on my 73 2l.there are a lot of paint marks from po on fan,and are not reliable in finding tdc.so i need to know if i line up rotor on dizzy to #1,use the crack on flywheel on top of trans ,this should give me tdc.i put straw in cylinder #1 with plug out at its highest point and assume that is true tdc,but crack on top of flywheel is off,shouldnt they line up .i know useing straw also has its variable positon.whats the most definitive way to get tdc?
Full Version: some confusion about finding tdc
QUOTE(rosenfe @ Mar 6 2015, 09:09 AM) 
whats the most definitive way to get tdc?
Whatever you do, don't use chopsticks!
What, not a chopstick? 
(Sorry, inside joke from many years back!)
The flywheel should be keyed to fit on the crank only one way. So the notch in the edge of the flywheel being visible in the notch at the top of the transmission bellhousing (for cyls #1 and #3) or the bottom of the bellhousing (for cyls #2 and #4) should be a very strong indication of one of those cylinders being at TDC.
NOTE: The crank goes through two complete revolutions for every complete four-cylinder cycle of the engine! So the notch being at the top will show that the engine is either at TDC for #1 or TDC for #3! You can check the rocker arms to verify; a cylinder at TDC will have some slack to both rocker arms. You normally just check the distributor rotor to make sure, but it is a lot easier to get the distributor in 180 degrees out than it is to put the cam in 180 out.
--DD
(Sorry, inside joke from many years back!)
The flywheel should be keyed to fit on the crank only one way. So the notch in the edge of the flywheel being visible in the notch at the top of the transmission bellhousing (for cyls #1 and #3) or the bottom of the bellhousing (for cyls #2 and #4) should be a very strong indication of one of those cylinders being at TDC.
NOTE: The crank goes through two complete revolutions for every complete four-cylinder cycle of the engine! So the notch being at the top will show that the engine is either at TDC for #1 or TDC for #3! You can check the rocker arms to verify; a cylinder at TDC will have some slack to both rocker arms. You normally just check the distributor rotor to make sure, but it is a lot easier to get the distributor in 180 degrees out than it is to put the cam in 180 out.
--DD
okay ,thanks,pretty sure my distributor is in correctly.so useing rotor pointing to #1 and having flywheel crack at top is what ill use.
QUOTE(SirAndy @ Mar 6 2015, 09:39 AM)
QUOTE(rosenfe @ Mar 6 2015, 09:09 AM)
whats the most definitive way to get tdc?
Whatever you do, don't use chopsticks!
You can use one, just don't let it fall into that cavernous combustion chamber.
another question about timing.useing 27 degrees btd with a timing light is what i read and done,but is there an advantage to useing timing light where i can dial advance .ive heard 35 degrees advance at 3500 is what i want.this is a stock carburated engine.
also,if useing timing light with dialed advance capability,do i use tdc mark as refernce point and then adjust dizzy accordingly to display or setting on timing light.?
I use a variable timing light (set to 34 degrees for carbs) , and the TDC mark on the flywheel.
A sharpie is the perfect thickness shim to hold the tin back while you set the timing.
A sharpie is the perfect thickness shim to hold the tin back while you set the timing.
Too funny!!! I was aware if the inside " chopstick" joke but had never heard the story.
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