<VV> Cylinder assemblies vs Pistons/rings + rebore/How Long Do They Last

[Tony Underwood]

At 11:09 AM 2/13/2011, HallGrenn at aol.com wrote:
>Dale brings up an old question on engine life.  How long do they last
>especially considering the '60s gearing and the fact that, when they 
>were still
>"new", our Corvairs were keeping up with bigger, higher torque engines.
>The original cast pistons with (I believe cast iron rings) lasted a long time
>if  the engines were kept tuned and the carbs were clean and synced.  My
>one  and only new '68 110 4spd blew a head gasket at about 127,000 miles, but


My '60 4-door, acquired in 1984, evidently had never had a head 
gasket issue although it sure did have valve issues.   Fixed that, 
and it managed to make it to 196,000 miles (that I know of) before it 
swallowed a valve about 5 years ago which did some damage to the 
piston and scored the cylinder... engine got swapped, original is in 
the garage awaiting repairs which someday will be effected.


>  kept  going after repairs and our '68 110 PG went between 190,000-200,000
>miles  with one head change (we were the second owners).  Neither had oil
>burning  problems (blue smoke on de-acceleration or startup--though 
>they burned
>more oil  than when they were younger of course).


Likewise the original 140ci engine in my '60 4-door.   Up until the 
valve ingestion (head came off the stem) it used a small amount of 
oil between changes but after the puff at startup it burned clean.


>So if a relatively well
>kept  engine with cast pistons and cast iron rings can go 150K+ shouldn't
>forged  pistons with chrome or moly rings go even longer than that?


I'm not entirely convinced that forged pistons and/or moly rings 
actually WILL outlast good cast pistons and good quality cast iron 
rings in a street engine that's not driven like a bank robber just 
stole it.   After all... those turbo engines used cast pistons, and 
I'm not real sure the rings were anything fancy in the over-all 
scheme of things compared to what's available today.


I've seen a lot of 'Vair engines that had never been apart with a 
bunch of miles on them still in the same car and still going, and 
running well.



tony..