[Gach]

Originally Posted by NeighborsComplaint

In another amusing, now closed post this "wive's tale" was brought up. I'm in my '70's and can attest to how this wive's tale grew legs ... because it happened, a lot.

The fact is increasing the valve sealing via a valve job along with guide rebuilding on a car with excessively worn rings usually emphasized the failing compression by increasing blow-by and oil consumption and a wive's tale "My motor never smoked or used oil before I had the heads done" was born. Yeah, it did, but they just never paid attention to it until they re-did the top end and just couldn't admit they wasted their money on a worn-out engine because that would be stupid.

As if that wasn't bad enough, inexperienced backyard builders would combine the cylinder head work (surface seats/valves and replace or knurl the guides) with an opportunity to install a performance camshaft and matching springs along with a four barrel intake upgrade on their 2 Bbl low compression, worn-out econo-motor.

The old, worn motor was RPM limited (protected) by it's original 2 barrel carb that ran out of juice and old valve springs that floated the valves just north of 4,000 rpm. With the upgrades, the motor would rev past what was a safe upper RPM limit for
its condition and well-worn crappy cast pistons with excessive clearance would rock in their bores, rod and main bearings became oil-starved at high rpm due to excessively worn clearances and of course crappy low-performance cast rods would get stressed as the bearings got hot. The continued abuses eventually would cause some combination of spun bearings, cracked piston skirts and broken rods.

Motors got grenaded and the old wive's-tale continued.

So true !