Carrera oilpump in a 2.7

[Geronimo '74]

What happens if one would install the Carrera pump in a 2.7 engine without performing the necessary modifications. (Upgraded springs and pistons for the relief valves and oil bypass modification (machining of the oil galleys)?

Is the machining of the case a must? If one does not do this, what will be the effect? No effect/benefit of the upgraded pump or will it have a negative effect?

Not asking this for my rebuild, I have a 3.2 with a new 3.2 pump.
I just would like to know.

[Flieger]

The pressure side was enlarged at the cost of a smaller scavenge pump. This means that there will be more oil in the sump when the oil pressure bypass spring is open due to insufficient scavenge flow rate. The oil-bypass mod corrects this by sending the bypassed oil back into the pressure side, which is large enough to handle the flow. This would be mainly occuring during start-up on cold days when the oil is more viscous.

[Walt Fricke]

Geronimo

It would be, well, stupid not to do the oil mod when installing a bigger pump in an earlier engine. Porsche started this with the late 2.7s, which were nothing super special as 911s go.

You can do it yourself with hand tools - a drill, a tap, a screw-in plug, and the parts (springs, pistons, guide tube, etc), which are cheap.

The toughest part is getting a drill bit started at a slant. You need some kind of tool to grind/cut something which will appear flat for your first drill bit so you can get a hole started.

Given the costs involved in having the case apart and getting a 3.2 pump, and buttoning things back up, the marginal cost of doing this has to be very, very low.

[Henry Schmidt]

If the bypass mod has not been done from the factory, do it.
2.7 cases had the bypass starting 75-76 model year.