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| otto and minis (help!) https://www.ausmini.com/forums/viewtopic.php?f=2&t=34692 |
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| Author: | deleted [ Fri Aug 10, 2007 11:20 pm ] |
| Post subject: | otto and minis (help!) |
Realllly basic question here guys. I'm a little embarrassed to be posting it, but i am completely baffled! When cylinder 1 is at TDC, its valves should be rocking ? ie. one valve has just closed, the other is just opening, right? Thats what I've been reading, i would have thought that at TDC cylinder one would have both valves closed, because its just had the intake cycle and has just sparked. I am completely baffled, i even started to think that maybe the cylinder closest to rad was cylinder 4 instead of cylinder 1, and i have had it wrong all these years. All this time i've claimed that there were no timing marks on my flywheel, but I've taken the cover off to check, and they are there! (just in a completely different spot to what i expected). Perhaps I'm wrong! As it stands, I've just pulled my engine out and have redone the timing chain because i wasn't confident it was spot on. When the dots are aligned, cylinder one (rad side) is at its top, the crank key is @ 12 o clock, and the camshaft key is approx at 1 oclock, the gears dots are lined up. The rocker gear on top of cylinder one has just closed one valve and is almost about to open the other valve. Is this correct?? It can be no other way in order for the dots to line up on the timing gear, but i thought maybe my camshaft had been keyed in the opposite spot or something. Please help confirmed or deny! its all reassembled again and ready to drop back in. THANKS |
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| Author: | Timbo [ Sat Aug 11, 2007 9:51 pm ] |
| Post subject: | |
Its a 4 stroke so there's two TDCs one at the end of the compression stroke/start of the combustion stroke, when both valves are closed. The second TDC is at the end of the exhaust stroke/start of the combustion stroke, where the exhaust valve is closing and the inlet valve is opening. Tim |
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| Author: | TheMiniMan [ Sat Aug 11, 2007 11:28 pm ] |
| Post subject: | |
Deleted, the way you`re doing the cam timing is right & yes at the point where you set "Doit to Dot" it will be firing on #4 cyl The marks on your flywheel being in the wrong spot is most probably because some goon has pulled the 2 pieces of the flywheel apart at some stage & has bolted it all back together in a diffent orientation. Now tell me that you have a one piece flywheel & i`ll just shut right up 
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| Author: | deleted [ Sun Aug 12, 2007 12:49 am ] |
| Post subject: | |
some goon indeed! thanks guys, its running bootiful now :) |
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