Hi my name is Bryan and I have called just about every tech line for help and no one is able to help me so I thought I’d write you guys. Here is my motor: 383 SBC, trickflow heads, 10.2:1, 294XE Comp Cam 250/256 Duration @.050 and .519/.525 lift 110 C/L, victor Jr, Demon 750 Vac sec, Mallory comp 9000 distributor W/ Hyfire 6al box. My problem is I set the motor on TDC “0” on the balancer lined up with the pointer and dropped my distributor pointing to #1 on the cap. Fired up the engine, got 5” of vacuum, idled at 1100RPM couldn’t get it to idle any lower after many adjustments to the carb and distributor, and it ran ok. At 1100 RPM (idling) I put a snap on timing light on it and adjusted the dial on the back to see what my initial timing was at, it was 17 degrees. I pulled the distributor and turned the rotor towards the pass side of car backing the rotor up and dropping it in the motor between the #8 and #1 terminal on the cap. Now the car has 10” of vacuum, idles at 950RPM and sounds great!! But now at the 950 PRM idle, I put the timing light on it and turned the dial to get the 0 degree mark to line up with the pointer and I’m getting 40 degrees at idle. Can this be possible??? There is no vacuum advance on the distributor either just to let you know. It still doesn’t idle like it has a radical cam in it, but the throttle response is outstanding and my vacuum came up. So I don’t know if I should leave the distributor here or what? I just can’t seem to get my initial advance where it’s supposed to be. Can anyone help????

 

Your timong is most likely OK or close to it. Timong lights that indicate the advance can be deceiving. Is the timing light set to work with an 8 cyl engine? It may be set for a 4 cyl engine and give double indications. What you should really do, is to get an accurate timing mark set up. It can be easily done by using a mechanical TDC locator tool, an adjustable pointer and timing tape to go around the front damper. The TDC locaors are sold by Jegs, Summit, and most good speed shops and cost around $25. After this is set up, you can use the timing light to watch the timing marks on the tape move under the pointer and get a really accurate reading.

 

Hey thanks for the quick reply Pete. Some more info for ya. The balancer has the timing marks laser etched into it. When building the motor, I put a depth gausge on #1 piston with a degree wheel and rotated the motor until I found true TDC and I set the adjustable pointer to line up with zero on the balancer. And I did check the timing light to make sure it was set up for V-8. I thought that might have been wrong too since my initail advance was so way off. The only thing I can think of is either my timing light is bad or something is wrong in the distrbutor or something. I have made mulitple calls to Mallory and Summit tech lines and no one has been able to help me thus far. I am so stumped! Thanks for the input though.

 

If you already have an accurate TDC mark and you have degree marks along the front pulley, then just use them in place of indicator on the timing light. May want to pick up a simple no frills light with a Xenon bulb, and just plug it in and fire away.

 

I have heard of the newer digital lights having issues with the msd multiple spark output.

 

That will definetely confuse the fancy timing lights.

 

All you did by pulling your distributor out (from the #1 position) and putting it back in (at the #8 position) is advance your timing without turning the distributor. 17° initial is not all that bad. since you don't have a Vacuum advance what you need to do is check your total timing. Run the engine up and see where the timing stops and at what RPM it stops. A loose general rule of thumb is about 36° total advance all in by 3000 for autos and 3500 for sticks. This can vary depending on the particular application though.

In all reality, you can put the distributor in at any position that you want. Just make sure that the #1 plug wire is at that same rotor position. Not that people normaly do that, but it could be done. Most people put it in point to the #1 cyl. so that the plug wires do the least amount of crossing.

Anyway, I doubt there is anything wrong with your timing light. If the engine won't idle below 1100 RPM (meaning you can't stall out the motor when turning your idle mixture screws all the way in) then you probably need to look at setting the carb properly. Sounds to me like you have your main idle circuit open too far (Idle speed screw/throttle screw) and the engine isn't working on the idle circuit when the car is well.. idling.

Set all of your idle mixture screws at just over 1 turn out and then back down your throttle screw. If you're not familiar with this, it may take acouple of tries to get it right. In fact you may have to start where it's at with the car running and work backwards from there. With the car running set the idle mixture screws at 1.5 turns out from bottom, then turn down your throttle screw about a half turn(ballpark) and adjust the mixture screws until you get the highest idle. Then back down the throttle screw again and repeat.

If that isn't as clear as mud, then you can always go out and get the Holley "blue" book.

RM

 

Well I wanted to thank all of you for your help. Ratmotor was right! Man I adjusted an adjust that Demon carb to death to no avail. One of my friends stopped over the toher night and said that he had an extra Holley Double pumper laying around to give it a try. It was like night and day! We got the mixture screws dialed in and the idle set and she sounds great now!! He said that there may be a piece of dirt hung up in the metering blocks to throughly clean the carb before putting it back on. I have 17 degrees at idle now 950RPM and 24 degrees total advance by 2900, with 11" of vacuum. Thanks all of you for your help!! Oh just for more helpful knowledge about those pesky spark boxes. The guys at Mallory told me that my box was giving me multiple signals to disconnect it to set the timing. Well after my experience the past 2 weeks, it made no difference at all in the timing when it was connected or not. Just a little info for you guys if you ever run across this problem. Thanks once again for all your input!!!