Early oil pump gear size

[Douglas Bok]

Hello all.
I have an oil pump assembly that I’m trying to figure out.
It is the Pre-A early 356A style with the removable housing, but the pump gears are only about 19mm. That seems smaller than what you’d expect but I haven’t been able to find any dimensions for the very early pumps.
It has the tach drive cover etc. so it appears that it is a Porsche part. Someone said it was probably a VW part but the early cars used as many VW parts as possible but tach drive shafts would not have been in the VW parts bin.
The circa 1953 Porsche publication “VW - spare parts applicable to Porsche cars” shows the oil pump housing as VW part number [111] 115 107, the housing I have has 111 115 109 cast into it. It appears that the housing may have been modified in the casting area around the driven shaft. (see 1st photo).
The same parts book has a VW part number of [111] 115 123 for the “Gear -Oil pump driven” but no dimensions are given. (See attached).
Any information or thoughts?
Thanks

[Ignacio Vivancos]

Douglas,
That is the correct oil pump for a PreA with a 2 piece engine. The oil pump case, vw part ending in 109 is correct. Many of those were cast in magnesium but yours look like aluminum. The gears are 17 mm, not 19 mm.
If you are interested in selling it, let me know as I have a couple of engines to build that use that pump.
Ignacio

[Alan Hall]

I agree with Ignacio the early 2-pc case pumps had 17mm gears. The only one I can put my hand on at the moment has a housing part number of 07.01.0 which is perhaps the early VW part number before the nine digit system. The later 3-pc case removable pumps had 24mm gears and housing had either a 539.07.110 part number or had no part number. I believe (but not 100 percent sure) that these later pumps can be used in a 2-pc case engine and would be a good upgrade!

[Ignacio Vivancos]

Allan,
Yes, you are right. The later preA/early A 24 mm oil pumps can be retrofitted to 2 piece engines. The casting is the same on the outside, only the “pockets” were the gears live are of course 7 mm deeper.