? (eurotrashrabbit)*


_Quote, originally posted by *eurotrashrabbit* »_41in/34ex biggest valve using a standard seat Tectonics $25 a valve nitrided 









Help me out here. You can do this because you've got enough room on the stock seat to cut it to fit the larger valves?


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## ABA Scirocco (May 30, 2001)

*Re: big valves? (Mk1Racer)*

For the 41/34 valves, you can recut the stock seats. For 42/35, you need to replace the seats with larger ones and for 42/36, you need the larger seats and they need to be "siamesed" so that they'll fit, with valves that big, there's only a fraction of a millimeter between the valve heads, that's the absolute extreme upper limit of what's possible.


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## eurotrashrabbit (Oct 25, 2001)

*Re: big valves? (Mk1Racer)*

Yes but they just barely fit and the OBD2 ABA runs a 39.5mm valve not truly a 40mm so it just barely squeezes in the standard seat. The machine shop was weary but I knew it would fit


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## JediKGB (May 21, 2002)

*Re: big valves? (ABA Scirocco)*


_Quote, originally posted by *ABA Scirocco* »_41/34 mm valves can be used with the existing valve seats, if you replace the valve seat you can go another millimeter larger 42/35.
For 41/34mm valves, do a Google search on "supertech performance valves", these are the same valves Techtonics sell, they're very nice nitrided one piece stainless steel valves http://****************.com/smile/emthup.gif, the stems are 7mm diameter, stock on most 8v heads is 8mm, so you'd need to change the guides, retainers and keepers in order to use these valves (use ABA guides, retainers and keepers).

so wait...your saying that if I go a mm larger on each valve (41/34) they'll just slip into the head without having the head reground ?


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## eurotrashrabbit (Oct 25, 2001)

*Re: big valves? (JediKGB)*

You have to "cut" the seats to match


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## ABA Scirocco (May 30, 2001)

*Re: big valves? (JediKGB)*

That's right. A bit of machine works is necessary, you don't have to replace the seats, you just have to have the original seats recut to take advantage of the bigger valves, that's just slightly more work than a normal valve jobs would be, well within the capabilities of an average automotive machine shop. 
But if you go bigger than 41/34, it gets much more complicated (and costly), you have to pull out the existing seats, machine the head to accept bigger seats, press new seats in, then have the seats machined to match up to the valves, you'd probably have to shop around a bit to find a shop willing to do that for you.


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## JediKGB (May 21, 2002)

oohhh
damn...already got the head back from the shop....dont really feel like sending it back ya know...
well how hard is it to swap an ABA head to solid lifters? cuz then I'd probably up the valve size of that one...


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## eurotrashrabbit (Oct 25, 2001)

*Re: (JediKGB)*

You need buckets,shims, valves and cam they are different


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## Auto Pilot (Nov 29, 2001)

*Re: (eurotrashrabbit)*


_Quote, originally posted by *eurotrashrabbit* »_You need buckets,shims, valves and cam they are different










Actually, now you can get solid lifters that work with the existing valves. I do not know the maker of them though. They are made to take up gap from the shorter stem 
The cam would be neccessary though http://****************.com/smile/emthup.gif


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## eurotrashrabbit (Oct 25, 2001)

*Re: (Auto Pilot)*

They are made by Piper or Kent if I am not mistaken they of a non OE design


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## JediKGB (May 21, 2002)

*Re: (eurotrashrabbit)*

oh thats it? i figured lifters, cam, shim, etc etc would be required...but I thought the welding of some holes or something of the sort in the head was required...if its just a simple equipment swap im golden


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## epjetta (Sep 19, 2006)

*Re: big valves? (Auto Pilot)*

Ive bought valves directly from supertech and I think they go for $20 if I remember correctly. but you have to ba a dealer to get them, they only do wholesale to dealers.


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## JediKGB (May 21, 2002)

I'm not sure if valves are required......at least in a counterflow head the mechanical valves and the hydro valves all have the same ETKA numbers.....
so with this in mind.....i dont think they'd be needed on an aba head either


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## ABA Scirocco (May 30, 2001)

*Re: (JediKGB)*


_Quote, originally posted by *JediKGB* »_......at least in a counterflow head the mechanical valves and the hydro valves all have the same ETKA numbers.....


Better doubt check those part #s, I don't think that's right, last time I checked, the letter at the end of the part number was different. 
Anyways, valves most definitely ARE required. The valve stems in hydraulic lifter heads (including the aba) are about 8mm or so shorter than the valves in solid lifter heads. 
That's also why you need to shim up the valves springs when converting to solids, solid and hydro heads use the same valve springs, installed at the same height so the valve spring pockets in hydro heads are machined deeper to allow for the shorter valves stems.


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## JediKGB (May 21, 2002)

Well I've taken apart a few hydro heads so far and are working on a mechanical head too so I will be able to compare them directly...but according to ETKA...
85 (mech)
Intake Valve for HT, & RD - *026 109 601 C*
Intake Valve for GX - 035 109 601 H
Exhaust Valve for GX, HT, RD - *053 109 611*
88 (hydro)
Intake Valve for PF, RV - *026 109 601 C*
Exhaust Valve for PF, RV *053 109 611*




_Modified by JediKGB at 8:12 PM 10-31-2006_


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## ABA Scirocco (May 30, 2001)

*Re: (JediKGB)*


_Quote, originally posted by *JediKGB* »_85 (mech)
Intake Valve for HT, & RD - *026 109 601 C*
Intake Valve for GX - 035 109 601 H
Exhaust Valve for GX, HT, RD - *053 109 611*


There's the problem right there. The HT, RD and GX heads are NOT mechanical heads, they're all hydros. Check part numbers for 84 heads, there should be two the JH and EN, the JH will be the big valve solid lifter head that we're interested in.
Intake Valve for JH should be - 026 109 601
Exhaust Valve for JH 026 109 611 F


_Modified by ABA Scirocco at 8:33 PM 10-31-2006_


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## JediKGB (May 21, 2002)

*Re: (ABA Scirocco)*

then why does ETKA list shims (adjusting washers) for the lifters?


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## ABA Scirocco (May 30, 2001)

*Re: (JediKGB)*

Maybe because the Sciroccos an Cabriolets in 85 with a JH were still using solid lifters which required shims. Anyways, this certainly wouldn't be the first error found in ETKA.


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## JediKGB (May 21, 2002)

*Re: (ABA Scirocco)*






















well I guess I'll just have to rip this other head apart and measure some...


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## Mk1Racer (Apr 16, 1999)

*Re: (ABA Scirocco)*


_Quote, originally posted by *ABA Scirocco* »_Maybe because the Sciroccos an Cabriolets in 85 with a JH were still using solid lifters which required shims. Anyways, this certainly wouldn't be the first error found in ETKA.

+1
It's easy to tell what head you have, w/o taking the engine apart. Pull the valve cover, and if there's no #4 cam cap, it's a hydraulic lifter head. If there is one, it's a mechanical lifter head (you can also see the shims on top of the lifters). The big valve (1.8) heads are easy to tell as well, as they have the water neck between #3 and #4, and there's an extra oil return galley between #1 and #2.


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## JediKGB (May 21, 2002)

*Re: (Mk1Racer)*


_Quote, originally posted by *Mk1Racer* »_
It's easy to tell what head you have, w/o taking the engine apart. Pull the valve cover, and if there's no #4 cam cap, it's a hydraulic lifter head. If there is one, it's a mechanical lifter head (you can also see the shims on top of the lifters). The big valve (1.8) heads are easy to tell as well, as they have the water neck between #3 and #4, and there's an extra oil return galley between #1 and #2.

I already know that I have an mech head. The head is off a car and only thing left in it is the springs and valves. We were trying to determine if ETKA is wrong since it lists the same part numbers for hydro and mech valves


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## ABA Scirocco (May 30, 2001)

*Re: (JediKGB)*

Well I'll settle it then, ETKA's wrong. The list you had shows various 1985 heads listed as mech, i.e. solid lifter, when in fact the ONLY solid lifter VW gasoline engine made for the North American market in 1985 was the JH. And, I know from personal experience that it most definitely does NOT use the same valves as any of the hydrualic lifter heads, JH valves are approximately 8mm longer than the hydro valves.



_Modified by ABA Scirocco at 11:07 AM 11-1-2006_


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## epjetta (Sep 19, 2006)

*Re: (JediKGB)*

Hydro Valves are shorter than mechanical valves. the thicker lifter makes it so that the lower spring seat is cast deeper into the head. it sort of crimps the port a little. the mechanical heads have straighter and larger ports from my observations.I have done alot of port work on all VW audi heads and compared them side by side.


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## WanganLLama (Apr 15, 2004)

*Re: big valves? (ABA Scirocco)*

at what point are the bigger valves just shrouded and there isn't much of a gain? i imagine the 42/36 would be super close to everything...


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