Oil Pumps - Spot the difference

[Matt Cook]

I’ve been trying to find “good” Hobourn Eaton oil pumps. I understood that the only difference between a Saab pump and a triumph pump was the spring.....pump on the left is a Saab, Triumph on the right.

[Dieter H. Marschall]

Hello Matt,
isn't the the Saab pump a bit off-centre?
Best wishes,
Dieter.

[Matt Cook]

Yes that’s right. Now I don’t know what the impact of using such a pump is but I’ve been advised not to use it. The rotors are good so I’ll use them in another pump body that I have

[I am Groot]

I always thought the only implication using the Saab or County pump was the spring. Lots of us are running them with no problem I've heard of.

[Matt Cook]

The county pumps I have seen (2 now) match the "triumph" pump. I have 2 other HE pumps that where the o ring groove is central.

[flying farmer]

Never actually seen a SAAB pump, but they were always sold as high capacity or uprated years ago which would imply to me that they shift more oil per revolution. I recall someone once saying to me they were going to fit a SAAB pump as their crank was getting a bit knackered and it was a cheap way to get some extra oil pressure when they sold the car!

If you pulled them apart you would soon see if the rotor on the SAAB pump was a bigger diameter than the Triumph one.

[Matt Cook]

Rotors are the same size and appear to be interchangeable. Inner rotor is ~40mm across the points

[davidf]

Yes that’s right. Now I don’t know what the impact of using such a pump is but I’ve been advised not to use it. The rotors are good so I’ll use them in another pump body that I have

It looks as though it is just the 'O' ring groove that is off-centre. If that still seats on the flat face of the block, then no impact.