Diary - 427TT install
Discussion
Harryoz said:
An update
Its been a while, but we have rebuilt her. After pulling the engine apart, it was all fine apart from this:
http://www.youtube.com/watch?v=Qws4TA8ISOI
Piston in no1 cylinder a bit of a mess. Plenty of heat in there such that you can see the gudgeon pin has domed the top of the piston.
Cause of failure a bit of a mystery having checked plugs, leads, injectors, noting that every other cylinder/piston was spotless....
Rebuilt engine and ran on Peter's engine dyno with the same components and found that there was a fault on the wiring loom to the coilpack on no 1. Turning the lights off in the dyno cell while running treated us to quite a light show. Massive arcing occuring leading to missfire.
All looks good now. Should be back at Rogers on Monday and back in the car by the end of the week (no pressure Roger).
thats deffently one screwed piston. you did well there Its been a while, but we have rebuilt her. After pulling the engine apart, it was all fine apart from this:
http://www.youtube.com/watch?v=Qws4TA8ISOI
Piston in no1 cylinder a bit of a mess. Plenty of heat in there such that you can see the gudgeon pin has domed the top of the piston.
Cause of failure a bit of a mystery having checked plugs, leads, injectors, noting that every other cylinder/piston was spotless....
Rebuilt engine and ran on Peter's engine dyno with the same components and found that there was a fault on the wiring loom to the coilpack on no 1. Turning the lights off in the dyno cell while running treated us to quite a light show. Massive arcing occuring leading to missfire.
All looks good now. Should be back at Rogers on Monday and back in the car by the end of the week (no pressure Roger).
stevieturbo said:
Cant see a coil pack or wiring causing that. There has been detonation there as well as running lean. I'd assume the cylinder head carries the same indentations.
Are all the other pistons still round etc ? No marks on any other cylinder at all ?
At least its on the mend.
Every other cylinder and piston spotless........Are all the other pistons still round etc ? No marks on any other cylinder at all ?
At least its on the mend.
Harry, was it cylinder one or cylinder two? Was it was the same cylinder as before? The damage shows sever detonation and it's unusual to get that on a front cylinder. Usually it's 5 or 7 with an ls engine. If it's the same cylinder as before and everything on the engine has been changed then it's an installation issue. Could be wastegate balance, headers or something else. You should fit exhaust gas temp sensors in the exhaust ports and are you using knock sensing? That would have made an awful lot of knock.
Boosted LS1 said:
Harry, was it cylinder one or cylinder two? Was it was the same cylinder as before? The damage shows sever detonation and it's unusual to get that on a front cylinder. Usually it's 5 or 7 with an ls engine. If it's the same cylinder as before and everything on the engine has been changed then it's an installation issue. Could be wastegate balance, headers or something else. You should fit exhaust gas temp sensors in the exhaust ports and are you using knock sensing? That would have made an awful lot of knock.
cylinder 1yes, very apparent when it let go.
ringram said:
Have the injectors been flowed? Off the shelf ones can vary quite a bit.
Good point. Mark found almost by accident that the spray pattern on one of my injectors was all cocked when he removed the spark plugs. Luckily there was no damage. All mine have been flow tested as it proves you cannot assume they work out of the box. I guess mismatched wastegates could also contribute but in the event of all the parts working correctly, I would suggest poor mapping is to blame.
Lets post some facts before the interent machine goes off at a tangent.
The engine broke one piston and one piston only. Fact
Any nonsense about mapping, is just that. If this was true, there would be some evidence on the other pistons. Fact.
The injectors have been tested all were ok. Fact.
Everything else has been checked and no broken rockers. Fact
Engine rebuilt. Fact.
Engine run on dyno with all original ancillaries, Fact.
Engine developed a misfire when under load or more accurately boost. Fact
Fault traced. When under load, the coil pack insulation broke down and the HT spark came out of the coil pack low tension socket and tracked along the coil pack wiring and down to the rocker cover. Fact
The evidence on the piston indicates a spark relate issue for those that know what they are looking for. Fact.
Coilpack replaced and engine runs fine. Fact.
These are the facts. I know because i was there. Fact
Anything else is just speculation. Feel free to continue the speculation regardless of the facts.
The original engine failed due to a defective coil pack. This is the second engine (not in this car) i have seen go this way as a result of a defective coilpack.
The engine broke one piston and one piston only. Fact
Any nonsense about mapping, is just that. If this was true, there would be some evidence on the other pistons. Fact.
The injectors have been tested all were ok. Fact.
Everything else has been checked and no broken rockers. Fact
Engine rebuilt. Fact.
Engine run on dyno with all original ancillaries, Fact.
Engine developed a misfire when under load or more accurately boost. Fact
Fault traced. When under load, the coil pack insulation broke down and the HT spark came out of the coil pack low tension socket and tracked along the coil pack wiring and down to the rocker cover. Fact
The evidence on the piston indicates a spark relate issue for those that know what they are looking for. Fact.
Coilpack replaced and engine runs fine. Fact.
These are the facts. I know because i was there. Fact
Anything else is just speculation. Feel free to continue the speculation regardless of the facts.
The original engine failed due to a defective coil pack. This is the second engine (not in this car) i have seen go this way as a result of a defective coilpack.
Edited by monkfish1 on Sunday 28th February 10:47
we like to speculate because it's interesting; a lot more interesting than some of the usual threads. Of course we don't have the facts but if I posted videos of melted pistons on youtube I'd expect a similar reaction.
Engines aren't consumables whichever way you look at it so of course people will ask questions when you are on your third.
Nobody means any harm, and I hope mine doesn't go the same way.
Engines aren't consumables whichever way you look at it so of course people will ask questions when you are on your third.
Nobody means any harm, and I hope mine doesn't go the same way.
Gassing Station | HSV & Monaro | Top of Page | What's New | My Stuff