Small Block Cam Change

[340Challman]

Has anyone successfully replaced their cam in their small block in the car? What pitfalls am I going to run into? Leaking oil pan? Leaking timing cover? If you've done it successfully, what steps/procedure did you use to accomplish it? I'm assuming I'm going to have to at least lower the front of the oil pan to get the timing cover out and in. What else will I need to do aside from the obvious like coolant, radiator, etc? If I have to I will pull the motor, but I'd really prefer not to at this time. Thanks in advance.

Kevin

 

[Challenger RTA]

It is possible to replace a camshaft in a small block engine without removing the engine from the car, though it is significantly more labor-intensive than a drop-in swap. Most enthusiasts and mechanics report that 9 out of 10 cam changes are performed with the engine in place, provided there is sufficient access.

To execute this repair, you must remove significant components to create a vertical pathway for the camshaft and lifters:

• Front Access: Remove the radiator, grille, fan, shroud, harmonic balancer, water pump, and timing cover. On some vehicles, the A/C condenser must also be moved.
• Top Access: Remove the intake manifold, carburetor, distributor, valve covers, and rocker shafts/pushrods. Keeping them all in order! Just to be safer than sorry. That is if your going to reuse the components.
• Bottom Access: You will likely need to drop the front of the oil pan to remove and install the timing cover properly.

While doable, this method carries risks such as scratching the paint or engine bay components during disassembly. Many builders prefer to remove the engine to inspect the block, replace the timing chain and gears, and ensure proper sealing of the timing cover and oil pan without the constraint of the vehicle chassis.

Extraction and Installation Risks​

Removing the camshaft requires extreme care. The cam is a long, heavy bar supported by tight bearings. As you slide it out, you must support its weight perfectly level; if the nose dips, it can gouge the bearings or the cam journals, ruining the cam bearings.

Having installed cams.
Key Risks:

• Bearing Damage: Scratching the cam bearings during extraction often necessitates a full engine tear down to replace them, as they cannot be easily swapped with the engine in the car.
• Timing Alignment: Reinstalling requires precise alignment of the timing marks on the crankshaft and camshaft gears. If these are off by even one tooth, the engine will not run, or worse, the pistons could strike the valves.
• Debris: Working in an open engine bay increases the risk of dropping bolts or debris into the oil pan or cylinder heads.

I take it you know what you are doing or you wouldn't have ask.

 

[Xcudame]

It really isn't that hard, just time consuming because you need to clean all the sealing areas up (timing cover, oil pan, intake mating surfaces, etc.). @Challenger RTA list is very good.

Go to your local hardware store and by a 7/16-14 bolt about six to eight inches long! Install it into the old camshaft to help with removal and use it in the new camshaft to install it. You can buy fancy ones from Summit and such, but the raw bolt works just as well. When removing and installing the camshaft, use one hand on the long bolt and the other to carefully guide the camshaft through the cam bearings. Don't forget to remove the intermediate shaft under the distributor!