Oil pipes

Hi Gents,

Does anyone know the internal diameter of the feed and return pipes of a 750 Commando oil tank?

The reason for my question is that I still use the Norton Dominator oil tank with my 1972 Commando engine and I wonder if it's OK to cope with the IN and OUT flows of a 6-start oil pump (vs the 3 start of my previous engine).

Maybe it's (hopefully) a no-brainer, but just to clarify ...

Thanks

Laurent

I have a spare tank and the feed is 7,82mm and return 7,45mm. Is the Dommie not a much smaller pipe bore?

Thanks a lot Keith! Quite helpful.

I'm going to compare with the Dommie ones, but I think they are smaller.

Laurent

The spigot on a spare Domi oil tank I have laying around is 3/8"

laurentdom said:

Hi Gents,

Does anyone know the internal diameter of the feed and return pipes of a 750 Commando oil tank?

The reason for my question is that I still use the Norton Dominator oil tank with my 1972 Commando engine and I wonder if it's OK to cope with the IN and OUT flows of a 6-start oil pump (vs the 3 start of my previous engine).

Maybe it's (hopefully) a no-brainer, but just to clarify ...

Thanks

Laurent

Click to expand...

FWIW .... a slight reduction in diameter in a section of tube results in an insignificant reduction in flow rate IF the LENGTH of the reduced diameter section is less than 10 times the reduced diameter. You need not worry about slight reductions in the RETURN plumbing diameter, as the scavenge side of the gear-rotor pump will develop the pressure necessary to return full flow.

My Atlas has the Dommie type oil tank, of coarse, but it also has a factory installed 6 start pump and I have never had any oil issues, evidence of oil starvation, or undue wear in 85K miles. In short, I do not think you have a problem. You might also check the internal diameter of the inflow galleries on the oil junction block, and the timing case. Mine measure 0.188 inches. These ports are likely a greater bottleneck than that of the oil tank.

No comments please regarding that 6 start pumps were not supposed to be factory installed in 1963 .... But I would welcome any info on how such may have happened.

Slick

Thanks to you all.

Clear enough and useful explaination!

L.