DIY Fan Clutch mod

[MRB 6.5TD]

Other than that precautionary note, it will work with any viscous clutch with external bimetal thermostat - I had one with a vernier-adjust setup on it, but gave up on the idea due to inertial mass imbalance

Great mod. Thanks JD. This will save alot of people money. May help 'freshen' up old clutches, and dial in kick on ealier will make most of us happier. Price is right too.

Saved me 250 bux I would have spent in the fall.

 

[JiFaire]

LOL... JD is full of all kinds of 6.5TD trivia. What we really need is to sit him down and interrogate him for about a week... between him, the Turbine Doc, and Bill Heath, we should probably get all the good poop on these engines down on paper...):h

Of course, they might not take kindly to being interrogated.

 

[MRB 6.5TD]

LOL... JD is full of all kinds of 6.5TD trivia. What we really need is to sit him down and interrogate him for about a week... between him, the Turbine Doc, and Bill Heath, we should probably get all the good poop on these engines down on paper...):h

Of course, they might not take kindly to being interrogated.

Especially if your goal is to get their poop on paper....:


:nono:

 

[JiFaire]

Hmmm... appears I mis-spoke...

 

[Brooklyn Tow]

Oooh, Louis, I'm not sure I'd be messing with a Kennedy clutch. If you screw up a worn-out GM clutch, you can always go tell yourself you needed a new one, anyway.

Once again Jim, the practical voice of reason......Gotta go find the clutch I took off, before I installed the "horse power bandit"

Other than that precautionary note, it will work with any viscous clutch with external bimetal thermostat - I had one with a vernier-adjust setup on it, but gave up on the idea due to inertial mass imbalance

I'll bite, what preytell is a "Vernier-adjustment"

So is that what would happen if you pulled on that coil (bimetal thermostat) to tighten it up and make the "bend" further back instead of foward......Seems it would be easier as you intended for earlier engagement

 

[gmctd]

Correct - to increase temp of engagement you would shorten the coil, lengthen the tab-strip, rotating the shaft in the opposite direction to open the gates

Had the adjustment by screw instead of the bend'n'reform method - had no reliable way to counter-balance the mechanism - can you say 'unidentified flying objects'?

 

[ghitch75]

Guys, I'm hearing too many talk about fan clutches to help the cooling at 60-75 mph. At freeway speeds your fan clutch shouldn't need to be doing squat. If you're having cooling problems at that speed you're not transfering heat well enough. Throw in some Red Line Water Wetter, bleed the air out of the top hose, clean the rats nest from between the rads, or something. My Kennedy clutch kicks in (KICKS in) when I'm going slow; that is with little or no air speed. Once I get some air speed I can feel and hear it unload. On the freeway it's freewheeling even with my trailer on and the ECT (scangauge) stays in the 190s. It was in the 90s here on Saturday and I never saw over 200* with the trailer on.

Mike

i guess i should have said in traffic or behind a rv or semi.....out of the draft it ran @ 190f but in the draft it would just be shy of 210f.....matter of fact i haven't ever heard my fan kick in....only when it's -10f out or colder till it gets warmed up....

 

[mfgguru]

Regardless of all the other comments about cooling, this mod. works. Just towed again this weekend, travel trailer, with a mild adjustment and it is about perfect. The fan cuts in now at about 95 deg C, right where I want it with not even a hint of overheating. I was convinced I needed a new clutch, but it looks like I am good for now. Thanks again GMCTD for the great idea.

KNOWLEDGE IS POWER!

 

[Diesel -T]

mfgguru
Could you give a precise measurement on amount of adjustment you ended up with ?
Thanks

 

[mfgguru]

That's a tough call because I did it in 2 stages. I would say I bent it about 1/8 longer than stock. It doesn't take much to change the engagement temp.

 

[Chevylover]

Still waiting for my 180°F thermostat from KennedyDiesel. Ordered on July, the 29th but till today, the friendly postman didn't show up with it. So I'm waiting........


Cu,
Sven

 

[Chevylover]

Got the thermostat yesterday. Today, I started to install the new 180°F from KennedyDiesel and WHAT I have see ??? The previous owner damaged one of the threads from the thermostat crossover housing ! Fu... Idiot ! ! !
This part isn't availbel in germany only via GM for 520 EURO and about 4 weeks delievery time ! WTF ??? So I tried to repair it with a special epoxygum called "Kaltmetall". After 30min it is hardened and you can drill etc. in it. First testdrive was good (hope it will last long enough). The overall temp on the highway with about 75mph, A/C full on was never above 185°F (compared to 210°F before). The fan clutch mod works also great. It engages much sooner than before.


Thanks for everyone's help and tips/hints.


Cu,
Sven

 

[625fireman]

Good to here you got her going... Gota love the suposed to be 5 min jobs, Always end up being an hour or so.

 

[Chevylover]

Good to here you got her going... Gota love the suposed to be 5 min jobs, Always end up being an hour or so.

An hour ? Took a half day !

Just came back from the second test drive. Towed my very little trailer (normally I tow it with my ATV) loadad with some things from my backyard and the truckbed load with the rests of a small tree.

Testdrive passed. A/C on, city driving with stop lights, etc. temp gauge never exceed 85°C ~ 185°F.


Cu,
Sven

 

[gmctd]

Get a thread-sert or heli-coil repair kit - you retap the stripped hole, insert the new steel threads to bring it back to original size, and yer good to go - at one time that was standard practice for aluminum blocks, heads, and associated equipment

 

[Chevylover]

Get a thread-sert or heli-coil repair kit - you retap the stripped hole, insert the new steel threads to bring it back to original size, and yer good to go - at one time that was standard practice for aluminum blocks, heads, and associated equipment

No possebility for helicoil, becauz a part of the crossover housing (passenger side screw) fell apart and you could see the complete thread of the screw from top to bottom. So there was only two possebilities : new crossover or repair with a special metal epoxy gum. Temp resistant till 260°C and resistant againt cooling water, oil and some other liquids.

I added some pics of the REPAIRED section. Hope these help a bit to understand why it wasn't possible to helicoil.


Cu,
Sven

 

[gmctd]

Understood - good pics and good job- if that decides to let loose, keep a long worm'n'gear-type hose clamp handy, long enuff to fit completely over'n'under the cover and manifold - that should hold it till you can get a replacement - see what they've got from military surplus, over there - Uncle Sam had plenty 6.5's over the years, maybe even moreso, now, from the Humvee's

 

[turbovanman]

Guys, I'm hearing too many talk about fan clutches to help the cooling at 60-75 mph. At freeway speeds your fan clutch shouldn't need to be doing squat. If you're having cooling problems at that speed you're not transfering heat well enough. Throw in some Red Line Water Wetter, bleed the air out of the top hose, clean the rats nest from between the rads, or something. My Kennedy clutch kicks in (KICKS in) when I'm going slow; that is with little or no air speed. Once I get some air speed I can feel and hear it unload. On the freeway it's freewheeling even with my trailer on and the ECT (scangauge) stays in the 190s. It was in the 90s here on Saturday and I never saw over 200* with the trailer on.

Mike

Yes and no, the issues is there isn't enough air movement, yes its true. I need to do this mod to my customers truck as it overheats going up hills and the fan kicks on too late,

 

[Chevylover]

Understood - good pics and good job- if that decides to let loose, keep a long worm'n'gear-type hose clamp handy, long enuff to fit completely over'n'under the cover and manifold - that should hold it till you can get a replacement - see what they've got from military surplus, over there - Uncle Sam had plenty 6.5's over the years, maybe even moreso, now, from the Humvee's

There is no change here to get parts or other things from or via the army since 9-11. There is only no change to buy cars/trucks from the army if they close a location. Everything that is good, will be send back in the US or to other bases. All bad things will be crushed. It is forbidden (in germany, don't know about the US, but I would think insied yes, but no exports of any "interesting" material like trucks, hummvee's, etc.) to sell trucks/cars, etc, (american equipment) to private persons after the 911.I'm located near Hannover, in Lower-Saxony in ther northern part of germany. Most bases from the Army and AirForce have been located in the middel and/or south of germany. A lot locations are closed and so there are only few that are still in use, like Rammstein Air Base.


Cu,
Sven

 

[625fireman]

There is no change here to get parts or other things from or via the army since 9-11. There is only no change to buy cars/trucks from the army if they close a location. Everything that is good, will be send back in the US or to other bases. All bad things will be crushed. It is forbidden (in germany, don't know about the US, but I would think insied yes, but no exports of any "interesting" material like trucks, hummvee's, etc.) to sell trucks/cars, etc, (american equipment) to private persons after the 911.I'm located near Hannover, in Lower-Saxony in ther northern part of germany. Most bases from the Army and AirForce have been located in the middel and/or south of germany. A lot locations are closed and so there are only few that are still in use, like Rammstein Air Base.


Cu,
Sven

I know you said the necks are unavailble "over there" but,Can't somebody "over here" send you one directly, or is that a no-no too? Not being a smarta$$ just curious.