2.8L failure
02-08-2006, 12:55 AM
#31
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Alright so looking at the motor today on a lift, there's a nice hole underneath the exhaust manifold. Block is toast. From what we can see, the bottom of #4 piston was ripped apart and sitting at the top of the bore, and rod looks to be in pieces. Marc thinks the rod's stuck to the crank too, so thus far it looks like Chris White guessed it right, failed rod bearings or nut/bolt failure. Odd that it was #4, isn't it usually #2 that fails?
Anyhow, once the motor is out, more will be known soon. I guess that means I broke the block, a rod, a piston, crank, bearings.... wait... it's easier to list out what's left. 3 JE pistons lol.
Anyhow, once the motor is out, more will be known soon. I guess that means I broke the block, a rod, a piston, crank, bearings.... wait... it's easier to list out what's left. 3 JE pistons lol.
02-08-2006, 01:07 AM
#32
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Sorry to hear that.
If the misfires you mentioned at 6000 rpm had occurred more than very briefly, there is a potential for hydro-lock, which competes for a cracked cylinder or a bent rod. Obviously a bent rod is seriously weakened, so maybe the daily load continued to bend it until failure.
If the misfires you mentioned at 6000 rpm had occurred more than very briefly, there is a potential for hydro-lock, which competes for a cracked cylinder or a bent rod. Obviously a bent rod is seriously weakened, so maybe the daily load continued to bend it until failure.
02-08-2006, 01:56 AM
#34
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Originally Posted by rage2
Alright so looking at the motor today on a lift, there's a nice hole underneath the exhaust manifold. Block is toast. From what we can see, the bottom of #4 piston was ripped apart and sitting at the top of the bore, and rod looks to be in pieces. Marc thinks the rod's stuck to the crank too, so thus far it looks like Chris White guessed it right, failed rod bearings or nut/bolt failure. Odd that it was #4, isn't it usually #2 that fails?
Anyhow, once the motor is out, more will be known soon. I guess that means I broke the block, a rod, a piston, crank, bearings.... wait... it's easier to list out what's left. 3 JE pistons lol.
Anyhow, once the motor is out, more will be known soon. I guess that means I broke the block, a rod, a piston, crank, bearings.... wait... it's easier to list out what's left. 3 JE pistons lol.
Any way you look at it I feel for you! Good luck!
02-08-2006, 02:48 AM
#35
Burning Brakes
Didn't you say you had a NA crank that was drilled? Maybe that area wasn't getting enough oil and F-d the rod bearing? I know on the 928 its the 2/6 bearing that starves under high load, but I really dont know how it relates to a NA crank used in the turbo... Just a thought
02-08-2006, 08:01 AM
#36
Originally Posted by TonyG
RPM's are what causes most rods to fail, assuming you didn't spin a rod bearing, not boost, and not the HP you were making, and not the sleeves, and not the lack of balance shafts.
While when it (the rod/rod bolt) failed you might not have been at a high rpm, the previous fun at over 6000 rpms takes its toll on the rods and more specifically the rod bolts. Were you using stock rod bolts? Were they new?
The rod and even more so, the rod bolts, are by far the most stessed part of the engine.
Get a set of Carillo rods. You'll never have this happen again.
And just because the pistons are larger, doesn't mean they weigh more than their stock counterparts. Thus the assumption that the larger bore was contributory to the rod failure is without merit without knowing what those comparative weights were (are).
The elimination of the balance shafts is done by all of the big name 951 engine builders. I've done it for years, as well as many people here. While this can and does cause some problems, the problems that result are very consistant on the 951, which include broken powersteering turn buckles, alternator turn buckles, vibrating lose bolts/breaking off bolt bosses from the block on bolts that have come lose, that either don't have red locktight, aircraft lock nuts, or some sort of lock washer in place. If everything is tight and locked down, the problems are fairly trivial.
Anyway, with respect to your problem:
The block has a very good chance of being toast. Hopfully the pistons, the valves, and the cylinder head are not. The crank is probably got chunks out of it and is probably toast as well. You'll know soon enough.
Sorry... It sucks I know.
TonyG
While when it (the rod/rod bolt) failed you might not have been at a high rpm, the previous fun at over 6000 rpms takes its toll on the rods and more specifically the rod bolts. Were you using stock rod bolts? Were they new?
The rod and even more so, the rod bolts, are by far the most stessed part of the engine.
Get a set of Carillo rods. You'll never have this happen again.
And just because the pistons are larger, doesn't mean they weigh more than their stock counterparts. Thus the assumption that the larger bore was contributory to the rod failure is without merit without knowing what those comparative weights were (are).
The elimination of the balance shafts is done by all of the big name 951 engine builders. I've done it for years, as well as many people here. While this can and does cause some problems, the problems that result are very consistant on the 951, which include broken powersteering turn buckles, alternator turn buckles, vibrating lose bolts/breaking off bolt bosses from the block on bolts that have come lose, that either don't have red locktight, aircraft lock nuts, or some sort of lock washer in place. If everything is tight and locked down, the problems are fairly trivial.
Anyway, with respect to your problem:
The block has a very good chance of being toast. Hopfully the pistons, the valves, and the cylinder head are not. The crank is probably got chunks out of it and is probably toast as well. You'll know soon enough.
Sorry... It sucks I know.
TonyG
I have to agree with all of this.
And we know that Rage has run for years (track also) with raised rev limits - with THIS bottom end/rods.
02-08-2006, 09:42 AM
#37
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One of the common quotes you hear after catastrophic bearing failure is that the engine felt like it was “tightening up” (NASCAR speak). Hard to explain this feeling other than it feels like it won’t rev freely. If you feel this take a serious look at your oil pressure so see if it has dropped at all.
A rod welding it self to the crank makes for some very serious forces – in a direction that the rod was not designed to resist.
Rage – if it helps I have 3 sets of MID Sleeves for the 3.0 blocks here…
Chris White
A rod welding it self to the crank makes for some very serious forces – in a direction that the rod was not designed to resist.
Rage – if it helps I have 3 sets of MID Sleeves for the 3.0 blocks here…
Chris White
02-08-2006, 02:34 PM
#38
Race Car
Interesting.
Marc at Alpine did all of the engine assembly, no? How does he feel about all of this? That is, what is he suggesting is the cause of the failure?
It is very interesting that #4 let go. However not entirely unheard of. If you had a knock problem or a misfire problem, I have heard that #4 is the most knock-prone cylider (For reasons beyond my comprehension), and perhaps there were excessive forces applied to that rod when this condition occured.
FWIW, I was in a friend's engine the other day (well, not literally IN it, but you know...) doing rod bearings, and I found that #4 was by far the worst. The owner was suffering from low oil pressure, and I suspected #2 rod bearing. He had a cross-drilled crank (FACTORY! The first one I have ever seen!!). My only thought was that the extra oil holes in the first 3 cylinders caused a slight oil starvation problem on #4. Perhaps this is why the factory cross-drilled crankshaft was not in production for long.
Marc at Alpine did all of the engine assembly, no? How does he feel about all of this? That is, what is he suggesting is the cause of the failure?
It is very interesting that #4 let go. However not entirely unheard of. If you had a knock problem or a misfire problem, I have heard that #4 is the most knock-prone cylider (For reasons beyond my comprehension), and perhaps there were excessive forces applied to that rod when this condition occured.
FWIW, I was in a friend's engine the other day (well, not literally IN it, but you know...) doing rod bearings, and I found that #4 was by far the worst. The owner was suffering from low oil pressure, and I suspected #2 rod bearing. He had a cross-drilled crank (FACTORY! The first one I have ever seen!!). My only thought was that the extra oil holes in the first 3 cylinders caused a slight oil starvation problem on #4. Perhaps this is why the factory cross-drilled crankshaft was not in production for long.
02-08-2006, 03:59 PM
#39
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Originally Posted by Chris White
One of the common quotes you hear after catastrophic bearing failure is that the engine felt like it was “tightening up” (NASCAR speak). Hard to explain this feeling other than it feels like it won’t rev freely. If you feel this take a serious look at your oil pressure so see if it has dropped at all.
At least I know what it feels like before failure next time it happens heh.
02-08-2006, 04:24 PM
#41
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6 years ago a friend of mine with a 2.8l had his bearings fail, which quickly (less than a second), shocked his rod into breaking & stuck it out the block, catching the car on fire.
His oil pressure was very low moments before this happened (on the gauge), a sure-fire indication that the bearing was toasting itself.
Sux to hear it though.
His oil pressure was very low moments before this happened (on the gauge), a sure-fire indication that the bearing was toasting itself.
Sux to hear it though.
Hope you get it up and running again soon. Good luck!
02-09-2006, 01:29 PM
#43
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Yep, hopefully I'll have 'er running again real soon. John Anderson has been great to me, and I've been talking to him the last few days for a replacement block.
02-09-2006, 01:31 PM
#44
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Originally Posted by MarkRobinson
6 years ago a friend of mine with a 2.8l had his bearings fail, which quickly (less than a second), shocked his rod into breaking & stuck it out the block, catching the car on fire.
Originally Posted by MarkRobinson
His oil pressure was very low moments before this happened (on the gauge), a sure-fire indication that the bearing was toasting itself.
02-09-2006, 02:01 PM
#45
Three Wheelin'
BTDT (been there done that) for me too!
Luckily replacement short blocks are only ~$250.
http://evilallianceracing.com/ipw-we...y/Reincarnated
The failure is exactly as described above. Engine "tightened up" (on a pitiful 21 second drag pass no less) and didn't finally lunch itself until I was limping away from the timing booth. The theory that the spun bearing super heated on the pass, then welded itself as the engine idled at the timing booth sounds spot on to me. The failure actually happened at/near idle speed. The engine continued to run on 3 cylinders until I shut it off. You can see where the crank chewed away at the piston skirt.
Fun stuff!
Luckily replacement short blocks are only ~$250.
http://evilallianceracing.com/ipw-we...y/Reincarnated
The failure is exactly as described above. Engine "tightened up" (on a pitiful 21 second drag pass no less) and didn't finally lunch itself until I was limping away from the timing booth. The theory that the spun bearing super heated on the pass, then welded itself as the engine idled at the timing booth sounds spot on to me. The failure actually happened at/near idle speed. The engine continued to run on 3 cylinders until I shut it off. You can see where the crank chewed away at the piston skirt.
Fun stuff!