Stock Problems/Issues Discussions related to warranty related issues and repairs, or other problems with the OEM parts and software for MINI Cooper (R50), Cabrio (R52), and Cooper S (R53) MINIs.

Finding Top Dead Center (TDC)

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Old 02-13-2011, 08:57 AM
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Finding Top Dead Center (TDC)

Hi. I'm standing in my garage with my car pretty much in pieces behind me. I'm replacing a blown head gasket and the faulty fan that caused it. I have just a couple of screws holding my intake on and my father-in-law working on the exhaust as I write this.

I know I should set the motor to top dead center before I take the timing chain off to keep me from ending up 180 degrees out when I put it back together, but how do I go about finding that position? I see two marks on the pulley on the side of the block that look look like they might line up with some bumps on the side of the block itself, and a line on the pulley that the timing chain rides on that is connected to the cam shaft but no obvious place to point that at.

also, while I'm at it.. any tips on loosening the tensioner for the timing chain?

I can post pics of what I'm looking at if it helps any..

thanks.
 
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Old 02-13-2011, 09:02 AM
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2003 R50, btw.. if it matter.
 
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Old 02-13-2011, 12:04 PM
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here's what i'm looking at right now...

From what I surmise I'm @ TDC here. I've inserted a straw in the 1st cylinder and this is where it is at it's highest point.. not entirely sure I'm at the top of the compression stroke or the exhaust stroke though. click pics for larger version

Finding Top Dead Center (TDC)-fmemum.jpg

pulley @ crank on side of block, note the small divot in the pulley's left side that is in line with the bump on the block beside is.. there are two divot here, and two bumps, but only these two line up, if I advance it further to line them both up then the straw in the above pic has already begun to fall.
Finding Top Dead Center (TDC)-ychqbm.jpg

This pic is showing the mark on the sprocket at the cam, lined up @ 90degrees with the head. Basically just pointing straight at the seam. It's kind of hard to see, but it's right there inline with and past the metal piece right in front of it.

Finding Top Dead Center (TDC)-qwywzm.jpg

Last one here shows a differently colored link in the timing chain that is now sitting on the "top" of the sprocket.. but it's not directly at the top in line with the head's orientation.. There's two links like this on the other side of the chain..

Finding Top Dead Center (TDC)-eihwum.jpg


ok... I turned it a few more times and I came to a point where I think I'm better off.. this pic shows those two different color links, they're pretty much right inline with the mark, and fill the distance between that mark and the top of the tensioner arm.

Finding Top Dead Center (TDC)-dnyimm.jpg

and another angle

Finding Top Dead Center (TDC)-flalnm.jpg


thoughts?

also, found some access ports to the tensioner bolts.. it's a huge allen wrench.. any idea what size that is? 10mm? i assume i've got to get to the two bolts that look like they're for teh head that are under them..
 

Last edited by ghurm001; 02-13-2011 at 12:13 PM. Reason: made images smaller
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Old 02-13-2011, 12:34 PM
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To find TDC, watch the valves as you roll the engine over slowly, as the intake valves close, the straw rises to the top of it's travel - that's your TDC. It really doesn't matter, as long as you get everything back in the same exact place it came from, but it's easier to put it on TDC #1 and mark everything from there.
 
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Old 02-13-2011, 12:44 PM
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thanks, Dave.
 
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Old 06-10-2011, 06:15 PM
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findTDC

The easiest way way for me to find TDC, especially with the head on is as follows.
remove all spark plugs, remove fan belt(makes it easier to turn over the motor)
put your finger in # 1 cylinder spark plug well, turn over engine with a 1/2 drive breaker bar or rachet, when you feel air being pushed out of the cylinder that means it is on the intake stroke. insert long thin screwdriver(anything that will stay rigid while cranking the engine) when the item in the spark plug hole reaches it' s farthest upward travel, that is TDC. you will know you have TDC when the item you have in the #1 spark plug hole starts going down,then back up the the point where it just starts to go up again and then wiggle ratchet or breaker bar a tad to make sure it is at TDC.
this is an old shade tree mechanic method, but it works. I have been doing it like this since i built my first engine in 1966.( a big block Ford)
 
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Old 06-11-2011, 05:42 PM
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FYI, MINI doesn't use TDC to time the motor. When all the timing marks are lined up all 4 pistons will be even.
 
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Old 06-11-2011, 06:21 PM
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thank you for the clarification. I just bought my Mini s. always had Detroit iron before, Montana was a union state when i got out of the Marine Corps in 1968, and i served an apprenticeship to earn my journeyman's license as a Mechanic. Worked at a Ford dealer and built Ford race cars(drag) for 20 years, so i am ignorant with the mini but learning fast.
thanks again.

maybe you can help me. i have my 04 Mini s in the shop because it was making a godawful screeching sound at higher RPM's the dealer and i thought it was the supercharger, the warranty people approved replacing it and it is still making the screeching sound. It sounds like a bearing going or a pulley seizing up. any ideas?
 
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Old 05-13-2012, 04:08 PM
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keeping a note of
 
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Old 06-13-2012, 11:52 PM
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i know this is really late but when i did it i just took 2 coat hangers and straightened them out then cut 4 equal length rods and placed one in each of the empty spark plug tubes and turned the crank until all 4 rods were even at the top. then positioned the timing chains copper links to match up with the arrows on the crank and cam gears
 
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Old 06-14-2012, 12:44 AM
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^^^This guy!! hahah
 
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Old 07-02-2017, 08:30 PM
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Originally Posted by terrysil
thank you for the clarification. I just bought my Mini s. always had Detroit iron before, Montana was a union state when i got out of the Marine Corps in 1968, and i served an apprenticeship to earn my journeyman's license as a Mechanic. Worked at a Ford dealer and built Ford race cars(drag) for 20 years, so i am ignorant with the mini but learning fast.
thanks again.

maybe you can help me. i have my 04 Mini s in the shop because it was making a godawful screeching sound at higher RPM's the dealer and i thought it was the supercharger, the warranty people approved replacing it and it is still making the screeching sound. It sounds like a bearing going or a pulley seizing up. any ideas?
Mine is doing the exact same thing. I still can't find an answer for it. Replacing my whole timing cassette this week and maybe I can help give you some answers
 
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