Poston Valve Springs......any info?

[jdpolzin]

I've got a set of Poston springs I'd like to use with my 4.1 build. We called postons to get a little more info and they had none to offer. I had my guides cut to clear .510 lift. My cam has a gross lift of .485/.489 and is a Comp flat tappet 216/218. The cam card doesnt give a spring requirement. I'm wondering if I will have any problems with the springs completely compressing. Any info would be helpfull. For now, I have the springs installed on the heads. I do plan to remove them and use stock springs for break in time. How do I know if my spring height is ok and if I need spacers or not? Thanks for the info.

 

[ericttype]

Hi, you have to measure spring height with a specail tool, once you know your spring ht you put the valve spring is a spring tester to see how much pressure you will have at the sea valve closed.. if its not enough you can shim it , if its too much you may have to go to different spring,you also have to check wide open spring pressure any shop that does head work should beable to check it, i would not guess, ps i never used stock spring to break in a cam prime motor and start it and keep rpm above 1500 rpms for 10 mins these cam have low pressure compare to alot of solids at the machine shop i worked at, they had 500 to 700 open pressure

 

[ericttype]

you need to find out what spring pressure comp cams wants and make sure your spring matches that, if comp want 120 at the seat, check spring pressure at the height from the retainer to head, the let say that reading is at 1.700 you will need to deduct your cam lift from that number and check spring pressure so 1.700 - .489 = 1.211 open pressure

 

[jdpolzin]

Ron, thanks for the help. Do you know if the parts store or Harbor Freight has the correct tools to measure spring pressure and height?

 

[ericttype]

not sure if they would have the tools need spring ht tool vineers and spring pressure tester they are not cheap may just be better to go to a good shop in your area, if these are for stock cams i dont think they will work but the only way to know for sure is have them checked, thanks