LS conversion VA heater plumbing

[Vega$69]

Originally Posted by Efi69Cam

I got that. The question is use a valve that shunts the water flow away from the core, or one that just shuts it off.

Shunts it to where?

[Efi69Cam]

Back to the water pump, bypassing the core. E.g. 4 vs 2 port heater control valve. Many OEM applications use the 4 port when flow through the heater core ports is desired. I thought I heard that the LS engines require flow for proper thermostat function.

[kevin_l]

I am in the process of installing my LS with vintage air too. This has been a concern of mine also. From what I read on other forums people haven't been having trouble. But I am interested to hear what you come up with.

[kevin_l]

Originally Posted by Vega$69

Shunts it to where?

I think he means we've always been told not to block off flow from the ls water pump. Most people who don't run heat have to loop the water pump inlet and outlets heater ports. The vintage air heater block off valve effectively blocks the heater flow. Some late model cars have a by pass when the heater is off but I haven't seen people use them. Like I said I am very interested to hear what you guys think on the matter. This is my first big build and I am always learning something new!

[Vega$69]

I've done 5 LS cars with VA valve. All have worked fine and continue to work to this day.

[kevin_l]

Originally Posted by Vega$69

I've done 5 LS cars with VA valve. All have worked fine and continue to work o this day.

Thats good to hear! I was going to go this route and hope for the best.

[Vega$69]

Originally Posted by kevin_l

Thats good to hear! I was going to go this route and hope for the best.

Keep in mind the small 5/8 nipple on the WP goes to the heater valve and the larger 3/4" fitting returns water to the pump.

I use the Dayco 87616 Small Id Hose to run from the 3/4" WP nipple to the 5/8" VA Heater fitting. The hose is a 5/8" hose the has a 3/4" bell on one end. Hose is 60" long.

Better the using adapters and crap. The 3/4" end is about 6" long. I cut off approx 5"

[71RS/SS396]

It's a myth that the heater hose needs to be looped back to the pump if your deleting the heater. I run both of our cars with ports completely blocked with no issue.

[Chad-1stGen]

It is not a myth and is how the thermostat is designed to operate from the factory. Every single LS equipped car used either a 4 port heater valve or in most cases no heater valve and instead air is diverted in the heater box.

That said the engine will run fine you just might see slightly warmer temps at idle. At higher RPM's the bypass in the thermostat opens so hot engine coolant will flow across the back of the thermostat even if the heater port is blocked.

I made a video about the difference I saw in thermostat behavior with and without flow through the heater hose port.

Edit. The video is long and boring but what you see is that with flow I get a normal cycle of the tsat but with it blocked my car idle temp is 207ish.


http://youtu.be/oxg4dICnCwc

[jwcarguy]

Originally Posted by 71RS/SS396

It's a myth that the heater hose needs to be looped back to the pump if your deleting the heater. I run both of our cars with ports completely blocked with no issue.

X2

I build off road sand rails also and none of the engines that I do have any type of heater ports, either welded shut or drilled, tapped and plugged and never any issues
In the off road community, there are alot of quality engine builders/ suppliers (ie. CBM Motorsports, Turn Key, Redline, etc.) that practice the same method, even in their highend engines and sand rails (engines $20k+, sand rails $180k+)
I am sure that a stock application / system will produce less than acceptable results as compared to a custom aftermarket performance setup, like most of us run
http://www.custombuiltmotors.com/


Now back on topic for OP

I have had no issues running the VA heater valve in various installs
I have adopted the plumbing layout as done by Detroit Speed with regards to VA valve placement and converting the o-ring fittings to a "AN" style

here is a couple pics that I have saved and a video:

https://www.youtube.com/watch?v=283BYw2f0Qc

Hope this helps

Jeff