The recommended installed height with the 918 beehive springs is 1.80". You will not get that height on an LT1 head with just spring locators. You can do it with 1/10" longer valves. Be careful, w/your lift of 577 there can't be any mistakes on the install.

On my heads, the final installed height was approx. 1.75". This is with stock valves, 3 angle valve job, CC locators, 918 beehives, chromoly retainers, and +.050 valve locks. The max lift on my cam is only 555 though (on the exhaust side).

It is important to get the correct installed height, otherwise you could be too close to coil bind.

The beehives have been flawless so far.

 

26918 beehive springs (source:ComCams)

26918 -Single Beehive Ovate

O.D.: 1.055/1.290
I.D.: 0.650/0.885
Seat Load: 130@ 1.800
Open Load: 333 @ 1.150
Coil Bind: 1.140
Rate(lbs./in.): 313
TitaniumRetainer: 772,762
SteelRetainer: 774,783,761,787
Cup/Seat: N/A
Shims: 4753

So, if installed at LT1 heads normal hight, 1.75", that leaves 0.610" before hitting Coil Bind.

I have .569"/.588" lift with 1.52 RR. That leaves me with 0.022" before Coil Bind.

The spring locator 4705 is 0.060" thick. So, I think there will be a problem, right?

However, Summit Racing's site lists the 26918 springs with 1.085 in. Coil Bind Height which made me feel safe installing them at 1.75 with 0.605" before Coil Bind, including the spring locator 0.060" hight.

Any thoughts?

 

Wait a min. Comp gave you the 1.140 coil bind #? Those ****ing bastards told me 1.085. DO NOT go by the 1.085 #.

My install height was 1.675, I had .568 lift. That put me at 1.107, or .022 from that 1.085 # they gave me. .022 is too close. One of mine broke, and destroyed my entire engine

One more thing, measure the install height. Do not go by the normal LT1 #'s. Mine with those same parts added up to an install height of 1.675, measured by a machine shop. If you have that same height, your spring will probably break upon startup.

 

Sorry, I should've said got it from Comp Cams site, see the link.

http://www.powerandperformancenews.c...Category_Code=

I think 1.085" is the correct Coil Bind hight, otherwise, you would've broken multiple springs with that lift and 1.675 installed hight.

1.675-1.14= 0.535. You can't have higher than 0.535 lift without breaking things if I assume 1.140 coil bind for these springs.

 

If you go to Comps spring chart, you'll see the following numbers for the 918s:



Notice they don't list numbers beyond 1.15", yet coil bind is listed as 1.085"

I assume this means they tested the spring up to 1.15, but the coils don't bind until 1.085". I personally would consider the 1.15" the bind #; just to be safe.

Oh, and if you look at the recommended install hight (1.80") and subtract the maximum lift (.600") you get 1.20". So maybe 1.20" is the minimum you want to run them at?

I installed them on my heads with a 1.76 install height, stock cam and 1.7 rockers. This gives me a max lift of .520 on the exhaust. Haven't had any problems with them.

Thomas.

 

Ok, I've been trying to decide what springs to run and have been trying to follow this thread while learning about springs at the same time. If the reccomended install height is 1.8, why are some people installing the with a lower height? I think that if you lower the installed spring height you increase the seat pressure, if this is right, then what advantage does this provide? What's the ideal pressure at the seat and open for stock or oem lifters? Thanks.

 

People are installing with a lower height because of the LT1 head. When I installed them on my car, I used a valve spring micrometer, and most of them were already at 1.75"-1.76".

The only way to increase the install height is to get longer valves (moves the lock notch higher off the head surface), machine the spring seats down, or use offset locks.

I chose 1.76 as an install height because so many of them were already so close, and my max lift allowed it. I had to shim 8 or so springs to bring them to the 1.76" number (some were in the 1.91" range). This does increase the seat pressure, but beehive springs are pretty forgiving, because their spring rate is usually lower than traditional springs.

For example, I debated between the 918 and the 987 springs.

The 987s have an open load of 388@1.2 with a rate of 344 lbs/in. Since my lift is only going to be .520, the max compression I will see on the spring is 1.23, that gives me an open valve spring pressure of 317.08 lbs/in with a 1.75 seat pressure of 138.2 lbs/in.

The 918s have an open load of 318@1.2 with a rate of 313 lbs/in. With the .520 lift, the max compression on the spring is still 1.23, which gives me open valve spring pressure of 308.41 lbs/in with a 1.75 seat pressure of 145.65 lbs/in.

You can see how the beehive springs are a bit different. They have a higher seat pressure, but a lower open pressure.

Thomas.

 

Take it from me, or take it from Bret Baur http://web.camaross.com/forums/showp...4&postcount=33

Do not run them that tight unless you have the $$ laying around for a new engine

 

Sorry for not reading carefully and thanks for warning me. I am sorry for you loss of your engine and I guess it will be worse with my higher lift if I put those springs without checking and having 1.800" installed hight.

Thanks again..

 

ZMASTER has a cool sig

I'm running a CC306 with 1.6 which puts me at .576 exhaust. my beehives are set up at 1.75 and I believe that they're about as close as you want them to coilbind there. how did you get a 1.675 installed height?! i'm guessing no +.05 locks and you shimmed them farther? using the correct locator and no special locks you get 1.70 installed, using stock locator (not great) you'll get 1.74ish and with the +.05 locks you'll get 1.79.

comp needs to come out with a thinner locator just for us LT1 guys so we can run .600 lift with no problems.

 

What's the part# for those +.05 locks. I think I need those locks for 11/32 valve stem, 7 degree single groove.

Is it +.05 or -.05? I found crane locks 99096-1; 7deg Machined Steel Locks for 11/32" diameter valve stems but it says: " -.050" installed height".

 

+.05 gives you .05" more installed height which is what you want, you'll want the 10 degree locks and retainers.

comps pn on the locks is.... 249-614-16, 24.99 from jegs

 

fwiw the stock locator is like .015". blue camaro, i'd get the comp locators and have them machined down to like .025" and you'll be fine running your cam.

 

Okay, here is my next stupid question.

What is the part# for 10 deg retainers for those 918 springs?

 

Done some search and here is what I found:

795-16 steel retainers, or
794-16 titanium retainers
611-16 locks (standard), or
614-16 locks (+.050)
4705-16 spring seats

So, with +0.05 locks and 0.060 spring seats, the installed hight of the 918 springs will be 1.8. Good for 0.600" lift as listed by Comp Cams if installed at 1.8" hight.