Just checking things under the hood today I noticed that the fan clutch has a lateral wobble of about 3/16". That can't be good. There must be a bearing/sleeve going bad. It's a thermal/coil unit. What would be a functional replacement at GM, AC Delco, or NAPA? Not concerned about originality this close to winter storage.
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Re: 1967 Fan Clutch Wobble
Paul------
If you're talking about a "wobble" of 3/16" AS MEASURED AT THE END OF THE FAN BLADES, that may not be very much out of normal range. There is a slight amount of normal "play" when seen at the end of the blades.In Appreciation of John Hinckley -
Re: 1967 Fan Clutch Wobble
the fan clutch in the picture isn't an original 67 unit(note the step in the shaft). what you have is similar if not identical to the fan clutch assemblies one could get over the chevy counter in the 70's thru 90's. haven't tried to order one recently so don't know if they are still available from GM. anyway, if its originality your after, you'll need to find a clutch with a uniformly outside diameter'd shaft. good luck and get the worn out clutch outa there before it launches thru your radiator/fan shrouh/hood. mikeComment
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Re: 1967 Fan Clutch Wobble
Thanks Mike and Joe,
Yes, that play is at the shaft, not the fan blade end. I have noted a little motor vibration at idle. So there is a problem. Funny how you find these things by poking and prodding during routine maintenance! I had just come back from a very nice ride today (sunny, 65*F) and was getting things ready for winter storage in two weeks' time.
I am not concerned about originality at this point. Just wish to get the 1967 off to winter storage in fine condition. GM is probably hopelessly expensive. Tomorrow is Thanksgiving here in Canada so I will try AC Delco and NAPA on Tuesday. But if you have some numbers for me that would be appreciated!Comment
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Re: 1967 Fan Clutch Wobble
Paul-----
The GM part number for the clutch is GM #3916141. It's about $240 GM list. It's not available through Delco. This appears to be what's on your car now.
You can get much less expensive versions in the aftermarket. However, they won't look like the one you have and they won't work as well, either. If you do, make sure you get a THERMAL type, not the real "el cheapo" non-thermal type.In Appreciation of John HinckleyComment
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Re: 1967 Fan Clutch Wobble
Thanks Joe. The hunt is on locally for thermal. If need be I will go with the catalogue people in the USA. With the $CDN/$US at par that is not as painful as it used to be.Comment
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Two vendors!
"the fan clutch in the picture isn't an original 67 unit note the step in the shaft"
There were two suppliers of fan clutch assy's for MY cars: (1) Schwitzer (bar actuated) and (2) Eaton (coil actuated). The Schitzer clutch used a stepped shaft while the Eaton clutch used a constant diameter shaft. From the '67 JG book:
"Clutch Design
One design contains a flat, rectangualr bi-metallic thermostatic element. The face of the element reads 'THIS SIDE UP THIS SIDE UP' stamped in black ink. The shaft of this clutch design has a step roughly midway between the flange and the clutch body...
Alternate Design
The second design clutch has a coil type thermostatic element. The shaft on this clutch is the same diameter the entire length without any step..."
So, I wouldn't say the clutch is wrong/incorrect just because there's a step in the shaft.
On preceived wobble, it's not uncommon for a used original fan to have been 'wacked' at one point in its prior life causing the blades to be mis-aligned. That would make the fan 'appear' to wobble during rotation as one or more of the blades are no longer in alignment.
The center spider the blades are riveted to is a hearty critter, very hard to bend! It's ususally a matter of one or more of the soft blades being deformed from their factory original stamped contour.
To check, remove the fan and lay the front side against a flat planar surface. The leading edges of the blades ought to be uniformly flush to the plane. If not, it's time to 'true' the deformed blades by gently bending them to regain their factory original stamped contours...Comment
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Re: Two vendors!
The 3916141 clutch is available from GMPartsDirect.com for around $130, and Paragon, LICS, etc. also have it. Corvette Central probably has it too, which is more important to you as a Canadian customer.Comment
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Re: Two vendors!
Jack,
The wobble is via me working the clutch/fan unit by hand back-and-forth laterally (12 to 6 or 9 to 3) against its shaft. There is definitely play there. I am not perceptive enough to see fan wobble with engine on but it may be present as well. The former worries me and I will replace with a #3916141 equivalent.
It's Thanksgiving here and I am not inclined to wrench today but I did take a quick pic with a mirror. The unit is Eaton WITH stepped shaft AND thermal coil. So I have no idea what the application for this fan clutch is or was. So many things can get changed out over 40 years. It obviously is not 1967 327 Corvette according to the judging manual. Having said that, It has worked well and my 1967 is not prone to overheating: steady 180 on the freeway that might rise to 200 in downtown stop-and-go traffic.
John,
I will order from Corvette Central this evening. Their assumption of the brokerage role for orders destined to Canada has been a real blessing and saved me many dollars in brokerage fees.
I very much appreciate the kind replies to my question!
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Re: Two vendors!
OK, I ordered that fan clutch from Corvette Central. Do I have to re-calibrate it?
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Re: Two vendors!
Paul, your picture of the front side tells a LOT! Note the reservoir ring surrounding the center actuating coil has two 'bulges' spaced 180-degrees apart. Also, they're essentially trapezoidal in shape. That means what's on your car is a service replacement clutch from the 70's. The shape of the reservoir bulges were essentially square or rectangular on factory original Eaton fan clutches from the 60's....
Adding the clarification you did (fan 'wobble' is noted with the engine off and applying side loading by hand to the fan) says even more. It tells me you are correct to suspect it's time to replace your fan clutch and something BAD is just around the corner if you don't act quickly!
Bottom line, it's still not a bad idea to check your fan blade for proper alignment when you R&R the clutch and it's not worth trying to 'save' your existing clutch because it's a service replacement version to start with....Comment
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Re: Two vendors!
Thanks Jack,
As I noted above I have ordered the #3916141 replacement from Corvette Central. These little projects are strange. You never know what little blessings these old cars present you with. Since I bought the car in 2003 I noticed a buzz in the rear-view mirror. I hope that goes away.Comment
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Re: Two vendors!
Check your copy of the AIM (UPC 1, Sheet E5) where the mirror is being assembled. Note the assembly consists of the mirror (Item 9), the support (Item 10), the mounting screw (Item and a bearing (Item 11). The bearing is often left off on restored cars due to lack of knowledge by the owner/restorer.
Without it, the mirror will be too loose (sags/droops) or too tight (rear view image distorts due to vibration). With it installed (it just slips inside the mounting hole of the mirror), the correct mounting tension is achieved rather independent of mounting screw torque...Comment
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Re: Two vendors!
I'll be darned! My mirror does not have that bushing. First item on my winter shopping list.
BTW, CC gave me a shipping date of October 20 for the fan clutch. That's very close to the date when I say goodbye to the 1967 for the winter. Thought that would be a pretty standard stock item....Comment
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Re: Two vendors!
Paul -
Normally the #3916141 Eaton fan clutches are drop-shipped direct from the Eaton plant in Mississippi that makes them (they're brand-new, not old service parts that have been collecting dust somewhere), but in your case, it has to go to CC first since it's going to Canada.Comment
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