fan clutch (last time ,I promise)

[Dennis D.]

Last week I posted about a clutch for my 70 L-46. Today I recieved a fan, (3955182), in great shape. How a couple of questions. There's another number,914166 B75. Old part number? Also it appears the blade was dipped in black paint. Is this how they were painted?

The fan clutch is a large diameter, just over 7". Dated 9 18 69. Figure this to be original to the blade. Can't find a part number. Am I not looking in the right location? The other one I bought for the fix is only 6". It's an older eston. Is this a 3916139? And the larger 69 piece 3937771? Both fit the 5/8 center with the smaller bolt pattern.

Thinking of using the larger one. (bigger is better mentallity) Last issue to button up the engine rebuild/ problem corrections, and I'm ready to fire it up.

[Jack H.]

Re: fan clutch (last time ,I promise)

The 7-inch clutch, 3937771 was used on BB engines in that era then existing stock was used up on '71 SB cars with A/C. Check your copy of the AIM for fan PN's, my recollection is only 7-blade A/C fans had PN (and date) embossed... Yes, fans were painted black and it wouldn't surprise me if the original process was an enamel dip vs. spray!

[Dennis D.]

Re: fan clutch (last time ,I promise)

Jack

The fan clutch I just received fits the smaller bolt diameter and 5/8 wp, 70 and earlier style. The 71 piece I replaced looks identical except for the larger wp application. In fact, I can't see any difference in the 69 dated piece compared to the 71 dated piece, forward of the hub .

I'm thinking my 70 L-46 could have had the 3955182 -7 blade fan, and the larger 7" clutch, if I had air. If not, I suppose the 5 blade 3888366 fan,( don't have), and the 3916139 -6" clutch, (have that one), would be correct.

Since I had all those 71 pieces, (WP,WP pulley, crank pulley,fan, clutch), and ran perfectly, a 70 version of the same fan/ clutch setup should give me similar results.(I hope)

Even though its not exactly right, I can live with it, and I've had about enough searching and need to do more driving. Thanks Dennis

[Terry M.]

Re: fan clutch (last time ,I promise)

Dennis,
I believe the #914166 is the part number (used internally) for the single blade. B75 indicates February 1975.

[Peter L.]

Re: fan clutch (last time ,I promise)

Dennis - Mid '60 ('66 thru '68 production for sure) air conditioning optional fan blade assemblies had a sequence of alphanumerics stamped on each fan blade. Basic order was a manufacturing date code (typically in the format month (A thru M) and single digit representing the year (the last digit of the year, so 5, 6, 7, or ; below that was stamped what is assumed to be the part number of the blade, typically a 6 digit number; and below that SC which is thought to be the manufactures designation. Pete

[Dennis D.]

Re: fan clutch (last time ,I promise)

Terry

The single fan blade number makes sense.In fact after reading your post I checked the 3991427- 7 blade, 1971 fan I took off to replace. It's been on the car since 1972 when I got it, and has a date of L70 with a blade number 914685.

As far as the 75 date, I guess the 3955182 fan was still produced in 1975, hence the B 75 date. Thanks dennis

[Dennis D.]

Re: fan clutch (last time ,I promise)

Pete

The fan has the number on just one blade.

It's funny you mention the "SC". That doesn't appear on the fan, but it does appear on both the 69 and the 71 fan clutch.

[Terry M.]

Re: fan clutch (last time ,I promise)

SC = the clutch manufacturer. I can't think of the name at the moment, and don't have my reference material with me. Sxxxx Clutch

Some fan clutches have the SC followed by a date (no code, straight up 12 25 69 for example) on the outer edge of the flange that mounts to the WP hub. I have also seen a few with the date on the face that contacts the pulley, strange as that seems. One wouldn't think they would stamp that surface out of concern for creating an uneven mounting condition. I have also seen some with ink stamped broadcast code on the front (as installed on the car) face.

[Dennis D.]

Re: fan clutch (last time ,I promise)

Yup

Both clutches have a date preceding the SC. 9 18 69, and 2 2 71.(both on the flange edge). No part numbers as far as I can find. There is a plate on the front with printing, "this side up".Thought I read these are Switzer? brand. Could the "S" in "SC" be Switzer?

[Terry M.]

Yep, that sounds good, allowing for spelling *NM*

[Joe L.]

Re: fan clutch (last time ,I promise)

Dennis-----

All fan clutches with the "rectangular bi-metallic plate" thermostat are Sweitzer Clutch-manufactured units. Fan blades with "SC" stamped upon them were manufactured by Sweitzer, too. All fan clutches with the "coil spring" type thermostat are Eaton or Delco manufactured units. As far as Corvettes go, virtually all were Eaton.

All Corvette 1970 and earlier fan clutches have a 1-3/4" fan clutch hub bolt circle AND a 3" fan-to-clutch bolt circle pattern. All 1971 and later have a 2-1/8" fan clutch hub bolt circle and a 3-1/4" fan-to-clutch bolt circle.