Low Tension Rings and Oil Consumption

I know this will never happen but it would be interesting to take a car that supposedly uses little to no oil and one that is claimed to be using excess oil and switch drivers for a few thousand miles and see if the oil consumption reduces or increases!

I feel the low tension rings are doing what they are designed to but some driving styles either increase or decrease consumption.

Constant high rpms lower gears not a lot of combustion pressure to expand the rings tightly against the wall will increase oil consumption. Remember these thin low tension rings are doing exactly what they are intended to do. They free up horsepower and increase fuel economy while allowing the engine to rev quicker through less friction from the rings against the cylinder wall.

Lower rpms with higher loads will increase ring pressure against the cylinder wall and decrease oil consumption. While higher rpms with little to no load will not create enough cylinder pressure to push the rings tightly against the cylinder walls to keep oil control at bay.

Those that track there car probably don't use a lot of oil since the engine is mostly under heavy load even at higher rpms since most are trying to get to the next corner as quickly as possible.

I am really surprised that I have not read one post unless I missed it of anyone doing a compression and leak-down on a engine that some state uses excess oil. I bet they will not find anything wrong.

If a engine truly has internal issues there would be other signs like excess smoke on cold start, rough running fouled plugs misfires etc.

I truly believe that there are very few issues with these motors and most perceived issues have a lot to with driving style. Just my opinion

I think u got it figured out, completely agree with you.

So I am burning a bit over 1 quart per 1,000 miles. About 1 quart per 750 miles. I dog the piss out of the car. Run it up to 8,200 often, carry high RMPs to hear the crackle when letting off of the gas. Maybe the crackle has something to do with burning oil? I am constantly trying to make it crackle for as long as possible. I am addicted to the crackle. I down shift a lot also. I have 4,5xx miles on the car. I broke it in per the manual. Consumption seemed to increase after 1,000 miles. Little to no oil consumed pre 1,000 miles. Since then, about 1 quart per 750 miles.

I've had the car up to 166 mph on a closed course.

Houston Kid said:

So I am burning a bit over 1 quart per 1,000 miles. About 1 quart per 750 miles. I dog the piss out of the car. Run it up to 8,200 often, carry high RMPs to hear the crackle when letting off of the gas. Maybe the crackle has something to do with burning oil? I am constantly trying to make it crackle for as long as possible. I am addicted to the crackle. I down shift a lot also. I have 4,5xx miles on the car. I broke it in per the manual. Consumption seemed to increase after 1,000 miles. Little to no oil consumed pre 1,000 miles. Since then, about 1 quart per 750 miles.

I've had the car up to 166 mph on a closed course.

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Sounds like high rpm low load situation to me and sounds perfectly normal. I think many on here like to drive this way since the sound of this car is very addicting.

How many other cars sound this good and are driven this way probably not too many?

Houston Kid said:

So I am burning a bit over 1 quart per 1,000 miles. About 1 quart per 750 miles. I dog the piss out of the car. Run it up to 8,200 often, carry high RMPs to hear the crackle when letting off of the gas. Maybe the crackle has something to do with burning oil? I am constantly trying to make it crackle for as long as possible. I am addicted to the crackle. I down shift a lot also. I have 4,5xx miles on the car. I broke it in per the manual. Consumption seemed to increase after 1,000 miles. Little to no oil consumed pre 1,000 miles. Since then, about 1 quart per 750 miles.

I've had the car up to 166 mph on a closed course.

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This pretty much mirrors my experience. No consumption before 1k then about same as you're getting. But I also started driving it similarly. I don't run it up to 8200 and let off, but I'll get to 7800-8200 on some shifts. I rev match almost every downshift, engine brake (not abusively) and ride the crackle for a few secs often -- it's a great audible warning to cars next to you trying to keep up that they should just back off lol.

Your idea has merit but how do you explain a quart of oil in 140 miles? That was my first engine. How about a quart in 400? That was the second engine before Ford took the car back.

The car only saw weekend spirited drives in the local foothills and around town.

If I can make a car burn that much oil with only driving habits something is wrong with the design.

After Ford took the GT350 I picked up a 2017 Zo6 (yes a glorified truck engine I know) and have 7000 trouble free miles. I add about a 1/2 quart every 1000 miles. Solid as a rock. :shrug:

Sammy said:

Your idea has merit but how do you explain a quart of oil in 140 miles? That was my first engine. How about a quart in 400? That was the second engine before Ford took the car back.

The car only saw weekend spirited drives in the local foothills and around town.

If I can make a car burn that much oil with only driving habits something is wrong with the design.

After Ford took the GT350 I picked up a 2017 Zo6 (yes a glorified truck engine I know) and have 7000 trouble free miles. I add about a 1/2 quart every 1000 miles. Solid as a rock. :shrug:

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As I mentioned in the last sentence of my post there are probably very few issues with these motors yours could have been one of them but I highly doubt you had two bad motors. Again its weird that I have not heard of a single compression leak-down on these motors! I am sure its been done but not posted. Also as many have experienced on long trips many have used very little oil this indicates to me the low rpm higher load of driving in 6th keeps the rings sealed tightly against the cylinder walls. Hell even driving in 5th at freeway speeds is around 3K rpm and very little load.

I still think the sound of this cars exhaust at higher rpms is intoxicating and most will drive the car this way because it sounds so good at higher rpms no load situations than most other cars causing the oil consumption.

It's really sad that some experience the amounts of oil consumption they do. I've posted in another thread that mine hasn't shown any loss of oil in just over a thousand miles. Personally if mine ever developed a propensity for using oil, it'd be gone.

Wriggly said:

It's really sad that some experience the amounts of oil consumption they do. I've posted in another thread that mine hasn't shown any loss of oil in just over a thousand miles. Personally if mine ever developed a propensity for using oil, it'd be gone.

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Mine did not burn any, well that I could tell using the dip stick, until after 1,000 miles. How I drove the car drastically changed after 1,000 miles. Prior to 1,000, I took it relatively easy on the car. Occasionally running it up to 7,000, no extended periods of riding the crackle, no running it to redline in 1st, 2nd, 3rd, 4th, and attempting to hit 8,200 in 5th. After 1,000, I do that all of the time.

I am convinced how you drive the car contributes to the amount of oil consumed. Take it easy, less consumption. Drive it like you stole it, more oil consumption.

I am not saying some engines don't have other issues causing massive oil consumption. Those are separate issues and until Ford offers an explanation as to why so many failed, we may never know.

this may or may not apply :

http://www.c5registry.com/2k2z06/page5.htm
Issues: Oil Consumption and Cold Piston Knock

"We have seen a greater percentage of complaints than we’d like about oil consumption," John admitted. "The condition under which we get that oil consumption is high-rpm, light-load–like if you drive in a city schedule but never take the car out of second gear. In that situation, the piston rings can get into a flutter condition and that’s when the oil consumption takes place."

Piston ring seal depends on a balance of four forces: combustion pressure, ring inertia, the ring’s radial expansion pressure and crankcase pressure. Ring flutter is uncontrolled oscillation due to an imbalance of those forces. Once a piston’s rings go into flutter, their ability to scrape oil off the cylinder wall as the piston moves downward is impaired, blow-by increases and oil consumption rises dramatically.

The combination of high rpm and the low crankcase pressure typical of low engine loads causes those four forces to become imbalanced. The small amount of LS1s and LS6es that see regular, high-rpm, light-load operation may suffer high oil consumption.

"The severity of this problem is specific to the driver," Juriga continued. "You can take a car that is a major complaint for one customer and give it to another customer who’ll have (different driving habits and) no complaints and get 5000 miles to a quart."

The common sense is that high-speed and light-load is not a duty cycle typical of normal use, even for an engine in a car like a Corvette. Who drives around town running 4000 or more rpm at part-throttle?

"It’s not the way most people normally drive," John agreed, "so it has not been a substantial part of our normal durability schedule.

...

I drive hilly roads, and usually am keeping the revs between 2000-3000, and often below 2000.

I have noticeable "piston slap" between 2K and 3K under light load, so I don't stay there much and will go to a taller gear.

I therefore believe I am more of the low-speed, high-load scenario, yet my engine consumes oil (something like 4 quarts over 7000 miles).

However, I did have a track day, and also will use engine braking to keep the speeds reasonable on downhills (usually between 2K and 3K RPM).

I will also run to redline once or twice per commute, just to keep things interesting.

Seems like I might not fit your theory.

One interesting tidbit on oil consumption though: I was watching F1 a couple weekends ago, and they mentioned that the engines are actually designed to consume oil, because they treat it like additional fuel. They are limited to burning 1 liter per 100 KM. That's basically one quart per 60 miles. And those engines actually last quite a long time given how stressed they are.

I would tend to agree that these voodoo engines will consume more oil that most engines due to their design, and that getting 1500 miles per quart probably isn't alarming. Getting 140 or 400 like mentioned above seems sketchy to me, and I doubt that would be significantly influenced by driving style.

Edit: Interesting points about the vette engine above.

-T

Trackaholic said:

I drive hilly roads, and usually am keeping the revs between 2000-3000, and often below 2000.

I have noticeable "piston slap" between 2K and 3K under light load, so I don't stay there much and will go to a taller gear.

I therefore believe I am more of the low-speed, high-load scenario, yet my engine consumes oil (something like 4 quarts over 7000 miles).

However, I did have a track day, and also will use engine braking to keep the speeds reasonable on downhills (usually between 2K and 3K RPM).

I will also run to redline once or twice per commute, just to keep things interesting.

Seems like I might not fit your theory.

One interesting tidbit on oil consumption though: I was watching F1 a couple weekends ago, and they mentioned that the engines are actually designed to consume oil, because they treat it like additional fuel. They are limited to burning 1 liter per 100 KM. That's basically one quart per 60 miles. And those engines actually last quite a long time given how stressed they are.

I would tend to agree that these voodoo engines will consume more oil that most engines due to their design, and that getting 1500 miles per quart probably isn't alarming. Getting 140 or 400 like mentioned above seems sketchy to me, and I doubt that would be significantly influenced by driving style.

Edit: Interesting points about the vette engine above.

-T

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Your driving habits pretty much exactly match mine. Knock on wood, no real oil consumption issues here. ~2/3rd quart over 6000 miles

I have a few theories of my own, originally I blamed it on the low tension rings myself. I had no real oil consumption in the 5k miles I owned my track package and my R only has a couple hundred miles on it. I was extremely careful warming my car up, and didn't drive it unless I had 130-140 oil temp and until it was closer to 180 I kept the loads and rpm light. I broke in per the book as did my best friend who also follows similar procedures for warmup and neither of us had any issue.

I've heard some of the consumption is actually a piston/cylinder wall clearance tolerance that was either not in spec from the manufacturer or has proven to have a variance that is causing some cars to consume additional oil. I guess my R will tell the tale for me once it's ready to rip and I start back on my normal driving habits. I don't drive the car like a sport bike revving to 5k on each shift etc. while cruising around. Some do and if it's your car that's your right to do so, but I feel like I have to agree with the OP on driving habits coupled with break in procedures etc. Have a friend who bought his car used and I feel it has had a hard previous life and it now consumes lots of oil and is currently under dealer oil level monitoring. Time will tell if there is ever a real explanation I suppose.

mustang1 said:

this may or may not apply :

http://www.c5registry.com/2k2z06/page5.htm
Issues: Oil Consumption and Cold Piston Knock

"We have seen a greater percentage of complaints than we’d like about oil consumption," John admitted. "The condition under which we get that oil consumption is high-rpm, light-load–like if you drive in a city schedule but never take the car out of second gear. In that situation, the piston rings can get into a flutter condition and that’s when the oil consumption takes place."

Piston ring seal depends on a balance of four forces: combustion pressure, ring inertia, the ring’s radial expansion pressure and crankcase pressure. Ring flutter is uncontrolled oscillation due to an imbalance of those forces. Once a piston’s rings go into flutter, their ability to scrape oil off the cylinder wall as the piston moves downward is impaired, blow-by increases and oil consumption rises dramatically.

The combination of high rpm and the low crankcase pressure typical of low engine loads causes those four forces to become imbalanced. The small amount of LS1s and LS6es that see regular, high-rpm, light-load operation may suffer high oil consumption.

"The severity of this problem is specific to the driver," Juriga continued. "You can take a car that is a major complaint for one customer and give it to another customer who’ll have (different driving habits and) no complaints and get 5000 miles to a quart."

The common sense is that high-speed and light-load is not a duty cycle typical of normal use, even for an engine in a car like a Corvette. Who drives around town running 4000 or more rpm at part-throttle?

"It’s not the way most people normally drive," John agreed, "so it has not been a substantial part of our normal durability schedule.

...

Click to expand...

Interesting very cool find kind of mirrors my thoughts!

I love this part!

The common sense is that high-speed and light-load is not a duty cycle typical of normal use, even for an engine in a car like a Corvette. Who drives around town running 4000 or more rpm at part-throttle? Answer= those with flat plane cranks that sound badass at 4000rpm!

It is normal... all other cars behave similar...

Some BMW's use up to a quart of oil per 500 miles depending on driving habbits. My M5 used to drink about that, but it was also hard not to take a V10 to 8000 rpms.