1967 BB A/C fan, 5 blade or 7 blade?

[David L.]

Re: 1967 BB A/C fan, 5 blade or 7 blade?

Michael,

Parts in the Chev. parts catalogs are service parts and not always the same as assembly line parts.

The 3931002 fan was a one year wonder, issued to various 1968 Chevrolet models with AC but not the Corvette. The fan has 7 aluminum blades, 18" dia., 3.00" bolt circle, 2 1/4" pitch, and was made by the Schwitzer Company. Each blade was stamped "3931002", "913894" (Schwitzer part #), and a date code. This fan also served as a service replacement as Joe previously mentioned. The 1969 Chevrolet models w/AC (exc. Corvette) and 1969 nZ28's were issued fan # 3937779 (Schwitzer # 914033) which was identical to the 3931002 fan except that the bolt circle is 3.25". Late 1969-1970 Chevrlet models w/AC (exc. Corvette) and Z28's were issued fan # 3947772 which was similar except that the pitch was 2 1/2". The optional assembly line 7 alum. blade fan issued on early 1969 Chev. models w/AC and 1969 Z28's was GM # 3947838 (stamped "H" for Hayes-Albion, "FRONT", and generally, but not always, "84" with a 2 1/4" pitch). The optional assembly line fan issued on late 1969-1970 Chev. models w/AC and Z28's was GM # 3956684 (stamped "H", "FRONT", and "94" (Hayes-Albion part # 159432) with a 2 1/2" pitch).

Dave

[Ken A.]

Re: 1967 BB A/C fan, 5 blade or 7 blade?

Actually the 3931002 was first issued in 1963 as part of the Z-11 option on full size Chevys along with other lightweight parts. You are correct re: blade stampings. I believe there was a service bulletin recommending this fan for customer complaints concerning cooling and poor AC operation.

[David L.]

Re: 1967 BB A/C fan, 5 blade or 7 blade?

Actually the 3931002 was first issued in 1963 as part of the Z-11 option on full size Chevys along with other lightweight parts. You are correct re: blade stampings. I believe there was a service bulletin recommending this fan for customer complaints concerning cooling and poor AC operation.

Ken,

After 34 years of researching Chevrolet parts I have never seen a GM part number starting with "39" before 1967 in any of of my many vintage Chevrolet parts catalogs, assembly manuals, etc. I also have Chevrolet Service News from Oct. 1962 to Nov. 1964 as well as Technical Service Bulletins from Sept. 23, 1962 to Oct. 11, 1965.

According to my 1963 Chevrolet Assembly Manual, Sect. Z-11, the engine used with this option was the same as RPO L-31 & L-80. The fan listed for the L-31 409 engine is GM # 3789562 (5 steel blades).

My 1964 Chevrolet Parts Catalog (Oct. 1963) lists GM # 3789562 as the fan for the 1963 PASS (8 cyl.) w/RPO Z11. My 1963 parts catalog (Oct. 1962) does not list a fan for the Z-11. My 1963 Chev. Parts Catalog (Oct. 1962) lists GM # 3749576 as the fan for the 409 engine.

Chevrolet Parts History for service parts:
3749576 to 3789562 in July 1964
3789562 to 3931002 in May 1972

I currently use a 3931002 7-blade fan on my 1966 instead of the original 5-blade fan.

Dave

[Domenic T.]

Re: 1967 BB A/C fan, 5 blade or 7 blade?

Does any one know if the 18" fan will hit the shroud on a 67 BB?

Dom

[Ara G.]

Re: 1967 BB A/C fan, 5 blade or 7 blade?

Here's a pitch comparison: a "3770529" small block is on the bottom and (IIRC) the BB fan you describe is on the top.



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Wayne, I swear there's NO part out there that you don't have a spectacular picture of. I chuckle each time you post, as I know you will be posting a picture that is EXACTLY on point with the topic. Bravo....ARA

[Joe L.]

Re: 1967 BB A/C fan, 5 blade or 7 blade?

Ken,

After 34 years of researching Chevrolet parts I have never seen a GM part number starting with "39" before 1967....



Dave

Dave-------



...and you never will. The 1967 model year was the first year that Chevrolet part numbers reached 3900000.