ConcoursMustang Forums
1st Generation 1964 1/2 - 1973 - Questions & general discussions that apply to a specific year => 1967 Mustang => Topic started by: V8_bloke_28 on March 23, 2017, 08:15:48 AM
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Hi
I have a 67 390 fback with a/c and I just put on a new clutch on the 7blade fan to no avail.
Is the clutch supposed to lock up once the car is hot?
When I turn off the car, the fan keeps spinning at least 10+ revs.
I don't know if this is normal. I'm out of ideas.
Cheers
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Clutch should lock up when the "clutch" is hot, not necessarily when the "car" is hot, but there is often a relationship between the two. Heat is transferred to the clutch via conduction (through contact with the engine assembly through mating surfaces and bolts) and convection (from air flow or lack thereof through the radiator).
For example if the engine is warmed up, the clutch could lock up while sitting at a traffic light in hot conditions, then as you get air flow when driving it could cool the clutch enough to cause it to release. If there is enough air flow through the radiator do that, the fan is not necessary. A clutch release saves energy. The fan spinning a bit after the clutch releases or engine is turned off is normal, an indication that it is not seized in a locked up position.
I have not done it but would think that a bench test with a heat gun might be a decent test. Of course without specified temperature setpoints and measurement points that is still a subjective test. I think I'll do that soon, and I'll include thermography data as part of the test.
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I have not done it but would think that a bench test with a heat gun might be a decent test. Of course without specified temperature setpoints and measurement points that is still a subjective test. I think I'll do that soon, and I'll include thermography data as part of the test.
Gotta love those engineers! This Youtube video explains them well! https://www.youtube.com/watch?v=nVteLb2ZoWM
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OK now that is pretty good. But I was worried at first
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Would I be able to solid fix the 7 blade fan and get rid of the clutch?
I don't want to drive it when it gets over 210.
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I could see going with a solid spacer of appropriate length temporarily until you can source the correct clutch. There might be a rebuilding service available, but I have no references for that myself.
Is the Concours correct clutch you are looking for unobtanium?
John
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It is normal for the factory style clutch to free wheel some as it never really "locks". It is not a mechanical on off thing, but works with a viscous silicone fluid. When you shut the engine off it will keep spinning some, this is normal. If you bought a new clutch, it is probably good.
I would caution using a solid spacer with the 7 blade clutch fan, as it was not designed for this. Most solid spacer fans have less blade area and will move less air for a given RPM. The larger total blade area of the 7 blade fans moves a lot of air and not meant to be "locked"
to the water pump flange - if so a lot of stress will be put on the fan and water pump bearing. The clutch allows fan to reach a maximum RPM range, above which clutch action allows to slip.
Kurt.
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I could see going with a solid spacer of appropriate length temporarily until you can source the correct clutch. There might be a rebuilding service available, but I have no references for that myself.
Is the Concours correct clutch you are looking for unobtanium?
John
They can be rebuilt but at approximately 300.00 to rebuild and a extended wait time (even more if international) to have them rebuilt you have to decide if that makes sense over a lower priced alternative. Yes no solid spacer for that fan blade. You are asking for trouble because of all issues mentioned. Get a flex fan from Jegs or Summit if you are going the solid spacer route .
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Thank you Bob and Lance and others. Terrific help.
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I have a 68 Fastback with a 427 in it...I have the stock rad,shroud and fan...The car has never over heated.Generally lives around 190 deg.I noticed one year it was creaping to 200.Turns out the oil had leaked out of my oem clutch...I pinned it solid (many years ago) and noticed a HP drop.I have replaced the clutch since then...It is a good set up and works fine when everything is working as it should...Yes the fan will spin when you shut it off.......JMO
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Generic replacements are available. I replaced one on the 67 Tbird with a 390. I was having over heating issues and covered everything (recored radiator, fan clutch, water pump and thermostat). Still was getting warm at 70 mph but not at 50. Shifter was misaligned and never hit 3rd gear. Duh...