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They talk about direct injection but wonder if this had any effect on the gen1 cruzes.
New Oil Technology Needed to Prevent Super Knock
New Oil Technology Needed to Prevent Super Knock
Interesting Info about LSPI.
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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 ..
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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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.
The second gens, those few that have had piston issues, it is always on cyl #1.
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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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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.
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.
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
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
Terry
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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.
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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Boroscope in the spark plug hole.
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