Valve spring ..... Your opinion
Thread Starter
Racer
Joined: May 2021
Posts: 384
Likes: 52
Valve spring ..... Your opinion
Hi .. the car Corvette 2003 convertible OEM except muffler and air intake... Time to change the valve spring my question is yes or no to go with PAC-1218 Drop-In Beehive Valve ?
Instructor
Joined: Aug 2009
Posts: 243
Likes: 27
From: New Jersey
Not sure about the PAC springs. Some people have used them.
When I changed my dreaded yellow springs in my 02 Z06 a few years ago, I used the blue GM replacements. I have not had any problems with them.
When I changed my dreaded yellow springs in my 02 Z06 a few years ago, I used the blue GM replacements. I have not had any problems with them.
Race Director
Joined: Oct 2004
Posts: 12,861
Likes: 4,664
PAC springs are as good as, or better than, any other brand valvespring, IMHO. Mine have held up for 8 years, 35,000 miles! Im running dual springs, so can't comment on beehives. If they're PAC beehives, you should be good to go. Personally, I'd never run single springs again, after an outer spring failed, and the inner spring saved my engine......
Melting Slicks
Joined: Apr 2021
Posts: 2,191
Likes: 82
I wouldnt hesitate to run 1218s on a stock cam or .550 lift z06 cam. Summit told me lunati worked with pac for a year developing the springs when i asked where they got the name pac-alloy or was looking into buying their springs. Said most used 1218s. I went with 1219s incase i did go bigger cam or 1.8 rockers.
Race Director
Joined: Oct 2004
Posts: 12,861
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Springs alone won't change your pushrod requirements where length is concerned. But definitely go with 11/32" diameter, .080" wall thickness, hardened pushrods, minimum. IDK if you can go bigger than 11/32" diameter, or not. I'm guessing not, but do your research on that one. Depending on what spring you end up with, if you can't go bigger than 11/32", you might want to get .100" wall thickness. Buy the length you have now, and you're good.......
Safety Car
Joined: Aug 2011
Posts: 4,447
Likes: 408
From: Portland OR
Those aren’t very stout springs. Excellent springs, but don’t require 11/32 heavy wall pushrods.
I bet stock would work fine, but just a nice set of 5/16 .080 wall hardened from a variety of manufacturers would work great.
BTW, the PAC 1218 is a .600” lift spring.
I bet stock would work fine, but just a nice set of 5/16 .080 wall hardened from a variety of manufacturers would work great.
BTW, the PAC 1218 is a .600” lift spring.
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Race Director
Joined: Oct 2004
Posts: 12,861
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Youre right about the springs. I realize they arent super stiff springs, but after viewing some spintron videos online, it's amazing how flexible pushrods are, especially the 5/16" PRs. Even GM went to the 3/8" pushrods on the LS7, which also has pretty tame springs. I'm also thinking about the "while he's in there" angle......
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I use PAC 1218 with stock pushrods in my '03 Z06. No need to change the pushrods when changing springs.
