Timing marks
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Instructor
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From: Belmont NC
St. Jude Donor '15
Timing marks
On a 72 Coupe 350ci,...
I am trying to determine where the top dead center mark is. I see the sawtooth plate that has about a 1/4 hole in it. I have a timing strobe (in a dusty box)
The plate and harmonic balancer have been painted and I don't see any degree markings that I am used to. i.e. +4, +2, 0, -2, -4, etc.
What should the correct timing be and how do i know what it is by looking at the plate?
Almost everything is original except for the electronic convertor instead of points.
I am trying to determine where the top dead center mark is. I see the sawtooth plate that has about a 1/4 hole in it. I have a timing strobe (in a dusty box)
The plate and harmonic balancer have been painted and I don't see any degree markings that I am used to. i.e. +4, +2, 0, -2, -4, etc.
What should the correct timing be and how do i know what it is by looking at the plate?
Almost everything is original except for the electronic convertor instead of points.
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Instructor
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From: Belmont NC
St. Jude Donor '15
Thread Starter
Instructor
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From: Belmont NC
St. Jude Donor '15
I stand corrected, sticker is there....says 8 degress BTDC at 800 RPM. However, I'll need to rig the power for the timing light.
Last edited by mtnance; May 29, 2015 at 07:37 PM. Reason: sticker there
Le Mans Master
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From: Gladstone MO
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For power clip the red lead to the output stud on the alternator and ground the other to a bolt head on the engine.
USe the center of the 1/4 hole as zero *- Ususally the biggest "Tooth" on the tab is centered on it.
USe the center of the 1/4 hole as zero *- Ususally the biggest "Tooth" on the tab is centered on it.
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Instructor
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From: Belmont NC
St. Jude Donor '15
That makes sense and I'm not sure why I didn't think of that. Thanks. Been a long week.
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From: Pittsburgh PA
Just timed my 77 the other day. I had to wipe paint off to see the degrees. 8○ btdc initially set by crankshaft with engine off in picture and then set timing to about +26○ at 3000rpm and then connect vacuum. 36○ total timing is what it is supposed to be and a good timing light with degrees helps which I do not have but I am close at 34○. -8 to +26○ =34○ range. The white spot I made is 36 degrees. I should have made it at 28 degrees.
I also used jumper cables to connect the timing light.
Last edited by JEBSi; May 30, 2015 at 12:51 AM.
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Drifting
Joined: Oct 2005
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From: Forth Worth TX
Just timed my 77 the other day. I had to wipe paint off to see the degrees. 8○ btdc initially set by crankshaft with engine off in picture and then set timing to about +26○ at 3000rpm and then connect vacuum. 36○ total timing is what it is supposed to be and a good timing light with degrees helps which I do not have but I am close at 34○. -8 to +26○ =34○ range. The white spot I made is 36 degrees. I should have made it at 28 degrees.
You should set the timing for 36*@3000rpm with the vacuum disconnected. Once that is established all you have to do is re-connect your vacuum. It doesn't matter where your timing ends up at idle. It's the 36*@3000rpm (mechanical, no vacuum) that's important.
In my 1970 I have 36*@3000rpm with no vacuum. When I release the throttle and the engine goes back to idle, I have around 12*-14* with no vacuum. Once I re-connect the vacuum the idle timing will then go up to around 24*. You will most likely need to re-adjust your idle screw because the idle will increase with that amount of timing in it.
Last edited by Revi; May 30, 2015 at 08:59 AM.
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From: Belmont NC
St. Jude Donor '15
Not sure if I understand what you are trying to say (26*@3000rpm, no vacuum?), but I think you are doing it wrong.
You should set the timing for 36*@3000rpm with the vacuum disconnected. Once that is established all you have to do is re-connect your vacuum. It doesn't matter where your timing ends up at idle. It's the 36*@3000rpm (mechanical, no vacuum) that's important.
In my 1970 I have 36*@3000rpm with no vacuum. When I release the throttle and the engine goes back to idle, I have around 12*-14* with no vacuum. Once I re-connect the vacuum the idle timing will then go up to around 24*. You will most likely need to re-adjust your idle screw because the idle will increase with that amount of timing in it.
You should set the timing for 36*@3000rpm with the vacuum disconnected. Once that is established all you have to do is re-connect your vacuum. It doesn't matter where your timing ends up at idle. It's the 36*@3000rpm (mechanical, no vacuum) that's important.
In my 1970 I have 36*@3000rpm with no vacuum. When I release the throttle and the engine goes back to idle, I have around 12*-14* with no vacuum. Once I re-connect the vacuum the idle timing will then go up to around 24*. You will most likely need to re-adjust your idle screw because the idle will increase with that amount of timing in it.
What's caused me to be wonder: it idles just a tad rougher than I think it should. Still has the power though at 30 mph. I can drop to 3rd gear and floor it without any hesitation or delay in the engine.
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From: Pittsburgh PA
Not sure if I understand what you are trying to say (26*@3000rpm, no vacuum?), but I think you are doing it wrong.
You should set the timing for 36*@3000rpm with the vacuum disconnected. Once that is established all you have to do is re-connect your vacuum. It doesn't matter where your timing ends up at idle. It's the 36*@3000rpm (mechanical, no vacuum) that's important.
In my 1970 I have 36*@3000rpm with no vacuum. When I release the throttle and the engine goes back to idle, I have around 12*-14* with no vacuum. Once I re-connect the vacuum the idle timing will then go up to around 24*. You will most likely need to re-adjust your idle screw because the idle will increase with that amount of timing in it.
You should set the timing for 36*@3000rpm with the vacuum disconnected. Once that is established all you have to do is re-connect your vacuum. It doesn't matter where your timing ends up at idle. It's the 36*@3000rpm (mechanical, no vacuum) that's important.
In my 1970 I have 36*@3000rpm with no vacuum. When I release the throttle and the engine goes back to idle, I have around 12*-14* with no vacuum. Once I re-connect the vacuum the idle timing will then go up to around 24*. You will most likely need to re-adjust your idle screw because the idle will increase with that amount of timing in it.
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Try setting it to 36 at 3000 and let the initial timing be what ever it is at that point.
I recently bought a craftsman digital degree timing light and have been kicking myself ever since for not getting it sooner.
I recently bought a craftsman digital degree timing light and have been kicking myself ever since for not getting it sooner.
Drifting
Joined: Oct 2005
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From: Forth Worth TX
The above should be done with the engine at full operating temperature, choke off, etc..