Why a broken ring land @ 10psi with mahle?
Why a broken ring land @ 10psi with mahle? Its been absolutely perfect running for approximately 10k and haven't changed a thing. The whole scenario here is that I made a drive of around 50 miles coming home on the freeway normal cruising when the SES light lit. I automatically assumed it was the MAF sensor circuit as with a previous case so when I got home, it was removed and cleaned. The next drive the light turned itself off and ran just normal. Then the next time, the light came on with the ignition turned on and started. It remained on for following start ups throughout that afternoon. On my way home, I hopped on it in second gear gettin on the freeway, shifted to third then eased out when I reached speed. I shortly noticed a slight vib then soon realized it dropped a cylinder, got home and parked it a few miles down the road. I pulled plugs on the drivers as the expected misfire side and they all looked perfect till no. 7 which was broken and battered. Pulled the head off and my assumptions were realized. But why would this happen on only 10psi boost and a very good dyno tune? The engine was fully built by a very reputable builder and tuner. I have yet to contact them because it's nothing to do with the builder but will probably be ordering parts through them.
Set-up:
Stock bore, stroke, block
Mahle 9:1 forged, callies rods
ETP heads, comp cam
STS @ 10psi
Dyno tuned by builder
Set-up:
Stock bore, stroke, block
Mahle 9:1 forged, callies rods
ETP heads, comp cam
STS @ 10psi
Dyno tuned by builder
Never pulled the code/s. Its only ever had the MAF air circuit sensor low. The MAF is new with the build, last fall. I don't have any way of getting the code since the builder/tuner is 200 miles away and he's the closest.
If the MAF was freaking out then it could have just gone lean and detonated. Also, sometimes MAF's have trouble keeping up with boosted airflow, just a thought. Sorry it happened man.
8 sec potential, 12 sec slip
iTrader: (50)
Joined: Apr 2002
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From: Savannah, GA
Looks like another related case to those crap dished Mahle pistons. Check out this thread: https://ls1tech.com/forums/forced-in...7-lbs-why.html
Teching In
Joined: Aug 2007
Posts: 47
Likes: 0
From: Greenville, South Carolina
Looks like another related case to those crap dished Mahle pistons. Check out this thread: https://ls1tech.com/forums/forced-in...7-lbs-why.html
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Verdad Gallardo Looks like another related case to those crap dished Mahle pistons. Check out this thread: https://ls1tech.com/forums/forced-in...7-lbs-why.html
As far as fuel goes, always highest octane pump, same type gas.
Ive never had a good feeling about Mahle's.Never personally used them, just from others experiences. Really didnt like them after that thread about the SLP motor and Mahle pistons that blew up.
Well seriously I've had the worst luck possible with this car so it came to no surprise. This is the longest time it has run since the last engine build. Its aptly named project nightmare. It blew the stock pistons(expected) two years ago, ate a rocker that wiped out the first new build last year and now this. Its just been ongoing and cost me what I have invested in my 6 year bachlor's degree. This time I will be doing the work for I cannot and will not drop another 6k in R&R.
Definitely sounds like something caused it to detonate. Thats the only thing thats going to destroy a spark plug and break a ring land. Had to be some pretty nasty/sustained detonation to break a forged piston.
My best guess would be that your MAF may have caused a lean condition, and if you run lean long enough and build up enough heat, you're going to get detonation. Which creates the damage you have to your engine.
My best guess would be that your MAF may have caused a lean condition, and if you run lean long enough and build up enough heat, you're going to get detonation. Which creates the damage you have to your engine.
If it was throwing a MAF code that means it reverted to speed density which on the factory style setup means it was probably lean as hell and was detonating like crazy when you were getting in to boost. Doesn't sound like the piston's fault to me.
I think you are spot on. The broken piece of piston and ring are what wiped out the plug. I think I made the mistake of running it into boost when it was not properly reading.