Inlet side thermostat install.

[440Magnum]

Originally Posted By: Gary Allan


It's just speculation with some semi-authoritative speculation thrown in. I have to figure that there's a reason why a cast engine can possibly warm so fast. I'm sure that they did something to help cope with the emissions issues in its latter years. I've never had any engine warm that fast.


Well as I said our old '93 3.5L was a quick warmer, but it had aluminum heads (still an iron block- the 3.5 went aluminum in 98, I think). I think a lot of it has to do with the cleanliness of the water jacket passages. Newer engines seem to have a lot less "junk" left in the water jackets than engines of previous decades. Some "semi-authoritative speculation" that backs this up is my recently rebuilt 440. Its a plain old iron-head iron-block engine built pretty much to 1969 specs, but it warms up almost as fast as the Jeep. But the block and heads have both been tanked now, so they're very clean inside.

 

[Gary Allan]

Well, there was nothing like a classic overheat in a Mopar with their casting issues of the 60's and 70's. In OEM trim, that is.

 

[Gary Allan]

Just an update. I haven't changed the inlet thermostat to 180F yet, but drove it for two 5.5-6hour highway runs of between 65-80mph. Flawless, as expected.

The only side effect that I see is that now, when restarting, the temp is higher ...like 215F. Before with just the outlet stat, you would have the stat open and natural convection would exchange the coolant (or so I reason). As the engine cooled, the outlet stat would cycle closed. If any residual heat was sufficient, the stat would reopen - repeat. Now with an inlet stat, I don't think this occurs. You've got nowhere to grab cooled fluid from.

Now it basically reacts like a older BIG V8

 

[Shannow]

Gary, I didn't notice that effect when I was using it, but only used it on one car with a temperature gauge.

And most of the time I was messing around with no fan, raised trailing edge of the bonnet trying to get enough natural airflow to negate the fan.

 

[Gary Allan]

I'm trying to find out who I can hit up from my list of accomplished machinists to make another one of (perhaps) lighter material ...not that it proved to be an issue here. Naturally, I have to pique their interest since it will be a side job ..so to speak. I can't afford the ante for a T&M job

I should have everything done this weekend. The 180F thermostat and the rerouting.

 

[Shannow]

Gary,
to simplify, and make things a little (maybe) easier, there are some regular thermostat housings that will fit face to face, and would need either a retaining groove machined in one part, or a super thick gasket.

When I was messing around with the one that you've got, I had a pre-emissions (Oz) 6 cyl outlet, and a post emissions. The pre was solid, and the post emissions had a port for a thermo controlled vacuum "switch"

The two housings, a thick gasket, and a brass nipple would have made a functional set-up...the hoses were too much of an issue to prolong that endeavour.

In the states there's bound to be something that would work similarly.

 

[Gary Allan]

That would work, I suppose. The bypass nipple is integrated into the housing on jeep inlines. The later versions having a tap for the temp sensor. It would create a "dog leg", so to speak.

This is what I need

I guess two of these and just making a spacer for the bypass tap would be ideal. It would surely be easier just making the spacer.

I was thinking along the lines of cheaper alternatives to this:

The devil is always in the details with these things. After what I went through with my minivan incorporating longer in line heat exchangers ... I must have had 10 feet of rad hose taking trips around the engine bay.

Some times ..you literally can't get there from here.

 

[Shannow]

Found my proper set-up while messing about in the shed yesterday...

This kit and the Caprice are going to have a get together some time soon.