kwhizz

Since entering the world of LS engines, I am on a continuing learning curve....LOL..........Installing these engines and driving these LS powered cars has changed my whole world........The problem is that being brought up in the Old School world and having that thought process as a data base......LOL
One of the things I always wondered about (but never analyzed) was the fact that in driving a new LS powered car, the temp gauge never fluctuated and always stayed at the same temp..........My converted LS powered cars always had a Temp fluctuation (10-20 degrees mainly at Idle)......So, after reading a thread here on how GM designed the system in regards to thermostat function and thinking it thru, I was able to see an issue with my system that would cause the fluctuation........
When adding an aftermarket A/C system......the heater control valve stops the flow of coolant going into the heater core when not needed (Heat).......The GM system has continuous flow thru the heater core.........Humm!!.....Why is that.......They designed the system with the hot coolant coming out of the top of the engine thru the water pump to flow thru the heater core and then back to the water pump to flow across the heat sensing side of the thermostat........Without that continuous flow of coolant across the thermostat, it doesn't have that link to see what the temp really is from the hot coolant coming out of the hottest part of the engine......
So........I bought a LOJ heater bypass block and added it to the system....Started the car and the Temp gauge now go's up to the thermostat temp and stays there........ https://www.lojkits.com/products/ls-...r-bypass-block
The car never had a problem with overheating........But........Just can't leave it alone ......always fine tuning.......LOL







Ken

1964SS

iTrader: (1)

That's a cool little setup. The link didn't work for some reason, but I did find the block on the website.

https://www.lojkits.com/products/ls-...r-bypass-block

-TheBandit-

iTrader: (1)

That's a nice looking part, but pretty expensive. I think there are some OEM versions out there that are vacuum operated like the original 60s-70s cars which act as bypass valves intsead of shut-off valves like the 60s-70s cars had. I have been planning to use one on my setup, but for now I just have a piece of u-tubing connecting the output of the water pump (no heater function for the moment)




I agree that for proper function of the thermostat, there should be flow between these ports.

Michael Yount

iTrader: (1)

I simply plumbed in a couple of Dorman 1/8" tees between the heater hoses. So there's a small "bypass" at work all the time providing the temp signal the GM engineers wanted to see. But when the (much larger) heater valve opens, the small amount of coolant bypassing doesn't affect heater output in any noticeable manner.

Attachment 716818

garys 68

iTrader: (1)

Looks like you're using an electric HCV, Vintage AC?
There are 4 port electric HCVs that provide the bypass function (Lincoln LS?). Just be sure to check if they're normally open or closed.

OLDSMAN

I recently found this Four Seasons valve: https://www.summitracing.com/parts/fss-74800
which is a 4 port affair which could be good too.

ls1nova71

iTrader: (4)

If you're looking for a factory vacuum controlled valve with the built in H, they come in Astro vans from the late 90's to early 2000's. I used one in my '71 shortbed. But to be honest I haven't noticed any difference from the ones that block it off completely.