Will an ABANDONED C10 Run & Drive? Mothballed for YEARS

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A little tip for old engines as long as you have a timing light: Hook up the timing light and look at the marks – rev the engine and let it decelerate while watching the marks – they shouldn’t change much at all (less than 3 degrees, the less the better). If they move more than 3 degrees, your timing chain is loose – if they move upwards of 5 degrees, maybe ought to replace it….soon (especially if you have any “strange” noise when accelerating / decelerating). This, of course, assumes that any vacuum advance and manual advance (distributor weights, for example) are plugged / removed.

You can also test the chain manually if you have easy access to the crank bolt. Open the distributor cap and note – exactly – where the rotor is pointing. Take a wrench and SLOWLY turn the crank back and forth – noting the amount that the crank turns before there is any movement of the distributor rotor. Once again, the less movement, the better.

So, why all this? You’ll find more than a few old engines out there that are parked because the timing chain needs to be replaced. At times, owners will park the vehicle not knowing that it’s the timing chain – all they’ll know is “it just never runs right no matter what I do”. Yep…cause a bad chain – well, the engine is rarely properly timed – might rev up really great, but then pop like hell on deceleration……

Edit: I should be more clear about 3 degrees, etc. If your standard timing at idle is say, 6 btdc, you’ll see the timing change to more and less than 6btdc (usually a little more on the accel side than the decel side). As long as your timing doesn’t change more than 3 degrees – more than 9 or less than 3 btdc – you’re generally fine. 3 degrees meaning you’ll see, on average, a 6 degree “swing”. Watch it, of course, if you see more than 3 degrees in either direction and certainly be concerned if you see 5 or more.