Jeff M

I am putting a cam in my truck and I have 8 double springs and 8 .600 lift beehive springs. Is there any reason i can't put one set on the intakes and one set on the exhausts? All of the springs are brand new and I don't see how it could have any negative consequences, and this way I don't have to buy a new set of springs just so they all match. The cam is just a TR224 so both sets are up to the task.

Old SStroker

I'm curious as to why you have a half-set of each.

I'd weight a beehive and it's retainer (to the nearest gram) and a double and their retainer. If the double is equal or less I suppose you could mix and match. With steel retainers, I'm guessing the beehive will be less. Probably even with Ti retainer on the doubles!

Less mass (weight) is always bettter in a valvetrain, all else being equal.

BTW, you only need to buy half a set to get them to match, or find the other guy with half sets and swap.

(Go for the beehives in the swap)

1Bad00SS

iTrader: (2)

Weird ... yes.

Will it hurt anything ... I can't think of a reason why you couldn't.. maybe you should add 1.8 rockers on the dual springs as well? That would be sick! lol

Jeff M

Why would it matter if the double weighs more, but be ok if the beehive weighs more?

I just weighed them all and the double are 100g and the beehives are 80g. For fun, I also weighed the retainer/lock combos, and with the larger locks in the ti retainers they don't weigh any less than the stock retainer/lock combo.

Odd that I have two half sets? You didn't look at the pic, there is one thing a little more weird than that about the combo

What would the difference in weight cause, what problems could this possibly bring up? I just didn't think it would matter at all since they aren't really connected.

Old SStroker

It looks like at least one oddball retainer.

Mass (weight) is the enemy in a valve train. As the valve opens and closes all of the moving parts (including most of the spring coils) need to be accelerated then decelerated twice per valve event. From Newton's Second law of motion, F=ma or the Force required to accelerate an object (or many objects in one cylinder's valvetrain) is proportional to the acceleration times the mass.

The lobe profile and rpm detrmine the accelerations, so more mass (weight) means more force is required which means more spring force is required. This causes more deflection in all the valvetrain bits, which makes the valvetrain harder to control as rpm increases. Without reducing mass (or increasing stiffness of the parts) more spring force is required and more deflection results...it's a no-win situation.

Now much of what the spring has to control is it's own mass which is moving as much at the retainer end as the valve . One of the most important advantages of a beehive over parallel dual springs is the mass of the beehive is much less in the top coils which do the most moving as well as the smaller retainers used on the beehives. You noticed that the (cheap) steel beehive retainer was the same or less mass than the Titanium retaner for the duals.

Cliff notes: Use the lightest spring/retainer/locks combination you can which will control your valvetrain. Even if the beehive is 5-10% heavier overall it will contol things better and with less seated load.

FWIW, cheaping out on valvesprings is a bad idea if you want your engine to perform. Summit sells Comp 918 beehives and retainers for about @225/set of 16. Ya' gotta quit shopping for your valvetrain parts at yard sales.

Jeff M

I do appreciate your patience to give me a lesson on valvetrain.

You didn't answer why you said "If the double is equal or less I suppose you could mix and match." 1) Why does the difference between two springs on one head matter. 2) You imply that it's ok to mix and match if the double weighs less than the beehive, but not ok to mix and match if it's the other way around. That's what I don't understand. Can you explain my situation if I do mix and match, and why it's ok to mix and match if one is heavier but not the other?

Old SStroker

The mass of the top coils is more critical than the overall mass. The bottom coil doesn't move, or at least shouldn't. The beehive bottom coils go solid (and stop moving) as the valve opens which makes the moving spring mass even much less. That's why a slightly heavier beehive can work better than a dual parallel spring. Valvetrain mass is the enemy!

Your duals + retainers/locks weight more than your beehives if I read your post correctly, so it's probably a moot point.

Why don't you ask your cam/valvetrain person what springs to use and at what installed height to set them. That's always a good idea as he should know exactly what works and what doesn't.

Jon

VIPRETR2

iTrader: (63)

Throw the duals on the intake and the singles on the exhaust. One thing to think about is you most likely have to replace the spring "seats" and valve seals with the double springs. You probably already have that stuff though. I agree with Old SStroker that a quality (PAC not COMP) single beehive would be a better way to go for all springs, but you should be fine using both. Plenty of guys use duals with the TR224, same goes for singles. Good luck,

Larry

Old SStroker

Just curious here, Larry. Why put the heavier springs on the heavier intake valves? That seems to be backward to me. Let's assume both springs have similar rates and lift capability.

Jon

VIPRETR2

iTrader: (63)

ASSuming the singles are 918s I would choose to expose them to the least amount of strain possible. Mainly because of the random reports of 918 failures over several manufacturing dates. I do see your point though and that didin't even occur to me. If they are "good" single springs I would definitely concur with your conclusion. Thanks for the insight,

Larry


BTW Old SStroker, since I have your attention. Do you know of any lash cap solutions for stock Gen 3 8mm valves? 8mm lash caps are plentiful but I can't seem to find anything in terms of recessed valve locks. I woud try LS7 caps but it seems to me that the LS7 valve lock grooves are machined lower on the valve in lieu of using a clearanced lock setup. Feel free to PM me on the subject.

SweetS10V8

iTrader: (4)

918s are fine they redesigned them completely. They are now silver, the blue striped ones were the ones that had a few issues.

I run 918s on my truck, and just bought the tool steel retainers for them too! Should weight just about the same as Ti. I also got the lightweight valves too. I don't want valvetrain instability issues.

Mass matters on the valve, retainers, locks. Moment of inertia, and stiffness matter on the rocker arm, the pushrod should be as stiff as possible. With our engines, and stock casting heads, we don't have many options but thicker wall 5/16" pushrods. So I went with .105" wall.