Timing Again
Thread Starter
Instructor
Joined: Sep 2007
Posts: 125
Likes: 0
From: Paso Robles CA
Timing Again
Just removed my timing chain cover and found a couple of interesting things. The mark on the crank gear is verticle however the mark on the cam gear is at about 5:30. I would expect them to be lined up??? The chain itself is very loose on the passenger side of the engine (left when facing the front of the engine) and very tight on the driver side. Does it appear I have jumped a tooth? The car was running and seemed to be running well when I pulled the engine. I am planning to put the crank and cam gears aligned vertically. If this is not right someone please speak up.
scott
scott
Burning Brakes
Joined: Dec 2005
Posts: 992
Likes: 56
From: Baldwinsville, NY
12 O'Clock or Dot's Together
I just completed a head and cam change.
When I removed the timing cover ( had #1 TDC and Distributor pointing to #1 Plug Wire) both dot's where at 12 O'Clock. I reinstalled the new cam with the dot's at 12. The sheet that came with the Crane Cam was not clear on this issue showing togheter and at 12.
I took 3 hours of rotating the cam and comparing the lifters and pistons to varify the power stroke on #1 so I could install the distributor.
When I removed the timing cover ( had #1 TDC and Distributor pointing to #1 Plug Wire) both dot's where at 12 O'Clock. I reinstalled the new cam with the dot's at 12. The sheet that came with the Crane Cam was not clear on this issue showing togheter and at 12.
I took 3 hours of rotating the cam and comparing the lifters and pistons to varify the power stroke on #1 so I could install the distributor.
Team Owner
Joined: Aug 2006
Posts: 24,125
Likes: 15
From: Columbia Missouri
It doesn't matter if the dots are both straight up or nose to nose. The key is that they are both perfectly vertical. Get the dots lined up, make sure #1 is on compression stroke, and stab in the distributor so the rotor is lined up with the #1 plug wire point.
Le Mans Master
Joined: Apr 2005
Posts: 6,346
Likes: 418
From: Seattle Area WA
Beg to differ, if you line them up dot to dot, you better rotate the crank 360 degrees because with the crank dot at 12 o'clock and the cam dot at 6 o'clock, you're at #6 TDC on the compression stroke, not #1 TDC on the compression stroke.
Team Owner
Joined: Aug 2006
Posts: 24,125
Likes: 15
From: Columbia Missouri
Oh I totally agree, I'm just saying it doesn't matter initially where those dots are so long as they are both straight up and the engine it turned so #1 is top dead center. Usually after the timing is on, you still have to turn the engine a few times anyway based on other components being added.
Corvette Stories
The Best of Corvette for Corvette Enthusiasts
150 hp to 1,250 hp: Every Corvette Generation Compared by the Specs That Matter
Joe Kucinski
8 Coolest Corvette Pace Cars (and Replicas) of All Time
Verdad Gallardo
Top 10 Corvette Engines RANKED by Peak Torque (70+ Years of Muscle!)
Joe Kucinski
Corvette ZR1X Will Be Pacing the Indy 500, And Could Probably Race, Too!
Verdad Gallardo
Top 10 Corvettes Coming to Mecum Indy 2026!
Brett Foote
Top 10 C9 Corvette MUST-HAVES to Fix These C8 Generation Flaws!
Michael S. Palmer
10 Revolutionary 'Corvette Firsts' Most People Don't Know
Joe Kucinski
5 Reasons to Upgrade to an LS6-Powered Corvette; 5 Reasons to Stay LT2
Michael S. Palmer
2027 Corvette vs The World: Every C8 vs Its Closest Competitor
Joe Kucinski
Thread Starter
Instructor
Joined: Sep 2007
Posts: 125
Likes: 0
From: Paso Robles CA
Okay now I am confused but think I am okay. I replaced the gears as they came off. I had a few too many Coronas when I wrote the original message. When I turned the crank the two dots lined up. Cam as 6 and crank at 12 so I installed the new gears and chain the same way. Later I turned the engine over by hand with thumb over number 1 plug hole. I felt the air pushing out and moved until the timing mark on the harmonic balancer was at about 0 degrees. I then installed the distributor with the vacuum advance (when looking from front of engine) at about 8 oclock and the rotor pointing to about 7 oclock.
How bad did I goof this up?
scott
How bad did I goof this up?
scott
Team Owner
Joined: Aug 2006
Posts: 24,125
Likes: 15
From: Columbia Missouri
Okay now I am confused but think I am okay. I replaced the gears as they came off. I had a few too many Coronas when I wrote the original message. When I turned the crank the two dots lined up. Cam as 6 and crank at 12 so I installed the new gears and chain the same way. Later I turned the engine over by hand with thumb over number 1 plug hole. I felt the air pushing out and moved until the timing mark on the harmonic balancer was at about 0 degrees. I then installed the distributor with the vacuum advance (when looking from front of engine) at about 8 oclock and the rotor pointing to about 7 oclock.
How bad did I goof this up?
scott
How bad did I goof this up?
scott
That's very close. The actual position or the rotor is irrelevant if you're that close because you can turn the body of the distributor, where the rotor stays put, until the rotor points to the #1 plug terminal.
Basically, if you got the dots lined straight up, have the balancer at 0 mark, and have the rotor pointing to #1 plug wire, and the firing order correct going clockwise, then it should fire right up.
Note - When I say point the rotor to #1, I will add that the metal part of the rotor should be just in front of the contact...as in before it gets to the contact, almost touching. That would be advances slightly.