Cam Timing

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Apr 7, 2001 | 11:29 AM

Thread Starter

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Joined: Apr 2000

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Cam Timing

I am thinking of retarding the timing about 4 degrees on the 351W I'm putting together. I base this on info from the Dyno SE program that shows I will get a more broad powerband in this configuration. A bit more power for freeway usage. So my question is this. If advancing the timing increases the combustion pressure, and possibly messing with my emissions. What do you suppose the downside of retardation would be, if any?
I'm in CA, hence the smog considerations. Any opinions or experiences?

Apr 7, 2001 | 12:22 PM

karljay

Cargo Master

Joined: Jul 2000

Posts: 2,281

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From: Northern California

Cam Timing

Advancing a cam will move the power band lower and retarding it will move it higher. I've heard that most cam grinders build in a few degrees adv for smog reasons. The main down side would be loss of lower end power, but that might be exactly what you want. As far as smog goes, you'd have to try it and have it tested to know if it makes that much difference.
I've heard of a poor mans way of timming a cam was to move it around until you get the highest compression reading. I plan on playing around with mine just to see what it does. If you have the multi-keyway timming gear, it's not very hard to change and shouldn't take but a few hours, otherwise, I'd get the changable type timming gears.
I'd also make several runs, change it and make several more runs and check the 60ft times 1/4 mile times, see if more top end power is what you want.
Keep in mind that if you make this change, you would probably benifit from changeing carb settings, ign timming... at the same time.