M70 Oil pump piston

[ctuls]

Anyone familiar with the function of the piston in the oil pump in this youtube video. Is making sure that is moving something that people have to usually worry about?

https://youtu.be/4nEsRZabV5A?t=966

[cartoonz]

It is a pressure regulator, and it commonly seizes when people put zinc additives in the oil.
You've addressed it properly.

Your scheme with the cylinders and pistons is questionable though, will be interesting to see how that holds up.

The Sunnen process for alusil bores requires the special lapping paste and felt pads for proper surface. The scotch Brite/ oil step is only part of the complete process.

The pistons are purposefully coated with a ferric oxide coating to play well with alusil. Hopefully, whatever you used will function the same way.

[ctuls]

@Cartoonz thanks! That is not my video thankfully lol

I also have my engine partly apart. I don’t know what oils were used in the past but it is currently at 80k miles. Would you recommend I take the piston out to make sure it is moving? I haven’t had the oil pressure light come on before when the engine is running

[cartoonz]

If you have the pump out, by all means carefully free up that piston.

[shogun]

as you have your engine partly apart, these engine data might be helpful with plenty of factory spec measurements, for download here ~ 400 pages technical data on various engines https://web.archive.org/web/20110516...cal%20Data.pdf