Detonation destroyed engine update

[TJC]

Did the engine oil used have the correct ratings as called for in the owner's manual? The correct oil has additives to help prevent low speed detonations (Low-Speed Pre-Ignition) which is very destructive.

https://www.valvolineglobal.com/en-ksa/what-is-lspi/

Yet another reason I moved to Valvoline Protect and Restore 5w30. The info below is straight from Valvoline website.

Better suited to modern turbo/GDI engines. Restore & Protect is specifically formulated for turbocharged and direct-injection engines and includes LSPI protection, which is particularly important in small turbo GDI engines.

Much newer oil specification. The current Restore & Protect 5W-30 meets API SQ / ILSAC GF-7A.

Deposit control is a major advantage. GDI/turbo engines can be particularly sensitive to piston and ring deposits. Restore & Protect's Active Clean technology is designed to remove deposits over repeated oil-change intervals and prevent new buildup.

Valvoline Restore & Protect has 79% stronger anti-wear protection versus GF-6-qualified oil.

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[oldnslow]

The engine oil should never be in the combution chamber, so it can't affect detonation. Be careful what you read from marketing people. All of those that I met in my jobs were better at throwing BS than understanding how the product worked.

 

[TJC]

The engine oil should never be in the combution chamber, so it can't affect detonation. Be careful what you read from marketing people. All of those that I met in my jobs were better at throwing BS than understanding how the product worked.

I agree that oil should never be in the combustion chamber. But if rings stick from carbon deposits, oil will find its way into the combustion chamber.

 

[RangerBill]

The engine oil should never be in the combution chamber, so it can't affect detonation. Be careful what you read from marketing people. All of those that I met in my jobs were better at throwing BS than understanding how the product worked.

It is a well-known issue with DI engines. There is always a small amount of oil that gets into the cylinder. That is how the piston is lubricated and some gets by the rings.

 

[Cmar]

Yet another reason I moved to Valvoline Protect and Restore 5w30. The info below is straight from Valvoline website.

Better suited to modern turbo/GDI engines. Restore & Protect is specifically formulated for turbocharged and direct-injection engines and includes LSPI protection, which is particularly important in small turbo GDI engines.

Much newer oil specification. The current Restore & Protect 5W-30 meets API SQ / ILSAC GF-7A.

Deposit control is a major advantage. GDI/turbo engines can be particularly sensitive to piston and ring deposits. Restore & Protect's Active Clean technology is designed to remove deposits over repeated oil-change intervals and prevent new buildup.

Valvoline Restore & Protect has 79% stronger anti-wear protection versus GF-6-qualified oil.

I did not realise this was a particular problem, detonation as I said above is a constant risk in a high performance petrol turbo engine and I could understand this when working the engine hard at full throttle when temperatures and combustion pressures, would be at their max. but this low speed detonation due to oil droplets I was not aware of before. I look up a similar spec oil from a local company which produces good quality oils and sure enough here it is, low speed detonation. Formed as a local alternative to imported oils, they are a major supplier to transport, mining, and farming industries.

https://www.gulfwestern.com.au/wp-content/uploads/2021/09/60001_SYN-X-4000-5W-30-2.pdf

 

[seasprite]

After honing, the valleys left from the process are suppose to hold oil for lubricating the rings in the cylinder.
Now if the amount in the valleys is enough to cause LSPI? Need someone smarter than to know that.

 

[RangerBill]

After honing, the valleys left from the process are suppose to hold oil for lubricating the rings in the cylinder.
Now if the amount in the valleys is enough to cause LSPI? Need someone smarter than to know that.

That and ring end gaps let oil into the combustion chamber.

 

[Frenchy]

If it proves to be a clogged injector, then this is another reason to stay with top tier gasoline, and a can of Techron in the tank prior to each oil change.

Keep those injectors functioning in tip top shape.

I personally use Berrymans B-12 every Oil Change. Even with Top Tier Fuel it can help keep the Fuel System Clean.

 

[Frenchy]

No coding required for the 2.3

I was wondering about that. I knew it was a thing for Modern Diesels, but I couldn't recall for Gas Direct Injection.

 

[Frenchy]

Did the engine oil used have the correct ratings as called for in the owner's manual? The correct oil has additives to help prevent low speed detonations (Low-Speed Pre-Ignition) which is very destructive.

https://www.valvolineglobal.com/en-ksa/what-is-lspi/

Good point. Ford has their specifications for a reason and not all oil is the same. Even with the tune I had in my Ranger, I don't recall any issues using Motocraft Full Synthetic.

 

[TJC]

When I supercharged my 93 Miata LE, low rpm detonation was always an issue, and getting fuel and timing curves optimized was critical, as were knock sensors. The problem with knock sensors is that they minimize the damage after the knock occurs. They do not eliminate it, they react after the first knocks occur. It better than nothing, but it is not perfect.

Consider.... Ford puts in a high performance GDI turbocharged engine into a 4500lb pickup truck, and then sets shift points at RPMs so low as to exacerbate the knock issue. Lugging a turbocharged engine at 1100-1800 RPMs is a recipe for disaster... it is just plain stupid. And every auto mechanic worth is salt (as well as automotive engineers) knows this.

 

[RangerBill]

When I supercharged my 93 Miata LE, low rpm detonation was always an issue, and getting fuel and timing curves optimized was critical, as were knock sensors. The problem with knock sensors is that they minimize the damage after the knock occurs. They do not eliminate it, they react after the first knocks occur. It better than nothing, but it is not perfect.

Consider.... Ford puts in a high performance GDI turbocharged engine into a 4500lb pickup truck, and then sets shift points at RPMs so low as to exacerbate the knock issue. Lugging a turbocharged engine at 1100-1800 RPMs is a recipe for disaster... it is just plain stupid. And every auto mechanic worth is salt (as well as automotive engineers) knows this.

The problem with LSPI detonation is that it occurs before the spark plug fires, so timing doesn't affect it. It is also more destructive to the engine in a shorter time frame then pinging is.

 

[TJC]

The problem with LSPI detonation is that it occurs before the spark plug fires, so timing doesn't affect it. It is also more destructive to the engine in a shorter time frame then pinging is.

Thank you for the clarification.

Seems low boost on low RPM lugging eliminated the problem, but impacted performance too much. Life is full of compromises... Reformulating the oil seems to have significantly helped. I suspect changing the shift patterns would have helped just as much, if not more. Ford has probably done both.

I've now educated myself on the topic... See the article below for Interesting read on the issue.

Low Speed Pre-Ignition: Causes and How Engine Oils Combat It
LSPI is a destructive, abnormal combustion event that occurs most often under low engine speed and heavy load conditions.

 

[Cmar]

Hey Airline Tech, is this a significant problem in supercharged or turbo charged piston aircraft engines as well? If so must have been a very big problem in say WW2 aircraft with big piston engines and no electronic controls in those days. I guess the higher octane rating of Av Gas would help, but how much I would not know.

 

[airline tech]

Hey Airline Tech, is this a significant problem in supercharged or turbo charged piston aircraft engines as well? If so must have been a very big problem in say WW2 aircraft with big piston engines and no electronic controls in those days. I guess the higher octane rating of Av Gas would help, but how much I would not know.

I have not touched a piston aircraft since A&P School - I have worked many fleets and engine types over the years from the B-1900 (Smallest) to the B-777 (Largest)
Which are all -Jet-A (Kerosene Based)

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