Cylinder Head Valves for a Turbo Engine

[TheSilverBuick]

Yesterday I recieved the cam for my OHC six turbo engine, and now know the base circle diameter so I can order valves and continue on with the head work. So the question is what kind of valves should I get and why?

The current thought is to get Manley Gen II stainless steel valves, and the main question is should I opt for sodium filled exhaust valve or not? Will I notice a benefit for springing for the extra cooling? Money is pertinent, cost vs. benefit of course.

This is an iron head with bronze inserts in the guides, 5/16 stem diameter, 1.94" intake, 1.6" exhaust. The exhaust seats/margin contact will be wider for additional heat transfer to the head. This will be mostly street driven with a few drag strip passes a year (Drag Week! )

[JeffMcKC]

Sodium is money well spent!!!

It wont wilt or tulip, or crack or take out the rest of the engine when if it does. The cost of the valve is the least part if things go wrong.

[BOSSMAN]

You need to look at the Ferrea line IMO. Sodium filled would be nice, depending on the boost level Inconel (Super Alloy) would be the best but they are a little heavier for an exhaust valve. A competition plus valve for the intake or 6000 series valve. Also depending on sizes and lengths cutting down LS3 valves would be another option (lightweight look at what is in the LSA/LS3 head for example). How long of a valve do you need? If you find some part #'s you like from their catalog give me a ring Randall - I'm a WD.

[TheSilverBuick]

Nick you have a PM waiting

BTW, you guys suck at voting. If I didn't know ya I'd assume you lived in Florida.

[Beagle]

but how are they at hanging chad

damn. Off topic again.

[TC]

Whatever type of valve you go with, make sure you go with a bigger diameter valve on the exhaust valve, like a 1.7 or a 1.8 and leave the intake valve alone........

As for sodium filled valves, what I've read about them in your application, you can take them or leave them, they are more for high rpm endurance motors...... But hey you can always spend the money for the bragging rights and if your really worried about the strength of the valve you can always step up to titanium........

Saying that the Manley's will be fine.......

[TheSilverBuick]

You see the size of the valves? The bore is only 3.875" to 3.905" with an overbore. 1.94"/1.60", the exhaust is over 80% the diameter of the intake, it should be more than good.

I'm still leaning towards the Manleys unless Nick talks me into the Ferrea's. I still need to do pricing on all of them.

[TC]

You see the size of the valves? The bore is only 3.875" to 3.905" with an overbore. 1.94"/1.60", the exhaust is over 80% the diameter of the intake, it should be more than good.

I'm still leaning towards the Manleys unless Nick talks me into the Ferrea's. I still need to do pricing on all of them.

If you read Vizard's books he recommends an exhaust valve the same size as the intake valve...... Though he does say your restricted to the design of the cylinder head..... If those are the biggest sized valves you can fit, then that is what you got to go with, but if you can squeeze a 1.7 in there, you'd be better off doing that than stepping up to a 2.02 on the intake....... On turbo motors filling the cylinder isn't the problem, it's getting the charge out of the cylinder that needs to be addressed.......

[OHC 6 Sprint]

If you read Vizard's books he recommends an exhaust valve the same size as the intake valve...... Though he does say your restricted to the design of the cylinder head..... If those are the biggest sized valves you can fit, then that is what you got to go with, but if you can squeeze a 1.7 in there, you'd be better off doing that than stepping up to a 2.02 on the intake....... On turbo motors filling the cylinder isn't the problem, it's getting the charge out of the cylinder that needs to be addressed.......

With a 1.94" intake next to a 1.60" exhaust, the space between the valves' perimeters is only about .020" - or just enough to accommodate some expansion over temperature. Exhaust port flow is more of a problem than valve size.

[Bob Holmes]

You're sizing is fine, Randal.

Inconel would be great no the exhaust. We do Inconel exhaust and SS intakes on the 2.3t Fords. However, I've also been looking into the sodium fill.

[DanStokes]

I voted for "Way off base" but only because I'd suggest working with Nick on this. We ordered a couple of special valves from Ferrea for a wastegate and they were super to work with. No doubt that working with Nick, they will get you exactly the best valve for your use.

Dan

[OldMachinist]

What kind of guide liners were installed? I personally don't like the K-line's especially if they were only broached in and not honed to size. Run a guide guage through and make sure they are the same size all the way through. IMO they are too soft to last very long.

I would like to hear others opinions expecially Nick's.

[Deaf Bob]

I didn't vote cuz I know nuthin... Of what you are doing..
So in that vain vein I refrain from voting.. Sorry..

[TheSilverBuick]

What kind of guide liners were installed? I personally don't like the K-line's especially if they were only broached in and not honed to size. Run a guide guage through and make sure they are the same size all the way through. IMO they are too soft to last very long.

I would like to hear others opinions expecially Nick's.

I have zero concern about the guides installed, the guy is uber anal retentive and knows these Pontiac OHC six engines and has done work on these heads before. And if you do know these engines that were only made a couple of years, you have to be pretty anal retentive from the machining stand point. I'm 100% confident the proper care was taken. That being said, I only took a look at them and "assumed" they are bronze, I know nothing about the installation or make of them.

[Aircooled]

Look to the factory Buick GN stuff for guidance. There are / were many hard driven GN's on a stock longblocks. I would worry more about bronze inserts in the exhaust guides. This really is a job for iron/steel.