Is this a 1962 or 1972 fan clutch?

[Charlie P.]

This post springs from a recent thread on '62 fan clutches, which seems to indicate the clutch pictured here may not be a '62. The date code is A 19 C, and it matches the description of the late '62 A19C fan clutch-2.jpgface in the JM, but the JM might be in error.

Apparently the "C" could signify 1962 or 1972, so my question is: does the fan clutch for a '72 look like this?

[Ronald L.]

Re: Is this a 1962 or 1972 fan clutch?

62, if you look further in the archives, there should be pictures that show along about 68 the face changed.

[David L.]

Re: Is this a 1962 or 1972 fan clutch?

Charlie,

I would say it is 1962 vintage.

The photo below shows two fan clutches.

The used one on the left is ink stamped "CJ" and "L27G" (November 27, 1966) and was attached to a 5-blade fan stamped "L6" (Nov. 1966), "912239", and "SC" (Schwitzer, the manufacturer) factory installed on 1967 Chevrolet models w/AC.

The NOS fan clutch on the right is ink stamped "FC-16" and "H 28 J" (Aug. 28, 1968 or 1969). I am not sure if the letter "I" was used on the ink stamped date codes.

Dave

[David L.]

Re: Is this a 1962 or 1972 fan clutch?

The fan clutch below is from a 1970 Chevrolet with A.C.
It is stamped "EATON" and "D20A" (April 20, 1970).
Dave

[Terry M.]

Re: Is this a 1962 or 1972 fan clutch?

The bolt hole circle for the fan clutch mounting bolts changed from 1970 to 1971. The 1971 and later bolt hole circle is larger to accommodate the increase in size of the water pump shaft and bearing. Regardless the front face, a comparison of the bolt hole circle ought to give an indication of the decade of the fan clutch.

[Charlie P.]

Re: Is this a 1962 or 1972 fan clutch?

Guys, I would like to find out precisely what a 1972 fan clutch face looked like. The previous thread I alluded to indicates that a clutch with a face like the one I posted wasn't used in '62; that probably only a flat-faced unit was used. The JM says this "lumpy" face came in late '62. I want to find out if a clutch with the lumpy face like the one I posted (date code A19C) was used in 1972. If a '72 did in fact look like this, then I probably have the wrong clutch.

I will check the mounting pattern to see if this clutch fits my car- if that is a fool-proof way to check, that should answer the question.

[David L.]

Re: Is this a 1962 or 1972 fan clutch?

Guys, I would like to find out precisely what a 1972 fan clutch face looked like. The previous thread I alluded to indicates that a clutch with a face like the one I posted wasn't used in '62; that probably only a flat-faced unit was used. The JM says this "lumpy" face came in late '62. I want to find out if a clutch with the lumpy face like the one I posted (date code A19C) was used in 1972. If a '72 did in fact look like this, then I probably have the wrong clutch.

I will check the mounting pattern to see if this clutch fits my car- if that is a fool-proof way to check, that should answer the question.

I do understand the term "lumpy" face.

A 1962 fan clutch would have a 1 5/8" bolt circle to for mounting on the water pump hub. A 1972 fan clutch would have a 2 1/8" bolt circle.

Dave

[Joe L.]

Re: Is this a 1962 or 1972 fan clutch?

I do understand the term "lumpy" face.

A 1962 fan clutch would have a 1 5/8" bolt circle to for mounting on the water pump hub. A 1972 fan clutch would have a 2 1/8" bolt circle.

Dave

Dave------


The fan clutch could, theoretically, be a fan clutch manufactured in 1972 for an earlier application. However, that's not the case here. The face configuration of this clutch indicates it was manufactured prior to 1970.

As far as the bolt circle goes, for Corvettes 1955-70 used the 1-5/8" bolt circle while 1971 and later used the 2-1/8". However, there may have been other Chevrolet models or, even, other GM car lines that used the 2-1/8" bolt circle prior to 1970.

[Charlie P.]

Re: Is this a 1962 or 1972 fan clutch?

The clutch pictured in my starting post here has the 1 5/8" bolt hole pattern, so with the A19C date, that says it is for a '62. The JG describes the face like this for non-early '62s. However, posts by very knowledgable '62 guys in a separate thread say that this face did not show up on '62s. So I have not quite figured this out yet.

The incorrect one that I am taking off my '62 has the same appearance as the D20A dated unit in Dave's post, except it is stamped DELCO. It has open slots instead of holes, so it could fit various bolt hole patterns.

[Joe C.]

Re: Is this a 1962 or 1972 fan clutch?

This post springs from a recent thread on '62 fan clutches, which seems to indicate the clutch pictured here may not be a '62. The date code is A 19 C, and it matches the description of the late '62 [ATTACH=CONFIG]47165[/ATTACH]face in the JM, but the JM might be in error.

Apparently the "C" could signify 1962 or 1972, so my question is: does the fan clutch for a '72 look like this?

Charlie,

The reservoir covers are identical to those of the earlier Eaton fan clutches. As you might have noticed, the finned aluminum housing is not typical of production for the same early Eaton clutches. Specifically, noting David's original and NOS pictured, you will see only 2 areas on the outer circumference where three fins have been combined to form two "blocks" 180 degrees apart. Those "blocks" are solid, unlike yours which has 4 "blocks" separated by 90 degrees each, with holes in them. I have not seen any like it.

[Charlie P.]

Re: Is this a 1962 or 1972 fan clutch?

Charlie,

.......... noting David's original and NOS pictured, you will see only 2 areas on the outer circumference where three fins have been combined to form two "blocks" 180 degrees apart. Those "blocks" are solid, unlike yours which has 4 "blocks" separated by 90 degrees each, with holes in them. I have not seen any like it.

Joe- I hadn't even noticed the holes you are pointing out to be honest, but they are obvious now that I look. Actually, the clutch pictured in the '61-'62 JG has the holes like mine.

Charlie

[Tony S.]

Re: Is this a 1962 or 1972 fan clutch?

The date code of D20A is decoded as either: April 20, 1960 or April 20, 1970. This particular fan clutch appears to be an earlier C3 fan clutch to me.

[David L.]

Re: Is this a 1962 or 1972 fan clutch?

The date code of D20A is decoded as either: April 20, 1960 or April 20, 1970. This particular fan clutch appears to be an earlier C3 fan clutch to me.

Tony,

As stated previously my fan clutch stamped "D 20 A" is dated April 20, 1970. It was removed from a 1970 Chevrolet 350 eng. w/AC. There is also a "CG" stamping that is barely visible. This style of fan clutch did not exist in 1960. The "CG" fan clutch is listed as GM # 4939900 in my 1970 Chevrolet (except Corvette) Parts Catalog for all 1970 Chevrolet 8 cyl. models w/AC. This 6" dia. fan has a 3 1/4" BC for the fan and a 2 1/8" BC for the W/Pump hub. I have studied fan clutches for over 30 years and have collected dozens of them in salvage yards and swap meets.

Dave