1968 Z28 smog pump assembly

[z28z11]

1968 Z28 Camaro fiends,

I have a complete 1968 smog pump/diverter assembly that includes a spacer between the pulley and the pump. It's perplexing, as this pump/DH diverter/bracket/hoses/Whittek clamps/fittings appears to have never been apart, very pristine and dated correctly, with the exception it has a "116" lo-po pulley instead of the "522" deep groove, and it has a spacer between the pump fan and the pulley. I've read in at least one back thread about the possibility of an occasional "116" pulley making it on to a Z (parts shortage on the line ?), but my real question concerns the spacer. Considering the lower performance V8 water pumps were shorter as compared to the "326" Z water pump, did the "taller" Z water pump require the spacer (either pulley) ? I cannot find any reference in the assembly manual to a spacer on any 1968 application - hence the question.

Regards,
Steve

[68camaroz28]

Steve, know I cannot help you but fully understand that some units were sent out with the wrong pulley (supply at time) but the spacer/shim? What does it look like and thickness? A local friend has a 69Z he purchased new with a picture of when he brought it home and it has a AM antenna but a AM-FM radio.

[KurtS]

I've seen those spacers before. IIRC, they are an aluminum disc. But I don't remember the application.

[WorkinProgress]

In the parts book, it shows only Corvette using spacers. It is in Group 3.650 Pulley-Spacer, Air Injection Reactor

                                                    - Warren

[ZLP955]

Agreed, only seen the aluminium spacer used on Corvettes. I posted a similar question (but for a '69) a few months ago after buying what I thought was the correct 3 bolts that mount the pulley to the pump fan hub, and finding out they were too long - by about 1/2" or so.

[KurtS]

I've seen that spacer in the junkyard. And there's no Corvettes in these yards. So there's some other applications.

[WorkinProgress]

I only checked Chevrolet Parts Books. Not sure if the '116 pulley is used on other GM models.

                                                - Warren

[Petes L48]

From the GM parts wiki site, in addition to Camaro and Corvette pulley 3927116 shows up under Chevy truck/passenger/Chevelle/Chevy II/Nova, Buick, GMC, and Oldsmobile parts books.

[z28z11]

For some odd reason, the phone and computer are not speaking to each other tonight, so no pics yet. The spacer is definitely steel, about .750" or so, recess on the bottom to accept the pump pilot, piloted on the top side for the pulley. Pump is dated 290/7, Whittek clamps are 3/7, so the assembly is a bit early, but still for a '68.

Thanks to advice and research from rare396bronze (who found the spacer listed for a '68 Vette 327 application), I believe it's most likely a Corvette early takeoff. Jerry's Definitive 67-68 chart of smog equipment shows multiple applications for the DH diverter: even though the numbers are good, it also has a black relief valve mounted in the pump body, accurate for Vette (but should be green for the Camaro according to McNeish).

Best thing I can picture at this point is to keep my eyes peeled for a 522 pulley, plus then decide how to get this one gutted without endangering the shape it's in. 

Regards,
Steve

[luv2sixty9]

Yes, the 68 Z28 does come with a spacer to shim out the orange smog bracket that mounts to the intake.

[z28z11]

This is the spacer I was questioning - coupled with a "234" big block no A/C pulley. All seems to add up to a '68 BB Corvette takeoff -

Regards,
Steve

[dale68z]

My early (10c) 68 z has a non deep groove pulley. The smog system came with the car when I bought it in 1985 from the original owner. It is correctly date coded. I will try to remember to look if it has the spacer, but I'm pretty sure it does not have the spacer.

[bertfam]

I'll add to this. The September, 1968 P&A 34 shows the following:

66-68 ALL (283, 302, 327, 350) ... SPACER (13/32 I.D. x 21.32 O.D. x 1/2 long) ... 3877600 (Note that per other P&A's, this spacer was also used on Corvettes, Trucks, Buicks, Pontiacs, etc...)

69 Chevy, Camaro (8 cyl.) (exc. P.G., T.H. 350),
69 Chevelle (8 cyl.) (exc. A.T.) ... SPACER ......... (No description of size) ........... 3955204 (Note that per other P&A's, this spacer was also used on Trucks, Full Size, Vega, etc...)

Ed

[KurtS]

The aluminum spacer that I've seen is maybe 3/8" thick. Nothing like that steel one!

[firstgenaddict]

I need a 234 pulley and a 3/4" thick steel spacer for my LT1 Corvette.
The 234 Pulley is the Small Block Corvette Pulley.