Re: Blown Packard inline 8.
Posted by Ross On 2009/10/5 21:16:10
Brian: Thanks for the great photos and info. Your roadster (on youtube) inspired me to build one also though mine is for general back roads cruising and is not blown.
Anyway, I agree that a full relieve job is not necessary and will just drop compression. I have had good success smoothing out the edges of the little saucers that the valves sit in. As the Packard valves are tilted toward the cylinder the mixture doesn't have to travel too far!
Here are some photos of a cutaway unmodified 288 (=327=356) as the architecture was all the same. You can see how the mixture would flow up out of the port and be directed by the hollow in the head. I also like to cut a big chamfer on the top edge of the intake valves to make a wee bit more space for the mixture to flow over the top and around from the back side. A little finessing goes a long way.
Am looking forward to further installments.
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Anyway, I agree that a full relieve job is not necessary and will just drop compression. I have had good success smoothing out the edges of the little saucers that the valves sit in. As the Packard valves are tilted toward the cylinder the mixture doesn't have to travel too far!
Here are some photos of a cutaway unmodified 288 (=327=356) as the architecture was all the same. You can see how the mixture would flow up out of the port and be directed by the hollow in the head. I also like to cut a big chamfer on the top edge of the intake valves to make a wee bit more space for the mixture to flow over the top and around from the back side. A little finessing goes a long way.
Am looking forward to further installments.
Attach file:
(100.57 KB)
(44.01 KB)
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