#3622 Power Piston Retaining Bushing
Lately we have received quite a few calls from customers bending their Rochester Quadrajet primary metering rods upon installation.
The primary reason for this can easily be prevented. What is happening is after the carburetor's power piston is inserted in the power piston bore and the primary metering rods are inserted/placed in each primary metering jet, the assembly is held fully down and the nylon retaining bushing is pressed down into the top of the power piston bore. The purpose of the retaining bushing is to securely hold the power piston / rod assembly down while the airhorn gasket and airhorn assembly is installed.
When the retaining bushing is worn or loose fitting, it will not securely hold down the assembly. If the power piston assembly slips up the primary metering rods can slip up/out of the primary jets. Then, when the airhorn is installed it will force the power piston assembly back into position and in the process bend the primary metering rod tips. Generally, the power piston pops up out of position during the installation of the airhorn gasket and the gasket blocks the view of the power piston assembly so its easy not to notice.
Bent metering rods will cause severe drivability issues during light throttle driving and wide open throttle positions, due to the excessively over rich conditions.
Preventing bent metering rods:
Replace the original power piston retaining bushing whenever you remove your quadrajets airhorn. Our #3622 split ring power piston retaining bushing is cheap insurance and easy to install.
How to install:
· Remove old original retaining bushing by cutting it off with a pair of side cutters. (DO NOT remove steel power piston hanger from brass piston)
· New #3622 is a split ring design, which allows installation by spreading bushing open and installing around power piston steel hanger. After properly positioning power piston and rods, press #3622 bushing into place. #3622 will securely hold the power piston in position. Easy and effective!
Early Quadrajet carburetors manufactured in the mid 1960's used a metal retaining clip instead and do not use the nylon retaining bushing.
Prevent Bent Metering Rods
Use #3622 Power Piston Retaining Bushing
Buy your carburetor parts at www.quadrajetparts.com