o no just the opposite.......as your car gets older the compression goes up. it gets meaner. my car has 260 thousand miles on it and its wayyyy meaner than it was the first day i rolled it off the bell honda lot in 91

 

Seafoam is your friend in terms of removing carbon deposits.....

 

I cannot comment on newer cars. The last car engine/s I had in pieces were a) Ford Pinto engine, b)GM 4 cylinder from an Opel Manta. Both these cars were 70's models
These had lost compression over about 80,000miles which was why I did the work on the engine which included re-grinding the crank, bores machined and slighlty oversize pistons and rings. What we used to call a "short motor". New engines may well be different.

However the only reason I could see an increase in compression on an old engine (old stock motor vs new stock motor) is build up of carbon perhaps?? Normally the rings wear and consequently allow gasses past them. The other thing to consider is wear on all bearing surfaces. Also the final power put down on the road through the transmission and wheels etc all the wear on these components will affect the overall power. Just my opinion and two cents worth ;-)

 

yeah that carbon builds up and does wonders on compression ratios. Provided the rings and valves don't wear out.

I seafoamed my motor and it was better than 4th of july as far as smoke goes.

 

Ah well I guess you learn something new everyday. Thanks mbo1985