Best oil pump size for Hydraulic lifters?

[Mystery Meat]

Hi guys,

I am almost ready to start building my new 1745cc type 1 engine, and I am going to use the Mofoco hydraulic lifters in it. Their kit didn't come with any instructions but I think I have pieced together most of the auxiliary information.

From what I have read, Roy has recomended a 30mm oil pump and 20w-50 oil with this kit in the past. This seems a bit much just for hydro lifters, so......

I was wondering what you guys would think of running a 26mm pump vs. a 30mm for hydro lifters?

For some more back ground, here is what I am doing/thinking on this endeavor so far:
Good used case with lifter bores re-sleeved and slotted, fitted to lifters
Super tight oil pickup tube (couldn't get it out of case)
Hoover HVX mods
Blueprinted, o-ringed oil pump, with gear lash checked, nice tight endplay, drive shaft length adjusted for proper tang engagement
Cast iron full flow oil pump cover, flatness checked/adjusted
5w-30 or 10w-30 motor oil
valve adjustment preload: 1/2 to 3/4 turn past zero

Can anyone think of anything else i should be doing?

Thank you for your help

[tencentlife]

A 26mm pump is more than adequate for hydros, the increase in flow volume they require compared to plain lifters is marginal. Only if you were adding a turbocharger, piston oil jets or rocker spray bars, things that do require extra flow volume, would you need to upsize the pump.

And you should run the lightest baseweight oil you can, such as the 5w30. Light oil is the secret to good hydro lifter operation, not heavy.

O-ringing the pump to assure it doesn't draw in any air around the body-to-crankcase fit is also worthwhile, aerated oil makes for poor hydro operation.

And of course they absolutely require oil free of any particulate so full-flow filtering is essential.

[Clatter]

Meat,

Who were you having do the HVX mods?
Specifically, the big long oil drilling in the case from cam bearing to galley...

[Mystery Meat]

Thank you Tencentlife! Glad to hear the 26mm pump is ok to use. That is what I will go with then.

Clatter, I am having a local guy do the machine work on my case, (Jimmy111 on The Samba). He was familiar with the HVX mods, but had not done them on a case yet, before mine.

[Bruce2]

...... Roy has recomended a 30mm oil pump and 20w-50 oil with this kit in the past. This seems a bit much just for hydro lifters, so....

IMO, anyone that recommends 20W-50 for a new engine doesn't have a clue about proper oils.

Why not do what VW of Mexico did when they built tens of thousands of cars with hydraulic lifters? they used a 30mm pump. Then use 0W-30 oil.