Ditto. There is a can of MMO next to my tool box and my air tools get a few drops before each day of use.

There was a time when the additive package in motor oil was somewhere between very poor and non existent. In those days the situation was aggravated by colder thermostats and draft tubes allowing for more moisture buildup in engine crankcases. In those days MMO was a drastic step that had to be taken under certain conditions and was about the best we could do. There are some folks who don't realize just how drastically all of this has changed, thus they cling to the old ways.

NOW, however, engines have very good crankcase ventilation and higher temps which boil away more moisture resulting in a lot less acid buildup. Add to that the EXCELLENT motor oil additive packages in premium oils and you have a combination that will never need such drastic cleaning if the oil is kept changed.

For those drastic cases where oil has not been changed to a point of buildup, a good oil, preferably one of those I have noted, changing very often and always draining hot for an extended period of time is the best and safest step toward cleaning the engine IMHO.

The Gunk is a decent way to clean a gunked engine, but I would personally use that approach sparingly and VERY carefully as you point out.

Have a great day,

It's an exhaust leak. Chevy doesn't use gaskets between the manifold and the head. Leaks develop which sound like bad lifters.

__________________
Regards

Warren

Currently 1965 220Sb, 2002 FORD Crown Vic Police Interceptor

Had 1965 220SEb, 1967 230S, 280SE 4.5, 300SE (W126), 420SEL

ENTER > = (HP RPN)

Not part of the in-crowd since 1952.

wbain,

Go back and reread the original post. He says that when he revs it up the noise goes away. An exhaust leak that goes away when you rev it up? I don't THINK so.

Have a great day,

You mite have an exhaust leak when the engines cold and goes away after it warms up due to expansion, but an exhaust leak that goes away by reving the motor once its warmed up is Impossible

Although an exhaust leak is possible on any engine, we have to look at the probabilities here. This is not an MB. The SBC has a VERY weak cam and valve train. The cam is too small, the lifters are too small and the rocker arms are a chincy, stamped piece that a cost conscious engineering group came up with over 50 years ago. Not to mention the original design was conceived to handle no more than a few hundred horsepower.

The SBC modified in '87 for roller lifters got no change in the rocker arm area. They are prone to having noise if the oil is not kept clean. The exhaust manifolds on the other hand are not known for leaking.

At this point we have to operate on probabilities like a physician. The probabilities are HEAVILY in favor of the noise being valve train related.

We also have to give the poster some credit for knowing the difference between valve train noise and an exhaust leak.

Have a great day,