Technical Verifying what I did was correct. Timing my SBC

Hi,
I timed my 327 sbc today. I installed a MSD timing tape and plugged timed port vacuum line on the carb. I got the engine to operating temp and them took all the mechanical advance out of the distributor about 3100 RPM and then turned the distributor counter clockwise to attain 32 degrees and then plugged my vacuum line back into the carb.

This is not something that I do on a regular basis. Have I done this correctly? I guess I am just second guessing myself because I have read a lot of different threads recently that have different ideas on how to set timing. Does it look like what I did was correct?
Thanks Jay

 

Yes you have set your total mechanical timing to 32* (Assuming your timing tape is correct) which should be in the ball park for most SBC's. You also may want to try pulling vacuum off of the manifold vacuum port rather than the timed port.

 

I concur.

 

Old timer told me to loosen distributor hold down, then put a cup of water on the air cleaner. Should be ripples/rings in water. Slowly turn distributor until water is calm. Didn't believe it until I tried it.

Also said they used to tune an AM resistor radio to a weak station. When timing was right station would come in clear. Kill the engine and the signal would go weak.

Not scientific with the obvious benefit of timing lights etc, but might be worth a shot.


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Connect a vacuum gage to manifold vacuum. Adjust the dizzy till you pull the greatest vacuum. Your engine will be happy.

 

this is why I am addicted to the hamb, love this type of stuff.

 

What you did sounds good to me. I agree that the dist needs to be hooked up to manifold vacuum not ported vacuum.

 

Ok I really appreciate you guys chiming in and giving me some input. The one thing that I did check that I wasn't sure about was the initial timing.

When I went back and checked my initial timing after the adjustment it was 11 degrees with the vacuum port plugged. When the engine is revved up to 3100 RPM with the vacuum port plugged the mechanical advance is all gone the timing tape reads 32 degrees. Does that mean that my total timing is 43 degrees? Am I right here? or is my total 32 degrees.

Jay

 

if you have too much you will know when you crank it to start you will think your battery died.do as voodoo twin said use vacuum gauge if you dont have one buy one you will be surprised what they can tell you.one of the best tools you will every own too many things come in to play with light.I have used one for over 40 years race and street cars.

 

Kid, after reading all those threads, you should have found that there's two ways to time your engine. 1st is bottom/up or setting your initial and hoping the curve is right, the advance weight is right and that your total is right at the right rpm. Great for stock parts, stock dizzy, stock engine following stock published specs. But Complete nincompoopery if there is any modification.

The second is Top/down,
Here you set the total at the rpm you choose, maximize power and control pinging detonation. Then you still need to make sure your curve is right and that your initial is dialed in.

What you did so far sounds great to me.
But there's a few more steps. You need to dial in your total by the stop watch seat of the pants dyno. Maybe it wants 32, or 34, or 30 or someplace in-between. You need to give it what it wants not what the book says. Then you need to make sure your initial is set in a livable place. The distance between initial and total can be set with a recurve or stops. The advance amount and quickness and sensitivity to vacuum change can also be dialed in with stops and different pots.

 

Definitely went from top down approach Vicky

It feels pretty good by the seat of the pants test. Definitely seems to run pretty strong and even stronger then before. No pinging under load or purposely lugging the motor ( I can do that because it is a stick.) Was nice and hot and fired right up. Seems to start better then before when it was cold.

So 32 degrees (mechanical advance) all out of the distributor (vac plugged) and 11 degrees initial (vac plugged) is where I am so far.
Jay

 

What we use to do is find a slight hill. Floor it going up hill. If it doesn't ping, add 2 degrees of advance. If it does ping, take 2 degrees out. So on and so forth..........

 

You do realize that an engine can be in dentonation or "ping" .... long before it can be heard by ear?

 

Don't do that in his hood....
You'll get a ticket!