Question About Coolant Bypass Restrictor Plate

Regarding your topic’s engine and its Windsor thermostat and restrictor plate, did you inadvertently omit telling us that it was a fully sealed restrictor plate?

🤷‍♂️

Larry

The bypass plate in my car is fully sealed.  I don't think the stock bypass plate is considered a restrictor plate.

I don't KNOW. . . but have an opinion.

I don't see having bypass when cold makes engine warm up quicker.   I think It would make it warm up evenly.   circulating flow.

running a centrifical pump "dead headed" is likely to cause cavitation, which eats away the impeller AND cause "loss of prime" ie no flow when needed

opening up the heater when cold could serve the same as allowing the design internal bypass.   don't other engines have a bypass hose that continuosly loops, wasting flow that should go to radiator.   at least the cleveland design doesn't waste that bypass once warm.

but I haven't sleep at a Holiday Inn in decades

Dead heading doesn't cause cavitation. Cavitation is the formation and subsequent collapse of vapor bubbles as the fluid travels from the low pressure eye of the impellor along the vane where pressure increases. Dead heading typically results in seal and possibly bearing failure due to excessive heat as the impellor continues to spin with no fluid flow.

As for the bypass system on other Ford small block engines, yes it is accomplished with an external hose. And yes, that coolant bypass is always active on those engines.

MANY years ago John Christiansen did an analysis of the OEM bypass plate and thermostat hat that showed the hat is not designed to completely block off the passage, but instead allows a coolant flow that is very similar to the coolant flow provided by the external hose.

somewhere in my files I might still have John’s calculations, but highly doubtful I can locate them at this time.

Larry

Without the bypass restrictor plate, water will merely circulate in the block.  There will be insufficient head pressure to drive coolant all the way to the front of the car, through the radiator, and back to the engine.

What water pump are you running?  The Weiand 351C water pump does not have the bypass passage. So if you are using a Weiand water pump, you can run either the 351C thermostat or a 351W thermostat.  It will make no difference.

There are two types of plates that we can use.  The aftermarket plate on the left and the stock plate on the right.  My car has something similar to the plate on the left along with a Windsor thermostat (no hat).  This setup disables the bypass system.  My old water pump was stock Ford (or similar) and the pump I am installing is Flowkooler.  Both have a port for the bypass which is negated by the aftermarket plate.

Thus we are back to my original question:

I am wondering what is down side to continuing with the coolant bypass restrictor plate that came with the car (the one on the left above) .  It seems the primary benefit of the stock bypass plate is that the engine warms up faster but this car gets warm as fast as my other Panteras.

Steve, I don't see a problem in running the restrictor plate, but I don't have any experience in doing so.  It is my understanding that once the thermostat opens, it shunts off the hat not allowing the hot water to stay in the engine and forced out the thermostat to the radiator to get cooled.  AS you mentioned, we are in So. Calif. and the Pantera is garage, so in dead of winter, it might get 40-Degrees outside so maybe 50-DEgrees in the garage.  I use the KISS principal; it was working before why change.  My 2-cents.   Hope to see you at the OC Panteras meeting next week.   Larry