Rear cam plug installation on the Ford Y-Block engines dictates that it not be installed so deeply that it actually interferes or contacts the rear of the camshaft. Besides the obvious wear issue that can occur at the face of the cam plug, detrimental wear at the rear side of the cam thrust plate can become evident or in a worst case situation, the thrust plate itself can break. Unlike a Ford FE engine where the cam plug actually goes into the block cup side first or facing in, the cam plugs for the Y are designed to be installed with the cup side facing the rear of the engine. This puts the flat face of the Y’s cam plug in a position to contact the rear of the camshaft if the plug itself is installed too deeply into the block.
When installing the camshaft in the block and without the cam gear yet installed, the front face of the camshaft is expected to fall behind the front of the block or behind the cam thrust plate at least 0.050”. If it does this, then the cam plug is installed correctly and not too deeply into the block. If the camshaft fits flush with the block or actually protrudes slightly in front of the block when the cam itself is pushed in as far as it will physically go, then the rear cam plug installation should be readdressed before going any further.
I’ll add that when assembling the engine, examine in detail all the individual parts. The cam thrust plate can be cracked from a previous installation and a single crack can be easily overlooked if not being watched for.
And last but not least, use some sealer on the outer edge of the cam plug when installing it. Although there’s no oil pressure between the plug and the rear of the camshaft, there is still oil residing in that area and seepage from a rear cam plug is very often mistaken for a rear main seal leak.
<Click on pictures for larger images>
Until next time, happy Y motoring. Ted Eaton.
Originally published in the Y-Block Magazine, Mar-Apr 2011 issue, Issue #103, Vol 20, No.8