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- Joined
- Mar 13, 2021
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- Washington
- Current Ride
- 2022 F-350 Tremor 7.3L
- Current Ride #2
- 1980 Mazda RX-7
Saw an interesting couple of videos from an engine builder out of Utah diving into 6.7 oil starvation on startup. If you're only going to watch one, watch the second one.
Here's the videos:
The highlights:
Here's the videos:
The highlights:
- Concern he has: it takes too long for the engine to build oil pressure and get sufficient oil to the bearings (cam and crank).
- Using water, he measures the volume of oil inside the engine, outside of the pan. Works out to about 2 quarts of volume the pump needs to fill before pressure is created. Measuring this is the majority of the first video.
- Using a machine to turn the engine over at 500 RPM (roughly what the starter turns the motor over at), he times how long it takes for oil to get to the turbo charger, showing the camshaft is filled with oil and no longer running dry. Findings:
- After a simulated oil change: 8 seconds
- After sitting overnight: 7 seconds
- After sitting for an hour: 6 seconds
- He installed a "secret" and custom modification on the oil pickup tube (he doesn't reveal details, but it's clearly a check valve of some form) to prevent the oil from draining out of the engine.
- Had oil flow immediately, albeit at low pressure.
- Took 4 seconds to build pressure (seemed to align with RPM as the machine spun up).
- He's installing this mod on all 6.7's he builds going forward. He's invested in it as he wants to reduce the number of warranty claims he sees.
- I was surprised just how much oil is in the engine while running. 2 quarts is quite a bit!
- How long does the starter take to get up to speed compared to his machine? A notable amount of time without pressure is spent waiting for the machine to get up to speed, so faster acceleration would reduce that time. It would also mean higher speeds without oil, so there's a tradeoff there.
- He touches on it in the video, but what is the impact of pumping air, instead of oil, through the engine on startup? He says pretty confidently that the air will blow any oil film off of the components, but is that true in practice?
- Isn't the oil filter supposed to have an anti-drainback feature on it to prevent the oil from draining out? Why does that seem to be having so little impact here?
- How does the 7.3L gas compare? What about engines from other manufacturers?