Freddie's Buick
Hell No! I'm not a junior
- Joined
- Jan 3, 2002
O.K.
I had mentioned on a previous post that big valves and a 3-angle valve seat cut is the way to go on the 3.8. I'm gonna have to take that back. My post was based on dated reading material, (why does'nt anyone correct me?
).
Last year I did a partial rebuild on the upper half of the engine. A solid cleaning and lap job on the stock valves and Felpro valve seals. Now that I removed the valves from the heads for the rebuild, the exhaust valves were in outstanding shape. But the intakes were all crudded up with carbon and oil residue.
The reason for this is because the back of OEM stock valves are of a porous grindy metal. This gives residue a sticking point to cling on to. Over a period of time this reduces flow and performance is minumized.
That is why the polished stainless steel valves flow better. There is nothing there for residue to cling on to. Therefore a 3-angle cut is unnecessary on these valves. They are of a better design. As for the stock exhaust valves they burn so well that no residue is left to cling on to anything.
As a result, all one needs is the larger polished stainless steel intake valves. And the stock sized exhaust valve. Followed by porting and polishing of both valve areas. Most of the metal removal will be on the intake port. Again, the exhaust port is excellant!
Now I got the big stainless steel intake valves from Poston's. And I also bought the stock sized exhaust valves from Poston's. This should be a decent, frugal and simple speed recipe!
And guys....correct me if I'm wrong...
I had mentioned on a previous post that big valves and a 3-angle valve seat cut is the way to go on the 3.8. I'm gonna have to take that back. My post was based on dated reading material, (why does'nt anyone correct me?
).Last year I did a partial rebuild on the upper half of the engine. A solid cleaning and lap job on the stock valves and Felpro valve seals. Now that I removed the valves from the heads for the rebuild, the exhaust valves were in outstanding shape. But the intakes were all crudded up with carbon and oil residue.
The reason for this is because the back of OEM stock valves are of a porous grindy metal. This gives residue a sticking point to cling on to. Over a period of time this reduces flow and performance is minumized.
That is why the polished stainless steel valves flow better. There is nothing there for residue to cling on to. Therefore a 3-angle cut is unnecessary on these valves. They are of a better design. As for the stock exhaust valves they burn so well that no residue is left to cling on to anything.
As a result, all one needs is the larger polished stainless steel intake valves. And the stock sized exhaust valve. Followed by porting and polishing of both valve areas. Most of the metal removal will be on the intake port. Again, the exhaust port is excellant!
Now I got the big stainless steel intake valves from Poston's. And I also bought the stock sized exhaust valves from Poston's. This should be a decent, frugal and simple speed recipe!
And guys....correct me if I'm wrong...
