I know a lot has been discussed on finding top dead center. I am curious why using the timing marks would not get you to top dead center. Are they not lined up with the number one cylinder stroke. Once you determined you are on the compression stroke could you not simply line up the timing marks? Thank you Jp
You can but would be taking for granted that the balancer is accurate/hasn’t slipped etc. 99 times out of 100 there’s no problem just verifying compression stroke and using the marks. If in doubt pulling the valve cover and observing both valves are closed, or using a piece of stiff wire in the spark plug hole can help confirm tdc
I changed the crank in my avatar car a few years ago. I thought I'd verify TDC before I re-installed the engine. It was off just over 1/4 inch, which equates to about 4 or 5 degrees of timing. Just for grins, I checked my under construction coupe. It was off almost the same amount. Before you do any tuning, verify that zero is zero. Not all balancers or timing covers are created equal. .bjb
Chevrolet has had at least four different balancers for small block Chevys and four different timing tabs plus the aftermarket ones it's just a verification that the Mark is correct Sent from my SM-J737T using The H.A.M.B. mobile app
While the above recommendations are correct, there is another alternative method. The most definitive way I know of for accurately determining TDC is with a tool that extends into the cylinder through the spark plug hole. You then gently rotate the crankshaft until the piston contacts the tool tip. Mark the damper at the timing pointer.....rotate the engine opposite direction until the piston again contacts the tool. Mark that position on the damper at the timing pointer. Half way between those two points is TDC. Such a tool can be home made with an old spark plug.
Its easier to make a piston stop when the heads are still off the engine....I like to get the timing mark verified before I finish assembling the engine. If the engine is already together, you probably don't know exactly what's in it anyways
It's very important for the guys who build high compression engines with the valves and pistons coming close to introducing themselves to each other. Sent from my VS835 using The H.A.M.B. mobile app
On some hard to see marks for an old fart like me I use the whistle that screws in the spark plug hole. On the old Chevy sixes with the bb in the flywheel it gets the pointer close enough to the bb that it can be spotted even if greasy or rusty. The whistle toots during the compression stroke and the quits at TDC.
No sense in using a timing light and fretting about 4 6 8 12 degrees or 34 36 38 degrees if the damn marks are off.
Don't worry about any marks, time it by ear. Find a nice long steep hill and drive up the hill several times advancing the timing a little with each trip to the top. When the engine starts to detonate back the timing off a hair. Or, do as has been mentioned above by the others. -Dave edit: That is as long as you haven't spent to many years in the field artillery.
And there are mountains {old & small now} in southern Missouri and northern Arkansas. I used the hill on 39th street in Independence just west of the Independence Center shopping mall back in high school when I needed to bump the timing on a 250 Chevy L6, so it would better burn the premium gas I was putting in the tank. Let's also not forget the foothills to the Ozark mountains you'll find when driving east out of Ponca City. Or, the Flint Hills that run north and south after getting west of Topeka. But, closer to home would be the 31st street hill that runs up Signal Hill from South West Blvd to the traffic way. -Dave
Depends on the "damper" (NOT balancer !) and timing mark. People change things over the years, put mismatched things together, thinking everything is fine, when the timing could be off...1 , 2 or as much as 6 degrees off. Best to check it or have someone check it for you. could save headaches later on. Mike
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