The hoses
The hoses looked to be in good condition but I don't remember their age. The coolant was at approx. 180* for some time so I assume the thermostat (large hole type with 1 drilled eighth inch hole) was fully open. The clamps were tight, the hose split open. This engine is a 322" Y running a large shaft truck water pump with the small dia. truck pulley and a flex fan behind a '55 Caddie radiator. I'm glad the heater core held up! lol


"FREE SAMPLE"

What condition were the hoses, to begin with?  If pressure got high enough to rupture a good hose, then it should also have been boiling out of the radiator cap.  Were the clamps sufficiently tight?  Was the engine was up to operating temperature and therefore the thermostat was open before the 5500rpm sprint?


Lawrenceville, GA

The cross sectional area of the bypass port is about .150 in² (so are the heater hoses if the valve is open) - anyone trying to put full output of a waterpump (at 5500 rpm) through it with a closed thermostat is going to get.........?? Sometimes I read things here that must have hurt.

I usually start my outfit - and let it run on the electric choke setting until it hits something like the t-stat setting - 160º. Haven't seen any evidence of the "hotspots - water seems to flow through the thermostat into the radiator at fast idle. What am I missing here?

 
 Steve Metzger       Tucson, Arizona

Lord Gaga, Did you drill the 3ea 3/16  holes into the thermostat? there has to be the ability for the engine to flow coolant before the thermostat opens, otherwise it is dead head pressure and the coolant in the engine is stagnant. this could also cause hot spots.

I tried the plug with the 1/8" hole in the bypass too. The first time I got on it and wound out to around 5.500 RPM one of the heater hoses ruptured! A big mess! Just glad I was close to home. That plug is a bad idea.


"FREE SAMPLE"

After many of the comments I took out the plug with the 1/8 hole in the bypass and everything returned to normal.  I am not using a Robertshaw type thermostat and at this point do not plan to.  I plane to do some engine work and am going to try the new space for Tbirds.  I may go to the smaller pulley too.  I really don't have a heating problem, but I want to make sure I don't.


54 Victoria 312;  48 Ford Conv 302, 56 Bird 312
Forever Ford
Midland Park, NJ

I haven't had any temperature regulation issues with any Robert Shaw style thermostat USA, or Chinese.  I've had 160 and 180 Mr Gaskets (China), 180 Milodon (USA).  However, none of mine are modified with the holes


Lawrenceville, GA

I have tried 3 of the 180 Robert Stats and had the same problem with all 3. I have One of the Napa 170 Stats coming so I will see how that works out. Changing the Rad, 6 Blade Fan, and smaller Pulley has made a big difference already. Temp is much more stable driving or idling at a Light. Doesn't move much from 160 which is what the Stat in it is right now.

  

Only specific trouble I've had, was with the 180º version of the Robertshaw style of t-stat. Didn't behave at all, the one I tested in the engine was inconsistent (as reported by others). With the 160º back in there - it all worked as I expected. The "leaking" (drilled) version slows the warm-up - and switching to the smaller pump pulley showed water flow before my temp gun showed enough heat to open the 160º t-stat.
Being sure the system is "burped" is sort of SOP I think - and the t-stat hole mods help to do that.


 
 Steve Metzger       Tucson, Arizona

When You changed Stat etc did You let it run with Cap off until Stat opened and let the Air in the System escape? I just did mine as you know with regular Stat( removed the Robert Shaw) and bypass restricted and had no problem. I have a Mechanical Gauge in front part of Intake( drilled Hole and Tapped) as well as the Dash Gauge. Both Gauges moved up as Engine warmed up.