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Oversized valves
http://www.gt4dc.co.uk/forum/viewtopic.php?f=1&t=904		 Page 1 of 2
Author:  two_OH_five [ Mon May 01, 2006 11:50 am ]
Post subject:  Oversized valves
Following on from the manifold thread tp prevent a complete hijack :-

Looking through the Ferrea catalog it would seem that the 3S-GE engine uses larger valves in the ST202

Has anyone ever looked into dropping these into a GTE head?

Also, has anyone thought about dropping an entire 3S-GE head onto the GTE block? I wonder if there are any serious pitfalls like water jacket, oilways etc. etc.

I know that the GE runs lumpier cams than stock GTE, has bigger valves, a sidefeed inlet manifold, a larger TB (I assume!) etc, etc. It seems to me like it would be ideal so I'm sure there's some reason why it won't worr :(
Author:  TrackToyFour [ Mon May 01, 2006 1:07 pm ]
Post subject: 
Steve,

Following Ians comment I was prompted to research this a bit more. I've summarised the findings in the attached table. The RM164E states the same dimensions for the 3S-GE and 3S-GTE Nov 1989 to Feb 1994 i.e. this covers the Gen 1 and Gen 2 3S-GTE's plus presumably the 3S-GE fitted to the ST202.

Bottom line is that if you want to fit Ferrea oversize valves to a Gen 3 head then some machining of the valve stem would appear to be required in order to get it into the tolerance range. I would assume that Jon Edwards is having to do this on Adrians 9000rpm race spec engine which is allegedly fitted with Ferrea O/S valves.

Image
Author:  matgt4 [ Mon May 01, 2006 6:58 pm ]
Post subject: 
Ooo. All good information here guys..will pass it on.


Many thanks
Author:  TrackToyFour [ Mon May 01, 2006 10:17 pm ]
Post subject: 
Mat, glad you saw that :mrgreen: . I was going to PM or e-mail you as I wasn't sure if you were aware of this.
Author:  datajon [ Sat May 06, 2006 10:51 am ]
Post subject: 
1mm over size, is not the only choice.., but it’s by far the simplest route for sure.

Yes some amount of machining is required for any performance improvement to any cylinder head, that’s the norm..

valve guides should be changed , either due to wear, or valve upgrade (1mm oversize)etc , allowing the valve stem Dia to be matched to guide id Dia. …

Pretty much standard procedure, when building up a modified cylinder head, making small adjustment is the name of the game.

Bottom line is, its probably one of the more easier upgrades to do. for power return..

Its when you want to fit 2.0mm over size valves, that the hassle start.
Author:  mook [ Sun May 07, 2006 9:17 am ]
Post subject: 
The guy who's going to sort my head recommends shorter duration/higher lift as a better option for more power throughout the range. As such, I'll probably plump for 264 inlet and exhaust, both with higher lift and maybe oversized valves too - obvious idea being get plenty more air/fuel in without the problems excessive overlap can cause.
Author:  two_OH_five [ Sun May 07, 2006 11:44 am ]
Post subject: 
! thing I have noticed:-
The 3s-ge oversized valves are 2m bigger than the stock 3s-gte. So a ge head on a GTE block ought to be pretty efficient. I assume that the pistons would need valve clearance work though
Author:  TrackToyFour [ Sun May 07, 2006 9:36 pm ]
Post subject: 
two_OH_five wrote:
The 3s-ge oversized valves are 2m bigger than the stock 3s-gte.


Steve, where did you get this info from....I don't have space under my bonnet for 2m valves :lol: .....I presume you meant mm!

Seriously though, the Toyota specs in manual RM164E don't give the valve dimaeter so if you have the source of this info I'd like to add it to my data sheet in my earlier post.

Thanks,
Author:  TrackToyFour [ Sun May 07, 2006 9:41 pm ]
Post subject: 
mook wrote:
The guy who's going to sort my head recommends shorter duration/higher lift as a better option for more power throughout the range. As such, I'll probably plump for 264 inlet and exhaust, both with higher lift and maybe oversized valves too - obvious idea being get plenty more air/fuel in without the problems excessive overlap can cause.


Mook, unless you have a Gen 3 head you will need to machine your Gen 2 ST185 head so that the high lift cams will have sufficient clearance. You probably know this already but I thought it was worth repeating for others.
Author:  Kris [ Sun May 07, 2006 10:06 pm ]
Post subject: 
Agree with Mook! :)

I like the sound of a closer to stock duration but a higher lift.

I'm thinking that torque might make a quicker car that horsepower?

Mook - "think" HKS offer a 256? duration cam, might be a better bet that a 264 as you will probably shift the power further up the rev range and have to rev the car out to take advantage of the cams?

A high lift 256 might feature in my shopping list :)
Author:  two_OH_five [ Sun May 07, 2006 10:40 pm ]
Post subject: 
Piper do a high lift 256 I think but rumour has it they've dropped them

But, as I keep banging on about, the standard ge cams are higher lift and longer duration to boot

Please read all the very useful data JP posted here

In addition to this the GE head has bigger valves and surely flows a vast amount better than the GTE. This is why I raised the subject :roll:

Don, all figures (which are in mm :D ) are direct from the Ferrea website/catalog. They have stock and oversize valves for the GE and the GTE
Author:  TrackToyFour [ Sun May 07, 2006 11:28 pm ]
Post subject: 
two_OH_five wrote:
In addition to this the GE head has bigger valves and surely flows a vast amount better than the GTE.


The Ferrea 2006 catalog lists Sport Compact Competition Plus Valves where the 3S-GE oversize valves are Exhaust 30.1mm and Inlet 35.5mm. This means that the Exhaust is only 0.1mm larger the Inlet 1mm larger compared to the oversize 3S-GTE Exhaust and Inlet valve diameters. Given the gas flow improvements between the Gen 2 and Gen 3 3S-GTE head design I'd be very surprised if the Gen 2 3S-GE head flows 'a vast amount better'

The other complication is that the 3S-GE valves are a different stem diameter to the 3S-GTE so would require the guides to be changed. I don't know if the valve guide OD is the same between the 3S-GE and the 3S-GTE. If not, then I guess it would be possible to commision a special set of guides but the price might be rather high. The valve overall length and tip length are also significantly different so more machining would be required. Even then, I'm not sure they would be suitable.

Dont forget with high lift cams you may also run into coil binding on the valve springs. I think Ian Smith encountered this on his initial monster engine build?
Author:  Kris [ Sun May 07, 2006 11:40 pm ]
Post subject: 
Don - some good points.

Yes think Iam has indicated that he dound the 1mm oversized Ferrea vales to be too long and these required grinding to reduce their length.

Steve - not ignoring you! :lol: Have "clocked" what you are saying...just thinking.

As Don has indicated, the 3S-GE valves are adifferent stem diameter? This may be a problem since the valve may overheat as the conduction of heat away from the valve head itself would be improved with a larger diameter stem? If so then a failure of the valve/valve seat on a 3S-GE head fitted to a GT4 might be an issue?

Also the valve seat itself may be of a different material? What about materials used and clearances? I am assuming that the 3S-GTE is subjected to higher temps that the 3S-GE and so possible different materials and different tolerances are utilised throughout? e.g. seat diameter, guide material and clearance?

Of course if this all proves to be the same then a swap to a super duper 3S-GE head would require further invesigation and maybe even fitment to a GT4 :)
Author:  two_OH_five [ Wed May 17, 2006 12:42 pm ]
Post subject: 
Further information from the 2006 Ferrea catalogue

Both valves for the 3S-GE
F1944P E 30.1 mm 5.46 mm 109.32 mm 2.25 mm 20º Flo. Oversize. Special Alloy
F1945P I 35.5 mm 5.47 mm 106.63 mm 2 mm 12º Super Flo. Oversize

So inlet is 1mm larger, exhaust is basically identical

So, 3S-GE valves would give a +2mm inlet, +1mm Exhaust over stock 3S-GTE

The downside is that the valves and head both need significant work

Valves need approx 10mm taken of stem length
Head will need (most likely) 3S-GE valve guides fitted to accommodate the narrower valve stems
Perhaps more effort than it's worth :(
If looking for more than a 1mm increase it would probably make more sense to start with blanks and machine them to suit the GTE head but even then Ferrea doesn't list anything that's really suitable :(

Looks like the best bet is likely to be +1mm and a little machine shop time
Author:  mook [ Wed May 31, 2006 10:42 am ]
Post subject: 
Spoken to my man again as he's starting to get the bits together for my head. His initial check over of everything would suggest the intake side is perfectly good, but nice gains can be made from amending the exhaust side. That'll be the main part he concentrates on porting. He's also recommended 1mm oversized valves on the exhaust side (intake remain standard) and we'll also be porting the exhaust manifold with attention to the no longer necessary with TD06 twin entry aspect, probably thinning out and bevelling the double entry 'exit' from the manifold. That with hopefully higher lift 256 cams should make a big difference :)
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