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ron37
330 Valve Springs


A buddy is building a 330 Desoto. He had a hydraulic roller cam made for it. The grinder said use valve spring not over 130 lbs. A mechanic told him that high would cause abnormal wear on his new cam. I said the guy was probably thinking about flat tappet type cams. What do you guys think would be okay for a billet hydraulic roller cam. He said it is a lumpy style street cam with low end to mid-range 5000. I laughed as mid-range. 5000 isn't mid-range to me. Thought I'd drop that in there. I think he meant it keep building some to 5K. So give me some ball park number of what you would do.
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on: Fri 05 of Mar, 2021 [20:20 UTC] reads: 2609

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ron37
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Re: 330 Valve Springs
on: Mon 08 of Mar, 2021 [18:51 UTC] score: 0.00
The cam grinder said not to go over 130 seated pressure. I think he is using Comp Cams lifters, which I think are a quality lifter. So from what I know of what will be his usage and your input, the 130 spring will be fine. Thanks for the help.

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George
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Re: 330 Valve Springs
on: Sun 07 of Mar, 2021 [16:34 UTC] score: 0.00
What spring pressure did the cam maker specify?

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DaveBlakeman
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Re: 330 Valve Springs
on: Sun 07 of Mar, 2021 [16:33 UTC] score: 0.00
From Web Hydraulic roller (HR) cams require higher pressures to control the inertia of the heavier roller lifters and the faster acceleration of valve train components allowed by the use of the roller follower. Pure street small blocks should have 260-300lbs open pressure. For performance use, aim for 300-350lbs open. Racing small blocks that regularly see 6,000+rpm need over 400lbs open pressure. At these pressures, premium valve train components including a “billet” type cam are required. Even with these components, there will be reduced service life and the consequent need for more frequent parts inspection and replacement. Big blocks need closer to 300lbs open pressure for street driving and 350-375lbs is preferred for performance use. A racing big block needs 450lbs. As with small blocks, premium components including lifters are needed at higher pressures and rpm. As with solid lifter cams, seat pressures should be in the range of 105-125lbs for small blocks and 115-130lbs for big blocks for performance street cars. Blower cars and race cars will need higher seat pressures.

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DaveBlakeman
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Re: 330 Valve Springs
on: Sun 07 of Mar, 2021 [16:30 UTC] score: 0.00
A 130 lb spring pressure is not out of the ball park if it is seated pressure open about 320 lbs.

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DaveBlakeman
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Re: 330 Valve Springs
on: Sun 07 of Mar, 2021 [16:25 UTC] score: 0.00
Fact roller tappets are heavier than flat tappets Fact Roller cams have aggressive ramp angles . Theory at 130 lbs you will experience valve float very early on. You better do some google searching on this but do not run 130 lbs.


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