Melted Pistons - Help
May 10, 2004, 11:12 PM
#1
Newbie
Thread Starter
Join Date: Oct 2003
Posts: 34
Likes: 0
Received 0 Likes
on
0 Posts
Melted Pistons - Help
This is the melted piston (No. 4)
This is the valves oneither chamber 2 or 3
This is the valves on chamber 4 where piston melted
According to tuner:
A/F was between 11.1 to 11.5 at WOT
Intake Temp was about 46 degrees max
Ignition was about 10 at 4000 rpm (onset of boost) and slowly crept up to about 21 between 5500 to 7000 rpm
what i can confirm from my meters:
Compression ratio is 9.0
Boost: running at max 1.65 bar
Ambient outside temperature was abt 27 - 28 degrees (2 am in the morning)
Oil temp die not exceed 82 degrees (sensor at oil pan)
Exhaust Temp did not exceed 720 degrees (sensor at beginning of downpipe just after O2 housing)
My cams settings:
Jun 272 duration Lift 10.8 for both intake and exhaust
Intake 5 degress timing 110
Exhaust 0 degrees timing 115
Was alerted to trouble when car was at about 6500 rpm when the oil pressure alarm sounded
The melting occured on the intake side of the pistons.
any ideas what happened?
This is the valves oneither chamber 2 or 3
This is the valves on chamber 4 where piston melted
According to tuner:
A/F was between 11.1 to 11.5 at WOT
Intake Temp was about 46 degrees max
Ignition was about 10 at 4000 rpm (onset of boost) and slowly crept up to about 21 between 5500 to 7000 rpm
what i can confirm from my meters:
Compression ratio is 9.0
Boost: running at max 1.65 bar
Ambient outside temperature was abt 27 - 28 degrees (2 am in the morning)
Oil temp die not exceed 82 degrees (sensor at oil pan)
Exhaust Temp did not exceed 720 degrees (sensor at beginning of downpipe just after O2 housing)
My cams settings:
Jun 272 duration Lift 10.8 for both intake and exhaust
Intake 5 degress timing 110
Exhaust 0 degrees timing 115
Was alerted to trouble when car was at about 6500 rpm when the oil pressure alarm sounded
The melting occured on the intake side of the pistons.
any ideas what happened?
May 10, 2004, 11:21 PM
#3
Newbie
Thread Starter
Join Date: Oct 2003
Posts: 34
Likes: 0
Received 0 Likes
on
0 Posts
Fuel settings?
i am using sard 700cc injectors, sard fuel regulator set at 3.0 bar (vacuum off)
The wide band lambda according to tuner was between 11.2 to 11.5 at WOT.
i am using sard 700cc injectors, sard fuel regulator set at 3.0 bar (vacuum off)
The wide band lambda according to tuner was between 11.2 to 11.5 at WOT.
Originally Posted by value
What about your fuel settings ??
May 10, 2004, 11:33 PM
#5
Newbie
Thread Starter
Join Date: Oct 2003
Posts: 34
Likes: 0
Received 0 Likes
on
0 Posts
Sent the injectors for testing.
They are workin fine. so the prob does not lie with the injectors.
They are workin fine. so the prob does not lie with the injectors.
Originally Posted by MalibuJack
Wow.. take a look at your fuel injectors.. its possible the one on the cylinder that nuked wasn't flowing adequately or failed and went lean..
May 10, 2004, 11:52 PM
#7
I'm stumped.. I suppose a momentary lean condition in one cylinder could cause failure like that.. But since you had the injectors tested and their alright.. maybe electrical? Possibly the injector harness?
I guess detonation is also a possibility, but I've never seen anything like that caused by detonation. Another possibility is oil starvation or coolant starvation.. but that likely would have caused more damage than just a isolated hot spot.
The location of the melt on the piston is what confuses me.. its like it was real lean on one side of the piston... I honestly haven't burned up enough parts to have seen anything quite like that.
I guess detonation is also a possibility, but I've never seen anything like that caused by detonation. Another possibility is oil starvation or coolant starvation.. but that likely would have caused more damage than just a isolated hot spot.
The location of the melt on the piston is what confuses me.. its like it was real lean on one side of the piston... I honestly haven't burned up enough parts to have seen anything quite like that.
Trending Topics
May 11, 2004, 12:10 AM
#8
Looks like repeated abuse to me. That looks like detonation, pre-igniton will melt pieces like that. No matter how "safe" the tune is, there is always a mechanical limit with repeated straining of a component. There is a limit to the stock components and that's a perfect example. For constant and repeated high boost operation Forged internals are the only way to go.
May 11, 2004, 12:14 AM
#9
Newbie
Thread Starter
Join Date: Oct 2003
Posts: 34
Likes: 0
Received 0 Likes
on
0 Posts
I am exploring the possibility of pre ignition as well but cant confirm.
these are forged and coated (thats why it is black) pistons
these are forged and coated (thats why it is black) pistons
Originally Posted by superz
Looks like repeated abuse to me. That looks like detonation, pre-igniton will melt pieces like that. No matter how "safe" the tune is, there is always a mechanical limit with repeated straining of a component. There is a limit to the stock components and that's a perfect example. For constant and repeated high boost operation Forged internals are the only way to go.
May 11, 2004, 06:17 AM
#12
Evolving Member
iTrader: (1)
Join Date: May 2004
Location: San Antonio Texas
Posts: 124
Likes: 0
Received 0 Likes
on
0 Posts
HI im sorry to see that first of all...
i can tell you from experience because i did that to one of my turbo civics a long time ago when i started tuning my own..the egt your were reading was a bit low because of the location of the probe--I would say that your failure was caused by repeated exposure to detonation at more than likely high rpm where its harder to feel and hear it..thats what broke the ring lands--coupled with high cylinder pressures and temps...the whole thing was induced by too much boost....if your peak boost was 1.65 bar, that is just a smiggin under 24 psi--23.93 to be almost exact. thats a crap load of boost by any standard. that looks almost exactly like the number four cylinder from my civic..
sorry too see that.
rick
i can tell you from experience because i did that to one of my turbo civics a long time ago when i started tuning my own..the egt your were reading was a bit low because of the location of the probe--I would say that your failure was caused by repeated exposure to detonation at more than likely high rpm where its harder to feel and hear it..thats what broke the ring lands--coupled with high cylinder pressures and temps...the whole thing was induced by too much boost....if your peak boost was 1.65 bar, that is just a smiggin under 24 psi--23.93 to be almost exact. thats a crap load of boost by any standard. that looks almost exactly like the number four cylinder from my civic..
sorry too see that.
rick
Last edited by justrick; May 11, 2004 at 06:20 AM.
May 11, 2004, 06:48 AM
#13
Newbie
Join Date: Sep 2003
Location: Soup of the world - Hot & Humid Singapore
Posts: 96
Likes: 0
Received 0 Likes
on
0 Posts
Sheesh Pred, what happened and when did this happened??? Recently on the trip up north??? man... stroker kit next? man, hope the guys here can help...
May 11, 2004, 08:17 AM
#14
Not enough octane for your boost.
What compression ratio pistons are they?
Also, it is possible that oil entered the combustion chamber BEFORE the damage occurred. Oil has a very low octane, so it is best to not burn it in the combustion chamber.
What compression ratio pistons are they?
Also, it is possible that oil entered the combustion chamber BEFORE the damage occurred. Oil has a very low octane, so it is best to not burn it in the combustion chamber.
Last edited by ShapeGSX; May 11, 2004 at 08:21 AM.