When the dots on the gears are aligned does that mean #1 is tdc firing or can it be 180 off on the exhaust cycle.
Aligned how... Both dots high ? Both dots low ? One dot high, one dot low ? The dots next to each other ? Mike
If done as a typical timing set installation, "dot-to-dot" with Cam gear dot at 6:00 and Crankshaft gear dot at 12:00 , so that they are as close to each other as they can physically be.....it is actually TDC Exhaust stroke for Cylinder #1,... at the same time it is also TDC Firing Cylinder #6. The most typical rookie mistakes made by Chevy guys is thinking "dot-to-dot" fires #1 and put the distributor in the motor like this, and thus are 180° out of time.
The reason so many are 180 out when you go to start them. Truthfully if you are a real mechanic it doesn't make a freaking rippy doo dah at that time because you are going to rotate the crank and cam several times before you should drop the distributor then and then you can Watch the intake valve and rocker on number one as you crank it over by hand and then bring the timing marks together at the same time. I normally do my start up setting on the valves before I put the intake on or distributor in and turn the crank and cam several times in the process. I'm also that shop teacher who cranked engines over so students had to set the timing the old fashioned way on engines they assembled.
When I was a young whipper snapper back in the 70's, did tuneup on a 350 with points. Replaced points, plugs, and rotor. Go to start it and was backfiring out the carb. Older tech said I messed up and it was 180 out. I swear to him I did not do anything that would make it 180 out. Took me a while but found the old rotor had the alignment pegs ground off so it could be installed in either direction. Someone before me didn't feel like resetting the dist correctly. The chit that stays in my memory for 50 yrs lol.
I just want to change the timing chain and sprockets. Of the dots on the sprockets align, am I in good shape to just remove the sprockets and chain and replace with the same orientation.
Thats probably what I did to get it running and out the door. Sure did not pull the dizzy. I was pissed!!!
When all else fails, simply align the dots in any fashion straight up. Then once all the valve lash is set, turn the engine over with your finger over #1 spark plug hole until you feel compression pop your finger off the hole. Then back it off until timing marks align, and stab the distributor so rotor points at #1. Foolproof, and no need to even have the valve covers off to do it.
You would not have to but if the engine has enough run time to need timing replaced checking the valve train might not hurt and using the companion cylinder is easy to find TDC when the covers are off.
I never said I did. I simply said you can find TDC without removing the valve covers this way. There are times we might need to find TDC and not be adjusting valves. You did read the original post that started this thread, didn't you? He's not sure which direction the timing marks go to know if it's TDC compression stroke. So cranking the engine over and feeling compression has been done for decades to find TDC without pulling the valve covers.
I agree but if you want to check your work with the timing set and use the intake valve just opening on number 1 or it's companion and the timing mark is not very close to TDC you have an issue, easy to do with those multi key way gear sets where someone used the wrong dots with the wrong key way
I'm kind of surprised they don't include the little paper sheet showing this with the set any more...
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