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Valve Stem Locators, Locks, & Lash Caps
Pontiac V8 Valve Stem Locators, Locks, & Lash Caps
The Parts Between The Spring And The Valve — Valve Stem Locators, Locks, & Lash Caps for Pontiac V8s
Valve locks, spring locators and lash caps are the small hardware that ties the retainer, spring and valve together. The locks set your installed height, the locator or cup positions the spring and protects the head, and a lash cap saves the valve tip on a high-pressure valvetrain. None of it is optional once spring loads climb.
Butler carries Comp Cams 7 degree race locks and 10 degree Super Locks, Butler, Ferrea and PAC 10 degree locks including +.050 versions, Pioneer heavy duty 7 degree locks for stock retainers, Comp spring cups and locators, PAC chrome moly locators and Comp lash caps.
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1. Seven Degree Or Ten Degree
The lock angle has to match the retainer angle. This is the first decision, and mixing the two is how retainers get pulled through.
| 7 degree | Comp's stock replacement 7 degree locks are recommended for street applications with lighter valve spring loads, and are stamped and hardened for wear resistance. Comp also offers a machined steel single groove 7 degree race lock in 11/32", which gives the same spring location accuracy as a Super Lock without changing to 10 degree retainers. Pioneer offers heavy duty 7 degree locks for stock retainers. |
| 10 degree | Comp's Super Locks use the wider angle to better distribute spring loads over the retainer, reducing the chance of pull-through failure. They are precision machined rather than stamped, and Comp recommends them in all race applications. Butler, Ferrea and PAC all offer 10 degree 11/32" locks as well. |
| Interchange | Comp notes any Super Lock fits any Comp 10 degree retainer, so you choose the lock by valve size and application rather than by retainer part number. |
2. What A Lock Actually Does
Comp's own tech copy corrects the most common misunderstanding on this page, and it is worth repeating at the counter.
| The tang is not the retention | the tang inside a valve lock is not strong enough to withstand open spring loads of 1000 lbs or more. Its only job is to temporarily locate the lock, retainer and spring relative to the valve until the taper of the retainer nests around the outside of the lock. |
| The collet effect | once nested, the two bind together, and the more spring force the retainer sees as the valve opens, the harder the collet holds. |
| Size the lock to the stem | there should always be a small gap between the two halves of a properly positioned lock. No gap means the locks are too large. If the locks fit tight to the stem but leave a gap between the middle of the lock and the outside diameter of the stem, they are too small. |
3. Plus Fifty Locks And Installed Height
A +.050 lock changes where the retainer sits on the valve, which changes installed height without touching the spring or the shims.
| Why you would use one | to recover installed height on a head that has been cut, or to land on a spring's rated pressure without stacking shims. Butler stocks +.050 10 degree 11/32" locks from Comp, Ferrea and PAC. |
| Comp also offers the reverse | a -.050 installed height Super Lock with a lash cap recess in 11/32". |
| Check the math | changing locks moves installed height on every valve. Re-measure and re-check coil bind and retainer-to-seal clearance afterward. |
4. Lash Caps And Recessed Locks
This is the gotcha that costs people a second order.
| The rule | Comp's 11/32" lash caps require recessed valve locks. If your locks do not have the lash cap recess, the cap has nowhere to sit. |
| Locks built for it | Comp offers Super Locks with a lash cap recess in both 3/8" and 11/32". |
| Read the listing | some +.050 locks specifically will not accept lash caps. Confirm before you order the caps. |
5. Locators, Cups And Shims
Old-style shims were never meant for modern spring pressures, and that is the problem a locator solves.
| Why a locator | Comp describes a thin hardened steel alloy seat that protects the head and the shim while also locating and holding the spring in place, offered with the locating shoulder on the inside so the head does not need to be machined heavily to accept it. |
| Comp sizes | a .060" thick locator at 1.500" OD with a .585" ID for a .690" spring ID, a .060" thick locator at 1.550" OD with a .570" ID for a .790" spring ID, and a spring cup at 1.635" OD with a .640" ID for a 1.515" spring OD. There is also a dedicated locator for the Comp and PAC beehive springs Butler stocks. |
| PAC sizes | chrome moly seats .030" thick, a 1.500" OD version for 1.500" to 1.550" dual springs and a 1.650" OD version for 1.630" to 1.650" triple springs, both for a .570" valve guide hole size. |
Bring the spring you are running, the retainer angle and the valve stem diameter. Those three numbers pick every part on this page, and guessing at any one of them is how a retainer ends up in the oil pan.
Not sure what your Pontiac needs?
Call our tech team at 866-762-7527. Tell us your engine, heads, car, and power goal, and we will put the parts together as one combination that works.