Air Cleaner Stud Kits

On a carburetted engine, studs hold the carburettor to the intake manifold and the air cleaner to the carburettor. This category holds ARP air cleaner studs, carburettor stud kits for a range of spacer heights and float bowl bolt kits, in black-oxide chrome moly or stainless steel.

The carburettor base is a thin casting that sits on gaskets and often a spacer, and it has to seal manifold vacuum. Clamped too hard or unevenly, it can warp; the throttle shafts can then bind and air leaks in under the base. Studs suit this joint well, as they locate the carburettor, spacer and gaskets as they go on and spare the manifold threads at every removal.

The air cleaner stud holds the lid down on the filter element. Its length has to suit the element’s height: too short and the lid cannot be clamped, too long and the stud may foul the bonnet.

Choose from the details in the title:

• Spacer height: kits suit no spacer, a 1/4 in base gasket, or spacers of 1/2, 1, 1-1/4, 2 or 3 in. Some give the overall length, such as 2.225, 3.200 or 4.700 in.
• Air cleaner studs: 1/4 in or 5/16 in thread, in lengths such as 2.225, 2.443, 2.700 or 3.200 in.
• Drilled studs: in some kits one stud is drilled for a wire seal, which race organisers use to seal a carburettor.
• Return springs: some kits are made to suit a dual throttle return spring kit, with or without a spacer plate.
• Float bowls: bolt kits for carburettors with single or dual metering blocks, and for a two-barrel type.
• Finish and nuts: stainless kits, some with drilled studs, sit alongside black-oxide 8740 kits. Most use nuts for a 1/2 in hex socket.

Screw the studs into the manifold by hand; some take a 1/8 in hex key in the end. Tighten the carburettor nuts lightly and evenly in a cross pattern to the carburettor maker’s figure, then check that the throttle opens fully and snaps shut. Two independent return springs are common practice, and some competition rules require them.

Cover the throats whenever the air cleaner is off, because a nut or washer dropped in goes straight into the engine. Tighten the air cleaner nut only enough to seal the lid; overtightening distorts it and lets unfiltered air past the element.