Re: [MV] M151A1 rocker arm push rod trouble

Muttguru@aol.com
Wed, 2 Jun 1999 04:54:01 EDT

In a message dated 02/06/99 03:32:52 GMT Daylight Time,
1966pontiac@email.msn.com writes:

<<
I have a problem with the rocker arm push rods falling out from under the
rocker arms on my M151A1. Can anyone help with some ideas?

Herb >>

Herb, it's not easy to diagnose the problem from afar, but here's a few
suggestions as to what could be happening:-

1. A valve is sticking in the "open" position, allowing the pushrod to
dislocate as the engine is cranked: Possible causes:-

(a) valve rocker arm sticking due to insufficient lube getting to the valve
rocker or rocker arm,
(b) weak or broken valve spring,
(c) bent or oversized valve.

2. A loose valve tappet adjuster screw (these should be torque-tested and
replaced if they don't meet the minimum). At a pinch, use something like
Loctite on the thread as a temporary repair.

The next two are highly unlikely.... but should be considered:-

3. the cam follower face (tappet) has a chunk missing, allowing it to drop
further than it should against the camshaft, when in a particular position.

4. the camshaft has a chunk missing from its operating face giving the same
results as above.

My guess is that reason 1 is the most likely, followed by reason two.

When you sort it out, please share the answer with the List.

Kind regards.....

Ken

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