The New And Improved Unofficial R65 Forum V2
Technical Discussion => BMW Technical Q&A, Primarily R65 => Topic started by: Oconner on September 11, 2015, 11:54:18 AM
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So last night started in on my first valve adjustment. Read the Manuals, watched the youtube, and saw a guy doing one at a tech day. So hard could it be?! I was cruising along and thought I was almost finished when I realized I never did the TDC. Back to square one. Did the TDC and got the left side done. Was late so I shut it down. Question is do I just rotate the engine 360 to get the right side TDC? How do you tell if your ready to do the adjustment? Stupid question # 4,456,789!
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Yes rotate the crankshaft one full turn as indicated by the OT mark appearing again in the timing window.
How did you determine TDC when doing the first cylinder ?
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Thanks Barry. I turned the engine over spinning the rear wheel and found OT in the view hole. Then did the left side. Was stumped on the other side as things seems so tight. Then I realized I had to get that side to TDC, thus my quandary, wasn't sure if I just spin the engine again 360 or if I should be looking for something specific?
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Thanks Barry. I turned the engine over spinning the rear wheel and found OT in the view hole. Then did the left side. Was stumped on the other side as things seems so tight. Then I realized I had to get that side to TDC, thus my quandary, wasn't sure if I just spin the engine again 360 or if I should be looking for something specific?
You are not the first, not will you be the last person who forgets to turn the engine over after doing one side, and then starts the poor thing and wonders why it sounds like the clappers of hell have got into it. Fear not, it is merely another club you have joined.
One thing I will say. In my significantly less than humble opinion, turning the engine over using the back wheel is an absolute crock. Disconnect the battery, take the front cover off and put an allen key into the alternator bolt and you can turn the engine accurately and easily.
Oh, and then you get to join another club, the "I forgot to take my allen key out before I started up to check my work" club.
Seriously, how long does it take to undo 1, 10mm bolt and 2, 6mm allen cap screws?
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When you have it right, both pushrods will spin on the side you want to adjust. if one is tight its not in the right spot
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I still use the rear wheel to turn the engine -makes the job a bit quicker, and less to remember to put back together -especially when you have crusty crossover pipes.
Oconnor - generally, the key thing to ID the proper side that is ready (at TDC and on the COMPRESSION stroke) is to note the bit of wiggle/play in the rocker arms and the ability to rotate the ends of the pushrod ends with your fingers - PROVIDED that there is some clearance there and the PO didn't completely frigg up the valve settings to begin with (or that they've completely closed to nil or below nil). That is usually a very rare case - but it is one I've had to deal with, too.
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Ayhe, as nhmaf said. I found it easy to turn the wheel with the sparks out to get TDC on each cylinder, look for the slack period. Also a previous owner had painted marks on the flywheel on either side of the TDC 'TO' stamp to better indicate when the stamp would appear through the timing hole.
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I never do the TDC thing with any engine - left intake fully open, set the right, same with the exhaust. Easy to see the valve moving by which ever method you like, or using the starter button. I don't know people make such a big issue out of it.
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One thing I will say. In my significantly less than humble opinion, turning the engine over using the back wheel is an absolute crock. Disconnect the battery, take the front cover off and put an allen key into the alternator bolt and you can turn the engine accurately and easily.
Oh, and then you get to join another club, the "I forgot to take my allen key out before I started up to check my work" club.
Seriously, how long does it take to undo 1, 10mm bolt and 2, 6mm allen cap screws?
I've got to say I'm with Tony on this one. I've tried using the back wheel I really have but my mechanical sympathy just won't let me do it. You can't or at least I can't turn the back wheel even in 5th plugs out, I have to jog it which puts shock loading on everything: rear wheel splines, all the gears the clutch splines and even the big end bearings. To me it's plainly the wrong thing to do.
I joined the rotating Allen key club years ago I thought it looked nice - kind of poetic.
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The spinning the rear wheel method is kinda a pain in but
Next time i am going to put a hole in the front cover and plug it with a timing hole plug :D
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Considering the amount of driveline shock which occurs during even sedate riding around town, downshifting, accelerating, etc. the little bit that one can exert while slowly turning the rear wheel doesn't even come close. So, be at peace, those who use the rear wheel. And if someone prefers turning things from the rotor end, that's OK too, even though you are turning the engine from a device that is designed/intended to be turned by the engine instead of the other way around
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Considering the amount of driveline shock which occurs during even sedate riding around town, downshifting, accelerating, etc. the little bit that one can exert while slowly turning the rear wheel doesn't even come close. So, be at peace, those who use the rear wheel. And if someone prefers turning things from the rotor end, that's OK too, even though you are turning the engine from a device that is designed/intended to be turned by the engine instead of the other way around
I wasn't objecting to turning the rear wheel slowly and smoothly to align TDC in the window if it can be done. I was objecting to using the free play in the transmission system to turn the wheel back and forth in a jogging fashion to get TDC in the window.
Those who can get TDC in the window by turning the rear wheel smoothly and without jogging are better men than me although I'm at something of a disadvantage in the overall gear ratio which will make the task on an R45 feel like it would to you in 3rd or 4th gear instead of 5th.
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So don't do the TDC thing if it causes problems. Much easier to watch the valve opening. It's a 360 degree firing engine so when the left side inlet valve is fully open, the right hand inlet valve is fully on the back of the cam...and so on for all other valves. I've been doing it this way on all engines for 45 years, this is the way were were taught as apprentices. I don't even use TDC on singles, always put the valve on the back of the cam.
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Any consistent method should work fine and your method is undoubtedly consistent and fool proof in that there is no question about which cylinder to work on.
I'm checking the points gap and static ignition timing at every service so I need the front cover off anyway and I need to turn the engine over very slowly and precisely. That can't be done with the back wheel or certainly not to my level of precision.