1.Remove tappet assemblies from engine being sure that each one is kept in it’s original tappet block.

NOTE: this procedure is the preferred method of installation. However, this kit can be installed without removing lifters from engine.

2. Remove hydraulic piston retaining wire clip from one assembly at a time.

CAUTION: Be careful not to bend wire clip during disassembly.

3 Completely disassemble tappet removing all parts.

4. Thoroughly clean all parts including tappet body. Remove any oil which may prevent hydraulic unit from fully collapsing during later adjustment.

5. Insert one spacer from the HQ-4100 kit in tappet body.

6. Reassemble tappet in reverse order making sure original parts are returned to their original positions. See picture below.

7. Replace wire retaining clip in tappet body.

8. Put tappet back in original tappet guide (block).

9. Repeat steps 2 thru 8 for the three remaining tappets.

10. Reassemble engine with modified tappets.

11. Adjust pushrods.

NOTE: In all cases engine must be cold and tappet must be at lowest point of travel for pushrod adjustment.

CAUTION: To prevent accidents, remove ground cable from battery.

A. Remove spark plugs

B. Bring piston to TDC on compression stroke in cylinder where pushrods are to be adjusted.

C. Extend pushrod adjustment, collapsing lifter until lifter piston is in contact with HQ-4100 spacer and pushrod is tight. If tappets contain no oil, as when pushrods are readjusted after engine has been run, or if all oil was not removed during installation, extend pushrod until valve is open (about 5 turns on adjusting screw). Allow 5 minutes for hydraulic unit to bleed down. If pushrod can be turned with fingers after bleeding down, lifter is not completely collapsed and this step needs to be repeated.

NOTE: Perform this operation on one cylinder at a time. Do not rotate engine (crankshaft) until pushrod adjustment is complete.

CAUTION-Rotating engine while valve is held open (held off seat) could result in valve to valve or valve to piston contact and serious damage.

D. Loosen pushrod adjustment until pushrod can be rotated with fingers feeling slight drag.

NOTE: Some engine builders prefer to adjust pushrods another full turn shorter. (We do it this way) This provides additional travel for the valve in the hydraulic piston assembly. Additional travel can improve the ability of the hydraulic unit to pump up and maintain zero valve lash.

E. Tighten pushrod lock nut.

F. Follow the same procedure for the other three pushrods.

G. Recheck pushrod adjustments after a few hundred miles.

NOTE - It is a good idea to recheck pushrod adjustment in a new engine as valve train may tighten up due to gasket compression and valve seat wear.

Upon initial start up after modification, HQ-4100 equipped lifters may be somewhat noisy for 10-20 miles until they get fully pumped up with oil. If the noise continues after this period it may indicate the lifters are bottoming out slightly on the washers as a result of not enough oil cushion, in which case pushrods should be adjusted 1/2 turn shorter. See step D.

This is the order in which parts should be installed