Trying to tackle missfires and zero compression issues on a 20016 R53 mini. One suspect is carbon build up. Is this a common cause for R53?

Would appreciate if you guys can share your experiences and DIY procedures on how to clean-up carbon build up. Is it only the intake manifold that needs to come off? What cleaners would I use?

Thank you

 

I haven't heard of any carbon build up on the R53s. All compression readings low?

Nik

 

Cyl 1 and 3

 

Ditto what Nik said, I've never heard of carbon build up on the S/C motors.
Can you tell us what the numbers were in all the cylinders?
Did the motor ever overheat?
Is it modified in any way?

 

the compression 0n 1 and 3 are zero. I have no specific numbers for 2 and 4.
no overheat issue
it is a stock R53 with no mods. It has 150,000 miles on it.

On further research on this site, and with your inputs that carbon build up is not likely, I am now suspecting worn out or broken valve springs. I experienced the same symptoms about a year ago (misfires error codes) and the compression then was acceptable on all cylinders. The problem was traced to a bad coil pack.

any ideas on a valve spring compressor for the R53? If the spring is the problem, should I only replace the bad ones or should I replace all of them? Is it easy to pinpoint a bad spring visually when still installed in car?

still runs fine on flat roads but loses power when going up hill and with rough idle.

 

You should be able to check things visually.
If it were me, if pull the rocker/valve cover and get someone to turn it over (don't forget to pull the coil wire so it doesn't try to start) and just look to see if something jumps out at you.
If not, then take a modified compression tester hose or dummy hose (the regular compression tester hose won't work because of the check valve) and charge each cylinder with air on the compression stroke to listen for leaks... But honestly, your probably looking at pulling the head no matter what. Good thing is, as long as there's no damage to the bottom end, if it was maintained well, they're usually good for 250-300k miles or more, so you could may just be looking at a head repair or replacement.

 

Broken valve springs are a possibility, head gasket, burnt exhaust valves (not very prevalent on the S but it does happen), melted piston (always a good one), but you need to start with a leak down or smoke test to diagnose where your compression leak is.

If it does turn out to need valve springs you can use a compression tester hose and compressed air to keep the valves closed while you remove the retainers and springs, it's tricky for a one man job, but it can be done and you'll be able to do the job without removing the head, or the need of a spring compressor.

 

thank you for the insights. planning on using TDC method instead of compressed air.

If it turns out that I need a head rebuild, how much would I expect to spend for a head rebuild?

 

one question. how do you turn the engine manually? I have not done this kind of work on the mini before so just wanted to make sure. I suspect i would have to remove the tires to access the crank. and what direction should I turn it (is it clockwise?)

Thanks

 

Clockwise. You could drill a hole in the inner fender with a hole saw to access the crank pulley.

 

Yes, pull the right wheel and inner fender cover (don't forget about the fasteners under the bumper cover and near the Jack Pad), the crank pulley bolt is normal (right hand) thread, so clockwise.

 

Thank you all for the responses. I am feeling more confident now. I have replaced the valve cover gasket recently so I know how to get up to removing the valve cover. The only additional step that I think I need to do to access the springs is to remove the rocker arm shafts both intake and exhaust. This will get all rocker arms out of the way allowing access to the valve Springs. I have.my universal spring compressor as well. Anything I am missing?

 

I removed the valve cover and the rocker arms to have a better view on the valve springs. The springs not broken or damaged.

I found however that the spark plug on cylinder 1 was badly covered with oil build-up. Further, 2 ground electrodes (out of 4) were missing (broke-off). I suspect this is the cause of the no compression on cylinder 1. I suspect the ground electrodes that broke-off caused the damage to the piston and/or valve. Of course I will need to remove the head to confirm, but the fact that I have no compression on cylinder 1 makes me conclude that this will need major repair.

Any similar experiences that you can share would be appreciated. I am hesitating to proceed any further at this point given the mileage (160,000), the cost of repair and the resulting value of the car.

Here is a link to NGK site on broken ground electrodes. This is the brand I used.
http://www.ngk-sparkplugs.jp/english.../10/index.html

 

A head job is usually about $2500 parts and labor, but if you end up needing valves it'll add up quickly.

If you just need the head gone through I would hold on to the car and fix it, but if the pistons are damaged you need to make the call on what you want to do.

 

The cost is exactly the concern. Right now, I continue to use it with a crappy idle as expected. Once it is running, it gets going and able to get me me to where I want to go. I hope it can last till spring when I will have more time and money to deal with the problem. Any concerns on using it with the cylinder 1 problem as is?

 

buy a good condition used r53 head. they run around 500 dollars.

although its very likely that there is piston / cylinder damage so..

 

Good to know about a used head. If I open up the head I need to be ready to commit on what to do if in case the cylinder/piston is affected. Right now I cannot afford without a ride. That is why I am using it as is and buy time till April next year. See pics attached. One looks like just after removing from head. The other after cleaning for a clearer view. Do you think the broken off electrodes could have caused damaged to the cylinder?

 

http://www.harborfreight.com/digital...era-61839.html Maybe get one of these you might be able to see if there is any damage. had my cylinder head reconditioned for $200.00, but it didn't need any valves or guides. I have a cylinder head on a engine I bought off craigslist. Which has bad rod bearings found that out after buying it.

 

There's a fairly slim chance that the car will make it til next April being run in its current state, as well as you'll be doing more harm to the engine which will increase your cost to repair in the long run.

Start with a leak down test to see where the compression leak is. Most common failure in this case is going to be the exhaust valves. I've seen cars that have ingested more particulate than that and not have piston damage.

 

Could not agree with you more. Cylinder 1 found with no compression so not sure what value a leak down would have.

Is it possible to tell if piston/cylinder is affected by visual inspection?

Any suggestion where to buy a rebuilt cylinder head?

 

A leak down test will show you where the leak is, whether it is exhaust valves, piston damage, HG failure (not your case). So it does have benefit.

We sell rebuilt stock heads, should have a few on the shelf as we speak.

 

I am not sure I follow your logic. Compression is zero so how can a leak down even be possible? Pls let me know what I am missing.

can you send me your quote for a rebuilt head? my email address is emmy.mendoza@gmail.com

 

I think what Nik is saying is that if you pressurize the cylinder you should be able to hear where the loss is coming from, it will be a simple and free test to see if you're talking valves or not. (Yes it could be both valves and a piston, but if there's nothing leaking around the valves at all, you'll know up front it's major.)

 

I used compressed air to keep valves from falling into a cylinder one time, and it worked, but it was scary. So many things could go wrong. Later I tried the feeding rope into the spark plug hole and pushing it up with the piston, and I felt much better while I was working. This wasn't on a Mini.

Just thought I'd throw that out there.

 

This is what I'm getting at. You will have a round about answer on what the failure is and where to start your diagnostic.

I will pass along your information to the office folk and have them send you a quote Banyan. :thumsup: