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| | | | Joined: Mar 2009 Posts: 71 Wrench Fetcher | | Wrench Fetcher Joined: Mar 2009 Posts: 71 | I have an aftermarket timing gear cover with timing tabs on a small block Chevy. I know I have the cam timing dialed in but now I'm worried the TDC marker on the harmonic balancer may not be in sync with timing tab since some engines had tabs positioned differently. Anyone got a trick for finding TDC on number one cylinder on a motor already installed? I have a dial indicator but getting it to read through the plug hole to the top of the piston is going to be a problem. | | | | | Joined: Oct 2003 Posts: 5,152 Cruising in the Passing Lane | | Cruising in the Passing Lane Joined: Oct 2003 Posts: 5,152 | I've used a piece of wire curved to ride the piston and side up and down in the spark plug hole. While you could probably rig a dial indicator off of that if it checks out as correct just watching the wire peak you may be satisfied without.
1955 1st GMC Suburban | 1954 GMC 250 trailer puller project | 1954 GMC 250 Hydra-Matic | 1954 Chevy 3100 . 1947 Chevy COE | and more...
It's true. I really don't do anything but browse the Internet looking for trouble... | | | | | Joined: Oct 2006 Posts: 843 Shop Shark | | Shop Shark Joined: Oct 2006 Posts: 843 | Take out all the plugs.Feed a bit of rope into #1 plug hole.Turn the motor by hand till it stops against the rope.Mark the damper.Turn the motor the opposite way till it stops.Mark the damper.Split the difference.TDC.
I hope this helps | | | | | Joined: Dec 2001 Posts: 14,522 Moderator: Welcome Centre, Southern Bolters, Legion Hall | | Moderator: Welcome Centre, Southern Bolters, Legion Hall Joined: Dec 2001 Posts: 14,522 | I just did this on my panel. Since I have brackets radiator and fan on my engine I just pulled the #1 plug, had my neighbor put his finger over the hole and I slid under the truck, used a long boxed eng wrench to turn the motor with the bolts in the torque converter. When compression stroke came up, you can feel the air blowing out, he then put a small screwdriver in the slot and watched it till he could tell when it stopped and started back down. I got lucky and my mark was correct. Dropped the dizzy in where it belongs and I hope to start it up sooooon!
I must admit, it helped that there is not fenders, or inner fenders on it so we could get right to the #1 plug hole.
Lots of ways to do it. You can also pull the valve cover and watch the valves.....
Good luck. Let us know how you come out. | | | | | Joined: Feb 2004 Posts: 29,751 Kettle Custodian (pot stirrer) | | Kettle Custodian (pot stirrer) Joined: Feb 2004 Posts: 29,751 | Knock the porcelain center out of a spark plug, and drill & tap, or just weld a 2" long bolt into the plug shell. Install the modified plug in #1 cylinder and turn the crankshaft slowly until you reach a stop in both directions. Mark the stop points. TDC is exactly halfway between the two stop points.
Jerry
"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
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| | | | | Joined: Mar 2009 Posts: 71 Wrench Fetcher | | Wrench Fetcher Joined: Mar 2009 Posts: 71 | Hotrod Lincoln:
I have a welder to rig this up so you may have the best solution "for me" so far. I like the halfway between two marks since there always seems to be a "flat spot" of wiggle room once the crank gets very near TDC.
Thanks to you all:
Dan B. | | |
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