Dougs951S

I just found out today that there are two different front crank seals. 83 and 84 engines got a 38 x 55 x 7 seal, and 85 onward cars got a 38 x 52 x 7 seal. This change was due to a decrease in the OD of the pump I would presume, so that sort of begs the question. Are the oil pump drive sleeves interchangeable between late and early oil pumps? The PET shows a slightly different part number, #944-107-161-02 for 83, and 944-107-161-03 for 84 onward which doesn't line up with the year change for the seal. I used the correct seal for my 83 oil pump when I did my rebuild but I used a drive sleeve from an 86 and I want to be sure before I start it that all will be well. Typically when Porsche changed just the last number like that it indicates a minor revision, and that the part is still essentially the same. For contrast, the 83-84 seal is a completely different part number than the 85+ so I figure the drive gears are ok to use on all pumps?

Edit: Nevermind, the drive gear did undergo a small revision in late 84 but is appears all drive sleeves are compatible with all pumps. on 84+ pumps the bore of the pump which sits in front of the bore containing the driven teeth got a 3mm decrease in it's ID, requiring the smaller seal.