8hp70 heater bypass

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caulk04

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Starting this thread to consolidate some information that we've been discussing (https://www.ramforum.com/threads/revmax-8-speed-thermostat-bypass.171776/unread) on the topic of keeping the 8hp70 cooler than stock.

Here you'll see the thermostat assembly broken down into its individual components.

IMG_20210201_194904752.jpg


I have parts on order to make my own device to bypass the heater and flow fluid through the cooler up front all the time. You'll reuse the black plastic plug and the pin next to it. If someone was to purchase the brass plug from revmax, it should work as well but I don't have one to be sure.

I should have something made up this week, will update this post then. End game, I'd like to make these available to purchase but we'll see.
 
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Wild one

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Starting this thread to consolidate some information that we've been discussing (https://www.ramforum.com/threads/revmax-8-speed-thermostat-bypass.171776/unread) on the topic of keeping the 8hp70 cooler than stock.

Here you'll see the factory thermostat and it's related components as you'd remove them from the heater unit on the side of the trans. Shown is the general direction of flow with the fluid cold/cool and the thermostat closed.

View attachment 236117

Here you'll see the thermostat assembly broken down into its individual components.

View attachment 236120


I have parts on order to make my own device to bypass the heater and flow fluid through the cooler up front all the time. You'll reuse the black plastic plug and the pin next to it. If someone was to purchase the brass plug from revmax, it should work as well but I don't have one to be sure.

I should have something made up this week, will update this post then. End game, I'd like to make these available to purchase but we'll see.

The Rev Max plug is identical to the original plastic plug.If this works with the stock plug,it should also work with the Rev Max plug
 
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caulk04

caulk04

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So here's what I've come up with. The longer spring in the factory setup is there to compress the wax motor as it cools. They do not retract on their own. No need for that spring in my design.

The shorter spring is a damper of sorts so the extension of the wax motor does not become limited and put high stress on the plastic cap. That means the brass washer seals off flow and the spring keeps it there.

The only thing I need to confirm is that the depth I've figured is correct to seal and seat properly. I'll do that on my truck soon.

Installation will be quick and simple. Gain access to the thermostat housing, remove snap ring, remove cap and thermostat assembly. You'll keep the cap and the pin from the stock assembly but replace the thermostat with my bypass plug.

IMG_20210203_191419165.jpg

IMG_20210203_191503410.jpg
 
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caulk04

caulk04

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Here's a couple clearer shots of what I've made. I won't make any specific claims about how much more flow there will be over stock (revmax says 87%), but suffice to say there's less restriction at the cap. IMG_20210203_195844874.jpg IMG_20210203_195818466.jpg
 
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caulk04

caulk04

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Installed the first one in my truck and it's all gone as expected so far. It fit in and compressed as I expected. Took a couple mile trip around the neighborhood to confirm no immediate issues, all good!

It'll be Monday before I go back to work for any good data, but I'll drive around some over the weekend for sure.
 

Different Drummer

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Installed the first one in my truck and it's all gone as expected so far. It fit in and compressed as I expected. Took a couple mile trip around the neighborhood to confirm no immediate issues, all good!

It'll be Monday before I go back to work for any good data, but I'll drive around some over the weekend for sure.
What kind of ambient temperatures are you at where you live right now?
 
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caulk04

caulk04

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In good time, I'll be driving it soon to find out. First drive was just to make sure I didn't miss anything and screw up royally.

Temps are mid 20's to teens overnight the next few days and by next weekend teens to 0 overnight. My truck is otherwise stock, including grille shutters.
 

Musky Mike

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That looks great, you did an awesome job. I'm looking for a 20-30 degree reduction in temp, but being able to quickly and easily return to stock (I have an extended warranty). I would like to purchase one if it works out.
 
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