Fan clutch upgrade...

My concern is not so much cutting the fan down but the fact that by the time you take 2” off the blades, there’s not a lot of blade left. Look close at that picture of the two fans on top of each other. The hub center on the 6.4 fan is huge. The blades are only about 6.5” stock. Take 2” off, there’s not much blade left. I think balance wise, the fan being nylon and the hub being so large it will spin up to 4K rpm no sweat. I don’t know what the blade area is on the IDI. Maybe it’s comparable. I’d have to measure.

Now. Another concern is that the 6.4 fan clutch is designed for that plastic fan. I haven’t weighed them, but I suspect it’s much lighter than the idi. I can see two things with that. It may cause it to be slower to lock up because it takes more friction to accelerate the fan. It may over the long term cause premature wear of the clutch.

Please don’t take any of that as a criticism. I very well may go this route myself. Just wanted to share some of the things rattling around in my pea brain. Hell I caught myself looking at auxiliary radiators today. I’m so close. Just need to shed a little more heat somehow. Either more fan/air, or more surface area or better use of what I have. But I need a little more to be completely comfortable and fully use the truck to it’s potential.

this is a great idea, i know i am a little late on this but i wonder if we could look at it from another direction.

could the electric activation part off the 6.4 fan be put on the IDI fan? that way we could use a regular IDI fan and just add the electric controller on the front. even if we had to drill and tap some little holes that could be sealed.

subway said:

this is a great idea, i know i am a little late on this but i wonder if we could look at it from another direction.

could the electric activation part off the 6.4 fan be put on the IDI fan? that way we could use a regular IDI fan and just add the electric controller on the front. even if we had to drill and tap some little holes that could be sealed.

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Yep subway... you are late to the party.



That’s exactly what @ifrythings did. IDI fan will bolt. Just need a shoulder bolt or the like as the idi is 5/16 and the 6.4 is 6 mm. Or do what he did and drill and tap the 6mm to 5/16”.

laserjock said:

Yep subway... you are late to the party.



That’s exactly what @ifrythings did. IDI fan will bolt. Just need a shoulder bolt or the like as the idi is 5/16 and the 6.4 is 6 mm. Or do what he did and drill and tap the 6mm to 5/16”.

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i got that part, i was thinking just the small center cap area in the middle of the fan. if all we have to do is turn the small center shaft to activate the fan. could we adapt the 6.4 fan actuator to do that?

that way we would be keeping the whole IDI viscous clutch fan itself.

sorry double post

Ah! I don’t think that will work, but I’m not sacrificing my 6.4 clutch to find out. Got a price on a bushing today and about had kittens. I will be looking further.

@laserjock I thought you already had a means to make a bushing?

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I did. Made one. Came out crooked. I couldn’t get the die started on it in the little lathe I had access to so ended up threading it by hand. It’s off just enough I wouldn’t trust it to run it. It wobbles. Now I don’t have access to a lathe anymore. I keep looking though.

I’ve said it before, and I’ll say it again. I’m not a machinist.

Interesting read. What kind of price on the bushing did you get?

~$500 for 2. Price per came down in quantity but I didn’t inquire too deep. I think I can do better. It was a crime of opportunity. My buddy drew it up and he happened to be stopping by a shop for something else so he asked for me.

Yeah, that's a bit much for sure. What are the dimensions and thread sizes again? My boss's neighbor is a retired machinist who still tinkers a little.

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They are on here. When I get the drawings, remind me and I’ll send you a copy if you want.

laserjock said:

Ah! I don’t think that will work, but I’m not sacrificing my 6.4 clutch to find out. Got a price on a bushing today and about had kittens. I will be looking further.

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ok, without having the parts in hand and possibly destroying one in the name of learning to find out, i though it "could" be a different solution. good luck, i dont have an IDI in my truck but i like the idea of this set up!

ifrythings said:

6.4 fan in an idi, it would self clearness eventually lol

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Shroud would push that hose up out da way.

subway said:

ok, without having the parts in hand and possibly destroying one in the name of learning to find out, i though it "could" be a different solution. good luck, i dont have an IDI in my truck but i like the idea of this set up!

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Well @subway, I must apologize. I may have been a little quick on the judgement for this idea.

Most of the things I had read showed the electroviscous clutches as been a linear actuation. That would not work. However, if you look near the bottom of this page, you'll notice that they have rotary too and that's the type the 6.4 looks like.

https://www.haydenauto.com/media/5478/hayden-evc_8pgs.pdf

I have a 6.0 that is also electroviscous. Wonder if it's worth the experiment to see how it is attached to the clutch body? @ifrythings don't you have a defunct 6.4 clutch that was bad when you started? Just curious.