replacing tstat
#12
05-02-2007, 01:54 PM
#13
05-02-2007, 01:58 PM
Grand Champion
#14
05-02-2007, 02:08 PM
RE: replacing tstat
The pistons and rings start off smaller than the bore. Yes, as the bore expands, so do the pistons but since they start out smaller, they expand less (given an equal expansion ratio). The hotter the engine gets, the looser it gets ... until the oil thins out so much that it cant lubricate enough ... leading to seizure.
#15
05-02-2007, 04:16 PM
RE: replacing tstat
Some of the exhaust gas is water in the form of steam,
some is CO2, some is NO2, some is NOx where x is 3, 6, etc.
These 'acidic' gases do cause a little corrosion of the metal bore walls by themselves just as gases, but the corrosion will get A LOT worse if the steam condenses to liquid water on the bore walls.
For the water to stay steam the bore walls need to stay above 212 degrees F. The metal bore walls will always be 15-30 degrees hotter than the coolant behind the wall they are transfering heat to, but if the thermostat is changed to something low enough the bore walls can start condensing liquid water and acids during the exhaust stroke which rapidly increases wear.
Continental Engine did most of the research on this. Most automotive technology textbooks have a graph showing bore wear vs coolant temperature.
some is CO2, some is NO2, some is NOx where x is 3, 6, etc.
These 'acidic' gases do cause a little corrosion of the metal bore walls by themselves just as gases, but the corrosion will get A LOT worse if the steam condenses to liquid water on the bore walls.
For the water to stay steam the bore walls need to stay above 212 degrees F. The metal bore walls will always be 15-30 degrees hotter than the coolant behind the wall they are transfering heat to, but if the thermostat is changed to something low enough the bore walls can start condensing liquid water and acids during the exhaust stroke which rapidly increases wear.
Continental Engine did most of the research on this. Most automotive technology textbooks have a graph showing bore wear vs coolant temperature.
#16
05-02-2007, 07:19 PM
RE: replacing tstat
ORIGINAL: HankL
Some of the exhaust gas is water in the form of steam,
some is CO2, some is NO2, some is NOx where x is 3, 6, etc.
These 'acidic' gases do cause a little corrosion of the metal bore walls by themselves just as gases, but the corrosion will get A LOT worse if the steam condenses to liquid water on the bore walls.
For the water to stay steam the bore walls need to stay above 212 degrees F. The metal bore walls will always be 15-30 degrees hotter than the coolant behind the wall they are transfering heat to, but if the thermostat is changed to something low enough the bore walls can start condensing liquid water and acids during the exhaust stroke which rapidly increases wear.
Continental Engine did most of the research on this. Most automotive technology textbooks have a graph showing bore wear vs coolant temperature.
Some of the exhaust gas is water in the form of steam,
some is CO2, some is NO2, some is NOx where x is 3, 6, etc.
These 'acidic' gases do cause a little corrosion of the metal bore walls by themselves just as gases, but the corrosion will get A LOT worse if the steam condenses to liquid water on the bore walls.
For the water to stay steam the bore walls need to stay above 212 degrees F. The metal bore walls will always be 15-30 degrees hotter than the coolant behind the wall they are transfering heat to, but if the thermostat is changed to something low enough the bore walls can start condensing liquid water and acids during the exhaust stroke which rapidly increases wear.
Continental Engine did most of the research on this. Most automotive technology textbooks have a graph showing bore wear vs coolant temperature.
#17
05-03-2007, 02:23 AM
RE: replacing tstat
[sm=rant.gif] I have read alot of posts about thermostats and this post is the last straw for me. I have to take out my almost 180deg stat before the cool weather this fall or my CEL will come on. So, it doesn't seem worthwhile to put in another 180 stat for the performance advantage because I have read more posts that sway me back to installing the factory stat. Thanks to everyone for the info that helped me make my decision final, done,[sm=sigh.gif] the end.