[Alex jb]

I have an oil pump for the 175/200 engine build, not sure wha it’s from though.
I believe fr m reading somewhere on the forum that the 200 pump is bigger than the 175, now I’m not sure if that is stroke or piston diameter.

Anyway, the pump I have reads 15mm dia piston, is this a 175 or 200 pump?


Sent from my iPhone using Tapatalk

 

[Simo]

Iirc it's a 200,
The bore diameter not the stroke

 

[Alex jb]

Thanks Simo.
As u have experience with the 200 pump, do you remember if the ball in the check valve should be loose or sprung?
I am not sure exactly how it works, but I’m guessing the ball falls into the seat during the pistons positive stroke hence spitting the slug of oil into the engine and then when the piston draws back the oil is sucked up through the gauze over the ball.


Sent from my iPhone using Tapatalk

 

[Simo]

Yeah that's it, you can check its working by using a piece of card with a hole in it (attach it like the con rod to the pump piston) and a low tray filled with oil.