Quick timing question
03-25-2007 | 05:35 PM
#1
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From: louisville, co
Car: 86 T/A
Engine: 383
Transmission: 700R4
Axle/Gears: 3.27 9 bolt
Quick timing question
Im trying to get the timing straight with my new cam, on the card that came with it states that "the above center line will make this cam 4* advanced". So when im setting the base timing with the EST wire disconnected I should take that 4* into consideration? I was told by a buddy that 8* advanced is about optimal for our elevation in colorado. So I should set it at 4* advanced? or just disregard what the cam card says and set it to 8?
and could not having enough timing in it cause it to run hot? I've tried it at 4* advanced and it will run up to 250* according to the dash guage. But when I have tunerpro hooked up to the aldl the laptop reads 163*.
and could not having enough timing in it cause it to run hot? I've tried it at 4* advanced and it will run up to 250* according to the dash guage. But when I have tunerpro hooked up to the aldl the laptop reads 163*.
03-25-2007 | 06:24 PM
#2
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Re: Quick timing question
The sentence you quoted on the cam card is incomplete. It SHOULD read
"... the above centerline will make this cam 4° advanced with respect to a stock cam".
Put the cam in where it belongs, and don't concern yourself with "advanced". If you assemble it correctly and then degree it, you should find that the intake lobe centerline is within a degree or 2 of whatever the cam mfr said it should be. Which is where they designed it to be. Which has NOTHING WHATSOEVER to do with where some other cam was designed for ITS intake lobe centerline to be.
ALl of this is a TOTALLY different issue from ignition timing. I'm guessing that's what the second paragraph of your question is about. Cam timing is about the relationship of the cam to the crank; ignition timing is about the relationship of spark to the crank.
I have no clue why TunerPro would read that. It's not relevant to where you should set your ignition timing though. It has no clue where the spark is occurring with resect to the crank, anyway; since it has no way to know where the crank is, it therefore CANNOT know what your "advance" is. All it can tell you, is something about how much it's modifying the spark (not cam) timing at any given moment, from the trigger pulse it gets from the distributor, which is something it looks up in its programming tables, and is entirely disconnected from where you have the distributor twiddled to.
Put the cam where it belongs and don't worry about it. Put the ignition timing where it's supposed to be, and alter it from there with the values you can see in TunerPro.
"... the above centerline will make this cam 4° advanced with respect to a stock cam".
Put the cam in where it belongs, and don't concern yourself with "advanced". If you assemble it correctly and then degree it, you should find that the intake lobe centerline is within a degree or 2 of whatever the cam mfr said it should be. Which is where they designed it to be. Which has NOTHING WHATSOEVER to do with where some other cam was designed for ITS intake lobe centerline to be.
ALl of this is a TOTALLY different issue from ignition timing. I'm guessing that's what the second paragraph of your question is about. Cam timing is about the relationship of the cam to the crank; ignition timing is about the relationship of spark to the crank.
I have no clue why TunerPro would read that. It's not relevant to where you should set your ignition timing though. It has no clue where the spark is occurring with resect to the crank, anyway; since it has no way to know where the crank is, it therefore CANNOT know what your "advance" is. All it can tell you, is something about how much it's modifying the spark (not cam) timing at any given moment, from the trigger pulse it gets from the distributor, which is something it looks up in its programming tables, and is entirely disconnected from where you have the distributor twiddled to.
Put the cam where it belongs and don't worry about it. Put the ignition timing where it's supposed to be, and alter it from there with the values you can see in TunerPro.
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