# Interesting Info about LSPI.



## dhpnet (Mar 2, 2014)

The video says Low Speed Pre-Ignition is a problem for direct injection engines, and the computers are programmed to avoid LSPI. Sounds like it is a potential problem for Gen2 engines more than Gen1.


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## brian v (Dec 25, 2011)

You guys with the newer GDI turboed 1.4 engines should not have to worry about LSPI unless you tune the precautionary code out of the ECM.s .

Todays oils with high flash point tolerances minumizes the possibility of LSPI from windowing a engine block ..

There are other concerns about preignition though .
Connecting rod ends have been letting go under the stresses of preignition ..


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## jblackburn (Apr 14, 2012)

The piston damage on the older 1.4T's does look a bit characteristic of LSPI where it blows a chunk out of the piston between the ringlands. No one seems to really be sure why it happens in the first gen motors, and it seems to pick a random cylinder as well.

The second gens, those few that have had piston issues, it is always on cyl #1.


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## EricSmit (Dec 21, 2016)

Cylinder #1 is disposable anyway.


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## XtremeRevolution (Jan 19, 2012)

brian v said:


> You guys with the newer GDI turboed 1.4 engines should not have to worry about LSPI unless you tune the precautionary code out of the ECM.s .
> 
> Todays oils with high flash point tolerances minumizes the possibility of LSPI from windowing a engine block ..
> 
> ...


LSPI is low-speed pre-ignition. You kind of contradict yourself by saying people don't have to worry about LSPI, then saying that there are other concerns about pre-ignition. 

Flash point has little or nothing to do with LSPI. LSPI is caused by the rapid oxidation of oil droplets. That oxidation comes from a number of sources. I bought an SAE case study (that has been widely misinterpreted) last year that outlines some testing performed by Toyota to try to reduce the frequency of LSPI. To quote the article directly, "Toyota has reportedthat the oxidation stability of engine oil can be a dominant factor of its auto-ignition, which is a function of its base oil andadditive components." 

Unfortunately, the test was not at all scientific. Toyota found that reducing calcium-based detergents reduced the frequency of LSPI, but they didn't just change the detergents, they also changed the base oil (and therefore volatility) of the oil, among other factors. Their data also suggests that this was not a scientific comparison. For example, they have a list of products tested. 

Product A, with 0.24% Ca, 0.08% P, and 0.07% Mo tested at 1.00 LSPI frequency; the reference oil. 
Sample J, with 0.20% Ca, 0.09% P, and 0.05% Mo tested at 0.17% LSPI frequency. 

If the mere reduction of Ca results in lower LSPI frequency, it should take more than just 0.04% to drop LSPI frequency to ~1/6 that of the reference oil. They go on to state that other factors involve increasing the amount of P in ZnDTP and increasing the amount of Mo in MoDTC or an anti-oxidant with Mo, which further validates that the problem is oxidation stability, and all other changes are a consequence of that. 

If anyone else wants to buy the study, here's the link: Engine Oil Development for Preventing Pre-Ignition in Turbocharged Gasoline Engine


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## brian v (Dec 25, 2011)

You 've answered my ? Andrei .
What exactly is detonating during LSPI ? 
1 should also remember that this phenomena is a rare instance that can happen when going to full throttle from a low speed and low RPM .
change your oil regularly ...


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## XtremeRevolution (Jan 19, 2012)

brian v said:


> You 've answered my ? Andrei .
> What exactly is detonating during LSPI ?
> 1 should also remember that this phenomena is a rare instance that can happen when going to full throttle from a low speed and low RPM .
> change your oil regularly ...


During LSPI, it's the engine oil that's pre-igniting, which in turn ignites the fuel. 

Note that this is only with respect to engine oil. There are more factors that affect LSPI, which include the tune, the fueling hardware design, temperature, pressure, and solid deposits around the combustion chamber.


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## a2chris (Jan 13, 2017)

So the engine is a gas/diesel hybrid. They should just use the stronger pistons from the diesel:smileystooges:


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## Terry B (Oct 18, 2018)

*2017 Cruze - Piston Problems*

My 2017 Chevy Cruze Premiere is in the shop now because of LSPI - all 4 pistons are being replaced, rings and gaskets. Unfortunately, since GM won't replace the motor, I will be getting rid of the vehicle. No guarantee that the motor isn't already damaged. It's a shame that driving 25 mph can cause LSPI to occur. GM called it a "design flaw", I'm calling it a waste of my money and now when I go car hunting I'll need to stay away from GM, Ford and Honda vehicles as all have been using the same downsized, boosted engines that can easily slip into LSPI.


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## MP81 (Jul 20, 2015)

How is that not covered under the PT warranty (unless you're outside of it)? Did you run premium fuel?


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## Robby (Mar 1, 2013)

Terry B said:


> My 2017 Chevy Cruze Premiere is in the shop now because of LSPI - all 4 pistons are being replaced, rings and gaskets. Unfortunately, since GM won't replace the motor, I will be getting rid of the vehicle. No guarantee that the motor isn't already damaged. It's a shame that driving 25 mph can cause LSPI to occur. GM called it a "design flaw", I'm calling it a waste of my money and now when I go car hunting I'll need to stay away from GM, Ford and Honda vehicles as all have been using the same downsized, boosted engines that can easily slip into LSPI.


Although all 4 pistons are being replaced I suspect only one has damage. As long as there is no damage to the bores (and there isn't, otherwise the short block would be replaced) I would not give up on the car so quickly.
Humans assembled the engine on the first go around and a human is assembling the engine now. Odds are this assembly will be more accurately built anyways since the engine isn't being chased down a assembly line.
Although you have not disclosed the current mileage you likely have a lot of powertrain warranty remaining so, why not continue to operate this car once the repairs are completed?

Evidently some type of redesign has taken place since all 4 are being exchanged......likely heftier in areas that needed it so the pistons can handle the occasional high pressure moment......you might end up with a better engine.

Just my thoughts.....but if the service appears well done and sanitary (wire harnesses reclipped, hoses correctly routed, etcetera) I'd say keep on cruzin in this car.

Rob


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## Terry B (Oct 18, 2018)

Rob - It has 25,400 miles on it. I will think about your advice, thank you. I really love the car - but I don't want issues down the road. Getting close to retirement and I don't want repair bills. I must admit, it's a beautiful car, and it rides very well. From all I've read on LSPI, it can ruin an engine completely. Unfortunately, I'm not mechanically inclined and I'm wary on how to know if this is a patch job or if fixed. 
Terry


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## jblackburn (Apr 14, 2012)

Terry B said:


> Rob - It has 25,400 miles on it. I will think about your advice, thank you. I really love the car - but I don't want issues down the road. Getting close to retirement and I don't want repair bills. I must admit, it's a beautiful car, and it rides very well. From all I've read on LSPI, it can ruin an engine completely. Unfortunately, I'm not mechanically inclined and I'm wary on how to know if this is a patch job or if fixed.
> Terry


It CAN, but it usually doesn't in these motors. Usually the #1 piston cracks around the ringland, causing lost compression and blowby. The cylinder walls aren't usually damaged when this happens, fortunately.


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## alanl11 (Apr 8, 2018)

Terry B said:


> Rob - It has 25,400 miles on it. I will think about your advice, thank you. I really love the car - but I don't want issues down the road. Getting close to retirement and I don't want repair bills. I must admit, it's a beautiful car, and it rides very well. From all I've read on LSPI, it can ruin an engine completely. Unfortunately, I'm not mechanically inclined and I'm wary on how to know if this is a patch job or if fixed.
> Terry


 There has been a lot of threads about LSPI ad the Gen 2 16.5-17 the I haven't seen any failures yet on the 2018 maybe GM is using stronger pistons and is why you are getting all 4 replaced.
A couple things you can do to help avoid it would be
Number one Use only Tier one premium 91/93 octane fuels
Number Two Use 100 percent synthetic Amsoil, though "full" synthetic oils claim to be synthetic they start of with a petrolatum base 100 percent synthetic is just that 100%.
Gm's Dexos standard allows for oils to have up to 4 LSPI events during testing. Though Amsoil is not "Dexos" approved that is simply because Amsoil won't pay GM for licensing fees. But it had ZERO LSPI events in all of it's testing.
I know it's an economy car and I believe that's why there are issues as GM is trying to squeeze out every MPG and they don't want to recommend High Octane fuel that would defeat the purpose of an Economy car.
Plus your car will run a lot better and a little more spirited on High grade.
Some like myself have actually used a tune along with the above, tunes will be programmed to help eliminate LSPI and make the car really more fun to drive.

PS and like yourself I am getting near retirement so I don't beat on my car but love the increased mid range power the extra 63 HP and 92 lbs of torque gives me.


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## Terry B (Oct 18, 2018)

Thank you, how do I know if the cylinder walls were damaged? Is there an easy way to tell?


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## Terry B (Oct 18, 2018)

I will try the high octane gas. The #1 piston is the one that failed.


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## snowwy66 (Nov 5, 2017)

What brand oil? Was it dealer serviced or elsewhere? What octane gas?


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## jblackburn (Apr 14, 2012)

Terry B said:


> Thank you, how do I know if the cylinder walls were damaged? Is there an easy way to tell?


Boroscope in the spark plug hole.


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## Terry B (Oct 18, 2018)

Thanks - I have no clue what that is, but will ask around.


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## alanl11 (Apr 8, 2018)

Terry B said:


> Thank you, how do I know if the cylinder walls were damaged? Is there an easy way to tell?


I would go to the dealer and ask to see the engine while it is still taken apart so you can see for yourself if there is any scoring of the cylinder walls,


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## Robby (Mar 1, 2013)

I don't think a borescope is needed since the head is on the workbench, heh heh.

Anyways, trust me on this.....there is no such thing as a dealer (or any real mechanic) willing to put pistons in a damaged bore.....that is a guaranteed comeback.

For whatever it is worth, the genII aluminum block has steel sleeves cast in place. These are so hard they can take a real beating and not be harmed......much more tolerant than the genI cast iron block.

Terry B........I AM retired and fully intend to continue replacing cars.......I hope you are not one of those 'This is gonna be my last car' types.
When I pull out of a dealer with a new ride (two years on average) I'm so excited I can't wait for the next one!

Anyways, IMO, don't frett....let them do their thing and report back.....they aren't re-inventing the wheel or anything. To you, sounds major, to me, (semi retired wrench) it's just another repair.

Rob


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## theshiftyjelly (May 26, 2018)

Terry B said:


> My 2017 Chevy Cruze Premiere is in the shop now because of LSPI - all 4 pistons are being replaced, rings and gaskets. Unfortunately, since GM won't replace the motor, I will be getting rid of the vehicle. No guarantee that the motor isn't already damaged. It's a shame that driving 25 mph can cause LSPI to occur. GM called it a "design flaw", I'm calling it a waste of my money and now when I go car hunting I'll need to stay away from GM, Ford and Honda vehicles as all have been using the same downsized, boosted engines that can easily slip into LSPI.


What were your symptoms for you to take it in if I may ask?


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## Terry B (Oct 18, 2018)

It was a small shake or shimmy at low speed. On the highway doing 70, car ran great. In town felt like I was riding in a tank.


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## Terry B (Oct 18, 2018)

Thank you, no trouble since the repair was done.


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