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post #1 of (permalink) Old 09-17-2000, 07:45 PM
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HEI Settings

I just gor done upgrading my ignition to a Chevy HEI system and was wondering what everyone is running as far as timing and idle. I set mine up by ear and ended up with about 2-3* before the 0 mark (oposite the timing scale) and around 600 rpms. I am running a weber 32/36, any suggestions would be greatly appreciated. Also is everyone setting the timing with the vaccum advance plugged?

84 Toy,86 Toy,73 CJ5,93 RM125
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post #2 of (permalink) Old 09-17-2000, 08:04 PM
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Re: HEI Settings

8 degrees BTDC at 800 RPM.

Good Jeepin'

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post #3 of (permalink) Old 09-17-2000, 10:11 PM
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Re: HEI Settings more Q\'s

OK I got it set up at 8* and 800rpms without the vacuum advance conected. After reconecting the advance and turning the idle down to 600 the timing has jumped up to about 12-15*. Is this normal, or should I reset the timing with the advance hooked up? Thanks

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post #4 of (permalink) Old 09-17-2000, 10:17 PM
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Re: HEI Settings


My preference is to use ported vac for the advance. Drive in all ranges of speed and load on the engine. Lug it off in high gear, wind it up on hard acceleration, all the conditions you can imagine it will operate under. If it doesn't spark knock, bump it up a couple of degrees until it does. Back it off until it doesn't or whatever your tolerance level is. Not much knock though, makes bad things happen inside the engine. Optimum timing is just before knock occurs. Under 98% of your normal driving you shouldn't hear any knock. Also, you can tune the advance curve by playing with the springs and weights under the rotor. Lighter springs: faster advance. Heavier springs: slower advance. Most parts stores have a kit with springs and weights for about ten dollars.

Has anyone else tried this method? If so, how did it work for you? I've had good success with it for 15 or so years. Sounds really low tech but every engine has a different timing tolerance and this is the most reliable and easiest way I have to find it.


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post #5 of (permalink) Old 09-18-2000, 05:56 AM
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Re: HEI Settings

Yeah, I also pretty much set it up by ear. I have a timing light, but no tach, so initially I set it up at what I thought was about 800-1000 RPMs
I also have the HEI and Weber 38 on my 258, and I went with the Crane adjustable vacuum advance and played with the spring to try and find my optimum advance.
Btw, trying different springs and amount of advance is a real fun project. It doesn't cost much, and you get to make all kinds of full throttle runs!
I just followed the instructions in the Crane kit, and didn't run into any problems really. The only odd thing I encountered was a knock on the highway at about 55mph, I had to retard the whole curve a little to elimate it.
Bob in MA

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