<VV> Banging Noise from Engine

tony.. tony.underwood at cox.net
Wed Jun 16 17:35:38 EDT 2021

On 6/16/2021 10:22 AM, Matt via VirtualVairs wrote:
> Several members of my local CORSA chapter [ACORN] and I have been trying to
> track down the source of the noise on a new member's car, a '65 Monza,
> 110-PG ['64 engine].
> 2 years ago I was GIVEN a ”Banger” engine others had given up on.  Same scenario!
> Turned out the one head had been over heated, dropped an intake seat and damaged the piston.
> Piston replaced, but installed backwards[ notch to REAR, not towards bellhousing.
> Seat replaced in head…  BUT  gasket register had   sunk or been cut.  Was 0.670” deep vs. 0.560” from factory.
> Replaced head with good used unit and engine is fine today.
> Try a different head!  Simple and fast to do.   Good Luck

I have taken engines apart that were noisy and found nothing loose in 
the bottom end.   A closer look showed the edges of piston(s) that were 
actually hitting the cylinder heads where metal had extruded from under 
the gasket surface because of extreme heating sometime along the way, or 
maybe excessive head nut torque, or both.   However it happened, there 
was a "roll" of aluminum that was actually extending down past the tops 
of the cylinders which was getting in the way of the pistons.   So 
Matt's comments on gasket surfaces are right on target.   A quick peek 
at the pistons also shows an eroded or polished edge surface from 
contact with the extruded aluminum in the head.

I've checked through my head collection along the way and found a few of 
them that show this same extrusion to some degree, some barely, some 
kinda obvious.


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