Ideal Timing Stock 305 TPI
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Member
Joined: Dec 2010
Posts: 136
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From: Houston, TX
Car: 85 IROC
Engine: 305 TPI
Transmission: 700R4
Axle/Gears: 3.42 Std. (3.73 posi, next winter)
Ideal Timing Stock 305 TPI
I know I have seen it in here, but can't find it...
I have a stock 305 TPI. What would be the ideal timing for performance?? This is a "drive for fun" car not a daily driver, so I'm not woried about gas milage. Just looking for the best overall performance off the line and cruising.
Any help and suggestions??
I have a stock 305 TPI. What would be the ideal timing for performance?? This is a "drive for fun" car not a daily driver, so I'm not woried about gas milage. Just looking for the best overall performance off the line and cruising.
Any help and suggestions??
Senior Member
Joined: Mar 2003
Posts: 851
Likes: 3
From: vacaville,ca
Car: 1988 camaro z28,1997 camaro lt1
Engine: 355 afr 195 heads,tpis big mouth
Transmission: 700r-4 built by me 3-4 z pack
Axle/Gears: 3.42
Re: Ideal Timing Stock 305 TPI
6 degrees is stock you can advance til it ping and just back it down some
Junior Member
Joined: Sep 2010
Posts: 96
Likes: 0
From: QC,IL
Car: 87 Iroc Camaro
Engine: 5.0
Transmission: 700r4
Axle/Gears: 2.73
Re: Ideal Timing Stock 305 TPI
got a newb question here, wut do you mean by ping? like the engine pings? im young and dumb and plan on doing this same mod here soon
Junior Member
Joined: Oct 2007
Posts: 22
Likes: 0
From: Maple Falls, WA (5 miles south of Canadian border)
Car: Yellow 85 IROC [Rare 1 of 205 GU6]
Engine: 5.0 TPI(30-over w/forged internals)
Transmission: 700R4 (NASCAR built)
Axle/Gears: GU6 3.42
Re: Ideal Timing Stock 305 TPI
Starting from the stock 6-degree BTDC spec, advance the timing in two-degree intervals.
With each increase, place the engine "under load." Assuming it's an automatic trans, put it in low, or 1st gear. Then firmly hold the brake down to keep the car from moving. Gradually press the accelerator to increase RPMs to somewhere between 1500 & 2000. When you get to the point where you hear a "rattling" sound (valve ping) under load, retard the timing by two-degrees & re-tighten the distributor hold-down bolt.
A couple of tips:
Before starting, mark your distributor's position. If anything goes wrong and you have trouble, you can always return your distributor to that starting point.
Loosen the distributor hold down bolt just enough so you feel a bit of resistance when you turn the distributor. It doesn't take much turning to change the timing so you don't want the distributor so loose that it turns "freely."
IMPORTANT: Remember to re-tighten the distributor EVERY time you adjust the timing, BEFORE you hit the accelerator to put the engine under load. If you don't, the distributor will turn by itself from the camshaft inertia.
Another caution: DON'T increase acceleration over 2000 RPM or so. Doing so can damage a motor mount. WATCH your engine as you increase the RPM. If it lifts more than slightly on one side, STOP! You probably already have a broken motor mount! In that case, you'll need to replace the mount before you have additional damage.
Hope this helps. Take it slow and a step-at-a-time. Good luck.
With each increase, place the engine "under load." Assuming it's an automatic trans, put it in low, or 1st gear. Then firmly hold the brake down to keep the car from moving. Gradually press the accelerator to increase RPMs to somewhere between 1500 & 2000. When you get to the point where you hear a "rattling" sound (valve ping) under load, retard the timing by two-degrees & re-tighten the distributor hold-down bolt.
A couple of tips:
Before starting, mark your distributor's position. If anything goes wrong and you have trouble, you can always return your distributor to that starting point.
Loosen the distributor hold down bolt just enough so you feel a bit of resistance when you turn the distributor. It doesn't take much turning to change the timing so you don't want the distributor so loose that it turns "freely."
IMPORTANT: Remember to re-tighten the distributor EVERY time you adjust the timing, BEFORE you hit the accelerator to put the engine under load. If you don't, the distributor will turn by itself from the camshaft inertia.
Another caution: DON'T increase acceleration over 2000 RPM or so. Doing so can damage a motor mount. WATCH your engine as you increase the RPM. If it lifts more than slightly on one side, STOP! You probably already have a broken motor mount! In that case, you'll need to replace the mount before you have additional damage.
Hope this helps. Take it slow and a step-at-a-time. Good luck.
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