NEED HELP!! FAN CLUTCH

Joined
May 27, 2021
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22
Location
Solomon Islands
I own a 1993 FZJ80 with a 1FZFE engine. Few weeks ago my fan clutch stop working, it just free spin which cracked my radiator. Theres no parts for FZJ80 here only 1HZ. I have to order online which might take 2-3 months due to boarder retriction and covid.

I managed to find a 1HZ fan clutch which is the same as the 1FZFE. But the only problem is the 1HZ pilot hole is smaller than the 1FZFE. (see attached image)

So my Question. is it okay drill the 1HZ pilot hole as the 1FZFE and use it.

PicsArt_10-11-11.17.12.jpg
 
Joined
Sep 15, 2016
Messages
830
Location
Chattanooga, TN
What's wrong with the old clutch? There's not too much too them to break so it's possible that you can drain it, refill it with the correct weight oil and adjust the timing (temperature at which the ports start to open) and do well with it.

Beyond the pilot hole it looks like the shaft length is also different on the two clutches above. What would your fan clearance from your rad be with the new fan clutch? If it's closer to the rad than it was from stock then you may not have enough from for blade flex/etc. and that may be your bigger issue, not the pilot hole.
 
Joined
May 27, 2021
Messages
22
Location
Solomon Islands
I don't know what happen with the fan clutch but it just free spin and i can't find the silicon oil here. I have order and wait for few months. As for the blade clearance, it's not close to rad
 
Joined
Sep 15, 2016
Messages
830
Location
Chattanooga, TN
It's possible that your fan clutch seal failed and leaked all of the silicone oil out, at least that would cause it to spin free. The thermostat spring could have also failed and may be keeping the oil from circulating but most of these will at least be stiff after sitting as they don't seal the fluid in fully when closed up I don't think. The shaft that the spring turns could be seized, etc.

I'd look inside your old clutch to see what's going on with it even though I wouldn't make any decisions on fixing it until I knew what the problem is. Clean it first then take it apart carefully just to try to assess what's up. It's easy to disassemble you just dont want to damage the seal, spill the fluid or break the fins/housing. You can possibly get an idea of the fluid condition and also test the thermostat to see if/when the ports open up on the clutch. Depending on what you find you may have options or even may be able to scavenge parts from the incorrect fan that you have on hand. The new clutch you have is full of oil at least and the seal may even be compatible. That may end up being a better solution than modding the shaft of a fan clutch that possibly isn't the right height anyway, but only if you know for sure that you can get the old clutch working.

Other's may have better ideas or know if you can run that new fan clutch and I'm skipping details here in an effort to quickly open up more opportunities for you to get your 80 rolling again. In the long run you can get the proper clutch, etc. so part of this is just to buy you time. FYI, I have personally installed a new Aisin fan clutch that didn't cool sufficiently out of the box and would allow my 1FZ to go over 220 degrees F. Learning how these clutches work and confirming that they are setup properly is very important in my opinion/experience regardless of using an old or new clutch and I encourage you to set yourself up to have a fully functional fan clutch when you are running again, be it new or old. In my opinion many of the 1FZ head gasket issues are likely the result of weak fan clutches, among the other causes of overheating that are out there.

Read up/search on mud for all you could ever hope to learn about fan clutch tuning. Drop this into Google to get started:

1fzfe fan clutch tuning site:forum.ih8mud.com​
 
Joined
Sep 15, 2016
Messages
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Location
Chattanooga, TN
To be clear, I would not order anything as a next step. See if you can figure out what's wrong with your current clutch as a next step. With a little reading and a < 30 minute inspection you may know what you are dealing with. Sharing photos of what you find in the clutch here will help if you are unsure. Based on what your current/old clutch looks like you will then know if you have the option of repairing it. A hair dryer or careful/partial submersion in hot water should tell you if the thermostat works. Draining what's in the clutch into a clean/clear container for measuring may also be pretty informative.

I would plan to change the fluid out in a new or old clutch before I drove it hard as a rule though so simply ordering fluid for whatever you run (new or old) is a good idea from that standpoint. I'm running 15,000 cst in my current aisin blue hub with a bit of timing adjustment and it works well.

Also, pictured in your first post is what looks like the Aisin black hub which has a great reputation and may be the best fan clutch available if it's servicable. To avoid downtime I would definitely consider draining oil from your 1HZ for the black hub, etc. but I'm getting ahead of things there. Evaluate the old clutch first then proceed.

Good luck,
 

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