Timing Question - Team Camaro Tech
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post #1 of 10 (permalink) Old Jun 26th, 15, 01:23 PM Thread Starter
 
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Timing Question

Hi everyone. Sorting out some issues on a 69 I bought recently and have a question about the timing and distributor setup.

I've verified proper TDC, marked it, and the rotor is pointing to cylinder one at TDC, however spark plug # 1 is pointing to #6. I've also triple checked correct firing order and plug wires and distrib are nearly brand new.

The damper also has the TDC and timing markings set up based off of #6 versus #1. The rotor points at #6 after one full rotation from TDC.

Prior owner/engine builder definitely set it up this way on purpose, but is it correct? I thought rotor and #1 plug on dist cap should all be pointing at #1 cylinder at TDC for starting, then timing would be set off of true TDC mark from there. If I set it up with #1 wire facing #1 cylinder, engine will not start and backfires/flames out of the carb. Runs when I face the #1 plug wire at #6 cylinder.

I started looking at it b/c power is still lacking and running too rich after a full rebuild of Holley so started to suspect distributor might be 180 off or something. Timing definitely doesn't seem right but wanted to check before pulling the distributor since I don't know Chevy motors that well.

Thanks.

Last edited by 69ro; Jun 26th, 15 at 01:26 PM. Reason: correction
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post #2 of 10 (permalink) Old Jun 26th, 15, 01:54 PM
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Joe
 
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Re: Timing Question

Welcome to the forum.

It does not matter where the distributor is physically rotated in relation to the position of the various cylinders. What matters is that at TDC on the compression stroke of #1 cylinder, then the rotor should be pointing at the corresponding terminal in the distributor cap for the #1 plug wire. Then follow the firing order.

The distributor can be physically rotated to any position, as long as the firing order is correct and at TDC the rotor is firing the #1 spark plug.

The important thing here is that you ask me what kind of car I've got. "I've got a BITCHIN' CAMARO"
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post #3 of 10 (permalink) Old Jun 26th, 15, 04:07 PM Thread Starter
 
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Right. That's what doesn't seem right here. When at TDC with the rotor facing the #1 cylinder, if I put the #1 spark plug wire there on the distributor where the rotor is it won't start. It will only start when I move the #1 plug wire over on the pass side facing cylinder #6.
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post #4 of 10 (permalink) Old Jun 26th, 15, 04:19 PM
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Scott
 
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Re: Timing Question

Sounds like you have the engine at the top of the exhaust stroke rather than at the top of the compression stroke when your at TDC.

69 Camaro Z/28 RS, original Azure Turquoise, M21 & 3.73 12-bolt posi. NOM 406ci, AFR 210 heads, Straub hyd. roller cam & Dynatech 1-3/4" > 1-7/8" headers, QuickFuel 750 Annular. Photos at:
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post #5 of 10 (permalink) Old Jun 26th, 15, 04:52 PM
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Steps
 
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Re: Timing Question

If the rotor points to #6 on firing stroke then the dizzy is 180 degs out.
The factory sets the position of the dizzy so the VA points just behind the passengers headlight.
This is so the Dizzy can be adjusted/ turned without interfering/ restricted with other stuff around it .... and the rotor points at #1 nearly directly straight forward.
Yes as mentioned above doesnt matter really where he dizzy is positioned, so long as the HT leads come off the cap to the right cylinders
But if one gets in the habit od setting up as per factory everytime.. then those times one is one tooth out, one still has room to adjust.

So.. with both #1 valves closing and feel the piston coming up with abit of wire... when stops coming up mark the balancer... then feel where it starts to drop.. mark that.. 1/2 way between is TDC... yep as accurate as using a piston stop...
With #1 now at TDC mark line up the oil pump with a long screwdriver and mirror...and drop the dizzy in with the VA pointing just behind the passengers headlight and the rotor pointing directly to the front of the car.....
Now check off the HT leads from the front at #1 as per timing order.

My Spelling is not incorrect...it is creative

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post #6 of 10 (permalink) Old Jun 26th, 15, 07:46 PM Thread Starter
 
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Re: Timing Question

Thanks. I'm certain that when the rotor is pointing towards #1 that I'm at tdc on the compression stroke. I double checked it with my tdc whistle tool. It only whistles on the compression stroke. That's where I'm confused. Can the rotor point to the number 1 cylinder when the motor is at top dead center and still be off by 180?

I'm just not understanding why when it's at tdc with rotor pointing to #1 cylinder it will only run with the number one plug wire on the dizzy pointing at #6. It won't run when I put the #1 plug wire in the normal location facing forward towards #1.
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post #7 of 10 (permalink) Old Jun 26th, 15, 08:41 PM
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Anne
 
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Re: Timing Question

I've always verified TDC for #1 cylinder by watching the rocker arms as I bump the engine over with a remote starter button.

Both rocker arms will not move on #1 cylinder as the balancer approaches 0 degrees (TDC).

It's a fool-proof way to be sure you are at TDC for #1.

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Last edited by Lawrence454; Jun 26th, 15 at 08:52 PM.
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post #8 of 10 (permalink) Old Jun 26th, 15, 09:29 PM
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Bobby
 
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Re: Timing Question

Your 180 off.
Like Joe said, it doesn't matter which direction the rotor tip is pointing as long as it corresponds with the correct post for the cylinder on the compression stroke.

Pop the valve covers to double check that whistle. Number one cylinder rockers will be both up (closed) like Anne said and number 6 cylinders will be rocking.

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post #9 of 10 (permalink) Old Jun 26th, 15, 09:43 PM
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mike
 
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Re: Timing Question

If it runs it is not 180 out. Why not inquire with the engine builder. What does the timing show with a light?
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post #10 of 10 (permalink) Old Jun 27th, 15, 04:18 PM
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Steps
 
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Re: Timing Question

Quote:
Can the rotor point to the number 1 cylinder when the motor is at top dead center and still be off by 180?
Yep...the timing mark comes upto TDC 2 times in every FOUR stroke engine.. in the case of a SB chevy.. because of the firing order.. does so on #1 AND #6

So do NOT try and fix what u have been doing..
Forget everything u have been doing.. go back to square one....start fresh and follow instructions EXACTLY as described above....

I add to them... when using the scew driver or wire feeling the piston come up... when the piston is low, put your fingire over the hole and feel the pressure... no pressure then u are are at #6 tdc and #1 coming up on exhaust stroke....both valves , as others mention , will not be closed.

My Spelling is not incorrect...it is creative

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