Finding TDC

[Straight six]

I'm trying to find TDC on 78 inline 250. There is no timing marks and I don't have a timing light. I took #1 spark plug out looked in the hole with flashlight and used a straw what am I looking for and feeling for. And the rotor on my hei is not pointing at #1 plug do I take the hei out then point to #1 plug then install carefully. This is not going well I look on the web and it sounds easy. Well now my truck won't start I turn the key it try's and backfires softly out of exhaust. Need help would love to drive my truck
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[Straight six]

Originally Posted by Straight six

I'm trying to find TDC on 78 inline 250. There is no timing marks and I don't have a timing light. I took #1 spark plug out looked in the hole with flashlight and used a straw what am I looking for and feeling for. And the rotor on my hei is not pointing at #1 plug do I take the hei out then point to #1 plug then install carefully. This is not going well I look on the web and it sounds easy. Well now my truck won't start I turn the key it try's and backfires softly out of exhaust. Need help would love to drive my truck
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[nheller76]

U need to watch the exhaust value go down then the intake go down. When the intake comes up u are on compression stroke. U then have someone turn the crank wile u stick a screw driver into the spark plug hole and feel the piston come up. When it starts to go down back it back up to the highest point. TDC!
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[Straight six]

What about the hei pointing at #1. What does that mean
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[nheller76]

Originally Posted by Straight six

What about the hei pointing at #1. What does that mean
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It means that it is making contact with the point on your distributor that is feeding the spark to your number one cylinder. Usually on a V8 u turn the rotor so it faces the #1 piston but u have a straight 6 so u can't really do that. Technically #1 can be anywhere u want on the distributor but u need to know the firing order so u can get the right sequence. Did u pull you distributor out?
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