I have a 2005 mini cooper S, poured lots of money into this car over the last two years. New brakes, rotors, complete SS exhaust from cylinder head back, rebuilt super charger, rebuilt steering rack, new right front suspension, and so on. It recently lost all compression on cylinder #1, need to try to figure out whether it can be repaired without replacing the engine.

Body is in good shape though not perfect, could use a new front bumper cover. Shows 140K for mileage. Two complete sets of wheels, factory alloys and steel for winter. 6 speed manual transmission.

Any guess what this car may be worth for parts or a project? I'm not terribly interested in having it sit while being parted out, prefer to just let it go.

Other options being considered are picking up a used low mileage engine. I'd replace the clutch and flywheel while it was apart. Use the car for a few more years, assuming the value wouldn't be too much higher than book even with a much lower mileage engine?

I may fish around with a magnet, see if there are bits of valve in the cylinder. In that case I'd assume damage probably would make repair of the original engine cost prohibitive. If not, maybe a closer look with a borescope.

 

Any horrible sounds? Have you pulled the valve cover? Rather than a "heart transplant", it may be just "minor surgery".

 

It's my daughter's car. Said it was making a "putting" sound, most likely misfiring. Garage took a look at it, said no compression on cylinder #1. They said there may be some debris in the cylinder, haven't looked for myself yet. If it bent a valve but didn't drop into the cylinder, maybe it can be saved? What would I expect to see under the valve cover? Broken spring? I'm thinking worst case scenario until I get a chance to have a look. A peek into the cylinder with a borescope would be definitive? I hate to scrap the car, it's in good shape overall.

 

First thing I would do at this point would be a leak down test. That way it would tell you if it is a head problem or bottom end problem. Top end problem is much cheaper and easier to fix obviously.

 

Just had this happen to my mini, it was a faulty spark plug.

Do the troubleshooting, don't jump to conclusions

 

I would do the leak down test like Way recommended, but it could very well be just a head problem.

If you have a good mechanic they shouldn't charge you very much to just take the head off and inspect it for damage. Replacement heads or a rebuild would only be around $500-700 , plus labor of course.

 

Here is a link to what a leak down test is. If the rings are gone then the cylinder wall is most likely scarred. If it is a valve spring then you might get out with only a new/used head. How good are you with wrenches?

https://mobiloil.com/en/article/car-...-leakdown-test

 

Thanks everybody for the words of encouragement.

The car died far from home, had it towed to a local service center where they did a quick inspection, did a compression test. They tell me cylinder 1 has zero compression, possibly some debris in the cylinder. We had it towed home so I may have a look for myself. From what the shop told me it sounds like it may be a dropped valve. I bought an inspection camera today, going to have a look inside cylinder 1, see what's going on. Assuming the cylinder truly has zero compression.

If a valve dropped, I'd expect piston damage and possibly scars to the cylinder walls. In that case, a used engine may be the most economical way to get the car going again should we choose to do so. I'm a bit on the fence in that case, wanting to keep the investment below book value if I can.

So far as value goes, I've wondered if the car would have more value than another mini cooper with the same mileage if i install a low mileage engine with a new clutch and probably a new flywheel. Seems the car would likely have a much longer lifespan than another with high mileage.

I will probably take a look sometime in the next few weeks, weather holding. It's getting to be rather cold now, may need to wait a while.

My mechanical skills are up for the task though I've not worked on a front wheel drive car before, experience mainly with older rear wheel drive cars. It looks like a lot of work either way, removing the head or replacing the engine.

 

Head is pretty easy to do. Check out the video and see if it's something you're comfortable doing.

 

These cars don't "drop" valves. I would say you've either got burnt exhaust valves, possible lifter problem, or piston/rings problems.

 

I took a look inside the cylinder with an inspection camera. No evidence of debris as the garage had reported. I can't see the entire piston top due to the angle of the spark plug tube and plug opening, see about 80%. All looks OK to me. No nicks or gouges, no foreign bits of metal, etc. No compression on cyl #1. About 145 - 150 on all other cylinders, cold, obviously.

I can't see the intake valves but can see some of the exhaust valves. They look ok, no pieces missing. Could be a burnt valve though this happened rather suddenly. I'm waiting for an opportunity to take the valve cover off, have a look. Maybe a broken spring? If I can't find anything there I'll probably wait until spring, consider taking the head off to have a look, repair if economical. Getting rather cold now. I'd rather save the car if I can.

 

Weather is finally warm enough for me to take off the valve cover, have a look.

It appears I have a broken intake valve spring on Cyl #1. The spring does not pull the valve fully closed, I can press the spring with just my thumb.

Now wondering if I may get away with just replacing the spring. Never tried to replace a spring with the head installed.

I'm going to check to see whether the valve will actually close and seal. Still possible it was bent?

Anyone else experience this? I'd prefer not to pull the head unless it's necessary. A lot more work.

 

Haven't done it my self but its not apparently a new thing:

Good Luck
Bruce

 

We've replaced broken valve springs with the head still on. You'll need a compression gauge adapter to pressurize the cylinder with compressed air to keep the valve closed.

There are two keepers on the valve stem, the spring perch, the spring itself. If you've got a buddy it may be an easier job to do, but still doable alone.

Take a socket that fits around the keepers and a small hammer, give the socket a tap and the keepers should pop out. Make sure not to loose them. From there just pull the broken spring and perch out and drop a new spring in. We've used large screwdrivers to push down and compress the springs while another person inserts the keepers back into the valve stem, but you can use a variety of different tools to apply downward pressure.