Moving on from diagnosing my Cylinder 3 Misfire. I honed the cylinders and the one that was blown has an small nick in it at the top of travel. Can I live with it? Should I keep honing to see if I can get it to level out? I can feel it with my fingernail.

 

You're honing it with the crank installed?

 

we’ll, judging by the question, I suppose I shouldn’t have. Don’t trust you tube

 

Yeah, you should remove the crank. Wouldn't want all that honing crap to get into anything else. I also wouldn't trust that ding in the cylinder wall.... Looks like you'll be doing a full tear down.

 

All righty. Engine is coming out. At this point, can I just unbolt the block form the trans or do I need to disconnect the drive axles?

 

As usual, njaremka is correct, you should be doing a full tear down and rebuild. HOWEVER, depending on the ultimate use of this engine, i.e., no track or high performance mods, just a daily driver, you could get away with what you've started --- clean up the cylinder wall, replace what needs replacing, and thoroughly rinse everything under #3 cylinder. How is the #3 piston / rings, are they in similar condition as the wall was? You should consider checking the other cylinders too. Then, how is #3 cylinder "roundness"? A hi-mileage engine is often not in spec and will burn oil until new rings get seated, unless cylinders are rebored. Personally, I wouldn't have ever gotten into this situation. I want nothing to do with OEM specs on rebuilt engines. Just be advised, this is a vast project, don't do a half-vast job with it. Again, consider the ultimate usage.

As for your "nicks", I'd be more worried about a protrusion than a dent. I've marked your pic showing what looks like something protruding from the wall --- this needs to be removed if it is. Then on reassembly, ensure ring gaps don't line up with the "dent".

 

Thank you! This is a daily driver. You missed the background from my other thread, but this was a new bottom end installed by the mini dealer 15k miles ago under a warranty repair. The #3 piston blew (0 compression). When removing the rods, I discovered another piston had failed. Photos below. Luckily, roundness is good on all cylinders.

There's no protrusion. I think what you see there is oil/dust mix buildup where I pulled the honing tool out. It's clean there.

I wish I knew why it went out on me in 15k miles. The previous owner has boosted the engine with a higher turbo which I think is what cause the first failure. When this one was put together the dealership installed a stock turbo. I wonder if the PO could have done something to the ECU as well to cause this failure...when I'm done here, I'll get the dealership to ensure the ECU is reset.

All that being said, I'm mentally prepared to pull the block unless you can think of a reason not to. Of course, I'd prefer not to simply because of the added cost at the machine shop, but I recognize taking it to the shop would suggest I won't be doing this rebuild again.

Thoughts greatly appreciated!

Can I pull the block from the transmission at this point or do I have to release it with transmission attached like I see in the videos?

 

Just took a quick look at your 1st thread in Gen 1. Did you ever find out why cyl #2 has low compression readings? The pic above shows two pistons. Is one of them from #2? With only 15K on the block, all cylinders should still be within OEM specs --- should be OK for seating new rings. Might even be OK for a shop to hone #3 a little deeper than the others.

I read somewhere (Bentley?) there are 3 different CR's for the different models ---
Justa is 11.0:1
MCS is 10.5:1
JCW is 10.0:1
With 10.5:1 pistons, be sure to use the thick head gasket. Don't want to add extra stress to the cylinders. I'm using CP's custom 9.0:1 CR with the thin gasket, but I'm far from a stock DD.

There's several "horror stories" on-line about Manic tunes causing blown engines, usually stage 1 or 2 tunes. I believe most of these failures were caused by poor maintenance, bad driving habits, faulty aftermarket parts, or some combo of all these. I've been running Manic's stage 4 since 2013 or so, and it's built as a "sleeper" --- a DD for an old retired goat. Yes, I've blown it up but I know it was my fault each time. Still, if you're rebuilding as a DD, go for the OEM tune to minimize one more variable.

When I separated my engine / tranny, it was on the bench and no special tools were used. No video was watched for "how-to" help either. Trying to pull the engine by itself means you need to separate the tranny then support it somehow. I found it easier to pull the pair as a package. Might need some extra help if you can't handle the weight / awkwardness, but it's very doable if in the service mode. If you're removing the crank, you might be able to reuse the crank bearings, just be sure to ID them with location and orientation. Then you can get the oil squirters out too. Don't forget to clean out the #3 squirter --- it probably got some honing crap in it. Or, as I suggested earlier, leave the engine mounted, do all the work yourself with the crank in place, then concentrate on cleaning it up.

 

unfortunately, I separated all the rods which I marked, but didn’t keep track of the pistons. After I separated them all I pulled the rings off and that’s when the one fell apart. I can’t say for sure, but can only speculate.

hmmm, when I talked to two shops, they said the pistons are the same. This is a JCW. I have the Bently and you’re right about the CRs listed in there. If I have a JCW, I’d prefer the JCW specs (10.0). Shouldn’t I get the 10.0?

I bought THIS .90mm gasket. Too thin?

okay, I’ll pull everything out tomorrow.

I truly appreciate your thorough response!!

EDIT, I just found THIS 10.0.

 

Having pulled my transmission for a clutch job, I couldn’t imagine pulling the engine without the transmission. It will be MULTIPLE time easier to pull as a pair and tear down outside the car.

Listen to OBW, he’s got some good knowledge.

 

If you're seriously considering the ECS pistons, get some assurances from them that they'll work with the rods you're using. There are some piston / rod combos that don't fit together or clear the cylinder wall when crank rotates. CP / Carrillo will work in the R56! I'm too lazy to convert the ECS recommended gasket thickness to metric, but you might need to order one from them to ensure the 10.0:1 CR. Also note ECS says "Availability:Back Ordered".

One more caution --- before draining tranny fluid, loosen the fill plug first, then the drain plug. Should the fill plug be "frozen", you'll never get fluid back in.

Have fun ---

 

I don't think I want to take a chance. I'm going to go with the 10.5s. Hopefully ECS will let me swap them out with not trouble - the machine shop will charge me $200 to bore them out so I think that's the way to go.

The CP instructions say I need a torque plate to check the rings - is that true?

I'm concerned this is the second blow after only 15k miles. I wonder if the ECU was modified. Is there a way to check it?

 

Dealers can determine whether or not the ECU map has been modified. Not sure what level of equipment is needed, Somebody else chime in???

 

that works for me. I’ll contact the dealer.

 

The torque plate might be used to make sure the rings are square in the cylinders? If so, the old school way of doing that was to use a piston to tap the ring into the bore... unless I'm understanding that wrong.

 

You’re right. That’s what I would do, by the Carrillo instructions say you need to use a torque plate. I was wondering if anyone has done it as you say with Carrillo or if they use torque plate.

 

So…while pulling the wires out of the way I discovered this. I didn’t check the oil level before I started. There’s quite a bit of oil on the trans, but not sure if it’s from 130k miles of use or the fact that the gasket wasn’t installed.

 

Any chance that's an old gasket that wasn't disposed of, and not the new one waiting to be installed?

 

Looks like a dirty engine component to me. I see a lot more coolant there...

 

thanks, the coolant is from the hoses during disassembly. I’ll pull the filter today to see what’s in there. I pulled the right drive axle last night. Left today, and hopefully pull the engine.

 

This is a 2011 JCW, True?

Pretty certain that you need to use 10.0CR pistons. Using 10.5s with JCW software will likely lead to further problems. Like blown pistons.....

Regarding the torque plate: My best guess is the CP instructions are expert friendly and that you misunderstood them. I won't get into why a torque plate is of value, but it is not used for ring checking.

You have been given really sound advice to pull the block and have it reconditioned by pro's.

If it is not too late, make sure your shop understands (and they likely do) that you need a "plateau hone" as Mini's use a low tension ring pack. Your ring manufacturer will have further information the shop will need regarding stones and surface finishes.

Do shop around and find out from mechanics in your area what shop has a solid reputation for block work. I would start with a BMW shop or some other high end brand. All auto machine shops are not equal.

Best wishes, you are still on the steep end of the learning curve!

 

What do you mean by "the fact that the gasket wasn’t installed" If you are referring to the o-ring, that is possibly the nose o-ring (11667610690) for the vacuum pump.

 

Although I hear a lot of recommendations for Cp Pistons, I can’t find a 10:1 CR set. The only one I can find is from supertech HERE.

Any experience with supertech?

also block is being sent to a local race shop to bore and assemble bottom end.

 

I have no experience with ST pistons. They make pistons for a wide range of engines, if there are issues with them, that might show up in a search

Mahle makes a PowerPak Piston in 10:25 (https://www.us.mahle.com/media/usa/m...w-template.pdf - $840 ish)

The STs are also available here: https://www.evasivemotorsports.com/s...ze-std-cr-105/

Seem to me that the STs should be fine.