So some background. I have a 2009 Cooper S w/ 68k miles on it. A camshaft sprocket bolt broke, slinging the timing chain into little pieces and damaging the engine. I took it to a shop that said, yup, replace the engine because the valves were damaged by the pistons.

Okay, so I'm pretty good at the DIY stuff, and I've other cars to drive so I don't need my Mini back anytime soon. The question I have... do I really need to replace the engine? Or can I replace the timing chain assembly and replace the valves in the head? This, of course, is going on the assumption that no piston damage occured.

Is this smart / safe? I know I'll need to drop the oil pan and make sure there's no bits of chain floating around in the engine. The head gasket and valve cover gasket will need to be replaced of course.

Any thoughts on this would be appreciated. Also, if this IS an okay way to go, what other things should I be looking at / replacing while I've got it in pieces?

Thanks so much!
-David

Edit: Perhaps it is notable that the car was at idle when the chain broke.

 

Honestly, the amount of money/time/and work that it takes to do the work on your motor just doesnt seem worth it. Go pick up a low mileage engine from a wrecking yard, do some preventative maintenance on it, and drop her in and drive! Your time and energy is worth more + you have no idea once you get in there if other stuff is damaged.
Good luck!

 

Just cleaning it all up and checking/replacing valves can work.

But it can also not work, and some of the failure modes can be really spectacular. (As in, "Oops--is there supposed to be a hole in the block with half a con-rod sticking out of it?")

No professional would take the chance unless the customer was very insistent--and probably not even then. But a professional tends to value his time more highly than a shade-tree mechanic.

So, what is your time/sweat/effort worth to you? How much $ are you willing to spend on parts for an engine that may blow up when you start it the first time, or a month or a year from then?

If you don't want to take a chance on a junkyard motor, it sounds like some vendors here (Way has been mentioned) can supply engines with some form of warranty. Check those options and see where the math takes you.

Then figure out the inconvenience or annoyance factor of having the MINI in pieces all over the garage for however long it takes to do the work. On the other side, there may be value to you in keeping the original engine with the car.

It can all be done, but often enough it isn't worth the bother.

 

+1^ on second post. +2 on third post.

 

Being the devil's advocate here. Let us assume he is really handy and we must because he is even thinking about doing this. If he pulls the head and oil pan and all checks out OK in the bottom end, then how much does it cost to rebuild the head?

I just did my Honda it was $300 from the best shop in the area and that included
them disassembling it and reassembling it. I could have done it for $200 if I wanted
to take the harder but cheaper route.

So let's say it takes him $1000 which I think is super high but that is for all the stuff,
including new timing chain and sprocket, and water pump and thermostat.
Might as well as long as you are there.

The Way engine is like $4000 plus shipping I figure.

I would like to add also that if you might consider pulling the engine out (not sure
how easy it is to do on our cars) to do the repair. Things are SO much easier with
the engine out of the car.

I say if you have spare time and another car GO FOR IT.

 

First off, thank you to everyone who took the time to reply. I really do appreciate the input!

I totally get where you're all coming from regarding replacing the motor. And if I had a spare $4k+ sitting around I would. Unfortunately, however, with a baby on the way come May, spare money isn't my friend. Time, however, is.

I do plan on pulling the motor out to do all the work as was suggested. My hope is that I pull it out, disassemble it and find that everything on the bottom end is okay. If it is, as the last poster said, a few hundred bucks and some time and the engine's up and running. If not, well, then it sits for a year while I save up the cash for a new engine. The thing I can't get my head around, however, when I'm told to replace the engine is that 90% of the engine likely is completely unaffected. It burns my sensibilities to pay for things I don't need to.

All that being said, I go in with my eyes wide open, understanding that I might be tilting at a very imposing windmill. Either way, however, it's going to be fun to tear it to pieces and hey, it's an excuse to buy a few new tools.

If anyone has any thoughts on other things I should replace while I'm in there let me know. Two thousand miles (if that) before it blew up I replaced the water pump and serpentine belt. I'm going to examine the motor mounts and see how they are and will definitely be replacing the thermostat.

Anyway, cheers! Have a great Easter, all.

 

I suggest that you share with us your location in case a member near to you has 'been there and done that.' Other people's experience is a valuable commodity.

 

That's a great idea, thank you. I'll be doing the work in Denton, Texas, north of Dallas.

 

Being in the midst of this process, be advised that engine removal is a PITA. Must pull with trans. means must remove driveshafts and clutch cylinder, etc...
Lots of work to do this. I removed the front core section to allow for easy access, this requires removal of ac charge as well. It all adds up but if you have pulled engines before, nothing so far is unmanageable.
Good Luck!
John

 

It's a good bet that since this happened at idle that it's at most needing a head rebuild, pull the oil pan and check for damage. If everything looks ok on the top-end and bottom-end, then perhaps all you need is a remanufactured head or have yours rebuilt.

 

What a coincidence. I live in Flower Mound, about 10 miles from Denton. My 03 MCS has been having overheating problems for over a year and a couple days ago while the wife was driving down Dallas North tollway, it gave it up. Stopped running and overheated. I found a heater hose junction T connector that had a hole in it spitting coolant all over the place. Checked the compression and it was 60 in a couple cylinders and when turning the engine over with the plugs out it started spitting coolant out the plug holes. So I figure I'm looking at a busted head gasket minimum. It won't start. looking down the number 1 plug hole I can see a shiny curved mark on the piston so I think it may have dropped at least one valve. I'm gonna pull the head and check the damage before doing anything else. It has over 100k miles on it so it's due for a rebuild with all the overheating. Did you ever use Will at Bob's Tire and Auto in Lewisville? He's a great mini mechanic but I think he left Bob's. If I'm going to rebuild the engine I would at least like to get his opinion on how to approach it. Since you are in the area, maybe we could help each other out with information etc. If you are interested let me know. I don't know about putting in a used engine. As long as the damage is localized you should be able to get all the debris out of the engine and just replace parts. I'm hoping to get away with a head job, new valve seat grinding, new timing chain, replace bent valves if any, new gaskets and new pistons and rings if necessary. As long as it's torn down I'll try to go with high performace pistons etc and maybe a high lift cam. Replace supercharger oil of course and probably water pump. Any advice from the experts on NAM would be appreciated.

Mike

 

@xcountryfreak (Mike) - It's good to hear from someone in the area. I'm going to get started on this in the next couple of weeks and will take lots of pictures. As I run into issues I'll note em all and maybe we can compare notes.

Thanks!

 

One thing to note...
the 03mcs has the tritec motor...gen1, cast iron, block, very clasic desgin
the op's is a gen2 car...much more modern motor, cast aluminum, etc....
pretty different, but i'm sure moral support and maybe a sharing of a few tricks might work!! Good luck to both of you!!

 

Quite true, thanks for pointing that out.