danltr450

I have a set of A50 motorsport valve springs and they have ratings of 110lbs closed @1.820 and a rate of 240lbs @1.400. My questin is if the rate can fihured out through math rather than taking it to a mchine shop and haveing them tested? I am looking for the rate @ 1.280 or .544 valve lift? If I do the math it comes out to 280. I take the 130lbs divided by the .420 lift given and then mutiply it by the desired .544 lift and add the 110 seat pressure back to it. my77stang, I need you with this one. I know you had plenty of history in the machine shop and want to see if I am close. I do plan to take them to the shop and have them tested , but I want to see if I am close or accurate with my math or thoughts.

mjr46

The A-50 valve springs to my knowledge were designed for the f-cam with max intended lift of .512....they were the ones that I believe ford racing reccommended when I was installing my f-cam and I set installed height to 1.820 if you don't match springs like it sounds as if you want to use a cam with more lift with these springs then there won't be enough spring pressure and you may experience valve flutter/float at higher rpm's ....that's what happened when I had stock springs and an e-cam before I could never get passed 5700 rpm's in 1st before it broke down like mad.

danltr450

i believe it will have the pressure, but just wondering.

Joel5.0

There has been a permanent typo on those specs for a long time......here are the specs for those springs:
110# @1.820" closed valve
320# @1.250" open valve
368# pressure rate
1.130" coil bind height

Suggest to have them tested though.....

danltr450

cool. where did you find those specs? The guy at fordracingparts told me what I had posted. I can only assume that he was reading from his book.

my77stang

seems to me that 110 lbs is too weak for a roller .544 lift. hell, i'd want more than that with a flat tappet .544

with my .500 flat tappet, my springs are around 110-120 IIRC, and thats enough to tag the 7k redline without float. probably helps that its a really long duration (300/300), so the ramps on the lobes arent steep.

without knowing what seat pressure your cam is calling for if i were assembling the heads for my car i would want 120-140 @ the seat, probably right in the middle @ 130. that should be a nice happy place for that cam in a street car.

danltr450

It calls for 120lbs seat and 295 open no more than 305 open

danltr450

http://store.summitracing.com/partde...p;autoview=sku

here are my specs for my cam