Valves

[rtseast71]

What size are the intake and exhaust valves in a stock head on my 87 t type was told I would get better performance out it putting undercut stainless valves instead of porting them

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[turbobitt]

You need to be careful because the wrong valve with a thin head can tulip. The valve is part of the combustion chamber and can cave in under extreme pressure.
AG.

 

[earlbrown]

1.7 intake and 1.5 exhaust.

and if what you posted is accurate, you need to talk to different people.


Undercutting the stock exhaust valve will git rid of a ski jump and get you more flow..... BUT if you brake a factory seal and buy two expensive head gaskets and an expensive valley pan gasket just to grind 6 valves and put it back together......


....you'll stand a very good chance of joining a club of people that had a fine running car and made it "better".... then sold it as a basket case after you got tired of messing with it.

 

[rtseast71]

I'm not cutting on the valves was talking about replacing them with valves like Manley Ulta flows . Was told they would give me better results than porting the heads

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[rtseast71]

And the motor is apart being rebuilt

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[earlbrown]

In that case get a set of Ferrea O/S valves. That will give you new meat on the intake valve seats. Have the machinist cut the exhaust guides for seals, then bowl port the heads to somewhere around 85% of the seat diameter. If you're bored, do some hand blending where the freshly machined throat meets the raw casting.

 

[turbodave231]

Listen to Earl: His advice is spot on.

Don't listen to your other source......they are full of fertilizer.

 

[ek02]

X2 on Earl and turbodave231's advise. The Manley valves are good and the Ferrea's are excellent. I have used both. The intake valves are available in 1.770 and the exhausts are stock size. Just porting the valve bowls makes a big difference in flow and takes very little time. Have all your guides cut for Viton seals with enough retainer to seal clearance for whatever cam you decide to run now or in the future.

 

[earlbrown]

It'll look sorta like this....

http://www.turbobuicks.com/forums/buick-v6-turbo-tech/79654-how-put-set-heads-together.html

 

[rag231]

Earl, you didnt finish your write up, you left off in 08

 

[earlbrown]

Yeah, those heads are still sitting in my laboratory....

I started doing this instead...

http://www.turbobuicks.com/forums/buick-v6-turbo-tech/88129-day-life-earl.html

I just wanted to cut them for the OS valves before I installed them in my engine.

What really sucks is just how undramatic the bowl porting looks in pictures. In real life it's more of a "holy shit, why did the factory choke the valve like that" moment.