Many thermostats have a bleed hole already drilled in. I drill one in to those I get that don't. Ken Quoting tom jennings <tomj@xxxxxxx>: > On Sat, Feb 6, 2010 at 06:25, Bruce Griffis <bruce.griffis@xxxxxxxxx> wrote: > > > I was wondering about the drilling the thermostat thing. If the t-stat > > button causes it to open to let coolant circulate, isn't drilling a > > hole in it kind of like leaving it always open? Or is the hole small > > enough so that there is only a small amount always circulating, then > > when it opens it gets enough flow to keep it cool? > > > > On the 195.6 OHV head, the thermostat is in a cast housing waaay up in front > of the cylinders. It's clear in the photo below, the little 'pod' that the > thermostat lives in. It's a design mistake for sure. > > http://wps.com/AMC/1963-Rambler-American/Nash-195.6OHV-engine/small/cleanheads2.JPG > > The water pump wants to suck water from the bottom of the radiator, push it > up the block, and into the head; the head is filled with many passageways > around all the combustion chambers and exits out the thermostat, into the > top of the radiator. > > If the thermo is closed, water doesn't flow to the radiator, and the > cylinder head heats up fast(er). The cylinder head is long and thin. > Remember, no water is flowing to the thermostat, so the water there remains > cold until it gets how by conduction! > > You can verify this youself. Engine cold, start and idle. Put your hand on > the head (distributor side, or the intake trough cover). YOu can feel it get > warm. At some point it's too hot to touch. Feel the bottom of the thermostat > pod... COLD! At some point, the head water is HOT HOT, and the thermostat > is... slightly warmer... it eventually opens and water flows and it > temperature-regulates. > > ONCE ITS OPEN it works right, because head water becomes thermostat water. > > Drilling a tiny hole in the thermostat is common, it lets air bleed up to > the radiator tank. A "big" hole (1/4"?) will let a decent amount of water > flow. I intend to have that water flow past the actuator button on the > bottom of the thermostat. Therefore, as the head warms up, head water will > flow over the thermostat, "telling" the thermostat how hot the head is. > Water circulating will mean like Mark says, even temperature distribution. > > The downside is it will take longer to warm up and if the hole is too large, > the head could run below rated thermostat temperature. But it's just a > thermostat, easy to experiment with. > -------------- next part -------------- > An HTML attachment was scrubbed... > URL: > <http://list.amc-list.com/pipermail/amc-list-amc-list.com/attachments/20100206/05293e6f/attachment.htm> > _______________________________________________ > AMC-list mailing list > AMC-list@xxxxxxxxxxxx > http://list.amc-list.com/listinfo.cgi/amc-list-amc-list.com > _______________________________________________ AMC-list mailing list AMC-list@xxxxxxxxxxxx http://list.amc-list.com/listinfo.cgi/amc-list-amc-list.com