bbc exhaust valve rotator eliminators

General engine tech -- Drag Racing to Circle Track

Moderator: Team

hammerdamage
New Member
New Member
Posts: 22
Joined: Sun Jan 27, 2008 2:59 pm
Location: stow, ohio

bbc exhaust valve rotator eliminators

Post by hammerdamage » Wed Dec 13, 2017 6:16 am

hello all,
i am putting together a pair of oval port "049" heads for a mild hydraulic roller street/strip car. the problem i am having is when setting valve spring heights my exhaust rotator eliminators are too thick. they are .300" and are too thick by .040" and my installed height would be 1.835" instead of 1.875".the intake valve spring heights are all good at +- .010". the springs are Howard Cams #98636 with 130@1.875 and 330@ 1.300. i don't have access to a lathe to turn .040-.060" off the bottoms of the hardened spacers so my question is can i stack 3 .060" shims under a .060 spring cup and then final shim to the expected install height? i believe the i.d. of the shims and spring cup are .640" with 1.687" o.d. and set up for 1.550" springs, mine are 1.514". i believe these will locate off the guide and prevent the spring from moving but i would like to hear answers from people with more experience than myself. thanks in advance for any replies, they would be greatly appreciated.

thanks, gary

mag2555
Guru
Guru
Posts: 2469
Joined: Sun Sep 18, 2011 11:31 am

Re: bbc exhaust valve rotator eliminator

Post by mag2555 » Wed Dec 13, 2017 7:34 am

I would get a cutter to take .040" out of the heads seats or have a shop do the same.
The drill powered cutters are about 95 bucks before shipping and I think that most shops will get 35 to 45 bucks per head to do the same .

Newold1
Guru
Guru
Posts: 1372
Joined: Fri Apr 08, 2016 9:50 am

Re: bbc exhaust valve rotator eliminators

Post by Newold1 » Wed Dec 13, 2017 8:48 am

Just use a simple low cost set of hardend +.050" valve locks. Your retainers move up .50" ,problem solved.

hammerdamage
New Member
New Member
Posts: 22
Joined: Sun Jan 27, 2008 2:59 pm
Location: stow, ohio

Re: bbc exhaust valve rotator eliminators

Post by hammerdamage » Wed Dec 13, 2017 9:04 am

Thanks for the replies.the machinist I'm using says he might hit water if he cuts .040 off the spring pockets and so far I haven't been able to locate +.050" retainers for a 3/8" valve stem. Anyone with experience know how much the spring pockets can cut before there is a problem? Thanks, gary

hammerdamage
New Member
New Member
Posts: 22
Joined: Sun Jan 27, 2008 2:59 pm
Location: stow, ohio

Re: bbc exhaust valve rotator eliminators

Post by hammerdamage » Wed Dec 13, 2017 9:31 am

I have been informed that Comp Cams makes +.050" 10 degree valve locks for a 3/8" valve and that this looks to be the answer to my dilemma. Thanks , gary

vortecpro
Guru
Guru
Posts: 1126
Joined: Fri Apr 24, 2009 11:10 pm

Re: bbc exhaust valve rotator eliminators

Post by vortecpro » Wed Dec 13, 2017 9:43 am

Isky makes a roto coil eliminator that is .050 thinner than the POS comp eliminator. We cut the comp eliminator often in the lathe.
Racing a NA NHRA stocker should be mandatory before any posting.

hammerdamage
New Member
New Member
Posts: 22
Joined: Sun Jan 27, 2008 2:59 pm
Location: stow, ohio

Re: bbc exhaust valve rotator eliminators

Post by hammerdamage » Wed Dec 13, 2017 9:46 am

That would work a little better than the .050 locks. Do you have a part number the Isky shims? Thanks, gary

hammerdamage
New Member
New Member
Posts: 22
Joined: Sun Jan 27, 2008 2:59 pm
Location: stow, ohio

Re: bbc exhaust valve rotator eliminators

Post by hammerdamage » Wed Dec 13, 2017 10:26 am

I found the Isky part #390-rc but they list that as .300" thick same as the Comp Cams part .do they run smaller as measured? Thanks,gary

prairiehotrodder
Expert
Expert
Posts: 797
Joined: Sat Dec 24, 2011 10:02 am
Location: melfort saskatchewan Canada

Re: bbc exhaust valve rotator eliminators

Post by prairiehotrodder » Wed Dec 13, 2017 10:42 am

I just put together a set of 781 heads and had a similar problem. The comp 911-16 springs i purchased were way stronger than they were supposed to be. Possibly boxed wrong? Anyways with stock length competition products valves i could not get the 1.900 installed height. I needed another .100 and yes i should have just bought +.100 valves. I ended up having the machine shop cut .050 off the rotator eliminators, cut .050 out of the intake spring seats and use the .050 offset keepers. It all cost me an extra $400 . By the way there isn't much valve stem sticking above those .050 offset keepers. The engine is running now and working fine and i never hit water with cutting the spring seats. That extra $400 i spent put the total investment into the 781 iron heads at $1830. Not very far from a pair of Edelbrock E-street BBC heads (talking in canadian dollars).
Live and learn
Brian
The Word of God is quick and powerfull
www.therocketshop.blogspot.com

Newold1
Guru
Guru
Posts: 1372
Joined: Fri Apr 08, 2016 9:50 am

Re: bbc exhaust valve rotator eliminators

Post by Newold1 » Wed Dec 13, 2017 2:14 pm

A helpful source for a lot of cylinder head and valve train parts is PEP -Precision Engine Parts in Las Vegas. Many times if its not on the shelf, they eill make it for you.
Keep them in your source files. JMO

Newold1
Guru
Guru
Posts: 1372
Joined: Fri Apr 08, 2016 9:50 am

Re: bbc exhaust valve rotator eliminators

Post by Newold1 » Wed Dec 13, 2017 2:16 pm


williamsmotowerx
Expert
Expert
Posts: 733
Joined: Sat Feb 10, 2007 1:24 pm
Contact:

Re: bbc exhaust valve rotator eliminators

Post by williamsmotowerx » Wed Dec 13, 2017 2:37 pm

What are rotator eliminators? Why would you want the valve to not rotate?

dave brode
Expert
Expert
Posts: 679
Joined: Sun Sep 28, 2008 11:06 am
Location: Frostburg, MD

Re: bbc exhaust valve rotator eliminators

Post by dave brode » Wed Dec 13, 2017 3:17 pm


pdq67
Guru
Guru
Posts: 7810
Joined: Thu Mar 04, 2010 8:05 pm

Re: bbc exhaust valve rotator eliminators

Post by pdq67 » Wed Dec 13, 2017 7:10 pm

I got into this and found out that BBC valve springs have two installed heights!

Old, early at 1.88" and later, newer at 1.80" so please keep this in mind.

I have the 1.550" dia. Manton valve springs, (from Comp. Products), on my heads along with the +.050" locks because I installed an old CC 282S solid cam and wanted to drop my seat pressure down from about 135 pounds to more like 125 pounds is all.

pdq67

vortecpro
Guru
Guru
Posts: 1126
Joined: Fri Apr 24, 2009 11:10 pm

Re: bbc exhaust valve rotator eliminators

Post by vortecpro » Wed Dec 13, 2017 9:22 pm

hammerdamage wrote:
Wed Dec 13, 2017 10:26 am
I found the Isky part #390-rc but they list that as .300" thick same as the Comp Cams part .do they run smaller as measured? Thanks,gary
Yes .050
Racing a NA NHRA stocker should be mandatory before any posting.

Post Reply