With the engine installed in the car, and timing mark aligned, with regard to distributor installation, what is the easiest way to tell if #1 piston is top of compression or exhaust stroke?
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Re: TDC COMPRESSION STROKE
Remove the plugs so the engine turns easy and put your thumb over the #1 spark plug hole and turn the engine by hand. If you feel compression, it is on the compression stroke. If not, the piston is pushing the air out the exhaust valve, exhaust stroke. Someone used to make a whistle you could use instead of your thumb if you want to make the effort and have the patience to go get one.
If you have a point type ignition you can do the following. Do not attempt with an electronic ignition. When you put the distributer in, line the timing marks up to where you want the initial timing. set the distribter in place. rotate the distributer body intill the coil wire archs to ground. If you do this correctly, you can always have the timing within 1 degree.
Jon -
Re: TDC COMPRESSION STROKE
Guess I'll have my wife stick her finger over the #1 spark plug hole (I'm sure she'll be glad to)....I do have TI.Comment
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Re: TDC COMPRESSION STROKE
Put her finger over the hole, not in it. If you have a bolt on the end of your crank, you can reach the hole yourself by using a socket and ratchet. Or if the spark plugs are out, you can normally put your thumb on the hole and turn the engine with the fan. A remote starter button will also work.
Good luck
JonComment
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Re: TDC COMPRESSION STROKE
Pop the valve cover off and look at the valves for #1 cylinder - if they're both closed, you're at TDC; if not, you're at #6 TDC.Comment
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Re: TDC COMPRESSION STROKE
KIle John says, I usually look at the valves. If there is any doubt, watch the valves as you appraoch the TDC mark. The intake valve should close just prior to reaching it.Comment
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Re: TDC COMPRESSION STROKE
I can usually get it within a couple of degrees of the timing I want by just watching the points - rotate the dist until you just see then begin to open, then back a hair.
Another way is to connect an ohmmeter between the negative coil post and ground. With the points open the resistance is infinite. When they close it goes to zero.
DukeComment
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Re: TDC COMPRESSION STROKE
If you want to go through the hassel of pulling valve covers and cleaning gaskets to check the valves thats fine. But the #1 intake valve should not be closing, both valves should already be closed during the preceeding compression stroke. If the intake valve is just finished closing at top dead center, you will have no compression and the engine will not run.Comment
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SORRY, I MEANT WITHOUT REMOVING THE VALVE COVER
Sorry, I should have mentioined in my initial posting that I don't want to remove the valve cover. I'll use the finger on the spark plug hole to feel for pressure method.....ThanksComment
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Re: TDC COMPRESSION STROKE
Once you manualy line up the mark on the balancer with the timing tab, can't you also take off the distributor cap and see if the rotor is pointing to the #1 position in the cap? If it is, I assume the #1 clylinder is ready to fire and on the compression stroke?Comment
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Re: TDC COMPRESSION STROKE
This is true, if the distributer is still in the engine. If the distributer is out of thte engine then you have to use one of the other methods.
JonComment
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Re: TDC COMPRESSION STROKE
I guess I should have said that the intake valve will be closing on that revolution of the crankshaft to be more corect. If you are approaching TDC and the intake valve hasn't just finished closing, you are probably on #6 TDC.Comment
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Re: Not to beat a dead horse, but
I mean no offence, but am trying to clear up a missundertaanding. The first half of your statement is correct. The second statement is not. If #1 piston is on the compression stroke, then piston #6 is on the exhaust stroke. Therefore, the exhaust valve on #6 is just closing and the intake on #6 just opening.
JonComment
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Re: Not to beat a dead horse, but
I am neither offended, nor have I ever installed a distributor 180* off.Comment
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