Valve Spring Recommendations
Thread Starter
Melting Slicks
Joined: Apr 2003
Posts: 2,150
Likes: 6
From: NS
Valve Spring Recommendations
I finally picked up a new set of LT4 roller rockers for my '95 LT-1. I don't plan to use my stock LT-1 valve springs, I know this is not a good idea. Can anyone recommend a good set of springs?
I was thinking about buying a set of LT-4 springs with the retainers. Is there a better alternative?
How critical are springs, can I just buy a quality set from my local engine builder? Should I stick with the LT-4 101lbs seat pressure?
Thx
I was thinking about buying a set of LT-4 springs with the retainers. Is there a better alternative?
How critical are springs, can I just buy a quality set from my local engine builder? Should I stick with the LT-4 101lbs seat pressure?
Thx
Melting Slicks
Joined: May 2003
Posts: 3,490
Likes: 68
From: Hewitt NJ
If you are keeping the stock cam and just adding the RR, then the LT4 springs and retainers would be an excellent and affordable choice. You can get them here:
http://www.superchevyperformance.com...s/12495494.asp
http://www.superchevyperformance.com...s/12495494.asp
Racer
Joined: Jul 2004
Posts: 285
Likes: 0
From: San Diego CA
Admiral94 -
Was thinking of doing the same thing the gentleman who started this post is doing now.
I was however under the impression that with the LT4 spring set it is recommended to also get the "shim" set. I assume this has something to do with the LT4 spring height vs the LT1. Another option might be to check with Crane Cams - they have a complpete kit (part number escapes right now) posted in JEGs or SUMMIT.
I am
thanks !
Was thinking of doing the same thing the gentleman who started this post is doing now.
I was however under the impression that with the LT4 spring set it is recommended to also get the "shim" set. I assume this has something to do with the LT4 spring height vs the LT1. Another option might be to check with Crane Cams - they have a complpete kit (part number escapes right now) posted in JEGs or SUMMIT.
I am
thanks !
Le Mans Master
Joined: Feb 2000
Posts: 9,715
Likes: 27
From: Kempner Texas
I always let the cam manufacturer dictate the correct spring to use. They've tested the ones that work best for a specific grind.
It's when you start choosing a set that's "just as good as" that problems can creep in. Differences in spring rate, seat pressure, open pressure, wire composition, diameter, installed height, etc., can make a difference over the long run; and occasionally over the SHORT run.
I recall a "new" set of valve springs that had just been bought and when I inspected them, I found one had a flat coil right in the middle of the winding; not round like all the others. These are the kinds of things that can jump up and bite you.
Just my thoughts.
Jake
It's when you start choosing a set that's "just as good as" that problems can creep in. Differences in spring rate, seat pressure, open pressure, wire composition, diameter, installed height, etc., can make a difference over the long run; and occasionally over the SHORT run.
I recall a "new" set of valve springs that had just been bought and when I inspected them, I found one had a flat coil right in the middle of the winding; not round like all the others. These are the kinds of things that can jump up and bite you.
Just my thoughts.
Jake
Melting Slicks
Joined: May 2003
Posts: 3,490
Likes: 68
From: Hewitt NJ
Originally Posted by gslotman
Admiral94 -
Was thinking of doing the same thing the gentleman who started this post is doing now.
I was however under the impression that with the LT4 spring set it is recommended to also get the "shim" set. I assume this has something to do with the LT4 spring height vs the LT1. Another option might be to check with Crane Cams - they have a complpete kit (part number escapes right now) posted in JEGs or SUMMIT.
I am
thanks !
Was thinking of doing the same thing the gentleman who started this post is doing now.
I was however under the impression that with the LT4 spring set it is recommended to also get the "shim" set. I assume this has something to do with the LT4 spring height vs the LT1. Another option might be to check with Crane Cams - they have a complpete kit (part number escapes right now) posted in JEGs or SUMMIT.
I am
thanks !
Thread Starter
Melting Slicks
Joined: Apr 2003
Posts: 2,150
Likes: 6
From: NS
Thanks Admiral.
Anyone know what the open pressure is for the LT4 springs using a stock LT4 cam? Or the LT4 spring rate? I've read the seat pressure is 101lbs, wondering about the other specs.
Thx
Anyone know what the open pressure is for the LT4 springs using a stock LT4 cam? Or the LT4 spring rate? I've read the seat pressure is 101lbs, wondering about the other specs.
Thx
Le Mans Master
Joined: Aug 2000
Posts: 8,838
Likes: 31
From: Australia
From the GMPP book.
LT1 #10206040
85lb @1.78
373lb avg
Coil bind 1.26
LT4 / ZZ4 Spring #12551483
101lb @1.78
332lb avg
Coil bind 1.22
Good for .525 lift.
1.78 appears to be the normal height for L98 / LTX valves.
The part listed as a "shim " is more of a seat to stop the valve gouging out the alum head.You would need proper shims on top of that if you needed to adjust height.
My understanding is if you use the complete LT4 / ZZ4 setup ;shims, springs and retainer you should have the correct installed height.
LT1 #10206040
85lb @1.78
373lb avg
Coil bind 1.26
LT4 / ZZ4 Spring #12551483
101lb @1.78
332lb avg
Coil bind 1.22
Good for .525 lift.
1.78 appears to be the normal height for L98 / LTX valves.
The part listed as a "shim " is more of a seat to stop the valve gouging out the alum head.You would need proper shims on top of that if you needed to adjust height.
My understanding is if you use the complete LT4 / ZZ4 setup ;shims, springs and retainer you should have the correct installed height.
Burning Brakes
Joined: Feb 2001
Posts: 769
Likes: 0
From: Granbury TX
The only new tech change in springs in years is the new Comp cam "Beehive" spring. I have installed these in my new rebuild. I'm vewry happy with them, but have no dyno test to prove anything although there has been plenty of magazine and builder feed back which indicates they do produce a few hunderd extra RPM by improving valve performance in all respects. I believe they are mde in 2 pressure ranges, but give Comp a call. They have been more than happy to answer any questions I've had.
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