Fan blade trimming

[Lenny33]

For the people out there that trimmed down the diameter of their fans, how much did you worry about it balancing and did you have any issues with fan blade balance after the fact?
My mind tells me to be super concerned with balance, but wondered if there was any feedback from guys that have done it?

 

[OGBeno]

For the people out there that trimmed down the diameter of their fans, how much did you worry about it balancing and did you have any issues with fan blade balance after the fact?
My mind tells me to be super concerned with balance, but wondered if there was any feedback from guys that have done it?

Trimming the fan is not an exact science.

When I utilized the 1HZ fan and fan clutch, I trimmed with a knife/cutter first, then “formed” the fan blades via a bench grinder.

You are trying to do the best you can to make it look like the fan blade previous to you cutting it.

I basically took the fan shroud, put it on the ground, and then trimmed/formed the blade to give me 1.5” all the way around to compensate for engine movement on WOT.

 

[saltycoconuts]

Trimming the fan is not an exact science.

When I utilized the 1HZ fan and fan clutch, I trimmed with a knife/cutter first, then “formed” the fan blades via a bench grinder.

You are trying to do the best you can to make it look like the fan blade previous to you cutting it.

I basically took the fan shroud, put it on the ground, and then trimmed/formed the blade to give me 1.5” all the way around to compensate for engine movement on WOT.

How has the 1hz fan been going for you compared to the 3b fan? Any notable differences or improvements?

 

[OGBeno]

How has the 1hz fan been going for you compared to the 3b fan? Any notable differences or improvements?

Well, yes. Both the fan clutch and fan are larger by a significant amount.

Search for my thread in this section where I delineate the methods and show the sizing differences.

The FC for a 1HZ engages much more often and pushes significantly more air. But I also have other mods I’ve made to cool the turbo and engine. The FC and fan are only one piece of the puzzle for cooling these engines for use in the US.

 

[OGBeno]

Here is the thread for the search amateurs..

3B/13B-T Fan Clutch and Fan Upgrade

I have been quite unhappy with the cooling performance of the tiny 3B/13B-T fan clutch and fan for quite some time. As such, I did some research. I picked up a 1HZ/1HD-T fan clutch as well as the appropriate fan assembly. This fan clutch is the black-base FC. As you can see, it...

forum.ih8mud.com

 

[saltycoconuts]

Well, yes. Both the fan clutch and fan are larger by a significant amount.

Search for my thread in this section where I delineate the methods and show the sizing differences.

The FC for a 1HZ engages much more often and pushes significantly more air. But I also have other mods I’ve made to cool the turbo and engine. The FC and fan are only one piece of the puzzle for cooling these engines for use in the US.

I followed your thread when you started it I was just curious if you any before and after numbers. I guess I’ll just have to take a swing at this and see for myself

 

[Lenny33]

Trimming the fan is not an exact science.

When I utilized the 1HZ fan and fan clutch, I trimmed with a knife/cutter first, then “formed” the fan blades via a bench grinder.

You are trying to do the best you can to make it look like the fan blade previous to you cutting it.

I basically took the fan shroud, put it on the ground, and then trimmed/formed the blade to give me 1.5” all the way around to compensate for engine movement on WOT.

And were you incredibly precise with your trimming or did small imperfections just not make a difference?

 

[OGBeno]

And were you incredibly precise with your trimming or did small imperfections just not make a difference?

I was precise to my eye. So, no I wasn’t precise.

These are tractor motors. Close enough is good enough for an application of this nature.

 

[OGBeno]

I followed your thread when you started it I was just curious if you any before and after numbers. I guess I’ll just have to take a swing at this and see for myself

Numbers?

These aren’t racing engines.

If I can keep things lower than 220F degrees on US highways in hot weather and at altitude, I’m stoked.

 

[saltycoconuts]

Numbers?

These aren’t racing engines.

If I can keep things lower than 220F degrees on US highways in hot weather and at altitude, I’m stoked.

These aren’t? Thought I had a high performance race truck all this time..

 

[Lenny33]

Understood - proceeding. Thanks

 

[c2dfj45]

When we cut down fans for clearance, we make a little template for the end of the blade out of cardboard for how much we want to remove. Mark all the blades off that template and then use a belt sander to get them cut down....maybe a little hand finishing. I guess if you're cutting a bunch, probably use an air saw to zip them off...then finish. Haven't had any issues.

 

[SNLC]

Most people probably are not into it but 90% of all tropical spec 70’s I have seen have no fan clutch. They run a direct drive fan. Everyone I have seen also runs very cool 24/7.

You can still get the fan hub without a clutch.

Cheers

 

[GTSSportCoupe]

I measured, drew lines, and cut with a hack saw on an Isuzu fan I first adapted to the Prado. Then I found an early 1HD-T one that fit perfectly with no modifications. Sadly the updated part number is larger and doesn't fit so easy. I think the 12HT/2H ones fit direct without mods though. Assuming you're talking 1KZTE KZJ78 here.

 

[Lenny33]

So this is what my thermostat looked like when I pulled it.

 

[GTSSportCoupe]

View attachment 2035591

So this is what my thermostat looked like when I pulled it. View attachment 2035591

Weird! Hopefully there is not more of that stuck elsewhere in your cooling system. Could wreak havoc on a radiator....

 

[Lenny33]

My optimistic theory is that piece of plastic is from the top of a jug of radiator fluid and that it made it all the way through the radiator to get stuck at the t-stat AND that that is the only piece. Fingers crossed!

 

[Hulsty]

Good find, as per others, I fitted a FTE fan and clutch to my 13BT, I simply marked them with a template and trimmed down with a linisher

 

[JuanJ]

Hello,

Measuring and cutting to millimiter/mils accuracy should be enough.

Perhaps I am stating the obvious here, but if all blades have the same length within 1 mm/40 mils range, then balance is good and so should be rotation.

Regarding tropical specification engines, I agree with Ian / @SNLC . They are designed to run cool at high ambient temperatures, so operation in colder environments is not a concern.






Juan

 

[Lenny33]

I ended up making a cardboard template and cutting with a jigsaw, then smoothed with sandpaper - looked pretty good - I’m sure it will be close enough.
Just at an idle, I can tell that it moves more air. I will take it for a drive tomorrow to see how it performs.