Rigtigt, på T7 modellerne, men det er gundet de tyndere skafter. Går du efter en B235R type er ventilerne på udstødningssiden envidere sodium fyldte med nimonic legering. Selve sædet vil ikke passe sammen med den gamle B234 top og ej heller styret. 1999 - 2000 9-5 B235 kører med alm. stainless steel ventiler bortset fra Aero, men efter som du går efter max burde optimal løsningen vel være at få en T7 B235R top tilpasset ( stort arbejde )..
Ret meget mere ved jeg ikke, blot noget jeg læste lidt om her inden den gule kom hjem fordi jeg var nysgerrig mht. til B235R og de modifikationer der var med bl.a. nimonic.
Her er lidt information sakset fra
http://www.saabscene.com/forum/index.ph ... c=31630762 og
http://www.saabcentral.com/forums/showt ... ge=1&pp=20 håber det kan bruges inden du kaster penge i projektet :
The following is information comaring the T5 "shortblock" valves to the T7 valves.
1 = Valve Stem Diameter
2 = Valve Guide Length
3 = Valve Guide Bore Diameter
4 = Intake / Exhaust Valve Cut Angle
5 = Intake / Exhaust Valve Diameter
6 = Intake / Exhaust Valve Cut Width
T5
1: 6.9565 - 6.980 mm
2: 42.5 mm
3: 12.000 - 12.018 mm
4: 45.25 / 45.25 degrees
5: 33 mm / 29 mm
6: 1.0 - 1.5 / 1.0 - 1.5 mm
T7
1: 4.9725 (Nimonic, slightly smaller for stainless)
2: 42.5 mm
3: 12.000 - 12.018 mm
4: 45.25 / 44.50 mm
5: 33 / 29 mm
6: 1.0 - 1.5 / 1.5 - 2.0 mm
As you can see, while you should be able to use T7's intake valves in a T5 head (and thus in any other Saab 16V head theoretically) if you also swap guides, retainers cones etc (lifters shouldn't need to be changed, or springs), you cannot use T7's Nimonic exhaust valves in any head except a T7 head ... unless you get a custom seat grind for the T7 exhaust valves.
The considerably thinner intake valves might very well be quite usefull if you're trying to get your non-T7 head to flow better. If you can get all the other required valvegear to do the swap for cheap enough it might be practical. But if you're starting from scratch, it would be cheaper to get a T7 head and adapt it, than to have your other head ported/polished and to buy the T7 valvegear.
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Firstly, the original B202 and B212 exhaust valves are compatible with the "shortblock" Trionic 5 exhaust valves. However that does not mean they are identical. The reason the part numbers are the same (91 65 598) is that the original valves are no longer made. (75 00 085) Same with the older 2.3L 9000 "longblock" heads. The original exhaust valves are NLS.
Secondly both Trionic 7 exhaust and intake valves are different from previous models. In fact, T7 has TWO different exhaust valves. A nimonic, and a stainless set. From 1999-2000 the lower level engines (B235E) used the stainless, while the Aero/Viggen got the Nimonic valves. Upoon MY 2001 all T7 engines had Nimonic exhaust valves. (Not in the EPC, but I have a Saab bulletin on that.)
T7 stainless: 93 99 965
T7 Nimonic: 91 79 219
T5 Stainless: 91 65 598
90-93 "longblock" 2.3L/2.1L: 91 36 250
B202 Stainless: 75 00 085
Also, the T7 valves are NOT compatible with T5 heads. They use smaller valve stems which will not work with the stock T5 head's valve guides. However, the valve guide bores are the same, so you may be able to use T7 valves, if you also use T7 valve guides. The valve head diameters are the same, and the T7 valves are cut differently and are lighter. (I don't know if they would line up with the T5 valve seats or not.) The increase in flow likely comes from the smaller/lighter valve heads combined with thinner valve stems. That's probably why it's nearly impossible to get the same flow from the T5 or earlier heads.
Also, when using T7 valves, because they are lighter, if you are using the stock springs (new) from another application you should be able to safely raise your rev-limit to some degree because of the reduced valve weight. However, only if you use both T7 intake and exhaust valves.
