73-87chevytrucks.com
73-87 Chevy _ GMC Trucks => Performance => Topic started by: bobcooter on November 01, 2010, 06:51:35 pm
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I've been reading for a while now about a lot of the guys in here advancing the timing beyond factory specs with good results. What I need to know is this; I am running flat top pistons and factory intake and exhaust manifolds with duals. My timing is set at 8 degrees BTDC and I am getting 12MPG and I have a pretty good pickup, more than with the headers and Summit Stage 2 intake. Anyway, is there a danger of harming my engine (mainly frying a piston of something) if I advance the timing as described in various threads? Mainly, advance it till it pings when you romp on it and then back it off some. It actually is running better than ever. Should I try it or just keep in hands in my pockets?
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If it ain't broke, don't fix it.
Just remember your initial setting and play with it from there. If you don't like it, put it back to spec. I don't think you'll fry a piston tho ;)
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I run 12 BTDC, and I only burn at least 89 octane. As long as it doesn't ping, you should be fine. You might see a little better mileage by advancing it a little. You can always turn it back.
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As long as it doesn't ping, the extra advance wont hurt a thing. since the timing is easily set and your reference marks are there, you can change it back to stock in about 3 minutes. I'd play with it, as its free extra power. Plus if your timing marks are off at all, you have no way to set it to stock in the first place.
I don't know exactly what my trucks set to, but the timing marks say its at 20 degress BTDC. and this is on 87 octane gasoline. I doubt it would run that well that high so I assume my marks are off a bit. And at 8 degrees like mine should be set to its a total dog.
When you test for spark knock, don't automatically romp on it to test for knock/pinging. as knocking/pinging is bad. on mine, I get up to about 40mph or so and press the gas as far as I can without it downshifting. doing this the trucks not so loud so I can hear the pinging better. then if that test goes well, floor it all the way and see what you hear. if you hear pinging, drive the truck EASY back to where ever you have to go to readjust the timing. I go up 4 degrees at a time to save time, and then when it pings I back off 2 until it quits.
On my truck, Having the advance set where it is as opposed to where the timing marks say to put it, I have to push my gas pedal about 1/4 less to do the same work it did before. It takes off faster on the primaries than it did before on the primaries and secondaries.
Play with it, if you feel uncomfortable with the adjustments, put it back to stock. you can always do that, and it will be perfectly ok.
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Thanks guys!