5/16" 7 degree bead locks?
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TECH Apprentice
Joined: Jan 2002
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From: Nottingham, Notts, England, UK
5/16" 7 degree bead locks? Hi, I'm looking for some help please as this issue must have happened to somebody else. I'm building up a pair of RHS Pro Elite heads with 2.250" Ti intake valves x .311" stems. The part number is 6068. My concern is that I can't find bead locls in that size. 5/16" equates to .310" and the 8 mm LS locks equate to .3135" iirc. The 8 mm locks do lock up nicely and will probbly be fine but I'd feel happier with the correct locks if they exist. I may be splitting hairs but defo don't want a dropped valve.
Anybody come across this before? Thanks.
Anybody come across this before? Thanks.
Hi, I'm looking for some help please as this issue must have happened to somebody else. I'm building up a pair of RHS Pro Elite heads with 2.250" Ti intake valves x .311" stems. The part number is 6068. My concern is that I can't find bead locls in that size. 5/16" equates to .310" and the 8 mm LS locks equate to .3135" iirc. The 8 mm locks do lock up nicely and will probbly be fine but I'd feel happier with the correct locks if they exist. I may be splitting hairs but defo don't want a dropped valve.
Anybody come across this before? Thanks.
Anybody come across this before? Thanks.
Thread Starter
TECH Apprentice
Joined: Jan 2002
Posts: 320
Likes: 5
From: Nottingham, Notts, England, UK
Thank you. Does this mean you've used the 8 mm locks on the .311" stems? Everything points to this being a working, safe solution but I expected 'correct' locks to be available. Argh! :-)
Again…as long as the locks don’t butt together, and they feel solid in the groove, I’d run it. Not sure your going to find a .311” lock.
Slide a retainer down the stem, put the locks in the groove, and pull the retainer up til it’s tight by hand, and see how it feels/looks…valve out of the head here…
This COULD mess with installed height a tad, being a couple thou smaller, so double check all of that on mock-up. Hopefully your guides were set up for this stem and the clearances are right. I hate it when folks come on tech forum and tell others to call the manufacturer…because that’s why your here…to find experienced help, but in this case as a last resort, contact RHS and ask them about these numbers, unless maybe a builder over there changed out the guides and set up the heads?
Thread Starter
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From: Nottingham, Notts, England, UK
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^ Thanks for that. They look interesting but I can't tell if they're bead locks. I'm looking at adverts for them now and the pics I see aren't clear enough. I'll do more checks and speak with PAC
Wowzers, on the PAC site they're described as radiused locks. Hopefully they'll locate like a bead lock. :-)
Wowzers, on the PAC site they're described as radiused locks. Hopefully they'll locate like a bead lock. :-)
Last edited by Boosted LS1; Aug 27, 2021 at 11:48 AM.
Yes, bead and radius are the same thing. The nice thing about the L8161 is it has a 5/16 radius vs an 8mm radius. The grooves are actually different sizes in each valve (5/16 vs 8mm).
No need to call PAC, you're talking to them now LOL.
No need to call PAC, you're talking to them now LOL.
Thread Starter
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Joined: Jan 2002
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From: Nottingham, Notts, England, UK
An update. The PAC GM LS 7 degree 5/16 locks arrived today. Firstly I fitted the 8mm locks onto the .311" valve and slid up the retainer as tight as I could get it. There was some slight play, not much but it was there. When I removed the retainer the locks fell off the stem really easily.
Next I did the test with the PAC locks. There wasn't any play. Also I had to give a gentle tap to release the retainer and the locks stayed on the valve. A gentle tap dropped them out.
.
Thanks guys for your input and I'll sleep well tonight as this build is a RHS block and heads. The last thing I'd want is a dropped intake valve. .311" diameter stem. The PAC locks are .310".
Thanks to TurboBuick6 (PAC) for coming up with a solution. This question's been asked before.
Mike.
Next I did the test with the PAC locks. There wasn't any play. Also I had to give a gentle tap to release the retainer and the locks stayed on the valve. A gentle tap dropped them out.
.
Thanks guys for your input and I'll sleep well tonight as this build is a RHS block and heads. The last thing I'd want is a dropped intake valve. .311" diameter stem. The PAC locks are .310".
Thanks to TurboBuick6 (PAC) for coming up with a solution. This question's been asked before.
Mike.
Last edited by Boosted LS1; Sep 6, 2021 at 11:52 AM.
Hi, I'm looking for some help please as this issue must have happened to somebody else. I'm building up a pair of RHS Pro Elite heads with 2.250" Ti intake valves x .311" stems. The part number is 6068. My concern is that I can't find bead locls in that size. 5/16" equates to .310" and the 8 mm LS locks equate to .3135" iirc. The 8 mm locks do lock up nicely and will probbly be fine but I'd feel happier with the correct locks if they exist. I may be splitting hairs but defo don't want a dropped valve.
Anybody come across this before? Thanks.
Anybody come across this before? Thanks.
Uh, 5/16"=.3125, and 8mm is .3149. The 'nominal' may be .310" & .3135, I don't know. Either way, the locks work against the radius of each diameter, which is only a .0012" difference on the two sizes, .00175 on the nominal. It is doubtful the locks are held to tolerances any tighter than + or - .001". I say you'll be fine. Yeah, not good if you're talking valve GUIDES. But locks aren't ever going to know the .001" difference......
PAC's tolerance in the ID of the locks are 0.0005" BTW.
Thread Starter
TECH Apprentice
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From: Nottingham, Notts, England, UK
This is an expensive build for a customer and I was feeling ou of my comfort zone with the 8mm locks. The difference in grip can be felt as I mentioned above. The retainer is rock solid/stable wih the 5/16" locks installed but has a small amount or rock with the 8mm locks.
Hey, guy, this is Mike. I drove down there last year for some Ti retainers for my PAC sprung LS7 heads. DAMN-Can't remember your name! I agree, close enough sometimes isn't good enough. BUT, any decent builder should catch the installed height diff, due to the groove height. I still think you'd be OK with the .001" diff on the radius, but installed height would be different, for sure. BTW, those Ti retainers I bought have the installed height reduced by about .040". I thought they'd be the same as the steel I was replacing? Anyway, if you remember, after 7 of my 8 Ti valves were losing the CrN coating, I replaced them with Ferrea hollow stems, which were slightly heavier, but ran tool steel retainers, not Ti. So the Ti retainers helped bring the weight back down. 31,000 miles on your dual springs (Hot Rod springs? 160lbs seat-420lbs at .600" lift? You said my springs were very popular duals for the LS), and 10,000 miles later on the Ti retainers, all is well, so a bit less of valvespring installed height is probably a good thing. Couldn't be more than a few pounds.....
Yup. Installed height ended up 1.750-1.760" on I, and 1.735-1.740" on E. NO valve float! BTW, I can't remember your name OR the part# on the springs. You said they're 1 of the most popular, and reasonably priced dual springs around for LS motors, if that helps. Also, I have a bit over 30,000 miles on these springs!!! VERY durable, and very satisfied with your product!!!
