Inliners International Forums General Discussion Hi Performance Need Help Setting Timing Wiht HEI

I don't know how to set up the timing on my 250-6 wiht HEI. I have the HEI totally out and need to strat from scratch. I have 2 timing marke on my balancer. It has been recommended that I set total timing at 36 degrees. Other than that - I don't know what to do. Can you help?

Basic steps for any engine:

Take off the valve cover (bent8's on the #1 cylinder side). If you don't want to do this, then you have to take out the #1 spark plug and crank the motor with your finger over the hole. Each time time the compression stroke happens, it will blow your finger off the hole. You have to stop cranking at just the right time to have the crankshaft close to the mark. I prefer to take off the valve cover or use a homemade whistle poked into the hole.

If you take the valve cover off, use a remote starter switch or breaker bar and socket to turn the motor until BOTH of the #1 cyl valves are moving. One of them will be closing and the other opening.

Get down in the front of the motor and locate the mark on the balancer. If you have two marks, then the one closest to the pointer tab is the right one.

Turn the motor a little more (forwards or backwards, doesn't matter) until the zero marks line up. Now turn the crank ONE COMPLETE REVOLUTION and line up the balancer mark with 8 degrees advanced on the timing cover tab.

Now you have to choose which one of the cap tits that you want to be #1 spark plug wire. Almost always, I will use a picture in a manual to locate the factory's choice, along with which way the vacuum advance points (front of car, back, side, up, down, wherever).

Stick the dizzy down the hole for a test fit to decide if your choice is OK. Chances are it will not go in all the way, as the oil pump drive will not line up. You will notice that the shaft turns as it drops down in. Lift the assembly up and down and reclock the shaft until it looks like the rotor will line up with your choice of location when it's all the way in.

Push down lightly on the housing and crank the motor until the dizzy drops all the way in. Crank it some more until the rotor comes back around to the #1 spot. Go back down to the balancer and line it up again with 8 deg before TDC. You can double-check at this point that the #1 cyl valves are NOT open. If they are not, then you did it correctly and you can reinstall the valve cover. If they are open a little (one opening and the other closing), then you have to redo the procedure, as the dizzy is installed 180 degrees out of time.

Go back to the dizzy and rotate the housing a little until the ring of pointers on the shaft (reluctor) line up with the ring of pointers on the pickup. Install the hold-down and tighten it. Install the cap and wires, keeping in mind that the rotor will point more or less at the tit on the cap that you chose for #1 wire. It will NOT point exactly at the tit, but should be about 1/4-inch CCW from it. The engine should start on the first try. Now get out your timing light and finish up the job.

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David
newbie #4153

David - thanks for taking the time to help me. If I follow your instructions, I'm sure I will get her started. Now - the recommendation is 36 degrees. WHat am I llokng for on the timeing tab when I shoot my timing light at it. I only see 12 degrees BTC and 12 degreed ATC on the tab. How will I know I am at 36 degrees. I'm dumber than shlt.

Thanks

Also - I am switching from an Accel Super Coil and MSD 6AL (It died 2x). Should I change my plug gap?

You're not so dumb that you're asking the wrong questions...

When you set the base timing at idle, the notch on the damper needs to line up with the tab at the second line past the 12 BTC line. Each of those lines should be equal to 2 degrees. The line exactly in the middle is, of course, zero (TDC). That means if you line the marks up as described, your initial timing is 8 deg BTC.

The 36 degrees of advance means that if you add up the initial with the mechanical and the vacuum, they total 36. You are going to have a little difficulty finding that number if you don't have a timing light that has an advance dial on it.

If you don't have one, then what you can do is to set the initial timing at zero, then rev the motor without the vacuum hooked up. Estimate how much the mark moves by the mechanical advance. Let it idle again and hook a manifold vacuum source to the pot on the dizzy. Or put a hose on it and suck on it until the mark stops moving. Again read and estimate the advance. You might be able to read them directly if they are 12 degrees or less. That would be nice and easy. Now add the two together and subtract the subtotal from 36. That number is what you want to set your initial timing at.

Example: 14 degrees mechanical + 14 degrees vacuum + 8 degrees initial = 36 total. If your mechanical and vacuum numbers are different, and I'm betting they are, then your initial advance may not be 8 deg.

and on a final note, you can set your gaps at 0.045 and not worry about it. They can be anywhere from 0.030 to 0.080 depending on the plug heat range, the compression, the fuel octane, the outside air temperature, etc., etc., etc. Just set them and drive it until you decide it needs changing.

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David
newbie #4153

OK - I'm starting to get it. This thing is on a dirt track race car. Their is no vacum advance. The tube is gone. All the guys in my calss run it this way. I have a lame timing light - just the basics. If I set it at 12 degrees BTDC would it be safe to assujme I will eventualy be at around 32 degrees total timing? Is there about 20 degrees mecahnical built in to the HEI ? Then, since my timing tab only goes up to 12 degrees BTDC, kind of eyeball it to determine the additional 4 degrees.

20 built in mechanical + 12 initial + 4 eyeballing it off the timimg tab = 36 total?

No, don't assume anything on a race car. Get a proper timing light if you are going to race. The mechanical advance units on HEI dizzys can be set up (at least in my experience) from 10 to 35 degrees. The range may be greater than that. You need a dial-type timing light or have the dizzy blueprinted by a specialist to find out the numbers. Your only option is to get timing tape or a racing balancer that has all the numbers on it so you can get a proper reading with the engine reved up.

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David
newbie #4153

David - thanks for taking the time to respond. I will get a real timing light. You're the best. I really appreciate the help.

Ed