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tashakes

Electric Fan Recommendation For M42 Swap

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Could not find a definite answer to this. Still waiting for my mounts to be delivered, got most of what I need. But not sure what folks have done for the fan. Is the mechanical fan too far out of the engine to fit once installed on the 02? If so then an electric fan is in. What size? CFM? Thermo switch temp for turn on? Where is the thermo switch mounted to? Or is there a connection for temp (other than the gauge) on the E30 harness that will trigger the fan? Any info appreciated.

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(edited)

Could not find a definite answer to this. Still waiting for my mounts to be delivered, got most of what I need. But not sure what folks have done for the fan. Is the mechanical fan too far out of the engine to fit once installed on the 02? If so then an electric fan is in. What size? CFM? Thermo switch temp for turn on? Where is the thermo switch mounted to? Or is there a connection for temp (other than the gauge) on the E30 harness that will trigger the fan? Any info appreciated.

 

I run a 16" pusher fan. I'm not sure of the CFMs, but it's almost definitely overkill. My first M42 swap turned out to have a head gasket that was on the way out, so I'm a little paranoid of overheating now

 

1600Running023_zpsdf534230.jpg

 

I'm sure that a 14" fan would do fine. The ultimate setup would be to have an adjustable, variable speed fan relay, but that might be a bit expensive.

 

You are correct: the mechanical fan does not fit.

 

The E30 radiator has a port for a thermo-switch, but I just bought an adjustable fan relay from the local parts store for around $30. Wire it to your fan relay and you can adjust it to suit your setup. It has a probe that you stick between the fins in your radiator.

 

DSC01013_zps8f20c89b.jpg

Edited by ClayW

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just use a stock e30 fan switch screwed into the stock switch port.  simple.

 

"stock switch port"?  The one on the radiator? Not the one on the block.  Right?

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radiator, as clay mentioned. this is assuming you are using an e30 radiator.

That's how my Spal pusher fan's relay is triggered and it works great.

I found that the radiator sender is for the a/c. I left the a/c pump on the M42 because at some point I am going to attempt to complete the Clardy system I have with it.

My plan is to run both the a/c and the fan off the same sender using a diode on each circuit so that they do not cross over.

Thoughts?

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I like the adjustable nature of my setup. The thermo-switch will look cleaner and nicer, but I like being able to adjust the ON setting for my fan. Also, If I ever get a smaller fan or change something, I can adjust for it.

 

If I ever get around to adding A/C, it will be wired to trigger the fan relay, too.

 

Just a thought.

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If I ever get around to adding A/C, it will be wired to trigger the fan relay, too.

Ahhhhhh. I see now. The switch on the radiator is to trigger the A/C fan..... Now I get it. I could not figure out the reasoning behind it. As I understood it, the inside temp setting switch for the a/c is what triggered the pump, so I had no clue what the switch on the radiator was for. Thanks for enlightening me Clay. I will use the one on the radiator for now till I finish the swap and get it all running, I may toy around with an adjustable switch.

Edward

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OK, OK, one more question....   The thermo switch on the radiator is a (-) connection right?  So it closes a ground loop not a power loop?  I ask because the way I think that the relay has to be wired for the A/C fan is that the thermo-switch triggers the (-) loop while the A/C fan switch inside the car triggers the (+) loop, right?  That way the A/C fan will only be triggered by the thermo-switch when the A/C is working.

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single 12in will cool an m42. i have a single 16in cooling the heavily modified 359cid cummins in daily driver/tow rig.

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