Mech. Rockers/Hyd Cams
A Guideline for Adjusting Stock Type Mechanical FE Rocker Arms when using with a Hydraulic Camshaft.
(1) Remove your Coil Wire.
(2) Remove all eight Spark Plugs and Wires (remember how they came off and you can save some time rerunning the firing order later) .
(3) Use a Remote Starter Switch To Turn Engine Over (On Fords). If you don't have one you can purchase at most local parts houses or borrow a friends.
(4) Remove Valve Covers etc.
(5) Be sure the Rockers are installed correctly and the Push Rods are correctly seated in the lifters. Look things over before you start.
Now The Basics..............setting lifter pre-load(lash)
The Cylinder numbers on an FE are really easy! 1-4 on the passenger side front to back and 5-8 on the drivers side front to back.
Start at Number 1 cylinder and turn the engine over until #1 Exhaust valve just starts to open. (The Exhaust valve is the one going the exhaust header) You can watch the valve or the push rod to see this movement.
Now you can adjust #1 Intake valve by tightening the lash adjuster while you spin the push rod between your finger tips....until you feel a slight drag(called zero lash). Then tighten the lash adjuster and additional 1/2 turn as this equals about .030" pre-load on the lifter.
Next, turn the engine over until the number 1 Intake valve opens completely and then almost closes (watch it closely).
Now you can adjust the number 1 exhaust valve using the same finger tips procedure above.
It's that easy!!!!!
Now you can go to number 2 cylinder and do just what you did on number 1 then go down the rest of that bank until your done.
Remember to rotate the engine the same way it runs when adjusting valves and you decide not to use a remote starter....you can turn the engine over using the Dampner Bolt too.
Reinstall the Valve Covers
Reinstall the Spark Plugs & Wires
Remove the remote starter.
Install the Coil Wire
Start the engine and listen for valve train noise...if it sounds like one may still be loose then recheck the Valve Adjustment.
Sounds a little crazy but if you do hear some valve Train noise you can take a large screw driver and put the handle end to your ear and the tip on the valve covers and you can pinpoint the noise.
Depending on the brand of camshaft and hydraulic lifters these general procedures can change. Always read the cam instruction sheets. Be sure the Push rods are Ball to Cup and the correct length.
Another Thing to watch for with today's performance hydraulic cams and adjustable rockers is the clearance the push rod has to the push rod bores in the intake manifold. I've seen stock mechanical rockers and stock hydraulic lifters with stock style push rods rubbing the bores in the intake manifold. If you don't catch this when you build the engine you're going to be taking the intake manifold back off and boring/drilling the holes larger where then rub. This is very common on intakes with 8 push rod tube bores like the Edelbrock Performer RPM 7105. This is not just a warning for Hydraulic Performance Camshafts but also Mechanical Cams when using After market Intakes...Check the clearance as you may find the clearance problem at the 4-6 O'clock positions.
These TechTips are provided as a service of Gessford Machine, Inc.
