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Old 03-12-2011, 08:46 AM   #1
johnt365
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Default Can engine run with timing 180 off?

My small block was running great. So I decided to do a cam change and tear it apart. I wanted to check the timing marks from the previous owners build. So I did the following.

1. Marked #1 plug on dist. base and removed cap.
2. Rotated crank until rotor pointed at #1 (confirmed compression) then put the mark on the balancer at zero on the timing tab.
3. Removed the timing chain cover.

Now at this point I was expecting to find the crank dot at 12 o'clock and the cam dot at 6 o'clock. That did not happen.

The crank was at 12 o'clock AND them cam sprocket was also at 12 o'clock.

When I line them up at 12 and 6 the rotor points at #6.

Is this possible?

I am confused
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Old 03-12-2011, 09:13 AM   #2
stingr4y
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I fired mine up 180 degrees off, and it was a scary violent experience. Although it ran, it sputtered, chugged, and flamed out the carb.

It was nowhere near driveable though.
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Old 03-12-2011, 09:21 AM   #3
johnt365
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What am I missing here?

I just don't understand because the cam sprocket is keyed to only go one way.

Here is a better question. When the dots are at 12 and 6, where does the rotor point? mine points at #6 plug

Last edited by johnt365; 03-12-2011 at 09:44 AM.
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Old 03-12-2011, 09:43 AM   #4
...Roger...
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The dots just need to line up at 12 and 6 or 12 and 12 ,don't worry about the timing tab at this point.
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Old 03-12-2011, 09:50 AM   #5
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Quote:
Originally Posted by johnt365 View Post
What am I missing here?

I just don't understand because the cam sprocket is keyed to only go one way.

Here is a better question. When the dots are at 12 and 6, where does the rotor point? mine points at #6 plug
Your trying to mix camshaft timing and ignition timing,you don't need to do that to set cam timing.

edit-removed part of my post, it was confusing and I said 180 when I should have said 360 and I misread what the OP was after.
Mike Ward covered it.

Last edited by ...Roger...; 03-12-2011 at 11:52 AM.
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Old 03-12-2011, 10:09 AM   #6
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Quote:
Originally Posted by johnt365 View Post
The crank was at 12 o'clock AND them cam sprocket was also at 12 o'clock.

When I line them up at 12 and 6 the rotor points at #6.

Is this possible?

I am confused
That's the way it's supposed to be. Many people make the mistake of thinking that #1 firing is with the dots pointed at each other.
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Old 03-12-2011, 10:16 AM   #7
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Quote:
Originally Posted by johnt365 View Post
Right, at #1 the crank is 12 and cam is 12.

I thought that at crank 12 and cam 6 the motor should be at TDC and rotor at #1

Mine is #1 compression (TDC) and both dots at 12 o clock. Is something wrong
Nope, perfectly normal.
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Old 03-12-2011, 10:33 AM   #8
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Okay, just so I can understand.

Dot to dot is TDC but NOT the compression stroke. To time the engine I need to rotate it 180 so that its crank 12 o'clock and cam 12 o'clock and that will be TDC on the compression stroke.

I was about to be "one of those people"
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Old 03-12-2011, 10:33 AM   #9
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Quote:
Originally Posted by stingr4y View Post
I fired mine up 180 degrees off, and it was a scary violent experience. Although it ran, it sputtered, chugged, and flamed out the carb.

It was nowhere near driveable though.

It no where resembles an engine running! My wife ran for the hills, the neighbors baby started crying, etc...
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Old 03-12-2011, 10:40 AM   #10
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Quote:
Originally Posted by johnt365 View Post

Dot to dot is TDC but NOT the compression stroke. To time the engine I need to rotate it 180 so that its crank 12 o'clock and cam 12 o'clock and that will be TDC on the compression stroke.
Correct!
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Old 03-12-2011, 11:15 AM   #11
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just about the time I think I know something... Bam! something like this happens.

Thanks fellas !
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Old 03-12-2011, 11:24 AM   #12
ZZ71S
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You can make sure by holding your finger over the number one spark plug hole while you turn the crankshaft over.
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Old 03-12-2011, 11:24 AM
 
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