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Ignition timing on 360 engine!

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Frank T View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Frank T Quote  Post ReplyReply Direct Link To This Post Topic: Ignition timing on 360 engine!
    Posted: Mar/02/2015 at 5:32am
I have a 360 engine with Edelbrock performer cam, intake and 600Cfm carburator, any good ideas to make my engine run with the perfect iginition timing Wink
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Ollie View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Ollie Quote  Post ReplyReply Direct Link To This Post Posted: Mar/02/2015 at 9:23am
Set your timing with a Vacuum gauge. Set at highest vacuum reading. You will be dialed in at optimum.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Lenni AMC Quote  Post ReplyReply Direct Link To This Post Posted: Mar/02/2015 at 10:55am
36° total timing is a good starting point..

Set at 3000-3500 rpm
Just remember to unplug the vac advance from the distributor when setting the timing at 36°
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Post Options Post Options   Thanks (0) Thanks(0)   Quote ridler3d Quote  Post ReplyReply Direct Link To This Post Posted: Mar/03/2015 at 8:51pm
Never thought of a vacuum guage
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Boris Badanov Quote  Post ReplyReply Direct Link To This Post Posted: Mar/04/2015 at 7:11pm
With all due respects Ollie I disagree with setting timing with a vacuum gauge.
Most engines will make more vacuum with idle timing settings that will send
the total timing well past the danger zone.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote FSJunkie Quote  Post ReplyReply Direct Link To This Post Posted: Mar/04/2015 at 7:52pm
This has been tested many times before and most people agree to the numbers.

10-15 initial at idle

30-35 total at 3500-4000 RPM, vacuum advance disconnected.

An additional 15-20 from the vacuum advance.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote purple72Gremlin Quote  Post ReplyReply Direct Link To This Post Posted: Mar/04/2015 at 8:15pm
I was taught that using vaccum to set the ti ming was the best way......But I found out that that would give it too much initial. .....
So I usually go by ear, or a combi`ation of going by ear & a timing light.     I would prefer to use a distributor machine, but no access to one. So I have used a timing light with the knob on it. It works.   And I almost never go by factory settings.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Frank T Quote  Post ReplyReply Direct Link To This Post Posted: Mar/05/2015 at 6:58am
Thanks so fare, I have also this distributor, anyone with exerience with that?? or is the original Motorcraft actualy better?http://www.ebay.co.uk/itm/AMC-JEEP-CJ5-CJ7-304-360-401-V-8-HEI-DISTRIBUTOR-6512-BK-/371072745638?pt=Motors_Car_Truck_Parts_Accessories&hash=item5665a8c0a6
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Post Options Post Options   Thanks (0) Thanks(0)   Quote uncljohn Quote  Post ReplyReply Direct Link To This Post Posted: Mar/05/2015 at 8:34am
Setting timing with a vacuum gauge is one way to get close, and I have used it a number of times when lacking a timing light. You set it at Idle and idle by spec is 600 rpm.
Timing adjustments according to TSM I have in front of me are made at 500 rpm with the vacuum line disconnected. And when done reset idle rpm to the manual spec of 600 rpm or what ever your personal preference is. This is to insure that the mechanical advance mechanism is not advancing the timing. Depending on which distributor you use, mechanical advance generally starts at 900 rpm.
But using this method, done with the vacuum line connected generally as others said gives too much advance. Thus if I use this method, I fined max. vacuum and then retard the distributor a tad.
It works.
A timing light works better.
Insure basic timing done with a light, again factory spec is 5 degrees. If you use another number, it is personal preference.
Mechanical advance generally will be an additional 12 to 16 degrees at about depending on the distributor.
Vacuum advance will depend on the distributor also, but is generally considered to be 17 to 19 degrees.
Thus maxim advance at an rpm about 2000 rpm and a maximum vacuum reading (do the adding) would be 12+17=29 degrees to 16+19=35 degrees.
Add to those numbers your initial advance setting and that will define your advance curve.
As your distributor, depending on the distributor, should have all mechanical advance in by about 2000 rpm, add that to vacuum advance and any rpm number over 2000 rpm is going to be the same number as long a vacuum stays the same.
And unless you have the capability of changing the mechanical advance built into the distributor and/or the vacuum can which defines when vacuum advance kicks in that is also your limitations.
One timing is set and a method is to use 500 rpm until timing is set and then reset curb idle rpm to 600 rpm in drive or 650 rpm if standard transmission in neutral, you get what you get.
I personally like a 450 rpm curb idle when I can get it. The limits being what ever the cam I am using will let me run, or as slow as I can get it to run.
Once initial timing is set and I use between 8 - 10 degrees generally, I choose a vacuum can (if I can) that lets maxim vacuum advance come in 1 inch below the maximum vacuum reading taken at curb idle. This is optimum for cruise conditions where I drive most of the time. The Rest?
Takes care of itself.

If you really have no idea what distributor you have they are all more or less going to get the job done and all parts on the distributor are functional forget all of the above, set initial timing to your preferred setting as slow as you can get the engine to run, preferably at an rpm under 600 rpm, with the vacuum line disconnected.
Use a vacuum gauge at that point in time to set idle mixture screws, 2 for a 2 or 4 bbl carb, 1 for a single bbl carb for a maximum vacuum reading at the same rpm used to set timing with and then reset curb idle rpm to your preferred number.
A TSM will say something like 600 rpm with automatic in drive and 650 rpm with a standard transmission.
So when done, adjust curb idle to idle rpm in manual or what ever you like and call it good to go and forget the rest.

As to the affect on pinging? That in part is going to be a function your engines compression ratio and the octane rating of your gasoline being used.
If in doubt, buy premium gas and tune using it.
The advantage? It runs better. Another advantage? In Europe, gasoline octane is higher than here in the US.
Here in the US. I have seen premium as low as 90 octane.
Where I live it is 91 octane. In other parts of the country it is as high as 94 octane and maybe 95.
The problem with pinging will in part relate to your engine compression ratio, the gasoline available and tune you use.
Most early 70's V8 engines were designed to run premium gasoline which at that time was leaded 100 octane.
No lead 93 octane is close to that.



Edited by uncljohn - Mar/05/2015 at 8:55am
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Boris Badanov Quote  Post ReplyReply Direct Link To This Post Posted: Mar/05/2015 at 6:01pm
+1
No lead 93 is roughly 97 according to a couple of web sites.
That's rougly the same as standard premium gas from name
brand gas stations in 1970.
 
But there is no lead today, much better for engine life
but highly detremental on pre 1970 exhaust valve seats.
 
I valve job with hardened seats and stainless exhaust valves
is a good idea for an older daily driver project.
 
If it is a short run street fighter or a hundred miles a year
cruise night special, don't sweat it, just mix in a little leaded race gas.
 
Sunoco "Ultra 94" or other 94+ super unleaded's are 98+ by the old MON "Motor" method.
 
Pure Toluene, if you can get it, is over 120 PN.
 
 
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