Cause of lifted ring lands on pro charger motor
 

As it says , what could be some causes of lifted ring lands on a procharger motor ? This was a fuel injected motor

The only thing that will lift the ring lands is detonation. Why did it detonate is the magical question.

What was the timing? Boost? Compression? Cylinder heads? Camshaft?

Cast iron world heads , timing don't know, it was a stock MpI motor, May not have had a good tune on it then.

This is a friend of a friend that had this issue, I don't know all of the details.

Just getting some possibilities for him. I thought detonation also when he said he had cast iron heads and too much timing or no boost retard set in the program.

TurboJack wrote this on a duplicate post

Detonation.

Detonation is caused by too much timing, engine to warm/hot, too much boost, lean afr, and octane of fuel.

Give us more details and we can figure out why.

I learned back in the late 70,s what detonation was when I blew a hole in a piston with a 850 HP gale banks twin turbo setup.

Too much timing, not enough timing, too little fuel, too much fuel, too much boost, too hot of intake air charge (clogged intercooler), too hot of a spark plug, too hot coolant temps, intake tract sucking oil in from somewhere, all things that can contribute.

I heard it was only 7-8 lbs boost on an M3

It was not a stock MPI motor.

So, if the tune was for a stock motor, that may have needed changing.

Furthermore, the ATI method of 'tuning for a supercharger' has always been a lackluster, not too mention their fuel systems themselves.

The stock 502 pistons and rings can usually take quite a beating....the headgaskets usually can't...but again, the heads and headgaskets have been changed to something stronger than OEM.

Funny. This all seems that it has nothing to due with the procharger, These are normal issues you need to deal with on a forced induction motor, He is removing and going NA this time around.
He just wants to from a to b and doesn't want to deal with the extra hassles of forced induction

Me no comprendo.

This stuff pertains to N/A engines as well.

I think that "only 7-8 lbs boost" may have something to do with it. This isn't the motor sitting in Tony's shop is it?

Actually I think it's worse with a N/A motor and some compression.

Not hard to figure out really, the stock timing curve on most mercuruiser efi programs goes to 35 degrees or so at wot when base timing is set at 8 properly, too much timing for boost really,they use a mefi2 or 3, I went to a mefi 4 that has a timing boost retard table, I pull mine down to 32/33 under boost using a -2, -2.5, -3 on the table. Procharger tells you to set base timing at zero or 4 degrees , cant remember its been so long since I paid any attention to there half ass instructions, but when you do this bandaid they want you to do the boat will barely idle and load up at part throttle so first thing everyone does it turn it back up. My 540 detonated on dyno even at 7 or 8 psi of boost when we tried 2 more degrees of timing past 33 total and its 8.2-1, a stock 8.8-1 iron headed motor will be even worse, prob had too much timing and or not enough fuel, fwiw, Smitty

Artic What fuel ratio range have you found to be ok with the procharger under some boost WOT 11:1 give or take?

yes, everyone thinks cuz its NA , this stuff doesnt happen. A NA engine can have as much, if not more PEAK cylinder pressures. Many have a hard time understanding this. Kind of like if you compared say an 8.5:1 blown engine with 7lbs of boost. Lets say that gives an effective compression ratio of 12.5:1, but can run on 93 gas all day, and maybe an NA, with 12.5:1, will detonate sooner on the same octane. Supercharging doesn't really increase the peak cylinder pressure, it increases the pressures from BDC to TDC more so, from better cyl filling. As the power per cubic inch increases, the chit hits the fan alot sooner, whether NA, or blown. An engine making .7HP per ci, is gonna be alot more tolerant than an engine making 2hp per ci.

7-8 lbs boost with the stock map was a grenade waiting on pin removal,stab gas and BOOM.

also increases cyl pressure from whatever advance before tdc ignition starts until the exhaust valve starts to open due to the xtra air-fuel charge from the supercharger or the xtra squeeze from higher compression ratio on the n/a engine.

some boost,,what do you mean by that?
I tuned some 540's w/ afr 335's and 8.5-1 comp ratio in a 382 fastech w/ arneson's,0-4lbs of boost is in the 12.2/3 range w/ 33° of timing,5-7lbs gets 11.6/8 w/ timing at 32° and 8-10lbs gets 11.2-11.4 w/ 31° timing.boats run a best so far to 112mph in the ocean.btw,I set up his cylinder heads.
video of us after some lower load cell fuel trimming
https://youtube.com/watch?v=OhwGR64_Ghw

That's how you make it rain!

Define "some" boost, at 14 lbs I shoot for11.2 to 11.6, made decent power there too, above 12.0 went down hill, below 11.2 dropped fast too. At 0-5 psi I start around 12.0 to11.8,

Pretty much EXACTLY how I tuned mine too

Now that's a Performance Boat.

Plain & simple, if you are running the procharger kit for a merc EFI they way they say to do it, the pin has been removed, their bandaid setup for the fuel/ECM is just that...a joke, all they do is jack of the fuel pressure to hopefully get by. pretty much a pull and pray method. if you want it to live need to fix the fuel rain issues, change the entire fuel delivery system and have the ECM tuned(at least) or upgrade the ECM to a aftermarket setup, ck with Haxby speed or Youngs performance, both know the deal very well, one other is to trash the merc EFI and swap to a blow thru carb or complete aftermarket EFI...good luck

Artic and Sutphen thanks for the feedback I was thinking 5-7lbs on a 502 carbed set up Ill shoot for 11.5