Overheating On Test Stand

[YY1]

The only other thing that jumps out at me-

Your top hose is WAY high.

Might be trapping air and impeding circulation.

Looking back, it looks like the radiator is also WAY low.

You don't want exceptionally high spots in the cooling system.

Center of radiator should be close to the center of the water pump.

Top and bottom of everything else should be within a foot, and no steep angles or vertical sections.

 

[RemCharger]

Bottom hose looks kinda kinky.

 

[Runcharger]

Factory sort of knew what they were doing. hence an engine driven fan, shroud, proper sized rad. You don't drive an engine stand, it runs, pull it off there and set it up in the car. Box fan air will take the path of least resistance, so some of it will go through the rad, some of it will go to the side. Factory tinwork was designed to force pretty much all air from the grille through the rad.

 

[MarPar]

Bottom hose looks kinda kinky.

 

[archangel]

Based on all of the feedback and insights, coupled with the fact that I am sort of done putting money into the test stand, my current plan is to run it maybe one more time to nail down the timing and then call it quits test stand wise. Thinking back I sort of lost sight of the fact that my initial goals, which I met, were to use the stand for engine break in, check for leaks and verify that all of the rebuilt components functioned properly.

 

[j-c-c-62]

Your coolant flow based on your radiator hose connections favors water flow thru less than half of your radiator. The top inlet connection on a down flow radiator should always be ideally on the opposite end than the outlet connection. You have your top connection slightly off centered and bottom on Drivers side on the test stand. Surprised a rad shop would build that. A thermal image heat camera would be useful here when overheating to discover what might be exactly happening.

 

[Mbrew]

Hey , just to cover bases , did you check to see if the bypass hole in the water pump housing is free and clear ?
Worked on a hemi awhile back that had an “extension” threaded into it and no thermostat.
I put in a 180 and ran it and before long it was overheating !
Removed the thermostat and then noted the bypass extension that was getting blocked when the thermostat opened!
Food for thought .

 

[joew94th]

I'm with the crowd that says you need a better fan. I'm running a factory fan and shroud with Aluminum radiator on my 360 Belvedere. There's no way I can idle for 15 minutes without it going to at least 220 degrees, and that's with the aftermarket AC off. My next try will be the most effective electric shrouded fan I can find. I set my total timing to 34 degrees BTDC.

 

[j-c-c-62]

BTW, there is little to be concerned here about the upper hose "trapping air" that is in this case the Outlet "pressure side". Any air in the hose is of no relative concern and will be pushed out as the flowing coolant will displace it as needed. If air remains in the upper hose, it causes no problem and only means coolant flow is insufficient to displace all the air. Water will still flow. Any air bubble in this upper hose will not block any coolant flow. We are assuming there is enough coolant to be pumped in the first place, and based on the robust size of the upper tank of the radiator, that should never be a concern once filled and verified with cap off.
Any air remaining anywhere else in the system, other than the upper tank, is a different topic and concern.

 

[archangel]

@j-c-c-62 If I am correctly interpreting what you said about the inlet/outlet positions...note that my factory radiator, which I plan on using in my car, has inlets and outlets on the same side. As a side, I do indeed initially run with the cap off, until after the t-stat opens, to purge air pockets whenever I mess with the cooling system.

@Mbrew Interesting thought. I had used a bore scope to check all of the water pump housing passages (including bypass hole) when I had installed a new aftermarket water pump. They all appeared to be clear. I went back to the rebuilt factory water pump since it did not make any difference. If I experience overheat issues, once installed back in the car and using all factory cooling components, I might consider tearing down the front of the motor to triple check all passages. I have a gut feel that that temps will be just fine though.

Overall a good learning experience for me.

I will end up selling my test stand. Should the buyer be a novice to test stands, as I am, I will point them to this thread with the thought that they can rework the cooling setup before use.

 

[Geoff 2]

Good point by J-c-c in post #26. You can feel the difference of the core side to side with your hand. One side, away from the top fitting, will be cooler because the coolant is favouring the other end of the core.

 

[YY1]

LOTS of factory Mopar radiators were built with inlet and outlet on the same side.

 

[toolmanmike]

I would find it interesting to see how hot it would really get and if it would puke coolant out if the engine continued to run. The OP said 210-215 when he shut it down. That's getting hot but not overheating/boiling over. The lack of a proper fan and possibly a shroud could help the situation. How long does an engine need to run on a test stand? 20-30 min. tops. Long enough to set basic timing and check for leaks and noises. You really can't "break in" an engine properly without a load. That requires a dyno or driving it.

 

[j-c-c-62]

LOTS of factory Mopar radiators were built with inlet and outlet on the same side.

And lacking in optimum design, unless a cross flow double pass design, like on my aftermarket slant six radiator.