Camshaft Installation (Small-Block Chevy)

Small-block Chevy engines have a weak spot, and that's the camshaft and lifters. They wear pretty fast, particularly if they're over-revved and don't get regular oil changes. Replacement isn't terribly hard, but a couple specialty tools are needed.

install camshaft small-block chevy

Read: Engine Disassembly/Remove Camshaft

This engine featured in this article from a 1966 Corvette. The original Chevrolet camshaft for this 327ci L75 has been long discontinued and homogenized into GM #3896929, which is similar. Several companies, such as Crane, offer this in their "Blueprint" series.

camshaft installation

Read: Camshaft Selection Guide

After a bit of research, we chose the Melling MTC-1 cam kit, which comes with American-made Johnson lifters. The following stats show how close this cam is to the original:

  • Intake Valve Lift: O.E. cam .390" vs Melling cam .422"
  • Exhaust Valve Lift: O.E. cam .410" vs Melling cam .444"
  • Intake Duration at .050" Lift: O.E. cam 195 vs Melling cam 204
  • Exhaust Duration at .050" Lift: O.E. cam 202 vs Melling cam 204

Step-By-Step Camshaft Installation

Clean and lube the new cam before installation. Most cam and lifter kits include a small assembly lube bottle. Coat the cam lobes, distributor gear, and fuel pump lobe completely, but not excessively.

Camshaft installation sbc

The cam bearing journals are lubed with conventional SAE 30W or 40W oil. Synthetic oil is not recommended during break-in.

Camshaft installation 327

Just like during engine disassembly, I re-installed the cam gear with one hand-tightened bolt to use as a "handle" to help guide the cam into the block. Care must be taken not to nick the cam bearings. After the cam is in the block, remove the cam gear.

Camshaft installation 327 SBC

If you're not sure how many miles were on the engine, replace the timing chain. An old chain stretches and can alter engine timing.

327 timing chain and gears

With the cam completely in the block, wrap the timing chain around the cam gear, and then under the crank gear.

The small-block Chevy engine uses a "dot over dot" alignment. On the cam gear, notice the manufacturer's pre-marked timing dot, which should be at the 6 o'clock position. Rotate the crankshaft until the same dot on the crank gear is at 12 o'clock. This sets the engine's rotating assembly at Top Dead Center (TDC). The front drivers side piston will be all the way up in the bore.

Bolt the cam sprocket to the camshaft. Make sure the sprocket is pulled up flush onto the cam.

Double and triple check that the timing marks are positioned properly and according to the engine manual. With a socket and ratchet on the crank bolt, I backed up the rotating assembly slightly and then forward lining the dots up again, to make sure I was getting the most accurate reading.

327 timing chain and gears

I put a dab of non-hardening sealant on the three cam-bolt threads and torqued them to the specified 30 lb/ft. This will insure the bolts remain torqued to the proper specification. A camshaft bolt locking plate could also be used.

To complete the camshaft installation, the timing chain cover was re-installed. First, it was sanded to bare metal, treated with phosphorous acid, and painted Chevy Orange (no primer required).

timing cover seal installation
camshaft installation

This is my timing cover seal "tool". It's the hub of an old SBC harmonic balancer.

timing chain cover sbc

Timing chain cover bolts require 7 to 9 lb/ft of torque, no more.

Read: Best Oil for Classic Cars