Technical hemi running to cold

I have a hemi 354 with stock bb chevy pump that was running all day at 160 no mater what temp out side, this winter I installed a weiand aluminum high flow big block chevy pump and now will run from 100 to 150 . goes up to 150 then drops to 100 then takes it time to go back to 150, I tried a new thermostat and same thing. the only differents I can see is that the water outlet on top of the pump is a bit diferent from my old pump and now I am pretty sure there is almost no flow coming out of it, comes out at an angle and kinks my by past hose, could this make a diferents in cooling.

 

even if that hose was completely block, should not run colder? also you can see the temp sensor on the water pump, that is where it was before on old pump. I need to get it to run hotter to burn fuel better with my intake set up, I have check with a temp gun and temp is accurate on block as gauge is telling me in car.

 

What temp tstat are you running?

And that is about as wrong of place to mount a temp sensor that i have ever saw.

 

160, I am thinks going higher but did not have problem last year, can someone explain water flow for the chevy pump and also the hemi bypass hose?

 

Sounds like your BB Chevy pump is a better choice than the Weiand. Why did you change out the pump? A constant 160 does not sound like it was an issue.

 

well did you mess with mixture or timing? that would throw everything off

 

I changed the pump because it had slack in the shaft, I did adjust the carbs

 

Find or make( drill and tap) a place in a cyl head or the intake for the temp sensor, the temp you are reading now is diluted with cooled radiator outlet water

 

Hemis should have 180-195 thermostats. Having 160 makes it run colder than it should & the cyl wall wear is 2-3 times higher @ 160 vs 180-195.

 

My bet is you were never reading true engine temp before or now due to sensor position , the new water pump just changed the temp you are reading slightly

 

IMHO the reason the temp goes from 100 to 150 fluctuate is the blocked bypass. The temp sender should be real close to the thermostat. The early Hemis have massive water jackets in the heads, I would put a hotter thermostat in it. My Hemi in my 32 takes 4 gallons of coolant, Hemis cool well.


Ago

 

my hemi holds 5 gallons, I will try a 180 but wondering if it will fluctuate still because of the blocked bypass, any solution for the bypass can you see for me.

 

I ran a 331 for years with the BB Chevy W/P with the bypass & water heater holes plugged w/o problems.

 

I would rather be able to plug them, the hose is so deformed that I am scared the it will burst
that is why I was wondering about flow and if I need it.

 

I never ran a bypass hose, also the sender should be in the block or the heads. Just a thought... how about putting it in the block off plates in the rear of the head? { I just thought of that- not being sarcastic} I ran my sender in the bottom of the water crossover, to hide it.

 

the sending unit was in the pump since I got the car and since it never gave issue I left it there, I will look see if I can put it in the water crossover, if not I will make a place in one of the block off plates, will also go to 180 thermostat.

 

that wiend High flow water pump is a very efficent piece vs the OEM , I have one in my OT pick up and it really moves the water and made the temp drop in my BBC just by changing the pump . and thats with a large pulley ( slow pump speed ) , the bypass should be run to help make the thermostat see the true water temp quicker. I would look at a 45* or 90* nipple instead of a straight one for it . to try to get the kink out . .

 

Block the radiator off with some cardboard or duct as a test.

 

blocked the bypass on water pump, installed a 180 thermostat and put temp sensor on back of the water crossover, ran in hot weather today and temp stayed around 180 - 190 all day, I also put a 1/8 hole in the thermostat , I find it keeps the coolant circulating and air out when thermostat is closed. temp stays more even

 

You will probably notice the lack of a temp spike the first time the tstat opens as the 1/8 hole allows hot water to the far side.
Glad you got it working!

 

with that 1/8 it is a lot easier to fill and empty coolant, goes 10 times faster, I tried it with the 1/8 hole and without 1/8 hole a few times this weekend while working on it.

 

I'm running HOT!! hmmm good info! I have a .060 bore '56 poly 331 with 354 industrial heads 9.0 comp ratio mild isky cam high volume BBC weiand water pump 180 tsat 3core radiator 16 inch fan running hot 200 and climbing. It maybe and a bubble in the system I'm raising the radiator and tilting the motor back a bit to help, also going to run two 12' shrouded fans and an underdrive pulley on the crank, after that I don'r know where to go. the temp sender is in the back cross over port

 

I'm running a 354 with '56 passenger heads, Hot Heads timing cover with a sbc short pump bought from Napa. The temp sender is in the stock location on the crossover near the 'stat. I use a brasworks radiator and the engine runs 180-185 in all weather. Drove to and from the L A Roadsters show this year. The hors each way and 103-106 ambient temps. Ran 180 all the way. Have 11k miles driving the snot out of it with no problems. I am NOT running any bypass and do not plan to. I don't mess with success.

 

I run the bypass from the BB water pump into the crossover. I never ran without, so I don't know if it makes a difference? It runs cool all the time.

 

my Desoto runs cold also. when I didn't have bypass hose it would get a air lock and over heat. I have the hot head 4 b intake and I don't think the gauge gets accurate reading there. is there anywhere else good to hook up sensor?