First time setting timing-questions
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First time setting timing-questions
To start, I've read the timing sticky by BarryK and also the papers written by Lars and John Hinckley. I understand the whole process, however I have a couple of questions regarding the beginning of the whole thing just to confirm that I'm doing things the right way.
I want to determine top dead center on my car. I have a piston stop. First: How far should the piston stop fit into the head?
Second: I take a few of the spark plugs out in order to relieve pressure, take the negative lead off of the coil, and with the piston stop in place, turn the motor over clockwise until it hits the piston stop. Then I make a mark on the harmonic balancer at the 0 degree mark. I then turn the motor over counter-clockwise until it hits the piston stop and make a mark on the balancer at the 0 degree mark. The exact middle of these two marks is TDC correct?
Third: What do I use to make a mark on the harmonic balancer? A white paint pen? Or sharpie?
Fourth: After doing this and lining the middle mark as described above at the 0 degree mark, my engine should be at TDC right?
Fifth: If I take my distributor cap off at TDC, the rotor should be pointing at the number one spark plug wire slot correct?
I think that's all the questions. Thanks guys.
I want to determine top dead center on my car. I have a piston stop. First: How far should the piston stop fit into the head?
Second: I take a few of the spark plugs out in order to relieve pressure, take the negative lead off of the coil, and with the piston stop in place, turn the motor over clockwise until it hits the piston stop. Then I make a mark on the harmonic balancer at the 0 degree mark. I then turn the motor over counter-clockwise until it hits the piston stop and make a mark on the balancer at the 0 degree mark. The exact middle of these two marks is TDC correct?
Third: What do I use to make a mark on the harmonic balancer? A white paint pen? Or sharpie?
Fourth: After doing this and lining the middle mark as described above at the 0 degree mark, my engine should be at TDC right?
Fifth: If I take my distributor cap off at TDC, the rotor should be pointing at the number one spark plug wire slot correct?
I think that's all the questions. Thanks guys.
Terrorizing Orange Cones
Joined: Oct 2007
Posts: 2,572
Likes: 17
From: Northern CO
...
I want to determine top dead center on my car. I have a piston stop. First: How far should the piston stop fit into the head?
Just like a spark plug: screw in until you reach end of tool threads. Do not force or torque down. It's just a reference tool.
Second: I take a few of the spark plugs out in order to relieve pressure, take the negative lead off of the coil, and with the piston stop in place, turn the motor over clockwise until it hits the piston stop. Then I make a mark on the harmonic balancer at the 0 degree mark. I then turn the motor over counter-clockwise until it hits the piston stop and make a mark on the balancer at the 0 degree mark. The exact middle of these two marks is TDC correct?
Correct.
Third: What do I use to make a mark on the harmonic balancer? A white paint pen? Or sharpie?
Whatever contrasts well to see clearly. Until you determine, use something that is temporary, even a small strip of masking tape (use the straight-cut side as the mark).
Fourth: After doing this and lining the middle mark as described above at the 0 degree mark, my engine should be at TDC right?
Correct.
Fifth: If I take my distributor cap off at TDC, the rotor should be pointing at the number one spark plug wire slot correct?
Correct.
I think that's all the questions. Thanks guys.
I want to determine top dead center on my car. I have a piston stop. First: How far should the piston stop fit into the head?
Just like a spark plug: screw in until you reach end of tool threads. Do not force or torque down. It's just a reference tool.
Second: I take a few of the spark plugs out in order to relieve pressure, take the negative lead off of the coil, and with the piston stop in place, turn the motor over clockwise until it hits the piston stop. Then I make a mark on the harmonic balancer at the 0 degree mark. I then turn the motor over counter-clockwise until it hits the piston stop and make a mark on the balancer at the 0 degree mark. The exact middle of these two marks is TDC correct?
Correct.
Third: What do I use to make a mark on the harmonic balancer? A white paint pen? Or sharpie?
Whatever contrasts well to see clearly. Until you determine, use something that is temporary, even a small strip of masking tape (use the straight-cut side as the mark).
Fourth: After doing this and lining the middle mark as described above at the 0 degree mark, my engine should be at TDC right?
Correct.
Fifth: If I take my distributor cap off at TDC, the rotor should be pointing at the number one spark plug wire slot correct?
Correct.
I think that's all the questions. Thanks guys.
Race Director
Joined: Jul 2001
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Correct except for a 'maybe' on your fifth question. The distributor turns at half the speed of the crank so it will only point at #1 every second crank revolution. It will point at #6 during the other revolution while at TDC.
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Great! Thanks guys.
Terrorizing Orange Cones
Joined: Oct 2007
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From: Northern CO
I remove all of them, just to simplify the resistance. Minimizes risk of damaging the harmonic balancer bolt and more importantly, the threads in the crank snout.
If you are doing this with engine in-car, remove as many plugs as possible. At least, loosen the most difficult one so it "bleeds" the compression easier.
When you're done locating TDC, reinstall, snug them each to spec, and move on.
If you are doing this with engine in-car, remove as many plugs as possible. At least, loosen the most difficult one so it "bleeds" the compression easier.
When you're done locating TDC, reinstall, snug them each to spec, and move on.
Race Director
Joined: Sep 2004
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From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
lets go over this again......the piston stop will stop the piston on its way up.....so after you make contact with the piston stop, make your mark on blue painters tape and you need to screw the piston stop out a little and rotate some more.....the piston will go up some more and stop, make your mark on blue painters tape on the harmonic balancer......let the piston stop out some more...rotate it again...it will stop again....now on one of these occasions you will hit TDC its just that you wont know it unitl the next rotation when it starts down again and doesnt hit anything.....got it? repeat this process for a couple of rotations and you will know exactly where TDC....i never go backwards (although they do make a neat tool for mounting on the harmonic balancer for rotating the crank both ways)
also if you are using the harmonic balancer bolt you can not turn it counterclockwise or it will loosen
DO NOT CRANK THE ENGINE WITH THE STARTER ONLY ROTATE IT BY HAND no need to ground the coil the car should not be turned on
also if you are using the harmonic balancer bolt you can not turn it counterclockwise or it will loosen
DO NOT CRANK THE ENGINE WITH THE STARTER ONLY ROTATE IT BY HAND no need to ground the coil the car should not be turned on
Last edited by bobs77vet; Oct 5, 2009 at 10:16 PM.
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Burning Brakes
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From: Europe, France
Yes, use a socket wrench.
If all spark plugs are removed, the crankshaft will turn easily. Otherwise, it's a bit harder, but still feasible.
Stop as soon as you feel a resistance.
It's better to check TDC when the piston is in firing position, because both valves are closed and won't interfere with the piston stop. Check the distributor rotor to confirm that it is pointing at cyl #1 and not cyl #6.
If all spark plugs are removed, the crankshaft will turn easily. Otherwise, it's a bit harder, but still feasible.
Stop as soon as you feel a resistance.
It's better to check TDC when the piston is in firing position, because both valves are closed and won't interfere with the piston stop. Check the distributor rotor to confirm that it is pointing at cyl #1 and not cyl #6.
Last edited by 73StreetRace; Oct 6, 2009 at 02:10 AM.
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From: mount holly NC
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Setting the timing!
Checking where the piston is at exact TDC should have been done when your engine was first assembled. All you want now it to set the timing so that it is all in at 36* BTDC @ 2,800 to 3,000 RPM. If your harmonic balancer has not slipped just use that mark and adjust your timing from there. Use your dial back timing light to go 2* over 36* and if you get detonation go back 2* at a time untill you get the best performance. PG.
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From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
Burning Brakes
Joined: Aug 2005
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From: Europe, France
If you remove all the spark plugs, you can turn it counterclockwise because the torque necessary
to rotate the crankshaft is normally much lower than the tightening torque of the bolt ( assuming the bolt is not already loosen
).
to rotate the crankshaft is normally much lower than the tightening torque of the bolt ( assuming the bolt is not already loosen
).
Last edited by 73StreetRace; Oct 6, 2009 at 10:31 AM.
Race Director
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From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
i must have super dooper valve springs because i could never go backwards
Melting Slicks
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From: Nashville TN
St. Jude Donor '09
I used the TDC procedure and marked balancer to VERIFY that the balancer's mark lined up with TDC (0*) on the timing tab on the timing cover. Once I verified, I painted the balancer mark white to make it standout when using a timing light. Then I followed the rest of the timing procedure as described in the papers. I was impressed with the performance difference!!!
Instructor
Joined: Dec 2008
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From: w. jordan utah
i bought the tool that mounts to the balancer its cheap and works great with a 1/2" breaker bar nothing worse than stripping out the threads in the crank! got it at summit i think for around $15 bucks. i use it all the time now. tom
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From: Reno Nevada
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I used the TDC procedure and marked balancer to VERIFY that the balancer's mark lined up with TDC (0*) on the timing tab on the timing cover. Once I verified, I painted the balancer mark white to make it standout when using a timing light. Then I followed the rest of the timing procedure as described in the papers. I was impressed with the performance difference!!!
Race Director
Joined: Nov 2002
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From: Taylor Michigan
You might try with the plugs either removed or unscrewed to relieve pressure, you may be able to rotate the engine by using the alternator fan nut...and go forward and backward. The only real drag would be the rings...
Race Director
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From: Arlington Va Current ride 04 vert, previous vettes: 69 vert, 77 resto mod
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I finally had time to get around to it yesterday. I took out the front six spark plugs and installed the piston stop in the #1 hole. With a large torque wrench, it turned over pretty easily. Thanks for the help. I will be setting the timing tomorrow.