This item says it is a direct replacement. It also says drilling required. What, where and why is drilling required if it is a direct replacement?
Asked by Tom from Sunnyavle Ca on
Tom, this Omix-Ada Aluminum Valve Cover is a direct replacement as far as size. But you may have to do some drilling because you are replacing a plastic cover with an aluminum cover. The following is copied directly from the Omix-Ada install instructions that are included with the valve cover. " Step.3 ( Tapping of blank holes) You may find 5 of the 5/15” aligned holes will have no threads. These holes were used as guide hole only for the plastic cover and will require tapping. Tap the holes with a 5/16” x 18 thread “bottom” tap. CAUTION!! DRILLING HOLES TO BEEP WILL RESULT IN DRILLING INTO THE WATER JACKET!!" and "Step.4 (Missing holes) On some early models you may find two holes missing on each end of the head. For this application it will be required that the hole locations be marked with the new aluminum cover in position. Secured the cover in place with all existing holes aligned and mark the new hole locations with a good permanent marker. With the holes properly located use a punch to mark the center of the hole to insure proper drill bit placement. With great care drill the holes and use a ¼” x 20 “bottom” tap." and "Step.5 (Rocker bridge replacement) It may be required to replace the studded rocker bridges used for the plastic valve with new non - studded bridges under part number MRM1718 (17408.11) or the studs may be cut off if they interfere with fitment of the aluminum cover. Additional modifications may be needed to air conditioning and or air cleaner brackets for proper fitment. DO NOT modify or cut the aluminum valve cover as this will void any warranty. " I hope this helps clear it up a little bit.
Answered by Jason L from Sunnyavle Ca on
Were is the "drilling" required to install this cover ? Why?
Asked by Chuck from Fairbanks, AK on
This valve cover is designed to replace the factory plastic valve cover. Some of the bolt holes on the head are blank because they were used as guide pins for the plastic cover. The new aluminum cover uses these as addition clamping force so drilling and tapping is required. Also you may need to cut the studs off the rocker arm bridges or replace them. The part number for replacement rocker arm bridges is #17408.11
Answered by Nick from Fairbanks, AK on