I have a 1954 Chevy Bel Air with Powerglide. There is a peephole on the passenger side of the bellhousing right above the starter. When I look through the peephole and I rotate the flywheel I see a silver ball embedded into the flywheel. Question: When the silver ball appears through the peephole does it always mean that you are at top dead center (TDC) for piston #1? If I line the pointer that protrudes from the side of the peephole up with the silver ball on the flywheel am I exactly on TDC? FYI only about this engine: Engine was recently separated from transmission. Flywheel was recently removed and reinstalled. Valve cover and side cover are installed with new gaskets (otherwise I would remove one or both to figure out when I’m at TDC).
Remove all 6 spark plugs, Turn engine by hand with socket wrench on crank pulley, Front cylinder is #1, As Intake valve is closing, piston will be coming up on compression, look thru spark plug hole, you should be able to see it or use a pencil or something to feel it. when at TDC, look at your marks to see if they line up. This should be pretty close +- a few degrees. You can make a hard stop by tapping the center of a spark plug and putting a bolt in it. Hope this helps. John
It's hard to figure out your problem with the info you provided. Was the engine up and running in the car before you pulled the transmission and flywheel. Just removing tranny and flywheel does nothing to the timing of your car. Did you pull your distributor and this is the reason for finding TDC. Assuming that your engine is in the car and you can turn it over with the starter, pull the plugs and place your thumb over number one cylinder hole and tap the starter slowly rotating the engine until the compression blows your thumb off the plug hole. Look to the front of the engine and find the timing marks on the crankshaft. Make sure you turn off the key and then either by using a socket on the front of the crankshaft or rocking car back and forth while in gear with a stick shift, align the TDC mark to the pointer. You now have TDC. If you want to time your engine, it is easy from this point. Find your setting such as 4 degree on the crank hub and rotate engine either with socket of moving car back and forth in gear to align pointer with (example) 4 degree mark. Your pointer should now be pointing the timing you want. Make sure car is out of gear and key is off. Go to the distributor and pull the cap and look to see if the rotor is pointing to the number one plug wire in the cap. If your distributor is out of the car, drop it in and make sure it bottoms out against the block, if not, you may have to pick it up and turn shaft a little until it does. At this point you can tighten the distributor hold down clamp so it turn with a little resistance. Rotate the distributor until the rotor aligns with the number one plug wire in the cap and attach cap. Turn on ignition switch and place a plug in the end of the number one spark plug wire and ground the plug to the block or header and slowly rotate the distributor back and forth and the plug should fire whenever you rotate past the rotor. You want the plug to fire as your rotating clockwise. Stop as soon as it fires and tighten down distributor, your engine is now timed and ready to run.
That ball is the timing mark, and yes, it is always #1 top when it is visible in the hole. Actually, I think since it is the timing mark, it is advanced a few degrees from TDC.
I believe R Pope is correct about the 'ball' in the flywheel being the timing mark.....but not TDC. If you want to nail TDC.......remove all spark plugs and the valve cover as suggested. Rotate the engine by hand until the intake valve in #1 cyl is closing. As suggested, you will need a 'stop' tool to insert in the spark plug hole of #1 to touch the piston. It needs to be sturdy enough to resist movement when GENTLY contacted by the piston. A common method is to take a old spark plug, separate the base from the porcelain insulator and attach to the base a probe of some sort, a round rod or long bolt shank, for example. It MUST be securely attached.....welded, brazed or a secure press fit at minimum. Now, with the piston coming up on the compression stroke and the tool screwed into the cylinder, gently rotate the engine until the piston contacts the stop tool. Now, make a mark of some sort on the flywheel or front pulley at a reference point on the bell housing or front cover. You must have both.....the reference mark on the fixed item AND a mark on the rotating part. Your engine has the pointer in the bell housing window.. Now, rotate the crankshaft in the OPPOSITE direction until the piston again contacts the stop tool. Make a mark on the flywheel or pulley. TDC is exactly in the middle, between the two marks you made when the piston contacted the stop tool. This process exactly locates top dead center. You may well find the 'ball' is not top center, but is a few degrees before top center "BTDC", in which case you have confirmed it was the original recommended timing reference.
Weird old way of finding TDC. Screw a pipe into the plug hole and put some bubble soap on the end. When you turn the engine the bubble gets bigger as you approach TDC, smaller when you go past.
First, thanks to everyone for the help. You folks always help me out. Very grateful. 1946 Caddy wrote, "It's hard to figure out your problem with the info you provided. Was the engine up and running in the car before you pulled the transmission and flywheel." The engine was running in the car. I pulled the engine and transmission together. I removed the flywheel so I could bolt the engine to the stand. I removed the distributor so I could paint the engine. After the pulled the distributor the crank was turned at one point and I am no longer sure where TDC is. The engine is not in the car. It's on a rolling cart attached to the engine. I'd like to install the distributor prior to putting the engine back in the car and starting the engine for the first time. 1946 Caddy also wrote, "Look to the front of the engine and find the timing marks on the crankshaft. " I assume you mean the timing marks on the flywheel. They talk about the timing marks in this thread. Assume that's the timing marks you are talking about. http://chevytalk.org/fusionbb/showtopic.php?tid/281807/ R Pope wrote, "That ball is the timing mark, and yes, it is always #1 top when it is visible in the hole." but Hnstray wrote, " believe R Pope is correct about the 'ball' in the flywheel being the timing mark.....but not TDC." Not sure which answer is correct at this point but thank for both responses. I've got a vacuum gauge setup which gives me some idea of when I'm close to TDC or just past TDC. I'll try to look through the hole and use the gauge to hopefully figure it out. Hnstray also wrote, "remove all spark plugs and the valve cover as suggested" Trying to avoid pulling the valve cover if I can. I sealed it prior to painting the engine. Want to avoid breaking the seal.
Oh my. Some good advice here, also some totally wrong off-the-wall bullshit you need to throw out. I will try to help you sort it out. The ball in the the flywheel you see through the peephole is the timing mark. For what you are doing, trying to time the distributor, it doesnt matter if its true TDC or not. It does matter, however, that you are on the firing stroke for #1 piston. It will be visible once on every rotation of the crank...#1 only fires every other rotation. As suggested, pull the number one plug and put your finger over the hole and rotate the engine until the pressure pushes your finger off...look for the ball. You may have missed the mark if it fires BTDC. Just make it line up, by turning the crank in the necessary direction. Drop the distributor in and make sure the rotor button points at the number one spark plug wire. If it doesnt , pick it up, turn it a bit and drop it back in until it does. If you have a helper , this whole thing will take you less time to do than it took me to type it. If you are by yourself it will be a little more aggravating, but still very doable. Good luck!
Rex A Lott offers a good, and simple, method of getting the timing very close for starting purposes. Also correctly points out that the ball indicates firing position for #1 only every second revolution. My lengthy explanation was in response to the title of the thread....you asked "how do I find top dead center?". The comment about the 'ball' being a timing mark but not necessarily indicating TDC is an attempt to explain to you the difference between TDC and the timing indicator. Engines are timed in REFERENCE to TDC but the ignition event necessarily occurs AHEAD of TDC in order to allow for the combustion event to occur and the gasses to expand at the optimum point of piston travel. That produces the greatest amount of useful force on the crankshaft for the fuel burned......"the most bang for the buck".
The ball is the timing mark If you look close there might be more marks lines on each side of the ball.
Either the bubble or balloon may work if the goal is only to be within a few degrees of either side actual TDC. There is a point at the top of the stroke at which the piston does not move perceptively while the crank turns several degrees and the rod lower end transitions from up to down.....
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