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The camshaft position determines whether the TDC position of the piston is the compression or exhaust stroke because the camshaft is controlling the valves. A piston at TDC cannot be said to be on the compression or exhaust stroke without a head on it. Which is why Willy correctly states that as long as the piston is TDC and the 3 dots are lined up that you're good to go. The camshaft is the determining factor.

To install 180 out would be to install the camshaft upside down which would make it the exhaust stroke instead of the compression stroke. But a piston that is 360 degrees out is in the same position, only the valves and camshaft move.
 

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The camshaft position determines whether the TDC position of the piston is the compression or exhaust stroke because the camshaft is controlling the valves. A piston at TDC cannot be said to be on the compression or exhaust stroke without a head on it. Which is why Willy correctly states that as long as the piston is TDC and the 3 dots are lined up that you're good to go.
I knew it was something like that................:D
 

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You do such a good job of answering these kinds of questions correctly and quickly that sometimes I have to pick up the scraps. So I write long drawn out confirmations of what you already posted so that others who might come across the thread later have more to read ;)
 

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Discussion Starter · #11 ·
good info guys! i was thinking (and i have been warned not to) that the compression stroke would be where the spark would occur and if i was off then i wouldnt get a spark at the right time. apparently i was wrong. thanks again

now for my next problem :)

i got it all together and tried to check compression and its low.. about 100psi
when i was doing this i hadnt put the cover back on that shows the tdc mark, the little cap.. and i was getting a large amount of air out of that as i turned it over. my guess is that the rings are also bad and im losing compression past them and into the crank area. i knew i should have went ahead and got a piston for this thing. the guy i got it from said it was good but why i beleived him, i dont know. try try again... lol
 

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I am unique
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good info guys! i was thinking (and i have been warned not to) that the compression stroke would be where the spark would occur and if i was off then i wouldnt get a spark at the right time. apparently i was wrong. thanks again

now for my next problem :)

i got it all together and tried to check compression and its low.. about 100psi
when i was doing this i hadnt put the cover back on that shows the tdc mark, the little cap.. and i was getting a large amount of air out of that as i turned it over. my guess is that the rings are also bad and im losing compression past them and into the crank area. i knew i should have went ahead and got a piston for this thing. the guy i got it from said it was good but why i beleived him, i dont know. try try again... lol
Even with zero leakage past the rings, you will get expelling from this or any hole in the base when the piston goes down, it will also draw in air when the piston goes up in the bore...........
 
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