Interesting oil consumption theory I hadn't heard

[Angrey]

I would think if it's as simple as a new calibration they would have done that.

Anyone ever examine whether the intake side goes so negative that it's drawing oil past the rings?

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[JAJ]

This was a known problem back in the 1980's, so there's no reason for it to return now unless the latest generation of engineers didn't listen to the old guys. In the old days, there was a mechanical "dashpot" on the throttle shaft that slowed down the closing of the throttle, and hold it open just a bit until the revs had dropped. That same "dashpot" function is in the calibration tables for all modern cars and presumably it works the same way and does the same thing.

As you say, if it was a problem with the Voodoo, a new calibration would have fixed it and saved a lot of money for Ford.

 

[honeybadger]

I had a couple engine builders in the early Voodoo days tell me this was an issue and it took some revisions on the piston and ring design to fix. There's some sense to it - a lot of the early custom Voodoo piston designs burned oil. I was told that the crank firing order of UDUD caused big vacuum issues. I don't personally have any data to independently verify, though. Tim at MPR Racing figured it out on the next build and I never had an issue again.

If I had to guess, it's a combo of the two. Ford changes the tune and piston rings in 2018+ engines and they clearly burned less oil. So wouldn't be surprised if they snuck some changes in that helped with that. But pure speculation on my part.

 

[JAJ]

I had a couple engine builders in the early Voodoo days tell me this was an issue and it took some revisions on the piston and ring design to fix. There's some sense to it - a lot of the early custom Voodoo piston designs burned oil. I was told that the crank firing order of UDUD caused big vacuum issues. I don't personally have any data to independently verify, though. Tim at MPR Racing figured it out on the next build and I never had an issue again.

If I had to guess, it's a combo of the two. Ford changes the tune and piston rings in 2018+ engines and they clearly burned less oil. So wouldn't be surprised if they snuck some changes in that helped with that. But pure speculation on my part.

Well, okay, but the only time it'll burn oil is when you take your foot off the accelerator, and where's the fun in that?

 

[WItoTX]

No idea if it's true, but my experience, I can run 8-10 AutoX events and if I stay below 7600 ish rpms, it consumes no oil. This last weekend, one course was 1/3 above that 7600, the other above 1/4 if you hit it right, and I burned/consumed a little less than half a quart.

On my track day, day one sitting behind way too many slow cars, almost no consumption. Day 2, in a faster group and higher revs, a very similar 1/3 quart burned.

I've also started idling the car until oil hits 170 before I push the car at all. So maybe some consumption at low idle is also an issue. I don't know. With the power curve, going above 7600 really isn't getting you much, and I've doney best to limit my time north of 7600.

 

[Angrey]

No idea if it's true, but my experience, I can run 8-10 AutoX events and if I stay below 7600 ish rpms, it consumes no oil. This last weekend, one course was 1/3 above that 7600, the other above 1/4 if you hit it right, and I burned/consumed a little less than half a quart.

On my track day, day one sitting behind way too many slow cars, almost no consumption. Day 2, in a faster group and higher revs, a very similar 1/3 quart burned.

I've also started idling the car until oil hits 170 before I push the car at all. So maybe some consumption at low idle is also an issue. I don't know. With the power curve, going above 7600 really isn't getting you much, and I've doney best to limit my time north of 7600.

If it follows the above, maybe it's not the RPM's that's causing the blow by, but the throttle shutting abruptly from full loading and creating a temporary excessive vacuum in the top end which is sucking it by.

I do believe that the motor has bad windage problems on the passenger side, which due to the rotation and the faulty windage tray creates more suspension through the CPV system.



7:00 - 10:00 he discusses how the little "lip" on the passenger side windage tray doesn't do a good enough job in protecting the drain back and the back build up of oil (combined with the lack of windage protections on the passenger side valve cover) ends up coming out the CPV system.

 

[WItoTX]

If it follows the above, maybe it's not the RPM's that's causing the blow by, but the throttle shutting abruptly from full loading and creating a temporary excessive vacuum in the top end which is sucking it by.

I do believe that the motor has bad windage problems on the passenger side, which due to the rotation and the faulty windage tray creates more suspension through the CPV system.



7:00 - 10:00 he discusses how the little "lip" on the passenger side windage tray doesn't do a good enough job in protecting the drain back and the back build up of oil (combined with the lack of windage protections on the passenger side valve cover) ends up coming out the CPV system.

Makes sense. My experience has been to empty the catch can every other oil change, and there really is no more oil than my Hellcat had.

Lot's of good information there.

 

[sk47]

http://www.fordservicecontent.com/Ford_Content/vdirsnet/TSB/EU/ (nhtsa.gov)

Hello; I believe this TSB addresses the issue. F-150 pickups with excessive oil consumption which had 5.0 Coyote V8. The fix was to program the throttle motor body to not close all the way when decelerating. This would prevent a lot of intake vacuum and slow oil being drawn past the rings. Best i recall a working theory was the plasma iron coating in the cylinder bores was very hard thus the rings took a long time to take a set. I also seem to recall reports of some Coyote V8 taking over 10,000 miles to take a set and for oil consumption to reduce.

Not clear to me if only pickup V8's were affected and i do not understand why Mustang V8 Coyotes would be exempt.

One other interesting aspect of the Ford fix was a second step. That being the dipstick was replaced. The one quart to low was replaced with a dipstick with a two quart range from full to low.

 

[Angrey]

http://www.fordservicecontent.com/Ford_Content/vdirsnet/TSB/EU/ (nhtsa.gov)

Hello; I believe this TSB addresses the issue. F-150 pickups with excessive oil consumption which had 5.0 Coyote V8. The fix was to program the throttle motor body to not close all the way when decelerating. This would prevent a lot of intake vacuum and slow oil being drawn past the rings. Best i recall a working theory was the plasma iron coating in the cylinder bores was very hard thus the rings took a long time to take a set. I also seem to recall reports of some Coyote V8 taking over 10,000 miles to take a set and for oil consumption to reduce.

Not clear to me if only pickup V8's were affected and i do not understand why Mustang V8 Coyotes would be exempt.

One other interesting aspect of the Ford fix was a second step. That being the dipstick was replaced. The one quart to low was replaced with a dipstick with a two quart range from full to low.

I always subscribed to the idea that in order to keep consumption at bay, it's best to flog the motor quite often to keep the rings nice and honed for best sealing.

It might compound the issue that Ford puts synthetic in the motor from day 1 (and doesn't employ a typical break in or conventional oil period) which might have helped with the ring seating. Furthermore, I can see this ring seating being a much bigger issue on trucks (how many people flog their trucks?).

In truth, there's probably a combination of things that result in oil loss. What is/was curious is that if it's burning so much oil, why it wouldn't show tell tale signs on most of the voodoo motors (colored smoke from the exhaust).

 

[sk47]

I always subscribed to the idea that in order to keep consumption at bay, it's best to flog the motor quite often to keep the rings nice and honed for best sealing.

It might compound the issue that Ford puts synthetic in the motor from day 1 (and doesn't employ a typical break in or conventional oil period) which might have helped with the ring seating. Furthermore, I can see this ring seating being a much bigger issue on trucks (how many people flog their trucks?).

In truth, there's probably a combination of things that result in oil loss. What is/was curious is that if it's burning so much oil, why it wouldn't show tell tale signs on most of the voodoo motors (colored smoke from the exhaust).

Hello; I question the how many flog a truck idea. A truck used as a truck can get some hard use. I also recall reading threads on this site about Mustang oil consumption, to the point of owners being given the it's normal as long as it is not more than a quart per 500 miles.

 

[ice445]

I think you're onto something. My car only burns oil if I do a lot of engine braking or high rpm shifts. 1000 mile trip at highway in steady state? Not a drop used. I wonder if there's a pcm update I could receive to address it. I don't get much blowby in a catch can either so the oil isn't even going through the pcv system.

 

[sk47]

I think you're onto something. My car only burns oil if I do a lot of engine braking or high rpm shifts. 1000 mile trip at highway in steady state? Not a drop used. I wonder if there's a pcm update I could receive to address it. I don't get much blowby in a catch can either so the oil isn't even going through the pcv system.

Hello; Very good questions. My hope has been Ford reprogramed the throttle body motors to help mitigate and prevent a sudden + strong intake manifold vacuum during deceleration. I do not know back in 2019-20 I was shopping for a new F-150 when i ran across the TSB I posted above. I went to a couple of Ford dealerships trying to pin down the details of any oil consumption issues of the time. I tried to contact Ford corporate a couple of ways. Basically no one would talk. So I passed on a decent F-150 deal at the time.
I am again shopping for an F-150. Seems some Coyote V8's do not burn much oil while others do. Sort of luck of the draw. I do not see how ford can risk such a problem on perhaps their best selling vehicle. The more common opinion was at the time the percentage of afflicted vehicles was small.

 

[Optimum Performance]

http://www.fordservicecontent.com/Ford_Content/vdirsnet/TSB/EU/ (nhtsa.gov)

Hello; I believe this TSB addresses the issue. F-150 pickups with excessive oil consumption which had 5.0 Coyote V8. The fix was to program the throttle motor body to not close all the way when decelerating. This would prevent a lot of intake vacuum and slow oil being drawn past the rings. Best i recall a working theory was the plasma iron coating in the cylinder bores was very hard thus the rings took a long time to take a set. I also seem to recall reports of some Coyote V8 taking over 10,000 miles to take a set and for oil consumption to reduce.

Not clear to me if only pickup V8's were affected and i do not understand why Mustang V8 Coyotes would be exempt.

One other interesting aspect of the Ford fix was a second step. That being the dipstick was replaced. The one quart to low was replaced with a dipstick with a two quart range from full to low.

Thanks for this, my Brother uses about 3-4 qts in 4K miles. Bone stock commuter truck.

 

[Angrey]

Is there a mechanical approach that someone could add to the intake side of things to keep the vacuum from spiking way negative?

 

[Optimum Performance]

Keep the crankcase negative pressure.

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