- Aug 5, 2001
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Hey guys i have ported and milled e7's on my stock bottom end 302 the springs are rated with a 110 #'s of seat pressure will that be enough to run a tfs stage 1 cam?
valve spring ?
- Thread starter saleen9973
- Start date
PLEASE use the valve springs that are recommended by the camshaft maker. You will save yourself a lot of grief if you do. You are asking for problems if you don't.
joel5.0
Member
- Aug 5, 2001
- 54
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What do you mean by valve open numbers? i only know what the machine shop told me when they did my heads. they told me the springs were rated at 110# seat pressure.
I think that is more than enough, I had 90# springs on my gt-40 heads with a really aggressive cam (not sure the numbers) and they worked great. My heads are in the shop now actually getting 135# springs because the valves were floating at 5k RPM, but then again that is due to the addition of 13 PSI of boost.......
The 110lb seat pressure is how much pressure the valve spring is putting on the valve when it is closed. If the cam opens the valve to .500 lift then how much pressure is the spring putting on the valve now that the spring is compressed? The open pressure is usually about 3 times the seat pressure. This is a VERY generalized statement. If you read the cam makers cam card, you will see how much spring pressure is recommended for both open and closed valve operation so that no valve float is encountered thru the operating rpm of the camshaft.
- Aug 5, 2001
- 54
- 0
- 6
O.k that is something i did not know. I guess my only choice will be to change the springs to what trick flow recommends. I am not sure of the open pressure. So i will just be safe. On 1 other note what does valve float feel like. My engine feels like it has a miss above 4800 rpm with the stock cam now. I changed the distributor and it got better. The motor has well over 100k on it. I was thinking possible timing chain slack?
thumper460
Founding Member
TFS1 call calls for 130 seat ( installed ) and 320-340 open!! Yes a lighter spring will work.... to a point!! there will be an issue with valve flow ( flying over and off the lobe) and when the valve closes there can be "seat bounce" ( the valve actually bouncing on the seat vs staying closed!! ) huge power loss!! Hope this helps.. IF you need a spring KIT ( springs/moly retainers/ keepers) shoot me a PM and let me see what I can do for ya... cool??
Just me....................................
Thumper
Just me....................................
Thumper
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