Topic: 1970 AC Compressor Clutch

[BHStang]

Trying to figure out what is the correct AC clutch and finish (painted or plated) for my Mach 1 factory AC.  It a June 10 DAP build H code.  Currently I have a york compressor with D0AA-2875A on the tag.  This is not my original compressor.  Note the tag has come off the compressor and I have not yet reattached, not sure its even the original tag.  It was barley hanging on when I got the compressor with a box of misc. parts.  The clutch it has on it was added by the shop that rebuilt it for me, and worked just fine.  I just currently have the engine out for detailing, so now is a time for making things more correct.

[preaction]

The compressor tag will have a date code on it.

[BHStang]

Its there a casting date stamp on on the compressor other than the tag?  I think right now though i'm more concerned with correct clutch and finish.

[Bob Gaines]

Its there a casting date stamp on on the compressor other than the tag?  I think right now though i'm more concerned with correct clutch and finish.

If missing the tag you typically have to rely on the shape/construction. Later versions have nuance shape differences compared to earlier ones. In my case I try and keep a known original core of the given MFG and year for comparative purposes.

[BHStang]

So what the clutch itself.  Should it be left black?

[Bob Gaines]

So what the clutch itself.  Should it be left black?

I have typically seen that type of clutch and electro magnet donut plated silver when new from the factory on the 69's that I work on . I typically only see the brush style clutch painted all black. I would think 70 would be similar but can't say for sure like I can on 69.

[Bob Gaines]

Where was your car bult? I typically see cast iron Tecumseh compressors on Dearborn and aluminum York on Metuchen and SJ in the later years . 

[BHStang]

It was a Dearborn car

[J_Speegle]

Here is another picture to illustrate the finish and style of clutch Bob was describing





Looking at pictures I've collected of H and M code Dearborn 70 Mustangs that are unrestored I found all with the York/aluminum style AC pumps except for one Tecumseh/cast iron  example out of slightly more than a dozen

Some of the examples below

[BHStang]

Thank you all this helps!

[BHStang]

So I am going to reopen this discussion, and ask more basic.  This might be something of an opinion question.  What is the correct clutch to start with?  Lets go ahead with the assumption that the york compressor I have is correct.  Did the York Compressor always use the doughnut type filed or could it also have the the brush type? The MPC Lists both types as possible on a 351 but does not specify a specify a specific compressor to clutch application.   The unrestored example pictures I dont think are conclusive as there is strong evidence (to me, tag/wiring clip used in 1970 is gone, compressor cereal plate is gone accept for 1, but that one is an unpainted compressor and I have not seen any other 1970 or earlier originals unpainted ) they have been altered from the factory.

Additional research seems to be that after 1970 only the type 5 "doughnut" field was used and it seems that the type 5 was the most common "service replacement" type available.  For sure that is what we see in most examples.  However, I have now found a few examples or what are claimed to be original 1970 compressors that are the York type and have the type 3 "brush" clutch.  Thoughts? 

[Bob Gaines]

So I am going to reopen this discussion, and ask more basic.  This might be something of an opinion question.  What is the correct clutch to start with?  Lets go ahead with the assumption that the york compressor I have is correct.  Did the York Compressor always use the doughnut type filed or could it also have the the brush type? The MPC Lists both types as possible on a 351 but does not specify a specify a specific compressor to clutch application.   The unrestored example pictures I dont think are conclusive as there is strong evidence (to me, tag/wiring clip used in 1970 is gone, compressor cereal plate is gone accept for 1, but that one is an unpainted compressor and I have not seen any other 1970 or earlier originals unpainted ) they have been altered from the factory.

Additional research seems to be that after 1970 only the type 5 "doughnut" field was used and it seems that the type 5 was the most common "service replacement" type available.  For sure that is what we see in most examples.  However, I have now found a few examples or what are claimed to be original 1970 compressors that are the York type and have the type 3 "brush" clutch.  Thoughts?

I have seen (many) early 68 and back Mustang applications York compressors with the brush type clutch . I have seen (many) later 68 and up Mustang applications York compressors with the doughnut eletro magnet clutch. There seems in the Mustang world to be a distinct change over in more use of one from the other. Not to say it was not absolutely used but one style is definitely more typical used then the the other in a given time period. FYI the wiring out to the compressor is identical regardless of clutch type. The pigtail to the harness from the clutch are the same length regardless so there is no help there. The safe bet is the electro magnet type for a 70 Mustang application IMO. 

[Bob Gaines]

One style vs the other use probably also has to do with a primary and secondary Ford vendor . Ford always had a back up plan to lessened the chance of shortages.