Confessions of a newbie shade-tree mechanic: Mini Cooper edition.

I had a cyl3 misfire on my '02 R50, ended up taking the cylinder head out myself & had a good machine shop do a valve job. They are reputable in my area so I'm confident they did the job right & reset the cam properly. What I missed was that the camshaft was not in the same position when it came out as when I put it back in.

Unfortunately, my knowledge was lacking when I reinstalled the head. I messed up the timing and the car turns over but doesn't start. So I took the timing cover off (no small task!). Turned the engine over by cranking the camshaft bolt clockwise until the 2 copper links were lined up with the 2 arrows on the crankshaft sprocket.



With the chain in the proper position, I found that the camshaft is retarded by 7 teeth on the camshaft sprocket.




So, my question for all the more experienced mini guys out there... How can I get the camshaft back in line?

The cam locking tool will only engage if it is lined up with the 2 holes on the sprocket (when the sprocket's arrow is at 90 degrees). If I turn the camshaft to get the sprocket to 90 degrees, I won't have the crankshaft in its "service" position anymore.

I see that there are 2 flat spots on the cylinder that the crankshaft bolt screws into. Do you think that if I turn the cam to get it locked in & once the chain is off the cam sprocket, I could turn the crankshaft with a wrench on those flat spots? I have to be able to lock the cam in place to counter hold and remove the cam bolt/ cam sprocket/ timing chain.

Quite a pickle, I know... Any advice would be greatly appreciated. There's no part of the service manual marked "if you do it wrong the first time"... So I'm on my own. :-/

 

You don't need to lock the cam.
Release the tension on the chain, unbolt the cam sprocket from the cam and rebolt it so the mark on the cam sprocket is lined up with the dark chain link.
So long as the three dark links line up with the three timing marks, you're good to go. The actual position of the crank and cam when theses marks line up is completely irrelevant.

 

I need some way to counter hold the camshaft sprocket in order to loosen the cam bolt.

The only way I can think to do that is to rotate the cam, which will then change the position of the crankshaft.

The cam sprocket only locks into place in one position. There is a pin that locks into a slot on the sprocket. The cam and crank shafts DO need to be in their correct places, or the time that certain valves open and close will not match up with the proper strokes of the pistons/crankshaft. The only good way to tell that they are lined up properly is by getting the arrows pointing to the copper links. But the sprockets can't just be put anywhere, as I've learned from experience.

Check out the sweet hole I punched in my cam sprocket by thinking you could bolt it down just anywhere. The pin that made the indentation should have been in that rectangular notch.

 

Ok, rotate the cam until you can use the locking plate to lockdown the cam. Break the cam bolt loose, but just loose, not out. Now remove the locking plate. Rotate the crank back to the position that the marks are lined up on the crank. Once that is done, take the bolt out of the cam/gear and pull the gear off the end of the cam.
You will need to take the gear out of the chain and place it on the cam and rotate the cam so the mark is 90 degrees to the deck. Once that is done, place the gear back in the chain and slip it back on the end of the cam. Lock the cam and tighten the bolts. Once that is done, release the tensioner to put tension on the chain and remove the cam lock. All of your marks should line up and the cam mark should be at 90 degrees.

 

Thanks, Kris! Your tips were very helpful. I did what you said & it seems to have worked. I ended up getting a large adjustable wrench to turn the crankshaft once the cam bolt was loose. The camshaft was a little bit of a pain to align correctly. It wanted to jump to its next position, so I had to find a balance point where the notch and pin were lined up. Also, the loose chain kept slipping by one tooth while I was trying to reinstall the cam sprocket... So I often found myself checking that the 2 copper links below we're still on the right teeth.

When I turned the engine over by hand, it wanted to rotate SO much smoother than before. I hope that's a good sign that the car will start once everything is reattached.

Got a lot of parts to put back on... Here we go...

 

 

Got all the engine stuff back in, topped off the coolant, connected all the fuel lines, harness wires, hoses, etc. turned the key a couple times to build up some fuel pressure, and then tried to start the car... Still just cranking but no start.

This is probably a ridiculous question, but I'll ask anyway... Does the car know the bumper & MFE aren't attached? I can't imagine the engine won't start because there's no bumper. I didn't want to put them on if I was going to have to take it apart again. It's on 4 wheels, no jack or stands, the oil pan is full, i even drizzled about 6-8 oz. of oil onto the head before i put the valve cover on. coolant is full & bled, spark plugs are in, torqued, dielectric grease on the coil contacts, plug wires are secure.

Now I'm wondering if I got the timing marks on the sprocket correct but what if the pistons aren't in the right positions? Does the crankshaft have more than one rotation per cycle? Like does it take more than one rotation of the crank to go through a cycle of combustion of each of the 4 cylinders?

Throwing in the towel for today... Back at it tomorrow. At least I'm a teacher with the summer off, so I have time to deal with this dang machine.

 

Yes your engine is a 4-stroke. It goes up and down 2X for one ignition cycle.

 

So maybe I have the crankshaft set for the exhaust stroke on cylinder 1 instead of the compression stroke? Does it make a difference as far as the operation of the engine is concerned? I'm thinking, if for each rotation of the crankshaft, piston 1 goes up and down, then does it matter whether the piston is rising for the "compression" stroke or the "exhaust" stroke? It's still going to rise, and my thought is that the cam position sensor would tell the injectors which cylinder to hit next. Again, I'm but a newbie to car mechanics, but I don't think the Bentley manual said anything about which "go round" of the crank shaft it should be when you set up the timing chain.

 

Please be careful about randomly turning the cam or crank with a timing setup apart... There is a risk of having the valves contact the pistons.. Which leads to bent valves.. Which leads to the head coming off for repair..

If piston 1 is at TDC that's all you need to set the crank. Double check the cam marks if the crank marks look ok.

 

If the timing marks are in the same places as other cars I've worked on, then...

When the crank mark is lined up, cylinder number one is at the top of its stroke.

Then when the cam lines up with its mark, both valves for that same cylinder should be closed.

This is the top of the compression stroke
Spark plug lights
Piston goes down
Exhaust valve opens
Piston goes up
Intake valve opens (exhaust valve closing or closed now)
Piston goes down
Intake valve closes (both valves closed now)
Piston travels up on compression stroke again
Spark plug fires

Repeat

 

Suck... Squeeze.... Bang... Blow..

 

What makes things more complicated is that Mini doesn't use TDC as their timing default.

I do understand how the 4-stroke engine intake, compression, ignition, exhaust sequence works... but I wonder if the Mini manual would've been more specific if there's more to know than just getting the arrows pointing at the copper links... like I said earlier today, I turned over the engine by hand and it was quite smooth.

From what I've heard/seen, I'm pretty sure (not positive, maybe someone can confirm) that my engine is not an "interference" engine... meaning that the valves don't reach the pistons or each other. So, while I know that can be a REALLY big danger, I'm not sure that it is true of my R50 engine.

I'm considering removing the cylinder head tomorrow to check for any damage. If it's damaged, it should be pretty easy to tell... I just had a valve job done, which is how this whole episode started in the first place... burnt valves.

 

Ok, after a quick search.. seems its not an interference engine.. good deal! Good to know.

 

Are you sure you have spark? Fuel pressure? If you dont have spark and fuel you can adjust the timming forever and it wont start. If you have fuel and spark when you crank the engine does it sound like it is turning over easy or kind of labored? if the timming is off the engine does not sound right when turning over.

 

The R50 is an interference engine. The R53 is not.

 

Well then be careful!

I recant my testimony from the court.

 

Always a sense of humor Dan.

 

rut roh.

better spend the morning taking apart the head to look for damage.

 

Fuel pressure seems good, after a few On/Wait/Off cycles of the key (before actually trying to start) seems to build up good fuel. I've checked at the fuel rail release valve, the juice is spurting out when I open the valve.

I haven't used a spark tester yet. I've replaced all but the spark plug wires... new plugs and new ignition coil. The car was running (poorly) when I parked it in the garage. I doubt that the plug wires broke while the car's been sitting, so I'm thinking it is probably getting spark. Might still be worth checking, though.

The engine sounded louder when it was turning over with bad timing, now it's turning over pretty quietly.

Gonna go pull the cylinder head now to see if I broke anything. crossing my fingers that it doesn't need a *second* valve job...

 

Wouldn't doing a compression test be easier?.

 

Yeah a compression check, check for spark and recheck all the electrical connections. You had to take the whole top end off to do the head. A lot of things were taken off and upluged could easily forgot to put sometinng back or not clipped in all the way. The last thing you should do is remove the head again.

 

If the cam is out of time you could get a low compression reading even if the valves are good.

You could have the engine 180* out of time.

 

I got the head out. It's scary when you realize you have most of the socket sizes memorized... Been working on this car for far too long.

Today is a sad day. It turns out that the R50 engine most certainly is an interference engine. Mine did some pretty good interferein'...

Just dropped it off at the machine shop for valve job #2. It's hard to start a car when all your intake valves break and are stuck open. Aside from a couple tiny marks, the pistons appear to be ok. Gonna check them out more closely when I go to the garage tomorrow.

Here are some pics of the damage. *facepalm*

 

Oh ouch...


New head bolts too... (Again..)