307 non computer controlled timing.

DoubleV

DoubleV

Royal Smart Person
Feb 25, 2011
2,018
96
48
Cleveland, aka 'The Factory of Sadness'
#43
Your engine doesn't know or care if it's running on the computer or not. The engine itself was designed/tuned to want X timing and Y fuel. Hypothetically, provide it with the same air/fuel and timing the computer did and it will run perfectly. Change those parameters and things can get very tricky.

And still don't rule out carb issues. Do you have any stats on your new carb? I don't know anything about Jet carbs but I would be very surprised if it was taylored to your specific engine.
 
Jimmy

Jimmy

Greasemonkey
Jan 25, 2016
137
150
43
Gulfport, MS
#44
Your engine doesn't know or care if it's running on the computer or not. The engine itself was designed/tuned to want X timing and Y fuel. Hypothetically, provide it with the same air/fuel and timing the computer did and it will run perfectly. Change those parameters and things can get very tricky.

And still don't rule out carb issues. Do you have any stats on your new carb? I don't know anything about Jet carbs but I would be very surprised if it was taylored to your specific engine.
I understand that things can get tricky but the parameters are changed when the computer was eliminated. I also understand that there could be an issue with the carb, however since olds did not make a 307 without the computer controlled it is logical to think that the same initial timing may be different than computer controlled timing. That's the reason I asked if anyone had any idea on timing without the computer. This is the carb: https://www.summitracing.com/parts/jet-32002
 
DoubleV

DoubleV

Royal Smart Person
Feb 25, 2011
2,018
96
48
Cleveland, aka 'The Factory of Sadness'
#45
My opinion is the parameters have not changed at all. Your engine is exactly the same as before. Decomputerizing doesn't suddenly make your engine want crazy different fuel or timing.
 
Jimmy

Jimmy

Greasemonkey
Jan 25, 2016
137
150
43
Gulfport, MS
#46
My opinion is the parameters have not changed at all. Your engine is exactly the same as before. Decomputerizing doesn't suddenly make your engine want crazy different fuel or timing.
Ok thanks
 
Jimmy

Jimmy

Greasemonkey
Jan 25, 2016
137
150
43
Gulfport, MS
#48
a wideband A/F gauge can help diagnose problems
I am hoping that just a timing adjustment and some minor checks will do it, before having to get into more extensive diagnostic procedures.
 
Clutch

Clutch

Comic Book Super Hero
Apr 7, 2017
3,156
2,724
113
Brick NJ
#49
Advance it until it pings and back it off a little done end of discussion
 
olds307 and 403

olds307 and 403

Comic Book Super Hero
Oct 14, 2008
3,446
820
113
Melville,Saskatchewan
#50
I understand that things can get tricky but the parameters are changed when the computer was eliminated. I also understand that there could be an issue with the carb, however since olds did not make a 307 without the computer controlled it is logical to think that the same initial timing may be different than computer controlled timing. That's the reason I asked if anyone had any idea on timing without the computer. This is the carb: https://www.summitracing.com/parts/jet-32002
X2 on manifold vacuum. You are completely wrong on the 307, Canadian cars were non CCC til 86. I owned one and worked on quite a few. I saw anywhere from 13 at 1100 to 22 at 1100 for timing specs. The one with 13 at 1100 honestly ran the shittiest. My car had 16 at 1100, 22 lost fuel economy, I think it ran best at 17 or 18. But remember it would have a 30 degree vacuum can, that is a ton of part throttle timing. The mechanical curves were no doubt different amongst them. The carbs were calibrated ridiculously lean, just freeing up the exhaust and removing the EGR made it stumble and backfire at part throttle. The only 307 have made ping was when I put very lean secondary rods in a Qjet, sounded like marbles were being thrown in when the secondaries opened.
 

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