1977 Pontiac Trans Am Distributor & Spark Plug Wiring

KCROOMS

MEMBER
1977 PONTIAC TRANS AM
V8
2WD
AUTOMATIC
125,000 MILES

I noticed that the current plug wire routing to the Distributor does not match a diagram that I found for a "Z" vin Code Pontiac 400 engine. Seems each wire is one off to the left?
Car seems to run decent. Engine was rebuilt years ago. How could this occur? How can I verify the distributor?

3 Replies

JDL

MECHANIC
16,098 POSTS

Hi, thanks for the donation. I don't trust those pictures. As long as the number one cylinder is on tdc of compression stroke and the rotor is leading into that spark plug tower and follow the firing order, it doesn't matter about the picture. The rotor doesn't know which coil tower is number one, it just goes round and round. Actually, you could time it off any cylinder, but, you wouldn't be able to see timing marks on balancer, that is located for number one cylinder.

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Monday, February 22nd, 2010 AT 10:21 AM

KCROOMS

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2 POSTS

Thanks for the reply. What's the best way to know tcd? Viewing the Timing Mark?

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Monday, February 22nd, 2010 AT 12:24 PM

JDL

MECHANIC
16,098 POSTS

Pull the number one plug, set the timing mark on zero. Depending on how hard the spark hole is to get at, sometimes, I use a fuel line hose that fits tight in the plug hole, if you can't blow air into the cylinder and the piston is up, should be on the compression stroke.

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Monday, February 22nd, 2010 AT 1:03 PM