Tuning an Olds engine, Is this accurate?

SRD art

G-Body Guru
Jun 16, 2011
518
63
St. George, UT
I just watched a video about tuning an Olds engine. Fellow says to set timing by idle rpms rather than with a timing light and you're good to go. I want to get my stock 307 running at it's peak, and bumping up timing advance was on my list.

Any truth to what this fellow says to do?

 
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69hurstolds

Geezer
Supporting Member
Jan 2, 2006
5,288
113
Other than apparently sounding like he has lung cancer, it was hard to listen to.

Olds engines come with a variety of methods for advance. Some run off ported vacuum, some run of ported OR manifold vacuum, and some have HEI with CCC that needs none of that. And don't forget the mechanical advance. It's usually wiser to include total advance as well. And 4 speed cars usually are set differently than automatics. Some have TVS's that swap your vacuum source when the engine coolant is too warm.

It may work on ONE specific car he might have worked on when he was 14 or so. But it doesn't apply to all Olds engines.

GM assigns tune-up specifications for all their engines. Follow those instructions for your specific engine application and you'll be further ahead than listening to this guy. Sounds like one of those "you might get by listening to this bunk" but if it were as simple as that, GM would put that in their instructions.
 

Texas82GP

Just-a-worm
Supporting Member
Apr 3, 2015
6,750
113
Spring, Texas
I just watched a video about tuning an Olds engine. Fellow says to set timing by idle rpms rather than with a timing light and you're good to go. I want to get my stock 307 running at it's peak, and bumping up timing advance was on my list.

Any truth to what this fellow says to do?

OzDFAZ.gif
 
Oct 14, 2008
7,081
113
Melville,Saskatchewan
He was hard to follow. I assume your car is still CCC? What year? I find low compression Olds engine like a lot of timing, it helps part throttle response, talking around 60 degrees. I ran 20+ base and 38 to 40 with mechanical advance on the Street felt best but 36 was faster at the track. 85 and up have 60 degrees of advance part throttle I believe already. Even the earlier 307's have aggressive advance, high 50's. A couple of degrees might help but only so much.
 
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SRD art

G-Body Guru
Thread starter
Jun 16, 2011
518
63
St. George, UT
He was hard to follow. I assume your car is still CCC? What year? I find low compression Olds engine like a lot of timing, it helps part throttle response, talking around 60 degrees. I ran 20+ base and 38 to 40 with mechanical advance on the Street felt best but 36 was faster at the track. 85 and up have 60 degrees of advance part throttle I believe already. Even the earlier 307's have aggressive advance, high 50's. A couple of degrees might help but only so much.
Mine is an 84.

Wow! that's a lot of advance compared to what I'm used to in my SBCs.
 
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fleming442

Captain Tenneal
Supporting Member
Dec 26, 2013
13,013
113
I haven't responded because I just don't know Jack about the CCC. I ASSUME that any changes would be "corrected" by the computer if so equipped. olds307 and 403 is correct, though. Low compression Olds engines LOVE timing. The rule of thumb is 16-20⁰ initial, 34-36⁰ total w/centrifugal, and the moon with vacuum applied.
 

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