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4.0 with Speedhut gauges?

tower210

tower210

Scrambler Junkie
Lifetime Member
City
Olathe
State
KS
I swapped in a 4.0 from a 94 XJ 4-5 years ago; new water pump went in with the swap. Pretty happy with it overall (another 40HP would be nice). I have the speedhut guages which replace the factory temp sensor with a more modern sender. It's always run (especially on the highway at 70MPH) about 3/4 the way to the top on the "normal range" for engine temp...

I wish the speedhut had actual temperatures on it... I have read that 4.0s under load tend to run 200-210F.

It never seems to creep higher than the 3/4ish up spot...but it does worry me a bit. Radiator is a cheap oreilys job that I had to do an emergency swap about 6 years ago before nationals...

Thinking about upgrading to a champion or similar before summer (toying with idea of heading to the national; know it will be HOT). Have the ford dual fan setup now; it's worked pretty reliably so far; but the plastic shroud isn't near as perfect as the new aluminum shrouds.... Seems a bit hard when ordering new rad not to just get new shroud and fans.....

Anyone else with a 4.0 and speedhut run in this range or know what the middle/top of the normal range correspond too?
 
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tower210 said:
I swapped in a 4.0 from a 94 XJ 4-5 years ago; new water pump went in with the swap. Pretty happy with it overall (another 40HP would be nice). I have the speedhut guages which replace the factory temp sensor with a more modern sender. It's always run (especially on the highway at 70MPH) about 3/4 the way to the top on the "normal range" for engine temp...

I wish the speedhut had actual temperatures on it... I have read that 4.0s under load tend to run 200-210F.

It never seems to creep higher than the 3/4ish up spot...but it does worry me a bit. Radiator is a cheap oreilys job that I had to do an emergency swap about 6 years ago before nationals...

Thinking about upgrading to a champion or similar before summer (toying with idea of heading to the national; know it will be HOT). Have the ford dual fan setup now; it's worked pretty reliably so far; but the plastic shroud isn't near as perfect as the new aluminum shrouds.... Seems a bit hard when ordering new rad not to just get new shroud and fans.....

Anyone else with a 4.0 and speedhut run in this range or know what the middle/top of the normal range correspond too?
Click to expand...
@bigwalton
 
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I hear the 4.0s like to hit 210 regularly and are happy there. Mine likes to sit at 195 normally and at 200 when pushing.

Have you tested with a temp gun to know what you are really sitting at? So you know what temp the motor is really at when your needle is 3/4 as you say?

Are the speedhut temp gauges adjustable? I was talking with someone this weekend who has them and said that was true about the fuel gauge. So maybe the temp gauge as well. Again, I would ask Eric (@bigwalton ) as he is the expert. I have not bitten the bullet on the speedhut gauges yet.
 
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You're 100% fine running there and this is a known issue with the Speedhuts and a 4.0L. As Dain said, 4.0s regularly run hotter than 258s and the range AND WARNING LIGHT is set up for the 258 range. I asked them about the settings of the built-in speedo temp gauge and whether it was customizable, like some of their other gauges are and they are not. This was the response on the range/warning light settings:

Screenshot 2023-04-24 at 10.51.36 AM.png

The thing that's problematic for me is how low the temp has to get to turn off. 220 just isn't that hot for a 4.0 and I could deal with it coming on there, but the fact that it has to get all the way down to 200 to turn off has been a PITA for me.

So you can figure out pretty well where things are knowing that 260 is H and I'd guess 180 at the low end. Their support is very responsive if you want to write in for clarification.

In hindsight, I would have done my four other gauges differently if I'd realized this about the built-in temp gauge in the speedometer relative to the 4.0 and done a dedicated water temp gauge because that one WOULD be customizable. I always thought I'd swap the clock for one of the four middle gauges and put the water temp in the clock spot for better visibility :shrug:
 
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@bigwalton Great feedback here... I'm not sure if I've never hit 220; or just didn't notice the warning light; but that is what I needed to know. I have the clock and like it for the aesthetic; but would prioritize knowing actual temperature. It looks like 210 is right in the middle of 94 XJ temp range......

I might splurge for a dedicated water temp gauge....
 
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bigwalton said:
You're 100% fine running there and this is a known issue with the Speedhuts and a 4.0L. As Dain said, 4.0s regularly run hotter than 258s and the range AND WARNING LIGHT is set up for the 258 range. I asked them about the settings of the built-in speedo temp gauge and whether it was customizable, like some of their other gauges are and they are not. This was the response on the range/warning light settings:

View attachment 108891

The thing that's problematic for me is how low the temp has to get to turn off. 220 just isn't that hot for a 4.0 and I could deal with it coming on there, but the fact that it has to get all the way down to 200 to turn off has been a PITA for me.

So you can figure out pretty well where things are knowing that 260 is H and I'd guess 180 at the low end. Their support is very responsive if you want to write in for clarification.

In hindsight, I would have done my four other gauges differently if I'd realized this about the built-in temp gauge in the speedometer relative to the 4.0 and done a dedicated water temp gauge because that one WOULD be customizable. I always thought I'd swap the clock for one of the four middle gauges and put the water temp in the clock spot for better visibility :shrug:
Click to expand...
Same issue with me with LS swap. Drives me crazy that I cant either change set points or turn idiot light off. Should just be a software update needed to allow us to customize this... I have requested that years ago.
 
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Are you all using the Speedhut temp sending unit that came with the kit? I made the mistake of trying to use the sending unit that was already on my 302 and it would very quickly peg the needle and turn the light on as running too hot. I spent a lot of time trying to determine why it was running hot until I purchased an old school analog gauge. The 302 was running fine. And then I called SpeedHut and they told me I needed to use their sending unit.
 
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STSFCTN said:
Are you all using the Speedhut temp sending unit that came with the kit? I made the mistake of trying to use the sending unit that was already on my 302 and it would very quickly peg the needle and turn the light on as running too hot. I spent a lot of time trying to determine why it was running hot until I purchased an old school analog gauge. The 302 was running fine. And then I called SpeedHut and they told me I needed to use their sending unit.
Click to expand...
Yes, you always have to use the one with the range corresponding to the gauge.

In theory you could potentially change the sender (all it is is a variable resistor with a known temperature-to-resistance curve) to one that moved the range just enough to better fit the motor in question, but that would take more effort and research than I would ever get into. Basically fool the gauge into thinking that the temperature is lower than it really is throughout the entire temp range of the sender.

Without the ability to change the programming on the temp gauge, Speedhut could theoretically find out options for alternate senders that would achieve that, but I don't think it's happening.
 
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On my 4.0, I bought a temp sending unit for a TJ and it pegged hot really quickly. Temp was normal. Put my CJ temp sending unit it in and bingo, it worked with my old gauge and read a correct temp. Sending unit needed to match the gauge (obviously), since I did not get a new temp gauge.
 
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bigwalton said:
Yes, you always have to use the one with the range corresponding to the gauge.

In theory you could potentially change the sender (all it is is a variable resistor with a known temperature-to-resistance curve) to one that moved the range just enough to better fit the motor in question, but that would take more effort and research than I would ever get into. Basically fool the gauge into thinking that the temperature is lower than it really is throughout the entire temp range of the sender.

Without the ability to change the programming on the temp gauge, Speedhut could theoretically find out options for alternate senders that would achieve that, but I don't think it's happening.
Click to expand...
could just add a potentiometer in line to change the resistance from the sender to trick the gauge... may have to look into that...
 
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ya my thoughts exactly... The original screen is 100% useless in a CJ. Would be nice to be able to retrofit our existing speedo with the new screen AND get the ability to calibrate the idiot light for the temp gauge.
 
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