BrianV

iTrader: (9)

Many people know of my engine failure last weekend. My car had been supercharged for about 1,500 miles. Total miles on the car were 79,000. Driving home from San Francisco at a steady 90-95 MPH I apparently melted piston 1 and 5. No damage was done to the head, block, or other cylinders. However, 1 and 5 just the piston was severely melted. Thus, I had to replace the engine. Anyways, I was curious if anyone knew why this happened, and what I can do in the future to prevent it. The car had brand new Mobil1 5w-30 (I'm religous about changing it every 2,500 miles). Also, the oil hadn't burned, the water temp hadn't risen, and there was no pinging or smoke or anything. It's almost as if those two cylinders got fuel starved.

My mechanic asked me if I was running racing fuel, but I wasn't just 76 Premium gasoline. However, two tanks before that I did run that Chevron Fuel System Cleaner (something I do about once a year). He said it definately burned through my system by two tanks, but those additives do make your engine run hotter so it burns away the carbons. If anyone has any expertiece with these additives, your comments are wanted. I do not plan on running that stuff in the future because I don't want to take the risk of that being the cause of my piston meltdown.

Thanks,
BrianV

deezo

iTrader: (3)

I know your trying to find the answers as to what happened to your pistons but do you think the additive could have really done this? I've never heard of additives making the internal temps run higher.

MardiGrasMax

iTrader: (14)

Well their is an off chance that some debris got stuck in the fuel injector for those two cylinders. You did JUST have the SC installed and part of this involves fuel lines and fuel parts.

Were you boosting at 85-90mph? Do you have your boost fuel pump wired up to run all the time? Are you running one step colder plugs?

BriGuyMax

iTrader: (1)

Wouldn't the ECU throw a "misfire" code if he was fuel starved in a cylinder??? I could be wrong...

MardiGrasMax

iTrader: (14)

Maybe, Maybe not.

BriGuyMax

iTrader: (1)

well that helps alot!

I got a misfire code last week...engine started running REALLY rough...so I pulled the plugs when I got home...and the number 1 cylinder plug's diodes were melted together!

All the other plugs were PERFECT...

1MAX2NV

iTrader: (5)

Maybe a pinched fuel line?

Chunger

iTrader: (1)

I was running a Redline FI cleaner in my tank up to SLO and Santa Cruz... I've used the Chevron stuff before (but not since the S/C)...

I don't think that would have caused your problems though, Brian.

You never answered my ? about how much boost and what ratio FMU you are running...

Shadow

iTrader: (15)

I got a misfire code for my #5 cylinder yesterday, but the car still ran fine. The CEL came on when the car was just idling, so I have no idea what happened.

BrianV

iTrader: (9)

6PSI, and I don't know the settings on the FMU. What setting do you recommend Chunger? I'll tell my mechanic that.

I'm pretty sure it's set to run all the time.

Chunger

iTrader: (1)

The original pulley gives you 6-7 psi and should include a 6:1 FMU, even for the V1, I think. That's what i am running now.

You can hear the aux fuel pump when it's on. If it's hooked up for full time, it'll be loud at idle. If it's run through the Hobbs switch, it surges whenever you go in/out of boost.

BrianV

iTrader: (9)

Mine is definately on full time. Is the FMU adjustable?

MardiGrasMax

iTrader: (14)

IMHO somthing in your fuel set up is installed wrong. I have only heard of this happening to one SC Max. The vacuum line to the FMU was unplugged on a dyno run with 10.5psi and he burned some pistons also. Go over the fuel lines, vacuum line and fuel pump electrical again. I bet your mechanic screwed somthing up.

1MAX2NV

iTrader: (5)

I agree. Some sort of fuel delivery problem. Steve from philly had the same thing happen. Once was running low on gas and the other time was a kinked/pinched fuel line.

brubenstein

Melted pistons are caused by lean mixture/high temp. Your oil will only help prevent the piston from seizing to the cylinder wall. I would guess that either you weren't getting enough fuel to the two cylinders, or there is uneven coolant flow through the engine causing those two cylinders to run hot (design problem).
In the future, run for a few miles at high speed and then pull the spark plugs. See if any plugs have melted electrodes or damaged center insulators (they will all be white). Any damage to the plugs indicates high temperature.

MardiGrasMax

iTrader: (14)

Couldnt have happend to a nicer guy...

1MAX2NV

iTrader: (5)

Matt...so whatever happened to the motor?

Chunger

iTrader: (1)

Brian, the FMU that comes with the kit is not adjustable but you can recalibrated it with a kit from Vortech... but with your 6psi... that shouldn't have been the problem IF everything was running the way it was supposed to... Some good suggestions were given above.

MardiGrasMax

iTrader: (14)

I disputed a fair proportion of the total purchase price, just the motor and a few other items that were misrepresented, with my credit card company. After six months of letter writing my credit card company decided in my favor. However I cant use paypal anymore... OH WELL!!! I still have all the items to, so I will soon open the motor up to see what was knocking.

thebigsadler

iTrader: (4)

You know Jeff, I just realized this and I am now thoroughly confused, but hurry up and get those colder plugs.. all that work and if your plugs foul or whatever that would suck..

demian

Hey Brian, I saw your car the other day at the shop. I've never seen anything like it! It's crazy. That sucks dude. At least they found you another engine quickly. I know what it's like to be out of a car for a long period of time. Good luck!

BrianV

iTrader: (9)

Yeah it sucks not having a car. Anyways, it looks like your car is pretty much done now.

Ramius83

Brian, did you end up selling all that stuff that you had for sale in the F/S Forum?

BlkCat

76 Octane? I always run with Chevron 92 or 94 Octane.
Last week I accidentally put in Shell Gold (91 octane) and I could hear engine ping when I really push the pedal to the metal. I then tried to dilute it with Chevron 94 and later on 92. So far the pinging has disappeared since.

Chunger

iTrader: (1)

I think he meant UNION 76 Premium (91 Octane)... that's all we have available in California now (except special places with race gas)

Your NA car pings with 91 Octane?

BriGuyMax

iTrader: (1)

BlkCat is S/Ced

BrianV

iTrader: (9)

From my experience Mobil has been the best gas for my Maxima for both performance and mileage.

Anyways, I get my car back today or tomorrow and does anyone have any suggestions for stuff I should have the mechanic check right before I drive it off?

Chunger

iTrader: (1)

That sneaky guy...

Brian, the mechanic should have it in 'driving' condition before he gives it back to ya. I would take it easy on the engine/SC. Listen for pinging/predetonation etc... Good luck!

BlkCat

Ohhhhh Union 76! We don't have them up here...

I was pretty close to the bottom of the gauge and I loaded half a tank of Shell 91 octane. In some spirited driving right after that I started to hear that ticking sound of premature combustion. I said "Huhhhh???, never heard that before and started to search for a Chevron station. Is that because I've been running on 92 octane for a long time?
I will never, ever buy (if I can help it) from a gas station that doesn't put up octane labels.