Getting #1 to TDC
Tech Contributor
Joined: Aug 1999
Posts: 14,356
Likes: 6,328
From: At my Bar drinking and wrenching in Lafayette Colorado
Make note of which "tower" is the #1 plug wire on your distributor cap. Then, remove the cap so you can see the rotor. Using the starter, "tap" the starter to bring the rotor to the #1 tower position. As you approach that position, watch the timing line on the balancer and continue to "bump" the starter until the timing line aligns with "0" on the tab with the rotor pointing towards the #1 plug tower position. That's it.
Lars
Lars
Melting Slicks
Joined: Dec 2004
Posts: 2,161
Likes: 0
From: pr, frederick md.
thats not entirely accurate. the best and most standard way, albiet not high tech. is to remove the #1 sparkplug and insert a thumb over the hole and then bump it around. when it is on the compression stroke, which is where you want to be, it will push your thumb away. continue to rotate the engine from the balancer to achieve TDC. another homemade method to achieve complete TDC is to insert a small screwdriver into the sparkplug hole and feel when the piston starts to go down. it will stay at TDC for a longer period of the rotation, then simply return to tdc by rotating in the opposite direction. this is very important as timing tabs are not always accurate ( old or new ), and 30+ year old balancers can and most likely are way off. simply make your new zero mark if needed
Melting Slicks
Joined: Mar 2006
Posts: 3,341
Likes: 7
From: Connecticut
Originally Posted by redc3
the best and most standard way, albiet not high tech. is to remove the #1 sparkplug and insert a thumb over the hole and then bump it around. when it is on the compression stroke, which is where you want to be, it will push your thumb away.
Always works for me 
Burning Brakes
Joined: Dec 2002
Posts: 1,069
Likes: 2
From: Sherwood Park AB
As mentioned above to get to TDC...
If you are removing the dist, but putting the same one in, you can mark the rotor to dist housing with a paint pen when rotor is fully engaged, and again when rotor has turned to disengage (use different color). When you go to put it back in, line up second mark, as rotor turns and engages, if first marks are lined up it is in exactly the position you had it originally. You can also mark the dist housing to hold down clamp to get the housing rotation correct.
Here's a tip that has helped me...
If you replace the cap, take the old one and cut out the #1 terminal tower. Put the cap on, spin over the engine, and you can tell exactly when #1 is in firing position.
If you are removing the dist, but putting the same one in, you can mark the rotor to dist housing with a paint pen when rotor is fully engaged, and again when rotor has turned to disengage (use different color). When you go to put it back in, line up second mark, as rotor turns and engages, if first marks are lined up it is in exactly the position you had it originally. You can also mark the dist housing to hold down clamp to get the housing rotation correct.
Here's a tip that has helped me...
If you replace the cap, take the old one and cut out the #1 terminal tower. Put the cap on, spin over the engine, and you can tell exactly when #1 is in firing position.
Tech Contributor
Joined: Aug 1999
Posts: 14,356
Likes: 6,328
From: At my Bar drinking and wrenching in Lafayette Colorado
Originally Posted by redc3
thats not entirely accurate. the best and most standard way, albiet not high tech. is to remove the #1 sparkplug and insert a thumb over the hole and then bump it around.
Why would you bother pulling a plug and sticking a finger in the hole when you can simply pop the cap off the distributor to observe when it's coming up on #1? The thumb-in-the-hole technique is only needed if the distrubutor has been removed or incorectly clocked, and you have to verify that you're on the compression stroke. On a running engine with the distributor installed, you just point the firing tab to #1 tower and line up the timing marks. No need to pull the plug.
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Race Director
Joined: Sep 2002
Posts: 10,362
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From: San Diego - Deep Within The State of CONFUSION!
Originally Posted by lars
redc3 -
Why would you bother pulling a plug and sticking a finger in the hole when you can simply pop the cap off the distributor to observe when it's coming up on #1? The thumb-in-the-hole technique is only needed if the distrubutor has been removed or incorectly clocked, and you have to verify that you're on the compression stroke. On a running engine with the distributor installed, you just point the firing tab to #1 tower and line up the timing marks. No need to pull the plug.
Why would you bother pulling a plug and sticking a finger in the hole when you can simply pop the cap off the distributor to observe when it's coming up on #1? The thumb-in-the-hole technique is only needed if the distrubutor has been removed or incorectly clocked, and you have to verify that you're on the compression stroke. On a running engine with the distributor installed, you just point the firing tab to #1 tower and line up the timing marks. No need to pull the plug.
The difference is the answer to the question: Is this a running engine or a new setup/install?