Timing mark
Thread Starter
1st Gear
Joined: Jul 2022
Posts: 1
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Timing mark
I have a 368 ci/430hp crate motor in my c-3 corvette. The timing marker doesn't have the usual indicators that I am used to. There is only a single marker. Does this indicate top dead center? How can I determine any setting beyond this mark?
Safety Car
Joined: Jun 2017
Posts: 4,786
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From: North Georgia, USA
The short answer to your question is called "timing tape" applied to the harmonic balancer.
General procedure for marking the timing marks on an unmarked engine:
General procedure for marking the timing marks on an unmarked engine:
- If the head is off, you can use a bolt and nut through a piece of flat bar stock or angle stock. Bolt the flat stock to the top of the block diagonally across the cylinder bore and fasten it with two bolts threaded into the head bolt holes. Have another bolt/nut through the bar as a "stop" over the piston. If the cylinder head(s) are installed, you can thread a M14 fine thread bolt into the spark plug hole. The effect you're going for here is a "stop" that will prevent the piston from reaching TDC
- Slowly turn the engine clockwise until the piston just touches the "stop" bolt. Mark the harmonic balancer there (us a sharpie marker or nail polish or some kind of paint/ink).
- Slowly turn the engine back counterclockwise until the piston just touches the "stop" bolt. Again, mark the harmonic balancer. Measure the distance between the marks. Exactly half way between the marks is TDC. I mark that by filing a small notch at that point.
Le Mans Master
Joined: May 2007
Posts: 5,007
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From: North tonawanda NY
Either a modern timing gun that has the **** or buttons to adjust where it reads the timing so you can for example set the gun to 36" and when the engine is at 36 degrees it will show the TDC mark on the balancer when strobing. Or timing tape.
Race Director
Joined: Nov 2006
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From: Sunshine Coast, Queensland, Australia
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Cruise-In VIII Veteran
Yup, A dial back timing light is definitely the way to go here.
Timing tape works but every time you go to adjust something your back at putting on the tape.
Once you own a decent Timing light, your good to go.
Timing tape works but every time you go to adjust something your back at putting on the tape.
Once you own a decent Timing light, your good to go.
Burning Brakes
Joined: Sep 2016
Posts: 917
Likes: 410
From: Dutchess county New York
My 350 is one bastard to turn over by hand. I pulled all the plugs and the driver’s side valve cover to eyeball the valves for #1 and make certain I’m on the compression stroke. Do NOT use the starter to turn the motor with the piston stop in. It only goes in one direction anyway. Sort of obvious but they print ‘do not drink’ on cans of paint for a reason ……..
A shop probably wouldn’t do that to find TDC but this is a hobby car and I don’t know about you but I am in no hurry with mine.
Plenty of videos out there to check this out
1967 Pedal Car Champion
Joined: Mar 2020
Posts: 8,891
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From: US-PNW
I think the OP meant the timing tab only has one mark which would make it difficult to time without a dial-back light. If that's the case, it may be less hassle to buy the light than change out the tab or add a degree sticker to the balancer.
