What tools are needed to remove the cylinder head on a Cat 3306?
I need to replace the head gasket on my Cat 3306 marine engine (8nm 0336). I'm planning to tackle the strip-down myself this weekend. What specific tools, socket sizes, and lifting gear do I need to get the head off safely?
Answer
You need a 3/4-inch drive socket set with a 3/4-inch 12-point socket for the head bolts, plus a 500 kg chain hoist because the bare cylinder head weighs around 160 kg. Standard Imperial (AF) combination spanners, flare nut wrenches for the fuel lines, and a stout breaker bar are also essential for stripping the top end.
Imperial Sockets and Spanners
The Caterpillar 3306 is a classic American cast-iron lump. Every fastening is Imperial (AF). Do not attempt to use metric sockets. You will round off bolts heat-cycled for thousands of hours.
The main tool is a 3/4-inch drive breaker bar paired with a 3/4-inch 12-point socket for the head bolts. The factory torques these bolts to 250 Nm (185 lb-ft). Breaking that initial stiction requires immense force. A standard 1/2-inch drive bar will flex or snap. Expect to pay £80 to £120 for a 3/4-inch breaker bar from brands like Facom, Sealey, or Teng Tools.
For the rest of the strip-down, a 1/2-inch drive socket set and combination spanners ranging from 1/2-inch up to 1-1/8 inch cover almost everything. This includes removing the exhaust manifold, intake, and thermostat housing.
Fuel System and Rocker Tools
Before reaching the head bolts, you must remove the high-pressure fuel injector lines and the rocker gear.
- Flare nut spanners: Use a 5/8-inch or 3/4-inch flare nut spanner (often called a crow foot) to crack the injector lines. Standard open-ended spanners spread and ruin the brass or steel retaining nuts.
- Cardboard template: Grab a piece of heavy cardboard and punch 12 holes in it. As you pull the pushrods, drop them into the numbered holes. They must go back onto the exact cam followers they wore in with to prevent premature valvetrain wear.
- Pry bar: A medium pry bar helps break the stiction on the rocker shaft pedestals once the bolts are out.
Safe Lifting Gear
Never try to manhandle a Cat 3306 cylinder head off the block. It weighs 160 kg. A slip will cause severe injury or permanent damage to the block face.
You need a mechanical lifting advantage. In a cramped marine engine bay, a 500 kg chain hoist suspended from a strong deck beam or a rigged A-frame is the best approach. If you have the headroom and floor space, a standard folding engine crane works perfectly well.