307 non computer controlled timing.

Jimmy

Jimmy

Greasemonkey
Jan 25, 2016
148
212
43
Gulfport, MS
#1
What should the timing be on a 307 olds after swapping to HEI distributor? I made the swap a couple of months ago but still think I may have a timing issue.
 
DoubleV

DoubleV

Royal Smart Person
Feb 25, 2011
2,035
205
63
Cleveland, aka 'The Factory of Sadness'
#3
No. Initial timing can't be set unless you know the advance curve of the new distributor you put in. Most Olds engines with HEI's we're set at 20 which is the same as the computer controlled HEI's.
 
Jimmy

Jimmy

Greasemonkey
Jan 25, 2016
148
212
43
Gulfport, MS
#4
The total mechanical advance is 20 degrees.
 
DoubleV

DoubleV

Royal Smart Person
Feb 25, 2011
2,035
205
63
Cleveland, aka 'The Factory of Sadness'
#5
A stock 307 should like around 36-38 total. I would shorten the curve so you can run 20 initial and still get 36-38 total. For now, I'd run 16-18 initial.

When is all of your 20 in by? What about vacuum advance? How much? You running an egr valve?
 
Jimmy

Jimmy

Greasemonkey
Jan 25, 2016
148
212
43
Gulfport, MS
#6
A stock 307 should like around 36-38 total. I would shorten the curve so you can run 20 initial and still get 36-38 total. For now, I'd run 16-18 initial.

When is all of your 20 in by? What about vacuum advance? How much? You running an egr valve?
approximately 1800 rpm is when total is in. Vacuum advance is 10deg and no EGR valve.
 
TURNA

TURNA

Geezer
Jul 24, 2009
6,608
8,511
113
Socialist NY
#7
Did you swap the carb too?
 
olds307 and 403

olds307 and 403

Comic Book Super Hero
Oct 14, 2008
3,923
1,788
113
Melville,Saskatchewan
#8
Add more vacuum advance, about double. The 18 base should be about right, I find low compression Olds V8's love a lot of timing part throttle especially.
 
airboatgreg

airboatgreg

Royal Smart Person
Oct 2, 2016
1,420
1,308
113
#9
And down the rabbit hole he goes
 
pontiacgp

pontiacgp

Canadian Prime Minister
Mar 31, 2006
24,191
9,405
113
Kitchener, Ontario
#10
With no egr you'll have to back off the timing a coupld of degrees. The egr cools the combustion chanber and without that cooling the advanced timing can cause pre-ignition due to the heat.
 

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