coil bind on valve spings

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greenracing
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coil bind on valve spings

Postby greenracing » Fri Feb 22, 2008 8:25 am

How close to coil bind can you run valve springs? I know this probably depends somewhat on what spring you're running, but what has everybody used as a rule of thumb?

Since my cam was a victim of the last explosion, I'm test fitting some of the other cams I've got in the shop (I've got like 5 of them :roll: ). They all have bigger lift than the one that was in there. The one that's closest puts to to around .030-.040 before coil bind on my springs. Too tight?

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Leon
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Postby Leon » Fri Feb 22, 2008 10:34 am

I like .050 at the closest coil.What about retainer to guide?

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SLICK VIC
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Postby SLICK VIC » Fri Feb 22, 2008 10:41 am

Green,
there are a bunch a variables that play into how
much too much,..lift, rpm range,.wire diameter, single, double
triple spring,.
.030-.040 is no where not enough,..coil bind clearence
typically starts at around .700 to 1.210,..it all depends
but ive heard min.1.100

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greenracing
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Postby greenracing » Fri Feb 22, 2008 11:14 am

I'm kind of with you Leon - I was thinking .050-.060.

I didn't specifically measure the retainer to guide, but there's quite a bit there. Looked at it when I had the checker springs on it checking v/p. Good question tho.

Vic - these heads are a real headache when it comes to springs. The valves aren't very long to get the right geometry, and the spring pockets aren't very deep because they're right over the intake ports and there's no material there. I end up with only a 1.700 installed height. Finding a spring that will give me 300lbs of seat pressure that won't coil bind on me is a pain. The springs I've got coil bind at 1.035.

The cam I was running had like a 550 lift. (I think if they made and RV cam for a 392 hemi, this may be it :lol: )

The cam I was looking at running has a 660 lift. I measured the actual valve travel at the keeper with correct lash and it came out to 623. That gives me an open spring height of 1.077 - only .042 away from coil bind.

Guess I'll order me another RV cam - it worked before - it'll work again...

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Leon
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Postby Leon » Fri Feb 22, 2008 6:31 pm

1.7? Im at 1.9 and 285 seat with 685 open. Howards springs which are 220@2.0.

greenracing
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Postby greenracing » Mon Feb 25, 2008 8:13 am

I'd love to be at 1.9 - my world would be so much easier :roll:

It doesn't seem like the Mastodon and 354 heads should be that much different. Unless they raised the top of the intake runners on the Mastodons. I can put my fingers in the port and on the spring pocket, and it sure doesn't feel like I've got .200 worth of material in there to work with.

What length valves are you running? It might be that the Titan rockers work with a taller valve than the Canode rockers do.

My427stang
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Postby My427stang » Mon Apr 28, 2008 6:29 am

You can (and some say probably should) run a tight clearance to coil bind, but if you do you better be darn sure you measured each and every valve and didnt make any mistakes. It helps manage spring surge.

I have seen a few of the more talented guys than me running as close as .020 on the intake side and .030-.040 on the exhaust, even with over .800 lift

I wouldnt run looser than .050 though, excessive coil bind clearance is not good either as harmonics can induce spring surge, I like to run a spring through its full travel.

Could you change retainers and run the setup that put you at the .030-.040 range?
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greenracing
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Postby greenracing » Mon Apr 28, 2008 8:41 am

After much head scratching and searching I found a combo that will work pretty good. I ended up with .100 high retainers and .050 high keepers. I found a set of Manley Nextech springs that will end up within .020 of the spec'ed open height for the spring (not the coil bind height, but the recommended open height). I'll end up with around 370lbs seat pressure. Should be a pretty good combo.


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