Large valve spring Dia vs Small valve spring Dia

talon · Post by **talon** » Mon Aug 29, 2005 12:07 pm

Good morning Gentlemen

I was selecting a spring application this weekend. The cam (.51 lift 220* @.05 hydraulic roller) called for a 1.44 dia with dampner 125# @ 1.8 and a spring rate of 360#'s. I have some 1.26dia with dampner 130# @ 1.8 and a spring rate of 366#'s.

This is for a 351 cast iron sbf head. Number wise this spring sould be fine. I was just trying to get your take on spring dia.

thanks
Jim

67RS502 · Post by **67RS502** » Mon Aug 29, 2005 1:34 pm

On hyd. rollers keep the spring dia. as small as you can, this will keep the retainer size/wt. down. Now both the spring and retainer will have less mass - meaning it will rev higher, as valve float can be a problem. also you could do the bee hive springs. Lobe design has alot to do with it also.

SStrokerAce · Post by **SStrokerAce** » Tue Aug 30, 2005 11:33 pm

Totally agree with all of that. Less mass is as important as the spring pressure.

You might want to put even more on the seated pressure if your springs can handle it with room to spare before coil bind.

Bret