1980 Fan Clutch Rehab or ???
01-11-20, 05:51 PM
#1
1980 Fan Clutch Rehab or ???
Hi All,
I think my 1980 fan clutch is constantly engaged (sounds like a jet taking off at all speeds).
I don't think this part is available anywhere.
Has anyone found an aftermarket clutch (Delco etc) that lines up with everything on an 80 SA? I've read some of the threads about opening up the clutch and trying to replace the oil.
Thanks,
Dave
I think my 1980 fan clutch is constantly engaged (sounds like a jet taking off at all speeds).
I don't think this part is available anywhere.
Has anyone found an aftermarket clutch (Delco etc) that lines up with everything on an 80 SA? I've read some of the threads about opening up the clutch and trying to replace the oil.
Thanks,
Dave
01-13-20, 04:33 AM
#6
When you start it cold the fan should engage and it will sound like a jet turbine. Then after a minute or so it should disengage, this should be obvious from the change in pitch and big drop in air flow into the engine bay. Then it should only reengage when the engine is really hot, like sitting in traffic. In my experience a 1st gen idling in the driveway will never get hot enough to engage the clutch fan.
I'm not sure the strobe will tell you much, the fan spins at a pretty good clip even when disengaged. But a simple test is to use a broom to stop the blade while it's turning. If the fan is disengaged you should be able to stop it with the broom bristles. Obviously do this carefully, don't get the broom caught up in the fan.
I'm not sure the strobe will tell you much, the fan spins at a pretty good clip even when disengaged. But a simple test is to use a broom to stop the blade while it's turning. If the fan is disengaged you should be able to stop it with the broom bristles. Obviously do this carefully, don't get the broom caught up in the fan.
01-13-20, 06:06 AM
#7
When you start it cold the fan should engage and it will sound like a jet turbine. Then after a minute or so it should disengage, this should be obvious from the change in pitch and big drop in air flow into the engine bay. Then it should only reengage when the engine is really hot, like sitting in traffic. In my experience a 1st gen idling in the driveway will never get hot enough to engage the clutch fan.
I'm not sure the strobe will tell you much, the fan spins at a pretty good clip even when disengaged. But a simple test is to use a broom to stop the blade while it's turning. If the fan is disengaged you should be able to stop it with the broom bristles. Obviously do this carefully, don't get the broom caught up in the fan.
I'm not sure the strobe will tell you much, the fan spins at a pretty good clip even when disengaged. But a simple test is to use a broom to stop the blade while it's turning. If the fan is disengaged you should be able to stop it with the broom bristles. Obviously do this carefully, don't get the broom caught up in the fan.
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01-13-20, 09:48 AM
#10
3D Printed
Hey Coochas, I was looking in the classifieds for your wtb but didn't find it - perhaps you haven't posted it yet. Anyway, I've got a good number of fan assemblies and I'd be glad to sell you one for cheap. Let me know if you're still looking.
And I'm sure there's others here that have some lying around as well, maybe even someone local to you.
And I'm sure there's others here that have some lying around as well, maybe even someone local to you.
01-13-20, 09:52 AM
#11
Hey Coochas, I was looking in the classifieds for your wtb but didn't find it - perhaps you haven't posted it yet. Anyway, I've got a good number of fan assemblies and I'd be glad to sell you one for cheap. Let me know if you're still looking.
And I'm sure there's others here that have some lying around as well, maybe even someone local to you.
And I'm sure there's others here that have some lying around as well, maybe even someone local to you.
I think I put the post in the right place but who knows! https://www.rx7club.com/1st-generati...lutch-1141275/
If you've got a 1980 fan clutch that is working I'm interested!
01-13-20, 07:49 PM
#14
This ^^^^^^ , the fan should spin feely by hand when cold. It won't free wheel, there will be a slight resistance but will easily turn by hand. If the round, finned outside drum does not turn freely from the inner shaft / mounting face, it could make that "jet sound" you describe at all speeds. Is your idle speed after its warmed up or at a higher RPM due to the choke still being engaged?
The fan clutch uses a silicon fluid contained in two internal chambers. As the operating temp rises, the Bi-metal strip on the front of the drum bends outward and opens a valve between the reservoir chamber and the clutch side. Centripetal force provides the pumping action to move the fluid. This causes the clutch to bite harder, increase its lockup and spin faster to provide more fan cooling. When cool, the valve is open for the fluid to be pushed back the other way. At start up, it will be pumped back to allow more slippage until the Bi-metal strip reaches temperature once again, reversing the valve and internal flow path.
If a clutch fan loses its ability to lock up, it can lead to engine overheating which is kind of critical for our rotaries. If it loses its ability to unlock (what you are suspecting) it can put additional stress on the clutch fan assembly if you rev the engine too high for a prolonged time. The clutch fan itself, isn't designed to turn 1:1 at 6-7 thousand revs. I've read that its designed to rev to a max around 5 thousand and will slip above that. Could be bad for your under hood detail job if the plastic fan blade assembly came apart at high RPM.
The fan clutch uses a silicon fluid contained in two internal chambers. As the operating temp rises, the Bi-metal strip on the front of the drum bends outward and opens a valve between the reservoir chamber and the clutch side. Centripetal force provides the pumping action to move the fluid. This causes the clutch to bite harder, increase its lockup and spin faster to provide more fan cooling. When cool, the valve is open for the fluid to be pushed back the other way. At start up, it will be pumped back to allow more slippage until the Bi-metal strip reaches temperature once again, reversing the valve and internal flow path.
If a clutch fan loses its ability to lock up, it can lead to engine overheating which is kind of critical for our rotaries. If it loses its ability to unlock (what you are suspecting) it can put additional stress on the clutch fan assembly if you rev the engine too high for a prolonged time. The clutch fan itself, isn't designed to turn 1:1 at 6-7 thousand revs. I've read that its designed to rev to a max around 5 thousand and will slip above that. Could be bad for your under hood detail job if the plastic fan blade assembly came apart at high RPM.
Last edited by Banzai; 01-13-20 at 07:53 PM.
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Maxwedge (01-14-20)
01-13-20, 07:55 PM
#15
This ^^^^^^ , the fan should spin feely by hand when cold. It won't free wheel, there will be a slight resistance but will easily turn by hand. If the round, finned outside drum does not turn freely from the inner shaft / mounting face, it could make that "jet sound" you describe at all speeds. Is your idle speed after its warmed up or at a higher RPM due to the choke still being engaged?
The fan clutch uses a silicon fluid contained in two internal chambers. As the operating temp rises, the Bi-metal strip on the front of the drum bends outward and opens a valve between the reservoir chamber and the clutch side. Centripetal force provides the pumping action to move the fluid. This causes the clutch to bite harder, increase its lockup and spin faster to provide more fan cooling. When cool, the valve is open for the fluid to be pushed back the other way. At start up, it will be pumped back to allow more slippage until the Bi-metal strip reaches temperature once again, reversing the valve and internal flow path.
If a clutch fan loses its ability to lock up, it can lead to engine overheating which is kind of critical for our rotaries. If it loses its ability to unlock (what you are suspecting) it can put additional stress on the clutch fan assembly if you rev the engine too high for a prolonged time. The clutch fan itself, isn't designed to turn 1:1 at 6-7 thousand revs. Could be bad for your under hood detail job if the plastic fan blade assembly came apart at high RPM.
The fan clutch uses a silicon fluid contained in two internal chambers. As the operating temp rises, the Bi-metal strip on the front of the drum bends outward and opens a valve between the reservoir chamber and the clutch side. Centripetal force provides the pumping action to move the fluid. This causes the clutch to bite harder, increase its lockup and spin faster to provide more fan cooling. When cool, the valve is open for the fluid to be pushed back the other way. At start up, it will be pumped back to allow more slippage until the Bi-metal strip reaches temperature once again, reversing the valve and internal flow path.
If a clutch fan loses its ability to lock up, it can lead to engine overheating which is kind of critical for our rotaries. If it loses its ability to unlock (what you are suspecting) it can put additional stress on the clutch fan assembly if you rev the engine too high for a prolonged time. The clutch fan itself, isn't designed to turn 1:1 at 6-7 thousand revs. Could be bad for your under hood detail job if the plastic fan blade assembly came apart at high RPM.
I've got posts on the forum looking for a good 79-80 fan clutch to replace my bad one.
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