1969 Camaro Big Block fan clutch tutorial

[WorkinProgress]

Over the years many people have needed info on the '69 Camaro Big Block fan clutches only to find very little. I have put together some info and took pictures to help anyone out that needs documentation.

From what I have seen there are three styles of '69 fan clutches.

The most common style is the Eaton. They have the coiled thermal spring on the front.

The Schwitzer clutches have the flat bar going across the front.

The original GM part numbers are 3946049, and 3946050. In the parts book they can be found in Group 1.050.

Fan clutch 3946050 was used on the Special High Performance engines and was coded CZ

Part number 3946049 was superceded to part number 3946050 on 4/73. Part number 3946050 was discontinued from GM on 7/81.

It appears that the '69 and '70 Eaton fan clutches did not have "STORE THIS FACE DOWN" stamped into the face, and were left blank.

http://www.yenko.net/attachments/usergals/2013/04/full-12894-4510-008.jpg

These pictures are of the Schwitzer clutch. They measure 6" across and are 2 9/16" tall.

http://www.yenko.net/attachments/usergals/2013/04/full-12894-4511-006.jpg

The clutch is coded CI

http://www.yenko.net/attachments/usergals/2013/04/full-12894-4528-074.jpg

Backside

http://www.yenko.net/attachments/usergals/2013/04/full-12894-4512-014.jpg

The Schwitzer clutches are dated on the hub. This one is dated 6-10-69. Also note there is hardly any clearance between the hub and the clutch.

http://www.yenko.net/attachments/usergals/2013/04/full-12894-4513-018.jpg

There is 1 1/4" from where the fan sits on the clutch to where the hub sits on the waterpump.

http://www.yenko.net/attachments/usergals/2013/04/full-12894-4514-020.jpg

This picture is a Schwitzer clutch that is 7 1/4" across and is 2 11/16" tall. Hub is dated 3-13-69

http://www.yenko.net/attachments/usergals/2013/04/full-12894-4515-070.jpg

Backside

http://www.yenko.net/attachments/usergals/2013/04/full-12894-4517-021.jpg

CZ stamp

http://www.yenko.net/attachments/usergals/2013/04/full-12894-4520-025.jpg

Eaton CZ

http://www.yenko.net/attachments/usergals/2013/04/full-12894-4529-030.jpg

Backside

http://www.yenko.net/attachments/usergals/2013/04/full-12894-4521-039.jpg

Early Eaton CZ, and later with STORE THIS FACE DOWN stamping

http://www.yenko.net/attachments/usergals/2013/04/full-12894-4522-043.jpg

Another picture of an early Eaton clutch

http://www.yenko.net/attachments/usergals/2013/04/full-12894-4523-044.jpg

The Eaton clutch is 7 1/4" across, and is 2 5/8" tall. It also has the 1 1/4 space between where the fan rests on the clutch to the hub face that rests against the waterpump.


If anyone needs different picture angles, or more info just let me know. Also, none of the fan clutches are for sale.

Anyone out there know how to breakdown the ink stamped date codes?

- Warren

[Donnie]

A 17 J = Jan. 17th 1969

[neresto]

Warren, is the measurement the same from the clutch to the hub on the Eaton and the Schwitzer CZ clutches?

[Ls6 Ragtop]

Nice info Warren. My info on early date code stampings coincides with Donnie. First character is the month followed by day and year.
Chris

[L78 Fred]

Thank you Warren, Mike, Bruce and all that have helped myself and those of us looking for the correct dated L78 Camaro components and a HUGE Thank you for Charlie and this site for getting us all together!!!

Now I just need to find one or two....

Fred

[WorkinProgress]

All three style Big Block fan clutches have 1 1/4" spacing from where the fan rests on the clutch to where the hub meets the waterpump. The CV clutch has 1 1/2" spacing.

Thanks for breaking down the date code Donnie and backing it up Chris! I had a feeling that might be what it was. I have a CV clutch that is dated E 14 J and it is from an 05E Norwood Z/28.

- Warren

[WorkinProgress]

Here are some pictures of the CV coded clutch.

http://www.yenko.net/attachments/usergals/2013/04/full-12894-4530-052.jpg

CV clutch with E 14 J date

http://www.yenko.net/attachments/usergals/2013/04/full-12894-4531-054.jpg

Ruler showing 1 1/2" from where fan rests on clutch to where the hub meets waterpump.

http://www.yenko.net/attachments/usergals/2013/04/full-12894-4532-059.jpg

The CV clutch is 3" tall, and is 7 1/4" across

http://www.yenko.net/attachments/usergals/2013/04/full-12894-4533-062.jpg

This CV clutch is dated D 22 A and is attached to a 70 1/2 LT1. Engine stamp is V0509CTB

[bergy]

Good info guys - thanks for posting!

[NoYenko]

Warren, Great job on posting this info & pictures. I have a Nov 68 built 69-396-325 with AC. It has a Eaton clutch on it with an "AC" marking and a date code of "B18D". Highlighted in photo. I can't seem to find any info on it and if it could be original. It needs to be rebuilt but I don't want to disturb the original markings if it is correct. Have you or anyone ever seen an AC stamp on the clutch? George.

[bergy]

Nice job & great service to the community Warren. This picture is of one of the boxes that my Schwitzer clutchs came in. You have boxes pictured with the same part number along side both Schwitzer and Eaton clutches. It appears that the short shaft clutch from either manufacturer could have been stocked under the same part number - do your records agree?

http://www.yenko.net/ubbthreads/pics/usergals/2013/05/full-2170-4614-img_2843.jpg

[WorkinProgress]

Hi George!

I really have no idea on your date code and it would only be a guess. One of the clutches I have pictured has a K28I date. I assume the letter I is for '68 since the letter J is '69. The CV clutch I have pictured that is attached to the engine is dated D22A. It's the same date as the one for sale by neresto. If the letter A is for '70 then on yours I would think the letter D would be for '73.

I have another CZ clutch and the date code is J14DC and is packaged in its original GM box that is dated 10/72. It has the same stamping "STORE THIS FACE DOWN" on the front like the B27DB I have pictured.

This is where it gets confusing for me. I do not know what year they started stamping "STORE THIS FACE DOWN", and used a two letter code for the year. Your clutch face has no stamping so it is an earlier Eaton clutch and only has one letter for the date code. Probably will need to see some more examples of clutches with the year car they came off of.


Hi Bergy!

I would say the CZ stamped Schwitzer clutch that is 7 1/4" wide would have had the GM part number 3946050.

The six inch Schwitzer clutch with the '050 parts label that I have pictured has been relabeled I would think at the parts plant. You can see the remains of the old label which would have been '049. Someone with a black marker wrote 3946050 on the box, then they attached the superceded number 3946050 over the old label.

The old computer punch tag on the top of the box has 3946050, so that one was shipped under the new number.

http://www.yenko.net/ubbthreads/pics/usergals/2013/05/full-12894-4616-008.jpg

Relabeled 3946050, remains of old label 3946049 visible

http://www.yenko.net/ubbthreads/pics/usergals/2013/05/full-12894-4615-009.jpg

Computer punch card on six inch Schwitzer clutch GM box.

On your box it says "LARGE PATTERN". Does that mean your '049 clutch was 7 1/4" across or was it the smaller six inch size?

- Warren

[bergy]

Hey Warren - this is the 7 1/4" Schwitzer clutch that came out of that #049 box when I opened it. Stamp on it is 1-7-69 SC. I did not have it since it was purchased new, but looked unopened when I got it.

http://www.yenko.net/ubbthreads/pics/usergals/2013/05/full-2170-4649-img_2849.jpg


Charlie - the picture posting thingy is really working great!!!

[bergy]

I'd say "large pattern" is for the fan bolt spacing

[ban617]

Hi,I was curious is there a place that restores/rebuilds them? I have a 69 Z/28 and would like to send it out to be refurbished .. Thanks Rob

[WorkinProgress]

Not sure of the bolt patterns on fan clutches, so I guess '68 and earlier would be smaller!? Bergy was there a letter code stamped onto your clutch and do you know what it was? - Warren

[NoYenko]

Warren, Thanks for the info on date codes, that seems to fit.I have never really found any other info on my clutch. As far as a re-builder here is a link to one shop that does this. (http://www.pamperedcorvettes.com/Pampered_Corvettes/About.html) George.

[WorkinProgress]

George, does your clutch have the 1 1/4" backspace from where the fan sits on the clutch to where it bolts to the waterpump? - Warren

[NoYenko]

Warren,Yes it measures 1-1/4". George

[69ssoramac]

Hello, Just wondering if you have a 3946050 or 3846049 you might be willing to sell. I need one. Please advise.

[bergy]

I just have a couple of 6" Schwitzers - dated 4/9/69 and 5/9/69. They are used. PM me if interested.