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If you've been following my sega the last couple days then you know that I removed the lower intake to have a bolt removed. I put everything back together with new gaskets and injector o-rings, rotor and cap. Thought I had marked the distributor correctly but the engine would not start. Check TDC of number 1 by placing my finger into the spark plug hole and waiting for air pressure against finger then put the dist back in with the rotor pointing towards number 1. Still no start. Had my brother in law come over and without touching a thing told my that my dist was 180degrees out. I figured what the heck and did what he said and bango, the engine started, never was there a better sound. Now can someone explain how I could feel compression in the cylinder but in must not have been the compression stroke??? The only thing I can think is maybe I was feeling the the exhaust stroke, but why would I feel air pushing against my finger?
the bottom end practically has 2 top dead centers for each rotation, it's very easy to get ignition timing off 180 degrees unless you can actually look at your timing marks behind the timing cover
You had your finger over the hole during the exhaust cycle. Clean the balancer next time wipe some chalk or white-out on the marks so you can see them come around. Line up the rotor with #1 mark on cap & as an extra measure, I make a sharpie mark on the dist. base & block before breaking the hold down bolt loose.
You probably were turning it to fast, did you use the starter? Or were feeling the exaust stroke you gotta push with that figer till it pushes it off not just pushes some air by. The trick is to do it slow either just click the starter or turn by hand while watching the timing marks on the balancer. Or better yet put the engine in TDC of compression before you remove the distributor by watching the rotor and stopping the engine when the rotor points to one and the balancer points to TDC, then take things apart and don't turn the motor.
You will feel air with exhaust stroke because valve must close before piston comes completely to top. As stated by others. The pressure of TDC is much stronger and will really push against your finger. Just did the same mistake with a 1968 Camaro.
One good tip is to not use your finger, push a stopper like a vacuum cap into the plug hole. It will free your hand to control/turn the motor and see the timing marks, the stopper will pop out on the compression stroke, then just crank a little further to TDC.
I've used nothing but my thumb, or finger, depending on what one is easier to get a seal on the plug hole for years to find the compression stroke. Never had a problem doing so, none of the other strokes will feel the same, not even close.
I Probably changed 6 or 7 distributors for one reason or the other in my life.
If memory serves me well..I think the dizz was 180 out on the first attempt on every job. I can't figure out how I screw it up every single time.