Here's a broad outline of the process:
1. Engine Preparation:
* Remove the valve covers: This provides access to the rocker arms and pushrods.
* Remove the rocker arms and pushrods: Carefully remove and keep them organized; label them if necessary to ensure correct reinstallation.
* Remove the timing chain cover: This exposes the timing chain and gears.
* Remove the timing chain: Carefully remove the timing chain, noting its orientation. You might need special tools for this depending on the chain tensioner setup.
* Remove the old camshaft: This usually involves removing the camshaft bearings (if present), and then carefully sliding the camshaft out.
2. Camshaft Installation:
* Clean thoroughly: Ensure the engine block's camshaft bores are perfectly clean and free of debris.
* Install new cam bearings (if necessary): If your camshaft uses bearings, install new ones according to the specifications in your repair manual. They require specific installation tools and precise alignment.
* Lubricate the camshaft: Apply a thin layer of engine oil to the camshaft lobes and journals.
* Install the new camshaft: Carefully slide the new camshaft into place, ensuring it's correctly aligned with the camshaft journals.
* Install the camshaft thrust plate (if applicable): This part prevents excessive camshaft endplay.
* Reinstall the timing chain: Make sure the timing marks on the crankshaft and camshaft sprockets align precisely according to the specifications in your repair manual. This is crucial for proper engine timing.
3. Reassembly:
* Reinstall the timing chain cover: Secure it according to the manufacturer's specifications.
* Reinstall the pushrods: Make sure each pushrod is correctly installed in its corresponding rocker arm.
* Reinstall the rocker arms: Carefully place the rocker arms back onto the pushrods, ensuring they are correctly adjusted.
* Reinstall the valve covers: Tighten the valve cover bolts to the specified torque.
4. Verification and Adjustment:
* Check the valve timing: After reassembly, double-check the valve timing to ensure it's accurate. This is critical for the engine's proper operation. Use the appropriate degree wheel if needed.
* Adjust valve lash (if applicable): Some camshafts require valve lash adjustment. Consult your repair manual for the correct procedure.
Important Notes:
* Repair Manual: This is absolutely essential. A generic guide is not sufficient.
* Tools: You'll need specialized tools for this job, including possibly a camshaft installation tool, timing chain tools, and valve lash adjusting tools.
* Safety: Take appropriate safety precautions, such as wearing safety glasses and gloves.
* Professional Help: If you lack the experience or tools, it's strongly recommended to take your car to a qualified mechanic. A poorly installed camshaft can cause serious engine damage.
This is a highly simplified overview. Refer to a factory service manual or a reputable aftermarket repair manual specific to your 1969 Pontiac GTO engine for the detailed and correct procedure. Incorrect installation can cause catastrophic engine failure.
