Mobil1 causing misfire/stalling on blown engine?

[2015R8]

Hi folks,

I've recently had a lot of trouble with my supercharged HSV with an LS3 motor in it and wanted to get some opinions from those in the know.

Short version for those that don't want to read my thesis below: could viscosity of oil cause engine running problems? (misfire, stalling, blowing smoke).
I had these issues with Mobil1 5W30, and now the problem has gone away with Castrol Edge 10W60.


Long version: I have an HSV Clubsport with an LS3 engine. Recently I had a supercharger fitted and tuned by a pro.

The car ran well after the install for 2 days, then started blowing a little bit of smoke. I took it back to the tuner who plugged in his laptop, he said the MAP sensor seems fine and all other variables are doing what they should.

While he was looking at the car, it got worse and started misfiring, stalling and running very rough at idle.

Then it wouldn't start at all. Seemed like an electrical problem as the dash would light up and gauges would jump all over the place. We had to get it towed to a dealership who replaced the alternator under warranty. While it was there I had them change the oil and filter, I have always put Mobil 1 in it myself and assume they do so too as its recommended by the manufacturer (possibly they're putting cheaper oil in though).

I took the car back and it was ok for a couple hours when it started blowing heaps of smoke, stalling, running rough again.

Back to the tuner I go and he asks me to leave it with him for a few days to investigate.

He tested the injector harnesses, valve stems, did a compression test, tested all electrical connections, checked the catalytic converters - all seemed fine.

Then he finally decides to check the oil and noticed its almost like water. He puts Castrol Edge 10W60 in it and a new filter, and its been fine ever since. He doesn't see how changing the oil could fix this problem, and neither can I. But.... the car is running nicely and has done for about a week (over 1,000 kms).

Mobil 1 is what's used from factory and I'm sure there's thousands of engines like mine running it. Even the GTS (Chevy LSA) version of my car uses Mobil 1 and that's supercharged from factory.

My car is running 8.5 pounds of boost.

 

[Koz1]

http://www.lsxtv.com/tech-stories/engine/preparing-your-ls3-for-surviving-boost/

650 Horsepower

At or around 650 horsepower with a boosted LS3, you won’t be stretching the limits of the internal components or the block. The LS3, like many of the other modern engines that are in production today, are more than strong enough to handle much of what you can throw at it, to an extent anyway. Many individuals and engine builders have pushed the LS3 into this realm of horsepower on the stock internals without fault. However, it is considered a good idea at this point to invest some money and do some overhauling of your short block.

At 650 horsepower, all our builders agreed that the stock GM crankshaft will handle boost like a champ and all agreed that there is no dire need to swap it out. For rods, some recommended stepping up to a set of steel, forged rods from reputable manufacturers such as Wiseco, or the H-Beam’s from Carillo. According to Borschke, aluminum rods are only suggested for use in full-on LS3 race motors, and unless you’re going that route, recommends sticking with steel.

Stenod Performance always upgrades customers’ engines once they exceed the 600 rear-wheel horsepower mark. These upgrades include cylinder head bolts, or most often, head studs, along with main stud bolts for additional clamping force to keep the rotating assembly from walking around.

Graham Behen, Chief Engineer at Lingenfelter Performance Engineering, explained that once you begin to push the LS3 200-plus horses beyond stock, an issue that can arise is oil blow-by caused by the excessive wearing on piston rings from the added boost.

“We have an oil/air separator, which essentially comes from the diesel engine technologies. What we do is plumb into the breather system, and return the oil from that which is pulled out of the air back into the pan with a scavenge pump. As these engines get larger and larger displacement in a smaller and smaller package size, oil control is a main problem once you start boosting these things,” said Graham.

Mobil 1 0w40 is run in Super Cars 10w60 might mitigate the problem but I doubt it fixes the problem.

 

[2015R8]

Thanks for the link. I'm not anywhere near that horsepower though.
Dyno tested at 476 HP at the wheels.

Still a catch can would be a good idea, a lot of guys I know with similar engine configurations run one.

 

[2015R8]

forgot to mention the spark plus were replaced and 6 were fairly fouled. It's starting to make sense...

Very surprised the tuner didn't mention blow-by, he was happy to charge me a lot of money to diagnose the problem though.

 

[Rat407]

Oil was like water? Sounds like it is running rich and getting serious fuel dilution. Oil is good for a few miles and then gets watered down. Just a thought. I know it is better to run rich than lean but then how much is too much?

 

[Trav]

Originally Posted By: 2015R8
Thanks for the link. I'm not anywhere near that horsepower though.
Dyno tested at 476 HP at the wheels.

Still a catch can would be a good idea, a lot of guys I know with similar engine configurations run one.


How big are the injectors in this engine, 475 HP isn't that much for that engine. Injector type, size and spray pattern play a big role in boosted engines.

 

[Brybo86]

I agree it sounds like it was running really rich and the oil got Diluted with fuel

Fouled plugs fall in line with this explanation as well

 

[440Magnum]

The oil is about the last thing I'd blame, and running 10w60 in an LS tells me that its band-aiding a much bigger problem. There's no reason that an LS at only ~500 wheel horsepower would need it.

Either the oil is getting horribly fuel-diluted as others have speculated, or maybe you broke a few rings and the 10w60 is hiding the problem. Either way, the problem will likely come back in a big way when the grooves in the cylinder walls get big enough...

 

[Jim_Truett]

I don't buy it either. Especially at that power level. There has to be more going on here. I've boosted a few cars in my day. I would look for detonation under load and the possibility of broken ring lands on the six pistons that had the fouled plugs. Sounds like detonation destabilizing the Pistons and ring pack.

 

[SteveSRT8]

Outrageous story. Does not line up with anything I have ever heard before.

I have rebuilt a drag racing engine that had all the top rings broken. It still ran fine, just would not idle well. When disassembled it had a broken main bearing web in the block, too. It could still burn 'em all the way down the street.

Heavy damage may have occurred, this sounds serious...

 

[kschachn]

The stuff people attribute to oil is amazing.

 

[CKN]

Originally Posted By: kschachn
The stuff people attribute to oil is amazing.



Yep!THIS^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

 

[Nick1994]

Originally Posted By: CKN
Originally Posted By: kschachn
The stuff people attribute to oil is amazing.



Yep!THIS^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
Yup

 

[demarpaint]

Originally Posted By: CKN
Originally Posted By: kschachn
The stuff people attribute to oil is amazing.



Yep!THIS^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^


Absolutely amazing.

 

[2015R8]

The car has 60 pound injectors in, the tuner said its running slightly rich but nothing abnormal, I'll try to post up the dyno report that shows the afr.
A compression test was done on the car and it's good.

 

[Ram01]

Do not blame Mobil 1.

 

[2015R8]

If fuel was contaminating the oil, surely fuel economy would have gotten worse? In the last week it's actually improved over the stock engine.
I'm wondering if the workshop originally stuffed something up, then fixed it but have been playing dumb so that they can charge me to diagnose the problem.
Something as simple as a damaged injector harness could have caused this.

 

[2015R8]

Originally Posted By: Ram01
Do not blame Mobil 1.


I'm not, but the workshop blamed it completely.

To paraphrase them "Mobil 1 is [censored], don't use it"

I've used it for years and it's always been great. It's not the brand of oil I'm thinking about, it's the viscoscity highlighting a deeper problem with the engine.

 

[CT8]

This is Bob Is The Oil Guy so is Mobil 1 causing misfire/stalling on blown engine? Why not.

 

[2015R8]

Originally Posted By: CT8
This is Bob Is The Oil Guy so is Mobil 1 causing misfire/stalling on blown engine? Why not.


Apologies sir. Thanks for your contribution.