Jerryl
Tall Unvaccinated Chinese Guy
- Joined
- Dec 14, 2004
- Messages
- 9,644
Exhaust valve spring retainer bottoms out around 0.435 travel
Cam spec: 0.456 lift with 1.55 rockers.
Stock rockers and retainers installed
Installed height 1.660 (Spec 1.700) for Comp 980’s
212/212 Comp Cam
Cam lobe lift verified to be correct at 0.2930
So the correct install height will give 0.040 additional valve travel before bottoming out resulting in 0.020 clearance between the retainer and valve guide. (Too tight right?)
Valve train geometry is correct and lifter pre-load is all 0.030-0.040.
(Should not effect this measurement at this point.)
Had a constant radius valve job done on the heads and stock valves are installed.
Someone who installed 1.65 rockers must have had similar issues.
According to GNTTYPE stock specs are:
Advertised Duration : 258/262
Duration at .050" lift : 192/196
Lift .384/.408
First question; “Why” do you think this is happening with stock parts and “replacement cam”? (Hot Air heads set-up for different lift?)
Second question; Anyone know which retainers I can use that have about a 0.050 offset?
Cam spec: 0.456 lift with 1.55 rockers.
Stock rockers and retainers installed
Installed height 1.660 (Spec 1.700) for Comp 980’s
212/212 Comp Cam
Cam lobe lift verified to be correct at 0.2930
So the correct install height will give 0.040 additional valve travel before bottoming out resulting in 0.020 clearance between the retainer and valve guide. (Too tight right?)
Valve train geometry is correct and lifter pre-load is all 0.030-0.040.
(Should not effect this measurement at this point.)
Had a constant radius valve job done on the heads and stock valves are installed.
Someone who installed 1.65 rockers must have had similar issues.
According to GNTTYPE stock specs are:
Advertised Duration : 258/262
Duration at .050" lift : 192/196
Lift .384/.408

