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#16357 04/26/2002 3:20 AM | Joined: Oct 2001 Posts: 45 Member | | Member Joined: Oct 2001 Posts: 45 | Hey guys, just a quick question. I'm not sure what setting my octane selector should be on? I know to time the engine it has to be on 0, but what about when i'm driving it? Thanks.
Chad
1955 Chevrolet 210 2 door Sedan
a 30,000 mile UNMOLESTED original, now my daily driver! Original 6 cylinder with a rebuilt '66-'69 Saginaw 3-speed Overdrive. Synchro low! Otherwise, everything original down to the spare tire. Interior is like new. Needs paint, but absolutely zero rust.
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#16358 04/26/2002 2:56 PM | Joined: May 2001 Posts: 1,907 'Bolter | | 'Bolter Joined: May 2001 Posts: 1,907 | Is it a mechanical advance/retard? When our '65 Chev was tuned at Laramie, Wyoming (Elev. = 7200 ft.), the engine would start to knock at about Baker, Oregon (when driving to Western Wash.) We would mix in the ethyl grade until we got back to altitude. A simple adjustment like this would have saved the day.
Chad, Zero rust in Minnesota? How'd that happen?
1948 3/4-Ton 5-Window Flatbed Chevrolet 34 Years. Now with a '61 261, 848 head, Rochester Monojet carb, SM420 4-speed, 4.10 rear, dual reservoir MC, Bendix up front, 235/85R16 tires, 12-volt w/alternator, electric wipers and a modern radio in the glove box.
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#16359 04/28/2002 5:05 AM | Joined: Oct 2001 Posts: 45 Member | | Member Joined: Oct 2001 Posts: 45 | Wally, its got both vacuum and mechanical advance. The octane selector is on the vacuum advance....not sure where to set it, though. Yea, rust free is kinda rare up here but an old guy had it so he probably took pretty good care of it. Plus it was ziebarted.....which isn't going to be fun taking off when I decide to restore it!
1955 Chevrolet 210 2 door Sedan
a 30,000 mile UNMOLESTED original, now my daily driver! Original 6 cylinder with a rebuilt '66-'69 Saginaw 3-speed Overdrive. Synchro low! Otherwise, everything original down to the spare tire. Interior is like new. Needs paint, but absolutely zero rust.
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#16360 04/28/2002 1:18 PM | Joined: Apr 2002 Posts: 23 Wrench Fetcher | | Wrench Fetcher Joined: Apr 2002 Posts: 23 | Hey Chuddy117,
As clean and well-kept as your car is, do you by chance have the owner's manual? The older ones explained what the "octane selector" did and why you'd change it.
Also, do you know if the owner had the valves changed to hardened valves to allow you to use unleaded gas without damaging the motor? The original owner of my '46 had it done in '85; I still have to do it on my '50.
Sounds like a nice driver!
A great lady, a stovebolt, & a small town! What else is there?
Aspiring '54 6400 dump truck owner
'Bolt On
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#16361 04/28/2002 4:38 PM | Joined: Sep 2001 Posts: 29,270 Bubba - Curmudgeon | | Bubba - Curmudgeon Joined: Sep 2001 Posts: 29,270 | Chuddy117,
This might be of little help.
Setting Timing (other readers please correct me, if I am wrong here):
- Set the point gap (and/or the dwell).
- Disconnect vacuum line at fuel pump; and, plug/cover/seal the end of the line going to the carburetor.
- Warm up engine; idle speed should be 450-500 R.P.M. (manual transmission)
- Check the dwell (reset points, if necessary)
- "Set the octane selector at "0" on the scale . . . loosen the distributor clamp and rotate the distributor body . . . " until timing mark and pointer line up.
The Chevrolet Truck Operator's manual states:
"The octane selector at the rear of the distributor mounting provides a means of advancing or retarding the ignition timing for the grade of fuel being used."
"Octane selector should be set for the grade of fuel being used to produce a slight "ping" on acceleration."
"Octance Selector: When changing to a grade of fuel with a higher or lower octane rating it may be advisable to advance or retard the spark slightly. Advance the spark to take advantage of higher octane fuel and retard it to to prevent excessive detonation with lower octane rated fuel. . . . loosen the clamp bolt and move the distributor assembly toward advance or retard as desired and tighten the clamp bolt securely. By adjusting the spark in this manner it can be readjusted to the original setting when desired without special ignition timing equipment. (They did not like to waste ink on commas back then)
I have never been confident about my ability to hear the "ping".
I think that microprocessors and sensors take care of these "fine adjustments" in modern vehicles.
Tim | | |
#16362 04/28/2002 6:26 PM | Joined: Oct 2001 Posts: 45 Member | | Member Joined: Oct 2001 Posts: 45 | Hey guys, thanks a lot for the info. It helped a lot. I know for a fact it doesn't have hardened valve seats, but thats alright. I'm going to build up a 261 soon so I won't be driving it much anymore. Thanks again.
Chad
1955 Chevrolet 210 2 door Sedan
a 30,000 mile UNMOLESTED original, now my daily driver! Original 6 cylinder with a rebuilt '66-'69 Saginaw 3-speed Overdrive. Synchro low! Otherwise, everything original down to the spare tire. Interior is like new. Needs paint, but absolutely zero rust.
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