Timing Curve Advice

[Gregski]

Originally Posted by RotaryRocketeer

Going to dial back the initial a bit today and see what happens. Been pretty busy with job interviews these last few days. Thread will be updated with results.

Good man, remember truck has to be fully warmed up, 10 minutes idling in the driveway does not count, lol, driving it for about 20 minutes to stretch its legs sort of speak is best, don't waste your time and effort tuning a cold engine, you won't get anywhere, just a reminder that's all

Change one thing at a time, either retard the timing by 2* or regap the spark plugs, don't do both

Also unless you are running 10.5 compression or something you don't need 91 octane, I realize you are trying to combat the pinging, but higher octane may be masking the real source of the problem

[RotaryRocketeer]

I know it's been a while, but just wanted to let everyone know all is well and say thanks for the advice. Dialed in the vac advance to the best setting, brought the initial down just a hair, and found out I was running leaner than I liked. The plugs were a bit white after some "spirited driving," so I stuck the big boy metering rods in with some stiffer springs. Running great!!

[RotaryRocketeer]

On another note, all that running around paid off. I got a job that's going to double my annual income! Riding pretty high these last few days!

[Gregski]

Originally Posted by RotaryRocketeer

I know it's been a while, but just wanted to let everyone know all is well and say thanks for the advice. Dialed in the vac advance to the best setting, brought the initial down just a hair, and found out I was running leaner than I liked. The plugs were a bit white after some "spirited driving," so I stuck the big boy metering rods in with some stiffer springs. Running great!!

always great to hear when a member gets their rig dialed in, good job and especially thank you for not abandoning the thread and giving it proper closure

[Gregski]

Originally Posted by RotaryRocketeer

On another note, all that running around paid off. I got a job that's going to double my annual income! Riding pretty high these last few days!

Congratulations, and do not mention your raise or promotion around any appliances as they tend to break, lol, don't ask me how I know!

[RotaryRocketeer]

Nothing bothers me more than finding a thread that sounds exactly like what you're experiencing, and then reading 4 pages to a dead end.

Thank you for the congratulations.

[Tom]

Originally Posted by RotaryRocketeer

1
350 w/Vortec 062 heads

Ding ding ding.
You need to mod the vaccum advance to only give about 10*. Vortecs only want between 32-34* total timing, the mechanical plus oem vaccum is in the 40* range. Lowering the base timing to get the less overall gives you a terribly running engine and poor performance everywhere except at cruise.

[RotaryRocketeer]

Originally Posted by Tom

Ding ding ding.
You need to mod the vaccum advance to only give about 10*. Vortecs only want between 32-34* total timing, the mechanical plus oem vaccum is in the 40* range. Lowering the base timing to get the less overall gives you a terribly running engine and poor performance everywhere except at cruise.

While I'd normally concede to your expertise, the truck is running phenomenally under all conditions (idle, light, moderate, and heavy acceleration, and cruise.) This particular combo seems very happy where it's at. Chops a bit at idle like it always has, and moves out quick when it's time to go.

[Gregski]

Originally Posted by RotaryRocketeer

While I'd normally concede to your expertise, the truck is running phenomenally under all conditions (idle, light, moderate, and heavy acceleration, and cruise.) This particular combo seems very happy where it's at. Chops a bit at idle like it always has, and moves out quick when it's time to go.

Agreed, there are many factors that can effect the outcome here. Is the original poster running Vortec heads in the original factory setup ie with all the air pump SMOG junk, I doubt it. What head gasket thickness is he using? What ignition, we know it's an aftermarket distributor with different plugs. What cooling system, water pump / radiator combo. What exhaust, the chocked up factory two into one, or true duals, headers or stock manifolds, etc. etc. etc.

[Tom]

Its run as good as you've known it to, doesn't mean its running as good as it can. Gregski is correct, many factors affect when you'll hear pinging/detonation. I ran 9.4:1 compression with oem gaskets and 87 octane because it was an oem take out truck vortec converted to carb. That doesn't mean the truck we're talking about now won't get better mileage and/or make more power with more adjustment to the timing curve. Just because vortecs chamber can handle more timing doesn't mean they like it.