Reground Ecotec Cams & Intake Valve Tip Height: Setting the Geometry
What a Regrind Can Change
Regrinding a camshaft can reduce the base circle. That changes the closed-valve relationship between the cam and rocker and can change the geometry that must be established at the valve and lash adjuster. The actual amount depends on the cam and complete assembly.
The Reduced Base Circle / Regrind version of the HF35.6 intake valve provides an extended-tip option for these combinations. The feature gives the builder another defined component choice; it does not remove the need to measure the head.
Establish the Closed-Valve Relationship First
Verify the valve is properly seated, identify the correct cam base-circle position and assemble the intended rocker, retainer and adjuster. Inspect how the rocker contacts the valve tip and follows the cam. Check for interference and unsuitable contact as the valve moves.
Tip height, valve seating depth, rocker design and adjuster height all contribute. A generic instruction to add a fixed shim thickness cannot replace inspection of the actual combination. Do not use an unverified overall length from another valve version as the setup target.
Solid Lash Adjusters Require Deliberate Lash Setup
BK supplies L61/LSJ-version solid lash adjusters and later-generation solid lash adjusters. Confirm the correct version for the engine. These use a mechanical shim arrangement; they do not automatically compensate like hydraulic adjusters.
BK commonly references .008-inch intake and .010-inch exhaust as starting lash values. Final lash, checking temperature and maintenance interval must be determined for the actual camshaft and engine combination. A cam designed for hydraulic operation needs an appropriate builder-established lash strategy when used with solids.
Recheck the Whole Assembly
After establishing geometry and lash, verify spring pressure at the measured installed height, coil-bind margin, rocker-to-retainer clearance, retainer-to-seal clearance and piston-to-valve clearance through the relevant crank angles. Check the intake and exhaust sides separately.
Use the tip-selection guide and the installation checklist. The existing exhaust-side regrind guide provides companion context, while the measurements remain specific to each assembly.
Frequently Asked Questions
Does the extended tip automatically fix every regrind?
No. It is an option for establishing the required geometry, which must still be verified.
Can hydraulic adjusters hide incorrect geometry?
Automatic lash compensation does not establish that rocker contact or other operating clearances are correct.
Start With the Complete Intake Valve Guide
GM Ecotec Intake Valves: Stock vs Performance, Sizes, Materials & Fitment brings the sizing, geometry, testing, tip selection and installation topics together.
Related BK Racing Products
- HF35.6 intake valves — set of eight
- Complete intake and exhaust valve set
- Ecotec performance exhaust valves
- 83 lb Ecotec valve springs
- Ecotec titanium retainers
- Solid lash adjusters — L61/LSJ version; verify fitment
- Solid lash adjusters — later-generation version; verify fitment
- Extra-clearance spring seats and Viton seals — add-on for BK 83 lb springs