Timing and Idle RPM - The 1947 - Present Chevrolet & GMC Truck Message Board Network

tblough · 04-05-2003, 02:18 PM

Anyone know what RPM I should use for setting the ignition timing on a 250ci 4.1L L6?

Also, any Idea for a normal Idle speed.

apstguy · 04-05-2003, 02:36 PM

Uh, usually there is a sticker in the engine compartment that has that info on it.

tblough · 04-05-2003, 02:56 PM

I forgot to mention that due to past bodywork, there is no longer VECI labels. The only label under the hood is the Jack Mount instructions.

Thanks

apstguy · 04-05-2003, 03:35 PM

oh IC. My Chilton's has a chart with idle speed on it & guess what it says for your engine? Note: See underhood sticker. Thanks for the help CHILTONS!!! What I can infer from the rest of the chart, idle speed with an auto is 650 and a stick is 700. It also says the timing should be 8 degrees

tblough · 04-07-2003, 11:39 AM

Thank you for your help!! Since I don't have a garage, I'll wait for some warmer weather to set the timing. It's pretty cold in North east Ohio right now.

Thanks Again,

apstguy · 04-07-2003, 08:22 PM

Sure! Just be sure to note that these are NOT the exact numbers in the book - it didn't have the originals. I infered it from the rest of the chart. Good luck!

tblough · 04-09-2003, 12:59 PM

Thanks again.

I haven't figured out where to change the idle speed on my vaccum controlled carb. So I connected the the tachometer to the TACH lead on the distributer. Removed the vaccum line from the distributer and plugged the loose tube, loosened the dist. tightening bolt. Had my wife apply a little throttle to keep 700 RPM, shined the light on the balancer and lo and behold 8 deg BTDC. I previously set the timing by listening to the engine until is sounded slow and smooth, and couldn't believe my eyes. How's that for luck?

Question. Does it make a difference is someone is applying throttle as opposed to setting the idle speed?

You guys are great!

79BIG10 · 04-10-2003, 02:17 AM

It's best to do it at idle speed. The range you were working with at 700RPM will not affect it too much.

On the idle screw whck by the acclerator cable linkage on the carb. You will see where the cable hooks up to the arm linkage. In front of that arm should be close to a screw that you need to adjust for the idle speed.

04-05-2003, 02:18 PM	#1
tblough Registered User Join Date: Mar 2003 Location: Ohio Posts: 42	Timing and Idle RPM Anyone know what RPM I should use for setting the ignition timing on a 250ci 4.1L L6? Also, any Idea for a normal Idle speed. __________________ tblough I love my Truck! '84 Custom Deluxe C10 LWB Inline 6 250ci 4.1L 2wd

04-05-2003, 02:36 PM	#2
apstguy LED King Join Date: Jan 2003 Location: Sacramento, CA Posts: 2,088	Uh, usually there is a sticker in the engine compartment that has that info on it. __________________ Tyler 1985 C10 305 w/ Bowtie OD TH700R4 3.42 LSD 202,000 miles 2006 Ford Focus ZX3 5-speed Stick 2016 Chevy Spark EV Gone: 2002.5 VW GTI 24v VR6 Gone: 2008 VW R32

04-05-2003, 02:56 PM	#3
tblough Registered User Join Date: Mar 2003 Location: Ohio Posts: 42	Forgot to mention... I forgot to mention that due to past bodywork, there is no longer VECI labels. The only label under the hood is the Jack Mount instructions. Thanks __________________ tblough I love my Truck! '84 Custom Deluxe C10 LWB Inline 6 250ci 4.1L 2wd

04-05-2003, 03:35 PM	#4
apstguy LED King Join Date: Jan 2003 Location: Sacramento, CA Posts: 2,088	oh IC. My Chilton's has a chart with idle speed on it & guess what it says for your engine? Note: See underhood sticker. Thanks for the help CHILTONS!!! What I can infer from the rest of the chart, idle speed with an auto is 650 and a stick is 700. It also says the timing should be 8 degrees __________________ Tyler 1985 C10 305 w/ Bowtie OD TH700R4 3.42 LSD 202,000 miles 2006 Ford Focus ZX3 5-speed Stick 2016 Chevy Spark EV Gone: 2002.5 VW GTI 24v VR6 Gone: 2008 VW R32

04-07-2003, 11:39 AM	#5
tblough Registered User Join Date: Mar 2003 Location: Ohio Posts: 42	Thank you for your help!! Since I don't have a garage, I'll wait for some warmer weather to set the timing. It's pretty cold in North east Ohio right now. Thanks Again, __________________ tblough I love my Truck! '84 Custom Deluxe C10 LWB Inline 6 250ci 4.1L 2wd

04-07-2003, 08:22 PM	#6
apstguy LED King Join Date: Jan 2003 Location: Sacramento, CA Posts: 2,088	Sure! Just be sure to note that these are NOT the exact numbers in the book - it didn't have the originals. I infered it from the rest of the chart. Good luck! __________________ Tyler 1985 C10 305 w/ Bowtie OD TH700R4 3.42 LSD 202,000 miles 2006 Ford Focus ZX3 5-speed Stick 2016 Chevy Spark EV Gone: 2002.5 VW GTI 24v VR6 Gone: 2008 VW R32

04-09-2003, 12:59 PM	#7
tblough Registered User Join Date: Mar 2003 Location: Ohio Posts: 42	Thanks again. I haven't figured out where to change the idle speed on my vaccum controlled carb. So I connected the the tachometer to the TACH lead on the distributer. Removed the vaccum line from the distributer and plugged the loose tube, loosened the dist. tightening bolt. Had my wife apply a little throttle to keep 700 RPM, shined the light on the balancer and lo and behold 8 deg BTDC. I previously set the timing by listening to the engine until is sounded slow and smooth, and couldn't believe my eyes. How's that for luck? Question. Does it make a difference is someone is applying throttle as opposed to setting the idle speed? You guys are great! __________________ tblough I love my Truck! '84 Custom Deluxe C10 LWB Inline 6 250ci 4.1L 2wd

04-10-2003, 02:17 AM	#8
79BIG10 I'm back with 2nd truck! Join Date: Feb 2002 Location: Texas Posts: 3,775	It's best to do it at idle speed. The range you were working with at 700RPM will not affect it too much. On the idle screw whck by the acclerator cable linkage on the carb. You will see where the cable hooks up to the arm linkage. In front of that arm should be close to a screw that you need to adjust for the idle speed. __________________ 1979 Chevrolet Bonanza Big10 "Tootsie Roll" 1985 Chevrolet Silverado (wife's) Member of the Southern Bowties Club "Don't underestimate how sexy a fat man who drinks to excess can be." Homer Simpson



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