dg8srt

For any guys running comp 918 beehives which valve seals are you running? Stock valves. The stock ones seem to fit too tight on the inside spring, and a set I tried from comp doesn't even fit. Any help would be great. Thanks

dg8srt

Does something need to be machined for beehives?

Chimera96

Comp 918 springs do not have a inner spring (aka damper spring)

some dual springs, especially ones with a damper spring in them, can hit the valve stem seal. In those cases people remove the damper spring or have the valve stem guide machined down to .500 and run smaller valve stem seals just for that reason

Comp 918 bee hive springs work on stock heads.

are you saying a 918 spring is coming in contact with the valve stem seal?

what cam specs (lift) and RR ratio are you using?

dg8srt

Now I'm looking and for some reason the part number on these springs is 986-16. Lift on cam is .3400 and.3610 and comp ultra pro mag 1.6 rr.

Chimera96

your lift #'s don't make sense...those sound like lobe profile #'s

when I did have 987 springs (not sure the difference from 986's) they were a double spring with a damper spring inside and my heads had the valve stem guide machined down for .500 seals for them to clear.

If your heads have not had the valve stem guide machined down than you need to run another spring

The Lunati 73935k5 would be a good kit or Comp 918's..I am just not a fan of Comp bee hive springs after running them...and having one break.

dg8srt

Sorry lift is .510 .540. What would be another good spring? The cam card calls for 918's.

Chimera96

the 918's are OK....I personally would not run them again but many do.

Crane 10308-1 kit

Alex spring kit...but it seems never to be available

Howards 98215 but you may have to remove the inner damper spring

TGGodfrey

Make sure the base of the beehive spring is not off centered. If it is then one side will make contact with the side of the seal. The 918 spring has an inner diameter of .885, you should have just barely enough clearance. If your concerned with it, have the guides cut down to .500 and install positive seals. If your confortable you can purchase the guide cutter and do it yourself on your workbench.



If you switch to positive seals, stay away from the hard teflon white ones. Everytime I have set those up on a motor they have failed early. Stick with the blue or red softer ones. Any machine shop has them in stock and they are fairly cheap.

If you switch to a different spring, its important to understand that the damper spring is the flat spring that is between a double spring setup or on the inside of a single spring setup. The damper is not considered a spring that is factored into spring pressures, its nothing more than a damper.

dg8srt

thanks for all of the replies. i really don't want to mess with machining the valve guides, is there any other springs that would work for this setup?

TGGodfrey

Well, I like Pac racing springs and they have a spring that will work well, downside is that its little more expensive that the springs you have.

You need to check a couple measurements on the heads you have. Remove one of your springs and with a caliper measure the diameter of the valve spring pocket. Eddy heads are 1.46, AFR heads are 1.460 as well. I expect the factory to be the same but manufacturing QC did vary.

You also want to check your heads for the max install height available. This will vary from head to head due to valve job work. Most aftermarket install heights on the LT1 are 1.800". Next larger spring looks for an install height of 1.880 or 1.900. Now you can install the springs to 1.800 but that is going to reduce the overall max lift of the spring and increase the closed pressure. Make sense?

Pac 1220X has the following specs (would be a good alternative)
Large end OD 1.445
Large End ID 1.000 ----- that should solve your seal issue
Small end OD 1.095 ---- yours are 1.075, .020 should not create a clearance issue
Small end ID 0.650 ---- Same as you have now
install height ---- 160LBS @ 1.900 (1.800 adds 40lbs seat pres)
Open height ----- 400 @ 1.250
spring rate ---- 370
Max Bind ---- 1.210
price ---- 15.24/spring

You can see how this spring has a higher seat and open pressure. but being a larger spring it will fit your seals. Factory LT1 springs are in the ballpark of 135lbs closed pressure so 160 too big of a jump.

If installed at 1.900 the max lift the spring is going to be able to handle before coil bind with be .690 (-.060 safety margin = .620). if installed at 1.800 the max lift is .590 (-.060 safety = .530 which is a no go for you). if your using 1.6 rockers the max lift that cam should produce is .577 and 1.5 rocker is .541. I personally would check your final lift with a dial indicator to check you geometry and see what your final numbers are. That can be done with a simple checking spring. I have a cam in a Chry big block now that with maxed geometry is putting out .030 higher than spec'ed so it does happen.

Pac 1220 has the following specs
Large end OD 1.445
Large End ID 1.000 ----- that should solve your seal issue
Small end OD 1.095 ---- yours are 1.075, .020 should not create a clearance issue
Small end ID 0.650 ---- Same as you have now
install height ---- 155LBS @ 1.880 (1.800 adds 30lbs seat pres)
Open height ----- 377 @ 1.280
spring rate ---- 370
Max Bind ---- 1.210
price ---- 12.15/spring

Max lift if installed at 1.880 is .670 before you hit coil bind and with safety margin your good to .620 lift.

You can see how these springs will depend on what your available install height is.

Hope that helps a little (or completely makes your head spin)

Most of the springs that install at 1.800 all have an inner ID of .885 at the bottom which is making contact for you.

Terry

TGGodfrey

Crane 10308-1

This may not work because this is dual valve spring with an overall inner diameter smaller than the spring you have. If you just remove the inner spring and run the outer only you are altering the operating pressures (lower poundage) of the spring and your likely going to float valves at higher rpms.

Chimera96

^^^^^^WRONG

the Crane 10308-1 spring kit is a direct drop in spring for the stock LT1 Aluminum heads. You do not need to remove any inner spring. It has a stock install height spec of 1.750"

While there are other spring options, the 10308 is plug & play for a replacement spring for stock or mild cams

The Comp 26915 or 26918 will also work with the only exception that their specs are for installed height of 1.800" so since stock LT1 aluminum heads are generally around 1.750" in height for springs (without machining down the spring pockets) their open and seat pressure will be slightly higher than their published #'s at 1.800". For stock or mild cams these to will work

TGGodfrey

http://m.summitracing.com/parts/crn-10308-1

http://www.jegs.com/i/Crane-Cams/271/10308-1/10002/-1

That is listed as dual spring with a .803 inner diameter. OP Has an issue with .855 inner diameter. If you pay attention to the details of that spring the install height is 1.850 not 1.750

Chimera96

Mr Godfrey

The 10308 spring is for the LT1 aluminum head. Many....many have used it as a upgrade spring for stock spring replacement for the stock or mild cam. No need to cut the valve stem guide and the inner spring clears the stock size valve stem seal. It is a direct replacement for the stock springs on Aluminum head LT1 engines. Like any spring install, installed height measurement and PR length is advised...although on stock heads on motors with non-decked blocks stock PR length of 7.200" will be good...although always prudent to use the proper tools to confirm

Many aftermarket springs have published pressure ratings of 1.800-1.810". If your spring pockets have not been machined down than installing a spring shorter will increase open & seat pressure compared to the 1.800" height.

However the 10308 spring is designed to install at 1.750" as noted above.

You need to be careful reading "part store" stats (JEGS, Summit, etc) but in the case of Summit...they got it right


Installed Height (in):
1.750 in.


Seat Pressure at Installed Height (lbs):
165 lbs.


Open Height (in):
1.110 in.


Open Pressure (lbs):
426 lbs.


Brand:
Crane Cams


Manufacturer's Part Number:
10308-1


Part Type:
Valve Spring and Retainer Kits


Product Line:
Crane Valve Spring and Retainer Kits


Summit Racing Part Number:
CRN-10308-1




UPC:
021174036114


Number of Springs Per Valve:
Dual


Outside Diameter of Outer Spring (in):
1.460 in.


Damper Spring Included:
No


Spring Rate (lbs/in):
408 lbs./in.


Inside Diameter of Outer Spring (in):
1.075 in.


Inside Diameter of Inner Spring (in):
0.803 in.


Valve Spring Style:
Standard


Coated:
No


Retainers Included:
Yes


Retainer Material:
Steel


Locks Included:
Yes


Lock Style:
7 degree


Lock Groove Quantity:
1-groove


Lock Material:
Steel


Valve Stem Seals Included:
No


Quantity:
Sold as a kit.


In-Store Pickup:
Choose In-store pick-up (OH, GA, NV) on our web site.


note the ID of inner spring is .803"...quite a bit bigger than the stock .662 OD valve stem seal.

If you run any spring without a locator it will "walk" and certainly hit the valve stem seal.


The Op initially tried C0mp 986 springs (not 918's)....it is a dual spring WITH a damper spring. The inner spring ID is .697...a little tight that it can contact the valve stem seal especially with higher lift cams. Some remove the damper spring. It really is not a good spring for the LT1 heads, even with stock cam

TGGodfrey

I see where he replied later with a 968 spring. I was basing measurements off 918.

On the 968 removing the damper spring won't help with clearance since the damper is between the inner and outer spring.

The superseded spring for the spring you listed is actually 99845-16 as Crane no longer makes the one you listed.

As for your info on setting up springs......I have been setting up my own heads for over 20 years.