Beehive valvesprings on all roller 408 smallblock

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port-holio

port-holio

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Comp 918 blue stripe beehive springs used with a Hughes hyrdraulic street roller on ported Edelbrock LA RPM heads. Took a little head scratching, but not too tough, since the heads are set up with 2.02"/1.60" Chevy tall race valves from Eddy.

I've been meaning to post this for some time and finally got around to it. Engine was built for sleeper torque with a Hughes 218/228 @ 0.050", 112 split, 0.565" lift hydraulic roller. Rocker set is Hughes 1.65 roller rockers.

In a 3400# w/ driver Duster, ran 12.76 @ 106.5 with a 2.76 ring gear. Idles about 600rpm with just a little chop. Cruises at 85mph at about 2900rpm with a 727.

PH
 

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mid teens around town, high teens on the highway averaging 75mph. this is rare - I can't keep my foot out of it most of the time.

My highway mileage suffers because it's a higher stall converter than it should have for a 2.76 gear. It's in drydock right now for an overdrive and 3.23s.

It's real well behaved and loves to lug. I need to turn down the advance and lean it out to get any idle lope at all.

1rst gear is a silly joke on 275 all seasons. Throttle response is instantaneous. If we mash it at the same time from a highway roll, I can hang with a few local turbo or giant cam/giant port NA cars that are breaking into 11s.

The extremely fast ramps on this cam make it act bigger than it's specs imply. I also credit Dave Hughes' valve job for a lot of flow.
 
You got a cool ride, just think what 2.94 or 3.23 gears would do. Then again 85 is about perfect on long drives and high teens for mpg, wow

you sure that Duster is 3,400 lbs ?
 
Thanks. I took it on a grain scale last summer with my fat azz and a trunk full of tools, and it was about 3650 pounds. I guess it could be more like 3300. I just had the new EFI system on it, and it was a little buggy. I didn't dare go too far without bringing a full shop along. Someday I'll weight it in race trim. Mentioning a 2.76 gets some strange looks.....
 
port-holio said:
mid teens around town, high teens on the highway averaging 75mph. this is rare - I can't keep my foot out of it most of the time.

My highway mileage suffers because it's a higher stall converter than it should have for a 2.76 gear. It's in drydock right now for an overdrive and 3.23s.

It's real well behaved and loves to lug. I need to turn down the advance and lean it out to get any idle lope at all.

1rst gear is a silly joke on 275 all seasons. Throttle response is instantaneous. If we mash it at the same time from a highway roll, I can hang with a few local turbo or giant cam/giant port NA cars that are breaking into 11s.

The extremely fast ramps on this cam make it act bigger than it's specs imply. I also credit Dave Hughes' valve job for a lot of flow.
Click to expand...

Sounds good. I'm just about ready to install my new 408 that I built pretty mild. Also going to swap in some taller gears eventually but to see what difference they make I'm going to run it with the 3.55's and check it first. Hoping it does decent on fuel. I'm familiar with Hughes cams quick ramps. Only live about 100 miles from them so I've been there.
 
Reviving another thread about beehive springs. I don't really care about the stability @ 7000 rpm. The smaller ends would be a plus..I may just go back to stock springs. tmm
 
FWIW, I shift at 5,500. I forget where I heard it, but the worst spring surge supposedly happens far below red line, and that's why they put dampers and such in there. I think it's a slightly different issue than valve float, and can cause broken stuff from fatigue.

but I digress. I mainly did it for the challenge and attempting to use as little spring pressure as possible. Probably reading too much Dave Vizard at the time......
 
Valve float can occur for a lot of reasons. But a big one is the spring harmonic. Bad harmonics can also break rockers, gall shafts, bend pushrods, and cause general mischief in addition to tearing up lifters and cam lobes. As I understand it, any spring has a certain rpm where the coils develop a harmonic and that vibration keeps the entire length of wire from functioning as a unit. That point is dependant on the cam lobe, spring wire diameter, overall spring diameter, and material. Because it's a harmonic with a certain frequency, it develops at even rpm intervals... Think like a driveshaft vibration that comes in at 40 and goes away, then comes back at 80, the goes away... Same deal. By adding the dampener, the frequency is delayed. Which is why a mild single spring can rev higher than a std spring. However, it doesnt remove the tendency for the harmonic to develop, it simply delays it. Eventually, it does come in and that is usually where the valve action gets uncontrolled and valve float occurs. This is why the inner spring (or springs) are wound differently. Each spring will have it's own rpm point. Put two or three together and you really delay the onset of it. The beehive design doesnt maintain a single outside diameter. So you bascially have different frequencies on the same spring, that tend to cancel each other out. So it's not a question of dampening, but rather offsetting the harmonics. So you really don't get to the point where the harmonic develops. Plus, you have less material in the retainer and lock, and smaller packaging.
 
Thanks Moper, that's the best explanation I've ever heard. I saw something like that at a diesel engine OEM once, but I understand it alot better now. There was a spring pulling the fan belts tight. Turns out, it's natural frequency happened to be the same as the engine at high idle. You could actually see a shockwave bouncing back and forth down the spring. When it got to the end, it would bullwhip the last coil, which would inevitably snap in a few hundred hours.
 
ps - the fan belt problem was fixed in many cases by slitting a section of radiator hose, and sliding it over the coils. the rubber absorbed enough energy to keep the spring from resonating, similar to the metal damper in valve springs.
 
Just a thought, can Magnum head beehives be used in place of stock LA springs?
 
With the right retainers and locks, correctly matched and fitted beehives can be used on anything. Not Magnum beehives, but Comp aftermarket.
 
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