Distributor rebuild questions

oldtime wrote:   For starters your chart should be adjusted as follows... The model prefix information  is correct but... you have your suffix data all messed up. The final suffix letter merely designates the year of manufacture and nothing else.

I know that the distributor tags had the month and year of manufacture stamped onto them, but I didn't realise that this is what is written into the table. The info in my table I simply rearranged from page 154 of the Universal Service Manual to make it easier to read:

So you mean that there was no model IAD-4008-T or -A or -AT as such, but that the original IAD-4008 was used on CJ-3A's starting in 1962 which is what the T represents? And the identical IAD-4008 on CJ-3B's in 1968=A? The IAD-4008-AT used on CJ-3B's and CJ-5's is confusing because as far as I know they used numbers and letters for month and year, never two letters. Any ideas?

oldtime wrote: I repeat ... there is no spring located underneath the cam breaker stop plate !

I presume you mean that there was no spring located underneath the cam breaker stop plate ON THE MODELS YOU MENTION, because there was seemingly a spring located on some models. It is shown in various exploded parts diagrammes and referenced in TM9-1825B:

In the parts listing it is Part L "Spring"

It is also referenced in TM9-1825B in another exploded parts diagramme and in the text where they call the same part an "anti-rattle spring" as part of their rebuild instructions.

Note they say "If anti-rattle spring is used......"

I am not sure if this is is a reference to the fact that not all distributor models had them, and the rebuild instructions cover various different models OR if this was an "optional" part that could be fitted if the rebuilder thought it a good idea. I'm thinking the former.... It would seem strange for the military to write a rebuild manual and then leave the installation of optional parts up to the individual.

So the question now becomes: We know that the anti-rattle spring exists and where it goes. Which distributors used it?

oldtime wrote: In fact no spring could even fit into that space.

This I don't agree with. I have measured a clear 0.061" gap between the bottom of the cam stop plate on my IAD 4041 and the top of the centrifugal weights, and this is plenty space for the spring to ride in without interference either with the plate or with the weights.

Here it is installed:

The spring is clearly visible with clearance both above and below the wire.

oldtime wrote: Yes there is a spring that is correctly referred to as the "anti rattle spring". It's function is just that.  It basically eliminates vibrations and excess motion at the base of the shaft where it enters the oil pump drive. It is made from flat stock and fits at the bottom of the distributor shaft just above the "oil pump index tang". All IAT IAD and IAY models have these anti rattle springs.

This I was not aware of, but is it indeed referenced in the parts list:

637615        SPRING, friction, distributor shaft................................1

Good to know! Do all the regular vendors sell it?

Thanks for all your comments and input so far!