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The oil pick up should be at the rear centre of the sump (don't know if it is on a Saab), so that the engine always has a supply of oil under hard acceleration and/or cornering. (A car I have owned previously had the pick up in the front, and would pick up air in flat out corners at 7000 rpm!!! I won't name the manufacturer, but I ended up with a sump with swinging baffles - a small help - and the running with oil 0.5 litre over the max mark which was a big help).

The amount of oil in various parts of the engine varies dramatically with operating conditions. When idling hot, there is little oil being pumped around, and it drains back quickly so most is in the sump. When charging hard near the red line, huge quantities are being pumped around, and so there is a lot in the head at any given moment. Also, there is a large vortex around the crankshaft at these speeds, a phenomenon which caused the designers of large capacity American Vee 8's to use a device known as a windage tray. This is basically a plate with holes/slots that fitted as closely as possible below the crank. Oil flying around or off the crank would hit the tray and drain down, and the vortex effect was prevented from reaching the surface of the oil in the sump. The use of a windage tray increased the power output significantly, as the oily vortex drained a large amount of power. I remember some years ago reading the results from the testing of the 440 cubic inch Chrysler engine used by Jensen (7.2 litres if you prefer). I think the windage tray was worth about 30 bhp.

Anyway, the conditions you describe are ideal for oil delivery problems, i.e. you accelerate hard, pumping most of the oil into the head and the drain paths, and hold a lot as a vortex around the high speed crank. You then brake hard, and cause what little oil remains in the sump to move forward, presumably away from the oil pick up, which then sucks up a bit of air. Although this is to be avoided, a small oil supply pressure drop with the throttle shut is infinitely preferable to any sort of oil supply problem under load. Just don't step on it until the light goes out. Please also check the oil level and make sure you keep it at max.

You may also consider whether the presure switch is entirely accurate.
 
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