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Discussion Starter #1
Hey guys, I was wondering if anyone knows how much over "max lobe lift" you can get away with when it comes to valve springs?

I have a set of Eddy's Victor Jr heads rated at 700 MAX LIFT. The cam they are specing out is 726 lift. I know that most EVERYTHING has a safety margin figured in for people like me who may push it a little past.

What do you guys think???? With springs rated at 700 lift, Would you trust them at 726 max lift? Will the .026 extra lift push my springs to unsafe levels???

All input and opinions welcome. To go up to the next step is 5-600 just for .026 more SAFE lift.....

Let me know what you guys think!

Thanks and have a good one!!!!
Auggie
 

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Some I tested recently going off my notes , coil bind was at 1.200" , installed height came in at 1.970-1.975. I had a solid cam with around .620" lift which gave me .150-.155" clearance . Spring pressures measured with the retainer on the spring were 150 on the seat . Around 360 open
At .726 I think you'd be getting as bit too close for comfort, wouldn't you need more spring pressure ??
 

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I think that you are supposed to have .060" clearance before coil bind.

Installed height - coil bind - .060" = max lift.

You would also need to know if the springs have the correct pressure too.

Jess
 

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Discussion Starter #5
springs

they are the dual springs that came with the Edelbrock victor jr heads. I have a spring pressure tester mounted to my bench and the shims to equal them out. Seat pressure IS something I am concerned with so I am glad that was brought up. When looking at their cam spec sheets they use 700, 800, 900 lift as cut off points for going with stronger springs.
My other concern is because I bought the heads used I have no idea of the hours on them. So I have no clue as to how much abuse they have had.
If I was going up to 800 lift it would be a no brainer. Plus, edelbrocks flow sheet for the head only goes to 700 lift. These have been ported and highly polished. Also factor that it is blown and not N/A.
But just going .026 more lift is so close to what they say is max that I thought I had better get some input on this one.

ANYONE have a set of dual springs with keepers and locks good for up to 800 lift for sale?? lol
 

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Auggie, I just got done building a Eddy RPM headed 472 and I done the same thing, I set up the spring on my height tool on the bench, I put the spring and retainer into it and went to .720 on the gauge and had my friend put a .060 feeler gauge inbetween the coils and it was snug but they could be used because he was not going to turn it over 6500 rpm, I told him I would use them if it was me, the next day he told me that he had changed his mind and wanted new springs, I told him it will be costly to go to a bigger spring, anyway I called comp and told them my problem and he said I have a spring for you its a 999-16 and its for the 1.550 retainer and it will give me about .040 to .050 more clearence with no mods, so thats what we did and it worked perfact
 

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The 999's spec out at :
1.550" OD,
H-11 material,
.710" ID,
230 @ 1.875" seat,
700 @ 1.200",
coil bind @ 1.100"
696 lb/in
So usable lift would be .715"
Actually, if you are assemblying to 1.950" installed then the 998's will give you .810" of usable lift.....if you don't mind going to a 1.625" diameter spring.
Seat on the 998's is 200 and open @ 1.200" is 735.
733 lb/in.
Less seat and more over the nose and more to bind.
I use the 998's in my 466" and I've zipped that thing to 8K without a hint of float with the Milodon Mega Flo stainless light weight valves.
Just saying......

Rob
 

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Your .726 lift cam will probably have less than .700 lift at the valve once you account for lash, deflection, and geometry.

That being said, you should measure your actual installed height and work from there with the spring specs to figure it out....then verify with actual physical measurements of coil bind, pressures, etc.


.
 

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I don't know how many of you remember an article in Hot Rod mag. about rocker arms and valve lift. They tested a bunch of different rocker arms for total lift and the results were surprising to say the least. The only manufacturer who was true to the advertised rocker arm ratio was Harland Sharp! All others varied and if I remember correctly, were less than advertised! Therefore, agreeing with Carl, you have many variables to deal with. Without a full mock-up, there is no way of telling for sure.Also what about retainer to guide/seal clearance? Just my two cents, Ernie
 

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Rob, the eddy rpm's have 1.550 spring pockets thats why we did that spring, I was able to do it myself at home and not another trip to the machine shop to have the spring pockets enlarged and we already had titanium 1.550 retainers too, it was the cheapest way out
 

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Discussion Starter #12 (Edited)
springs

Thanks guys! Lots of good information and like some say.... when you are literally straddling the line that "they" draw it is hard to decide which way to go.

I pulled one of the new springs I installed in my cast heads last year that were matched to the new cam from last year and it is the same number that is matched with all their cams up to 700 lift. Then I checked the spring pressures of the springs from the eddy's and they weren't even close!!! I bought the heads used and it had a few valves replaced. But I really didn't give much thought to the springs and if they were possibly upgraded already. The spring rate on the ones I put in last year was 391 and in the tester they showed aprox 330 at .750 and the pressure maxed out at aprox 380 all the way to bind. The springs in the eddys were over 500psi at .750 and pegged my needle when pushed towards 1.5 and wasn't even close to bind. Thinking that when they replaced the couple intake valves that they upped the springs too.

I feel better now with all the numbers you guys supplied and info on different readings and outcomes. To be honest, whenever I installed dual springs in (sorry in advanced for the swearing) sbc's. 610 lift was considered huge! That's how long it has been, lol. And dual springs, as long as they didn't bind, never had an issue, lol. NOW, there are so many different springs out there that it just gets confusing at times!!!

Thanks for all the input and different things to check/double check/triple check, lol

Thanks again!
Auggie

PS
I am doing a full mock up right now and have the adjustable pushrods to get my geometry right and check for ACTUAL clearance BEFORE I order the new cam. Don't want to put a valve into the top of one of those nice shinny pistons Carl! haha And thanks again, everything is starting to come together with that block :)
 

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Discussion Starter #14
done

Did you get it figured out?
Got it all figured out. Previous owner put much stronger springs, keepers and locks in. Seat pressure is now 320 and ramp is 645. Assembled them and got all heights within .007 using 1- .030 shim, 6- .015 shims and one odd intake valve was replaced and needed no shims! Installed height is 2"...... Now to install it and check coil bind but all looks good. THANKS!!!!!
Thanks to everyone who offered input.
 

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In race applications or steel valves over 6,500 I run the spring at .050 off of coil bind after checking max lift with lash and proper geometry. I do this so the spring will coil bind but in an "unloaded" condition from intetia only. In this unloaded condition the spring is not damaged as it would be with solid mechanical interference. I saw some spintron photography of the retainer and locks in slow motion and it was enough to stop me from ever revving my engine again. The spring inertia took the retainer with it and the locks seperated from the valve stem big time. How it all stayed together amazed me. It's obviously happening in milliseconds and would never be seen except for the super slo mo photography. It becomes a little tricky to manage spring pressures to something reasonable , but spring life is great. I have used my Isky roller springs for 5 years and over 500 1/4 mi passes at 8,000+ ( with ti valves) with only a 10lb pressure loss. I am very surprised and credit a portion of the life to the way I set them up. Others may not agree and that's ok , it's just what "I" do.
 

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Discussion Starter #16
In race applications or steel valves over 6,500 I run the spring at .050 off of coil bind after checking max lift with lash and proper geometry. I do this so the spring will coil bind but in an "unloaded" condition from intetia only. In this unloaded condition the spring is not damaged as it would be with solid mechanical interference. I saw some spintron photography of the retainer and locks in slow motion and it was enough to stop me from ever revving my engine again. The spring inertia took the retainer with it and the locks seperated from the valve stem big time. How it all stayed together amazed me. It's obviously happening in milliseconds and would never be seen except for the super slo mo photography. It becomes a little tricky to manage spring pressures to something reasonable , but spring life is great. I have used my Isky roller springs for 5 years and over 500 1/4 mi passes at 8,000+ ( with ti valves) with only a 10lb pressure loss. I am very surprised and credit a portion of the life to the way I set them up. Others may not agree and that's ok , it's just what "I" do.
Thanks for the input!!! It looks as though I'm going to be safe from my tests in the bench mount spring pressure tester and the mock up with a 726 lift cam. But until I get the new cam (should be here by Monday, Tuesday) and set up my geometry and turn it over.... I won't know for sure. But I really do feel pretty good about the set up!
 
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