R56 Misfire, no compression on cyl 4
#26
01-08-2015, 01:28 PM
2nd Gear
Join Date: Jan 2009
Location: Florence, Oregon
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Run the #s, it may start making sense.
Brand new (and/or factory rebuild) N14 can be had for ~$3.5K from select MINI dealerships. If you can DIY, with a few extra tools you will have a brand new engine for under $4K. And that buys you a new water pump, oil pump, thermostat, spark plugs, removal of all oil leaks from your current engine, and removal of any and all carbon deposit on the intake valves. Basically, around ~$1.5K worth of goodies that your current N14 already needs, or will need real soon now.
The alternative is to ditch the R56 for scrap metal, to part it out, or sell it to someone else who is willing to repair it. Figure $500-$3K at most.
As long as you R56 is worth more than $4.5-$7K, you are way better off fixing the car and enjoying the brand new engine for at least another 60K miles.
Even bare bones clean first-year '07 MCS still go for around $10K these days.
Add a bit of curiosity, and a tinkering bug, and a dropping in a new engine becomes an obvious course of action for any DIY guy.
If you can't DIY, or are sick of your car, than the decision tree branches differently.
a
Brand new (and/or factory rebuild) N14 can be had for ~$3.5K from select MINI dealerships. If you can DIY, with a few extra tools you will have a brand new engine for under $4K. And that buys you a new water pump, oil pump, thermostat, spark plugs, removal of all oil leaks from your current engine, and removal of any and all carbon deposit on the intake valves. Basically, around ~$1.5K worth of goodies that your current N14 already needs, or will need real soon now.
The alternative is to ditch the R56 for scrap metal, to part it out, or sell it to someone else who is willing to repair it. Figure $500-$3K at most.
As long as you R56 is worth more than $4.5-$7K, you are way better off fixing the car and enjoying the brand new engine for at least another 60K miles.
Even bare bones clean first-year '07 MCS still go for around $10K these days.
Add a bit of curiosity, and a tinkering bug, and a dropping in a new engine becomes an obvious course of action for any DIY guy.
If you can't DIY, or are sick of your car, than the decision tree branches differently.
a
I sent off a nasty-gram to BMW-USA, mentioning that today's auto consumers expect modern engines to last more than 80,000 miles - even if it is a British motor. I requested they "participate" in the engine repair as a matter of loyal customer good-will (I've owned 2 MINIs) even though the car is way out of warranty. They sent back a check to cover 25% of the cost!
#27
01-09-2015, 02:24 AM
6th Gear
Thanks for the comments. Since I elected to go for the new engine, I also replaced all belts and rubber hoses, "renewed" the transmission (clutch, seals, etc) since it was already in parts on the shop floor. I have nothing but applause for MINI of Murray (Salt Lake City) for working with me. Just turned over the 1,500 mile break-in point and the car seems to have seriously more zip than the old motor had - or maybe it's just all that money talking ...
I sent off a nasty-gram to BMW-USA, mentioning that today's auto consumers expect modern engines to last more than 80,000 miles - even if it is a British motor. I requested they "participate" in the engine repair as a matter of loyal customer good-will (I've owned 2 MINIs) even though the car is way out of warranty. They sent back a check to cover 25% of the cost!
I sent off a nasty-gram to BMW-USA, mentioning that today's auto consumers expect modern engines to last more than 80,000 miles - even if it is a British motor. I requested they "participate" in the engine repair as a matter of loyal customer good-will (I've owned 2 MINIs) even though the car is way out of warranty. They sent back a check to cover 25% of the cost!
#28
03-24-2015, 07:54 AM
I had the same problem. I changed the number 4 and number one ignition module. This solved the problem. The connection was a bit corroded. Just swapping probably scrapped some of the stuff off. Then I cleaned it and it ran about the same. Pretty darn good. For the brave of heart. Take out the number four plug before the next oil change. Use one of those long skinny auto transmission funnels and pour a whole can of seafoan down into the the piston and let it sit overnight. Replace the spark plug and crank it up the next day. It seemed to get rid of most of the carbon though it did smoke like hell for a few minutes. Before the next oil change do the number one piston the same way and be sure to change the oil afterwards. Continue to go through all cylinders until you've done them all. Make take a year of so. Or you can take it and have the walnuts shot into the manifold and pay a few hundred. Can only say it worked for me. 141,00 and still going strong.
#29
06-21-2015, 06:21 PM
ThumperMCS wins the brownie points on this one.
I finally had time (a year later!) to pull the head on the old engine, and to my surprise, all valves on cylinder 4 looked just fine (pic #1 below). However, pistons didn't look as pristine (pic #2), and piston #4 in particular seams to have a piece missing (pic #3) with some cylinder wall scarring to go with it.
I still do not understand what happened in cylinder #4, but the residual damage is that the spark has lost its electrode, and a piece of cylinder #4 has gone missing without a trace, and scarred the cylinder head.
Weird.
Any ideas on what could have transpired?
Any thoughts on whether the block can/should be salvaged?
TIA,
a
I finally had time (a year later!) to pull the head on the old engine, and to my surprise, all valves on cylinder 4 looked just fine (pic #1 below). However, pistons didn't look as pristine (pic #2), and piston #4 in particular seams to have a piece missing (pic #3) with some cylinder wall scarring to go with it.
I still do not understand what happened in cylinder #4, but the residual damage is that the spark has lost its electrode, and a piece of cylinder #4 has gone missing without a trace, and scarred the cylinder head.
Weird.
Any ideas on what could have transpired?
Any thoughts on whether the block can/should be salvaged?
TIA,
a
#30
06-22-2015, 01:27 AM
6th Gear
ThumperMCS wins the brownie points on this one.
I finally had time (a year later!) to pull the head on the old engine, and to my surprise, all valves on cylinder 4 looked just fine (pic #1 below). However, pistons didn't look as pristine (pic #2), and piston #4 in particular seams to have a piece missing (pic #3) with some cylinder wall scarring to go with it.
I still do not understand what happened in cylinder #4, but the residual damage is that the spark has lost its electrode, and a piece of cylinder #4 has gone missing without a trace, and scarred the cylinder head.
Weird.
Any ideas on what could have transpired?
Any thoughts on whether the block can/should be salvaged?
TIA,
a
I finally had time (a year later!) to pull the head on the old engine, and to my surprise, all valves on cylinder 4 looked just fine (pic #1 below). However, pistons didn't look as pristine (pic #2), and piston #4 in particular seams to have a piece missing (pic #3) with some cylinder wall scarring to go with it.
I still do not understand what happened in cylinder #4, but the residual damage is that the spark has lost its electrode, and a piece of cylinder #4 has gone missing without a trace, and scarred the cylinder head.
Weird.
Any ideas on what could have transpired?
Any thoughts on whether the block can/should be salvaged?
TIA,
a
#31
06-22-2015, 08:24 AM
Interesting I wonder which happened first, the electrode falling into the cylinder or the piston failure. Depending on how big the broken piece of piston is it's possible it made it into the exhaust manifold, hope it didn't come into contact with the turbo compressor. I think your alright cylinder wise if you machine the cylinders, you might as well replace all the valves and pistons and rebuild your engine. I'm assuming you'll do most of the labor, now is your chance build it with stronger pistons and rods.
The fact that the piston would loose a chunk, even if there was excessive detonation, is extraordinary. I have to assume it went first, as I can't imagine a scenario where a broken electrode would take out a piston. I could see it bouncing around and damaging one of the exhaust valves on the way out (not present!), but taking out a piston - that would be remarkable.
My present working assumption is that excessive denotation, causes unknown, was not properly mitigated by the knock sensor + DME, and that produced enough of an explosion to both take out the spark plug and the chunk of a piston.
The one remaining mystery is where the chunk of that piston went. It is too big to have exited out the exhaust valve hole without causing some damage to the valve (again, exhaust valves are not damaged!!), the only other place to go would be down past the crankshaft to the oil pan, but that path is not viable as only the top portion of the piston is damaged (there is no through hole).
a
#32
06-22-2015, 09:25 AM
2nd Gear
same thing happened on my car around 75k. #3 died. unfortunately, they didn't let me keep the old engine, so i couldn't tear it down to see if the valve or the piston died (couldn't see a hole in the piston with the boroscope i had before i took it in).
I asked the tech the same thing when he was replacing my engine "well, if something broke off and shot out...it had to go somewhere right??" he actually let me inspect the turbo once he got it out and it looked fine. from reading many of the failure analysis threads on here, seems like 50/50 chance either a valve broke, ring broke, or piston melted (although, my engine finally failed under a steady cruise while still getting up to full temp, so i doubt that).
I asked the tech the same thing when he was replacing my engine "well, if something broke off and shot out...it had to go somewhere right??" he actually let me inspect the turbo once he got it out and it looked fine. from reading many of the failure analysis threads on here, seems like 50/50 chance either a valve broke, ring broke, or piston melted (although, my engine finally failed under a steady cruise while still getting up to full temp, so i doubt that).
#33
06-22-2015, 03:38 PM
It is hypothetically possible that the piston chunk did not break off in one piece, but in multiple shards, that made it past the exhaust valves and were routed straight into the cat (if the waste-gate was closed).
Does anyone have a lead at a shop in NE that could machine the block?
Some experience with MINI's would be plus.
TIA,
a
Last edited by afadeev; 06-22-2015 at 04:58 PM.
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