Jerry:
I believe that the "performance" valve springs that Moss is
selling under part number 839-160 for $82 are the PI springs. They are
dual springs that require you to omit the inner spring shim. My
understanding is that these are springs used on the PI motors in England
for the original 280 degree cam. I installed them on my motor for a 270
degree cam, and I can testify that they are a step up from the stock
springs, at a very reasonable price.
It may be that the part numbers you are seeing are for the later
256 degree PI cam, which is the same as the later US spec cam. It would
make sense that the later PI springs would be identical to the US
springs, since the cams were the same. The European cam was derated to
make the car more "civilised", while in the US the cam was uprated to
recover some of the HP that was being lost to the restrictive emission
laws.
The earlier Euro cam is the "hot" cam at 280 degrees, and would
require the uprated springs.
Course, I could be totally wrong on this (pro'lly am...) but
that is my understanding. With my memory, you can never be sure.
Slightly befuddled,
Vance
-----Original Message-----
From: owner-6pack@autox.team.net [mailto:owner-6pack@autox.team.net] On
Behalf Of Jerry C Shaw
Sent: Wednesday, November 24, 2004 1:08 PM
To: 6pack@autox.team.net
Subject: PI Valve Springs?
A lot of listers are recommending using valve springs for the petrol
injection model, yet when I look at the parts list, it lists the same
part
number for both carb and PI engines (part # 157229 - outer and 157476 -
inner) for my '74.
Where can I get PI valve springs?
Also, my machine shop asked about specified spring tension, since he can
measure the tension and shim the springs to spec. to avoid valve float.
Is there a spring tension specification for a mild street cam, or should
I
just use new standard springs and forget it?
For those listers in CT, this machine shop (Kehl Tech Performance, in
Northford) is great. He hot-cleaned the block and head, glass-beaded the
head, magnifluxed them and the crank and knocked out the old guides,
with
overnight turn-around. I'll elaborate more in another posting.
BTW, thanks to all who have been graciously offered much useful advice
in
the past.
Thanks
Jerry
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