Damn, my engine requires 18 degrees of timing at base (idle with no advance). And it lopes really nice there. If I turn it up to 22-24, the idle smooths out, but it over advances at WOT. Im not sure how big that cam is, but if its big like mine, it may require 18 to run. I still need to ess around with mine some. It isn't perfect and Im sure I can get it better with some tweaking. I haven't fooled around with the timing curve springs in the dizzy yet.

 

It doesn't work that way. The only way this could happen is if the ring slipped on the balancer or if the pointer was bent. To check this, pull the timing cover, align the timing marks on the timing gears and reassemble without turning the engine. The timing pointer should be pointed at "0" on the balancer. Tooth placement of the dizzy gear has absolutely NOTHING to do with the actual timing of the engine. I can take my distributer out, turn the rotor 180 degrees and put it back it. It will work just fine as long as I move the plug wires 180 degrees also. The only thing that matters is that the rotor is pointing to the #1 plug wire when the #1 cylinder is at TDC on the compression stroke. (Of course the wires have to be in the correct order too, but their actual placement on the cap is irrellavent). Fine tuning and adjustment is done by rotating the distributor housing. If the light shows 18 degrees and the balancer isn't messed up or the pointer isn't bent, then it is at 18 degrees. Maybe Im being harsh here, but when it comes down to this it seems it is often mass confusion about tooth placement and all that bull. It irratates the crap out of me. Once and for all, Tooth placement does not matter as long as the #1 plug wire is lined up with the rotor at TDC of compression stroke of Cylinder #1.

 

Tyler, you are right that some engines need more intial timing, but those are also idling pretty high. What is your idle RPM? My guesses are based on 700-850rpm idle. In the case of high idle engines, you may need more inital timing and less total timing advance because you are already running a bunch of initial timing. I know my MSD dizzy had about 22 total advance with a slow timing curve from the factory. If you run a bunch of intial timing, you may need to change out the timing advance stop and springs to get the total timing you want when you want it. When I first put my engine together, I needed 22* to not foul the plugs which put me at about 44-45* total timing (detination at higher rpms). Once I got the tuning closer and the air fuel right, I changed out the timing stop and springs so that I am now running 12* initial and 37-38* total timing with it coming in by 3000. I still have some detination when it is hot, so I may need to back the total timing stop down a little. It all depends on your motor and your air/fuel ratio. The reason we have timing advance changes is to allow the fuel time to burn when the engine is at higher rpms. If you have too much advance at any rpm, you will create detination and/or heat issues. Too little timing advance will cause the fuel to burn in your headers instead of your combustion chamber and you will loss potential power.

My guess is if you need a bunch of inital timing, you are way rich at idle and/or you are idling very high.

 

You know.... you just made me think of something. I get valve noise that comes in right at 3300-3400 RPM. It doesn't matter how hard you are pushing the throttle, you can ease into it, or stomp it and the results are the same. I am wondering if my dizzy is actually over advancing my timing some still and is causing it to get pre detonation. Thanks for mentioning that, I am goin to fool with it some tomorrow and see if I can't retune the dizzy to prevent this and to also get some more power out of her!

 

thanks for the info Urban!

 

How about tuning your carb and bringing the idle down a little. If its running rough before until you get it up to 18* you probably need to tune the carb and check your points also. Does the car smell like fumes? If you are running too rich you may need that timing, and your car will probably smell pretty bad "like mine".. Im running rich after replacing a leaking brake booster, and I can definately smell it.

 

Whats your idle RPM?

 

as tyler says: Tooth placement of the dizzy gear has absolutely NOTHING to do with the actual timing of the engine.
+1 on that. If you are one tooth off you just need to turn the dizzy a bit more which will look crap or won't work because something is in the way. but no bother theoretically

Tyler: in your case I'd clearly check again for slip on balancer and if that's all ok change the springs so you are not running 40+degrees at 3500+ or something

wonder if the poster got his problems solved

 

Thanks for the inquiry Kalli.

I have come to realize that 20* is the best for my car. i have the idle set at 750 rpm and the carb seems to be set nice. below 18* the idle is very rough and choppy and the car engine will die most of the time after about 2 min. of idling.

I expect a very rough idle with the cam that i have but the fact that it dies after a short time tells me that i need to advance it a little.

The car still runs cool and seems to be in good shape. It doesnt accelerate too quick but im not pushing it because it is not broken in yet.

 

20* initial...what total advance do you have? Do you have any detination under WOT? With a stock curve and advance stop, you are probably over 40* total advance, which is pretty high. You say you ahve a big cam. What are the specs? I am running a 280 advertised duration cam with .650 valve lift and do not have to run a bunch of timing. I did have to jet down until I had some surging and then set the timing. How do your plugs look? If you need a bunch of advance to keep the plugs from fouling, you are too rich. If you have pinging at WOT, you are running too much fuel and/or too much timing. I have not messed with real radical race engines, but I would guess you would need a pretty serious cam idling 2k or so to need that much initial timing.