hello all


I have an opportunity to pick up a 2007 Mini Cooper S hatch, 85K on the clock, and one owner. car is in very good shape except for the fact it has no compression in cylinder number 1, and isn't currently running. I am very experienced in engines and rebuilding, but ive never worked on a mini.


I have been seeing common issues such as timing chain failure, cylinder head failure etc etc.. but im just reaching out to get a feel for someone who has torn into these motors. my initial plans are to pick up the car, run a leak down test, and pull cylinder number 1 plug to inspect with a boar scope. are these interference motors? im assuming if we had timing chain complete failure the guy would have had very scattered numbers on compression throughout all 4 cylinders. is this a common thing for the vehicles to jump timing if one of the runners were to break? I would assume I should pull the pan to inspect possible broken parts laying in there.


any advice from you fine gents would be greatly appreciated!

 

I'm not a mechanic, but why bother with the bore scope? Regardless of what you might see, the head is coming off. If there is no compression in one cylinder, chances are one of the valves has cracked/broken. And yes, it is an interference engine.

 

I believe it is pretty uncommon for the timing chain to jump a cog.....might be a holed piston, esp if the intake valves were not cleaned and a chunk of carbon came off a valve. However, the engine would likely run on three cylinders if that is the case.

MINI parts are likely more expensive than the other engines that you've worked on. 2007 - 2010 MINI turbos with blown engines are pretty common and tend to be pretty cheap because of the cost to rebuild the engine. I understand that you've done some research, but don't forget that at 85k the high pressure fuel pump might be the original and if so is probably reaching the end of it's service life. Replacements are expensive!

 

thanks for the input man I appreciate it! and yes those fuel pumps are very expensive. I do however have experience in working with vehicles where parts are costly, having built a supercharged audi engine last year, and a small block chevy which costed nearly 12K to build. internal parts were an arm and a leg. the guy im purchasing the vehicle from has some aftermarket accessories such as an intake, full exhaust, and a mini maniac stage 1 tuning package. what blows my mind is that this motor is 10.5:1 compression? just wondering why mini chose such a high compression with forced induction. previous forced engines ive built usually were roughly 9:1. he advised that the manic tuning setup is just through the OBD2 port, and can flash with a click of a button for three different settings.


and to answer your question AZDsrt, yes that would be a question someone who wasn't a mechanic would ask. A bore scope is an excellent tool to utilize because mechanics don't like surprises, and I own one so its readily available. I understand the head is coming off regardless, but would you like to see an issue before you just dive in? I always ask for no onions on my burgers, but always take the top bun off before I take a bite just in case.

 

Go for it. It's only parts and time. You'll be taking much of that engine apart.

 

yes! That's the go getter boost I needed! Lol picking the car up Thursday. I'll be in Central America for a minute but gonna tear into it after I get back. I'll do some diag before I leave but don't wanna start tearing it down until I get back. Anyone have experience with the Maniac tuning software?

 

Best way to know a car is to rebuild it, lol.

 

amen brother. learned the hard way many o times when I was younger rebuilding engines.

 

Manic dealer here. The Stage 1 tune you have has four modes of operation. Stock, Map A, Map B and Map C. Hopefully the car came with the SPS switch that allows you to change modes on the fly, even while driving. No having to load different maps as their in the ECU not the switch. Boost levels are 1.0, 1.1, 1.2 and 1.3 bar respectively. So Map C tops out about 18.9 psi. The 10.5 compression was chosen to maximize thermal efficiency when not it boost. The pentroof combustion chamber in conjunction with direct injection is what makes the static compression ratio workable.

The factory pistons have been known to suffer ring land failure on factory tuning. The Manic tune works well by keeping AFR's very low in high boost to suppress detonation. If the HPFP failed at WOT though no tune would save the engine. Hopefully, it's nothing that serious but the borescope should help identify the problem pretty quickly. Timing chain stretch or gear slip can also cause a valve to contact a piston. That never ends well.

 

thanks for the info man i really appreciate it! yes the car did come with the SPS switch, the original owner was showing me it when i arrived last week. so i haven't even touched the car yet but the exterior is 10/10, literally flawless. this is what the son told me what happened while driving its last trip. "i was driving on the highway with the cruise control on, and i went to pass someone because my exit was near, so he got on the gas and could tell something wasn't right. a large loss of power, started sounding funny." he pulled off on the exit and his low oil light came on. he pulled over immediately and opened the hood to see oil literally everywhere. the dipstick was out of its closed position about two inches or so. then they never started the car again.

sounds a lot like a PCV system failure causing positive crankcase pressure? although it may not explain their local "Friend" who is a mechanic couldn't get compression in cylinder number 1. i did take a look in the coolant reservoir and its awfully dark, feels like possibly some oil in the cooling system. bottom of the cap is clean, not sure if the mechanic cleaned it or not, when i picked the car up the engine bay had been cleaned. Im assuming the best place to start is a leak down test on the cooling system, and get a good compression reading.

any special comments for checking compression? do you pull the fuel pump relay to do so? or are there any other special things i need to keep in mind before i run the comp test?

 

There's a fuse in the engine bay box for the fuel pump that needs to be pulled. Pulls all four plugs and borescope before proceeding since you know there's a problem. Run through 10 compression cycles so the results stabilize. Throttle to the floor while cranking.

Coolant on our vehicles is blue in color but should contain no oil. A valve cover check valve failure could cause pressurization of the crankcase under boost and blow oil out. Unfortunately, it could also cause oil to be blow into the inlet. Oil does not compress and even worse can lower the effective octane of the intake charge to 87 or lower. Another reason an OCC is so important on the PCV boost side.

 

thanks for the info man I really appreciate it! yes will start with a compression check and see where we're at. been doing some reading about the check valve failure and see its a built in unit where the complete valve cover would need replacement. wondering if that's the situation he got himself in as he stated he jumped on the throttle, plus the added boost of the tune caused serious positive crankcase pressure by the valve cover PCV failure.


will check back once ive got a good compression test under my belt. thanks again for the info sir, I appreciate it.

 

so last night a friend and I had some time to take a look at the car and we believe we are looking at some ring land failure in cylinder number 1. the guy I purchased the car from removed his CAI setup but gave me the stock JCW airbox setup, but he unfortunately didn't give me the turbo charge pipe that connects from the turbo to the airbox. but we did inspect initially with the borescope and there was some significant oil atop the piston in cylinder number 1. no signs of catastrophic failure at this point though. reason for thinking its ringland failure is when we crank the vehicle over, we're getting significant blue smoke coming out of the PCV outlet on the drivers side of the valve cover, as well as blue smoke smelling like fuel coming out of the dipstick tube. it did start momentarily but seems like some type of electronic override shutting it back off immediately, would rev to 1k then shut right back off. so next step is to get the charge pipe to get everything back together and plugged in, and do a cylinder leak down test on each cylinder to see where we're at.


anyone have some input here or thoughts?


thanks guys I greatly appreciate all the help!

 

The plastic inlet tube with a rubber seal is a disaster waiting to happen. I went through two factory inlet tubes before changing it. The last time it took out my turbo and intercooler.

 

what would you recommend as a replacement? I have seen a couple threads on that as well. definitely don't want to rebuild a turbo in this whole process that's for sure!

 

I chose the aluminum Alta. There's a thread in the JCW section. They make one for S and JCW models. But, any inlet tube design that doesn't have a gasket that can get sucked into the turbo would be good. I just like metal parts for some things.

 

nice, also seeing a silicone option made by forge through ECS for about 150 bucks. anyone around here using that?


IF it is ringland failure, and assuming the cylinder walls are in good shape, replace all pistons and rings so this problem goes away? or just replace whats broken? I guess it all depends on what im doing with the car, with a lot of these common internal issues im seeing we might just get the car running and possibly flip it, as I have another project that absorbs much of my time. seeing a lot of people with ringland failure on cylinder 3/4 but not so much on cylinder 1.

 

ECS carries quality products. I suspect you couldn't go wrong with it.

 

ok, just ordered one up. unfortunately looks like its on backorder for a couple weeks. oh well, I can wait. ill report back tomorrow even after the leak down test / compression test results.

 

There's a sensor on the original. I transferred the hose and sensor from my old inlet tube. Are you missing the sensor?

 

no surprisingly I got the sensor. apparently when removing the original it broke that's why the owner didn't give it to me when I picked up the car. what is that small sensor? I have been reading multiple posts about if hoses and what not are cracked or off, the car will run horrible, or not at all. with the turbo pipe removed, would that keep my car from running? it definitely seemed electrical when I was just cranking it over. it would start, touch 1K RPM and then shut off like I had turned the key off.

 

It goes from the inlet line to the valve cover. Looks like a crankcase vent sensor of some sort.

 

It's a heater element that heats up when it's extremely cold. It's designed to prevent moisture that can accumulate from freezing which could dislodge and damage the turbo. On the N14 it can be left off but has to be bypassed with a resistor if removed from an N18.

 

Ah ok that makes sense! Thanks for the input tigger I appreciate it.

 

well its official, we came up with 155lbs of pressure in cylinder 2-4, and a whopping 5lbs in cylinder 1. so looks like we are gonna tear it down and build it back up. fingers crossed we have no cylinder wall damage. tentative plans will be to replace all pistons/rings with CP, most likely plan to lower compression a bit and take advantage of that manic tune. been getting tons of help around the forums and plenty of people reaching out to help in any way they can. i really appreciate it, this forum is very active and the people have been more than accommodating for a new mini owner like myself.