So have a friends car in my garage and it had a weird issue, wasn't at all down on power (or at least didn't seem to be) specs are GTX3576 single turbo, E30 mix, JB4, MHD BMS back end flash, watermeth kit, 6MT, 7" IC etc. Nothing super crazy, just a basic responsive single turbo setup.
So after a few races one day it developed an issue where it would blow some smoke, tips of the exhaust were oily. Suspected damaged turbo to begin with, so turbo was sent away for testing and came back fine. no dramas with the turbo what so ever. No visible signs of damage on the turbo either.
So I investigated it a bit more and couldn't find any real faults. Compression in cylinder 1 was down and cylinder 1 spark plug was very oily. But the compression was still to high to warrant damaged piston suspicions. (compression was 150psi cyl 1, 180psi 2-6)
Got the engine stripped down today and found a very unusual break that I thought I might share with you guys. The car has 80k km on the clock and is a 1 owner AFAIK, always serviced at 5000km, good fuel used, quality parts always fitted.
First thing I noticed was the wet oil in cylinder 1, the head was coated, the piston was very oily, and once wiped off there was no noticeable damage to the piston top, or the cylinder head, I did notice there was a lot of severe detenation on top of piston number 5 and also evident in the head of that chamber. I can only assume it has a faulty injector and that has caused the detenation in that cylinder alone. as all other cylinders are near on perfect.
Cylinder 5 Det marks:
Cylinder 1 Oily
Cylinder 1 piston top, oily but no damage:
Damage on cylinder 1 bore:
Piston number 5, clear signs of severe det:
First sign of damage on cylinder 1 I noticed was when the engine was pulled to TDC the piston didn't come all the way up, which I thought was odd but isn't unheard of on some engines. But when inspected cylinder 5 I noticed it came the whole way up, so I knew something was astray.
Piston number 6 all the way up:
Pulled cyl 1 back up to it's resting point and also noticed it was sitting unlevel, it was approx 20thou down on the back side of the piston, but at least 80thou down on the front side. this is the way the gudgeon pin runs, so I was concerned from this point that either the pin had collapsed or the rod had bent.
Piston number 1, clearly not at TDC and not running straight:
On to disassembling the bottom end, and all bearings, mains and big ends were perfect, you would expect this engine to have traveled no more than 10,000km it has been kept that clean inside. the bearings look near on new. Infact all the bores (apart from cyl1) looked very healthy also.
Removed the piston and rod combo from cylinder 1 and found a whole heap of mess. The conrod has bent into an S shape and tilted the head a little, causing the piston to run on a funny angle, pushing the piston skirt into the wall of the cylinder and obviously jamming the oil ring tight on one side and more than likely not touching the other side, hence the excessive oil movement from that cylinder but not to much compression loss.
This doesn't look super straight:
Piston skirts being mashed up against bore:
Other side:
Rod 1 vs Rod 2:
This is a very odd failure on such a mild setup (considering how far other people have pushed the N54, myself included)
So after a few races one day it developed an issue where it would blow some smoke, tips of the exhaust were oily. Suspected damaged turbo to begin with, so turbo was sent away for testing and came back fine. no dramas with the turbo what so ever. No visible signs of damage on the turbo either.
So I investigated it a bit more and couldn't find any real faults. Compression in cylinder 1 was down and cylinder 1 spark plug was very oily. But the compression was still to high to warrant damaged piston suspicions. (compression was 150psi cyl 1, 180psi 2-6)
Got the engine stripped down today and found a very unusual break that I thought I might share with you guys. The car has 80k km on the clock and is a 1 owner AFAIK, always serviced at 5000km, good fuel used, quality parts always fitted.
First thing I noticed was the wet oil in cylinder 1, the head was coated, the piston was very oily, and once wiped off there was no noticeable damage to the piston top, or the cylinder head, I did notice there was a lot of severe detenation on top of piston number 5 and also evident in the head of that chamber. I can only assume it has a faulty injector and that has caused the detenation in that cylinder alone. as all other cylinders are near on perfect.
Cylinder 5 Det marks:
Cylinder 1 Oily
Cylinder 1 piston top, oily but no damage:
Damage on cylinder 1 bore:
Piston number 5, clear signs of severe det:
First sign of damage on cylinder 1 I noticed was when the engine was pulled to TDC the piston didn't come all the way up, which I thought was odd but isn't unheard of on some engines. But when inspected cylinder 5 I noticed it came the whole way up, so I knew something was astray.
Piston number 6 all the way up:
Pulled cyl 1 back up to it's resting point and also noticed it was sitting unlevel, it was approx 20thou down on the back side of the piston, but at least 80thou down on the front side. this is the way the gudgeon pin runs, so I was concerned from this point that either the pin had collapsed or the rod had bent.
Piston number 1, clearly not at TDC and not running straight:
On to disassembling the bottom end, and all bearings, mains and big ends were perfect, you would expect this engine to have traveled no more than 10,000km it has been kept that clean inside. the bearings look near on new. Infact all the bores (apart from cyl1) looked very healthy also.
Removed the piston and rod combo from cylinder 1 and found a whole heap of mess. The conrod has bent into an S shape and tilted the head a little, causing the piston to run on a funny angle, pushing the piston skirt into the wall of the cylinder and obviously jamming the oil ring tight on one side and more than likely not touching the other side, hence the excessive oil movement from that cylinder but not to much compression loss.
This doesn't look super straight:
Piston skirts being mashed up against bore:
Other side:
Rod 1 vs Rod 2:
This is a very odd failure on such a mild setup (considering how far other people have pushed the N54, myself included)
