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HybridZ

timing, carb adjustment


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So I just bought my latest z, and it has a sbc that I don't know much about. The only info I could find in the receipts covered the rebuild and assembly but nothing too specific. The day after I got it I went out check all the basic settings to see where they were at and I'm glad I did, the distributor bolt was loose! I'm having troubles finding a good setting for the timing and mixture screws on the 4 barrel Edelbrock, which were 3 1/2 turns out from snug. I know it varies from motor to motor but I was wondering what a good base setting is then I can fine tune from there. It has a mild cam also.

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Without knowing more about it, some very general guesses are about it. 

 

Look it over good and make sure you don't have any unconnected hoses or ports.  A vacuum leak will give you fits.  Some where around 10 or 12 degrees initial timing will be in the ballpark, maybe 34 total.  It should crank without dragging when it's good and hot, and not ping at all.  Set that with the vacuum advance unhooked if it's there.

 

3.5 turns out seems like a lot, but it's been a while since I messed with an eddie.  There used to be a good tuning guide on their site.

 

SBC's are generally pretty forgiving.  Tinker with it and see what it likes.

 

jt

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A good base setting is 1.5 to 2.5. If you don't have a vacuum gauge, turn 1 in until the engine starts to run rough, then turn it out until it starts to run rough then split the difference between the low and high. Then repeat the process with the other screw. Do this with both a couple times.

 

I would also pull the cap of the distributor, go to tdc on cylinder 1 and check the wiring, and make sure the firing order is right.

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  • 2 weeks later...

Thanks guys. Turns out when the distributor bolt was loose the timing retarded itself so far that I couldn't even see the real timing mark originally, and was going off the wrong one. Got the timing just right now and man what a difference. I still feel the carb isn't quite right so I bought a vacuum gauge to get it figured out.

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