Timing set at too high?!
Timing set at too high?!
At initial timing it runs 100% at 20 degrees BTDC? Has anyone heard of it going that high? I know TPI's generally run 6 degrees, but with my cam this sounds crazy. Could it be since I didnt degree the cam when put I the motor together? Here's specs on the cam:
Duration @ .050" lift: 211/219 (int/exh)
Valve lift: .499"/.525" (int/exh)
Duration @ .050" lift: 211/219 (int/exh)
Valve lift: .499"/.525" (int/exh)
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From: St. Louis, Missouri
Car: 1989 Firebird Formula
Engine: 383 Stealth Ram
Transmission: 700R4
Axle/Gears: 3.73 9 bolt Posi
Re: Timing set at too high?!
Are you unplugging the ESC connector before timing the engine?
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From: Charles County, Maryland
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Re: Timing set at too high?!
Are you measuring 20 BTDC with the set timing wire disconnected? If so, that is way too much timing. If you are not familiar with how to check timing on an ECU controlled engine and you are just shooting a light at the balancer w/o disconnecting the set timing wire, 20's at idle is normal.
Stock 305 and 350 TPI bins still get 34-36 total timing at WOT. If you really have 20 degrees base timing, with the ESC wire disconnected, you are giving the engine 48-50 total timing at WOT right now. Your knock sensor is going to pull as much timing as it can and it is going to throw your spark tables way off. Do not drive the car like this. You need to bring your base timing (set w/ the set timing wire disconnected) back
Stock 305 and 350 TPI bins still get 34-36 total timing at WOT. If you really have 20 degrees base timing, with the ESC wire disconnected, you are giving the engine 48-50 total timing at WOT right now. Your knock sensor is going to pull as much timing as it can and it is going to throw your spark tables way off. Do not drive the car like this. You need to bring your base timing (set w/ the set timing wire disconnected) back
Joined: Mar 2000
Posts: 43,187
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From: Littleton, CO USA
Car: 82 Berlinetta/57 Bel Air
Engine: L92/LQ4 (both w/4" stroke)
Transmission: 4L80E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
Timing the cam and setting the timing have nothing to do with each other.
20 degrees BTDC at idle with the ESC wire plugged in sounds about right.
20 degrees BTDC at idle with the ESC wire plugged in sounds about right.
Re: Timing set at too high?!
Interesting. I had it disconnected while adjusting it. I set the **** at 12 degrees BTDC which was recommended with my mods etc and pointed the damper mark to Zero. The engine barely starts and if it does catch it just misfires. I tried going lower/higher and suffered on all attemps. I then brought it up to 20 degrees BTDC and It runs like a champ from Low to Top end. Hmmm
Joined: Mar 2000
Posts: 43,187
Likes: 42
From: Littleton, CO USA
Car: 82 Berlinetta/57 Bel Air
Engine: L92/LQ4 (both w/4" stroke)
Transmission: 4L80E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
Are you using a timing light to make these adjustments?
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Joined: Mar 2000
Posts: 43,187
Likes: 42
From: Littleton, CO USA
Car: 82 Berlinetta/57 Bel Air
Engine: L92/LQ4 (both w/4" stroke)
Transmission: 4L80E/4L80E
Axle/Gears: 12B-3.73/9"-3.89
Stock damper? It isn't unheard of for the ring to slip on the hub.
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