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Post Info TOPIC: Timing and carb adjustment
jim larson


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Timing and carb adjustment
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Well today was the 1st time I drove the car for any significate milage, about 20 miles.  Car seemed to prefore well.  Deceided to check and adjust the carb and check the timing. It has a original 3419 Holley carb (rebuilt a couple of yrs ago) for the 66 360hp and the original 66 bb distributor with points and condensor and stock coil.  Car idles at 600rpm with air mixture screws turned out 1 full turn.

Initial timing reads a  constant 8 Degrees, with vac can disconnected and line pluged. Dwell angle is set at 30.  Just by looking at the timing mark move while manualy increasing the trottle, looks like the distributor adds 28-30 degree @ around 4000 rpm.   Is there an accurate way to watch and check the number of degrees of advance the distributor  adds  and at what rpm that happens? Like it add 10 degrees at 1500 and 20 degrees at 2500 and 30degrees at 4000.

I then hooked up the vac can and it added nothing at idle.  When I slowly brought it up to around 3500 rpm, you could see that the timing mark had advanced around 10-14 degrees (again a guess) beyond where the timing mark was with the vac can disconnected and line pluged.  A quick acceleration with the throttle rod droped  the timing advance as expected with a loss in vacumn to the vac can.  Timing mark then moved up to where it previously was as vacumn increased. So I think that is working OK.  According to the stamping on the vac can it is suppose to add 12 degrees. Is there some way to check how much advance the vac can is adding.?

What I would like to do is make sure that I am  not getting to much advance.  From what I have been able to find  the initial plus the mechanical should be a total of 36 degrees and the vac can should add an addition 12 degrees.

I plan to keep the ignition stock as opposed to going with a pentronix unit or something else.

Mitch has offered to modify the distributor weights so that the distributor doesn't add to much.  Thanks



-- Edited by jim larson on Friday 8th of April 2011 06:29:43 PM

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Jim L

Lake City
Scott Parkhurst


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To really dial in the advance, you have to pull the dist and get it on an old-school Sun machine. They're still around if you look a bit, and it's the best-possible way to make sure it's right.

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Scott Parkhurst

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jim larson


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Thanks Scott. Maybe someone will chime in on a shop that is located on the S side of the metro, since I am down below Red Wing. All I have to check timing is and old school light from the 60's and a guage that I hook up to the coil to check dwell, voltage, and it checks rpms to around 1200 that a friend gave me since he nevers uses them any more.

So I just ordered a Equus 3568 from Amazon, total price including shipping was $33.38. Price from sumitt was $110 plus shipping. Pays to check around.

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Jim L

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Chris R


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How about the guy Stan went to?



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Chris - Ramsey, MN.

Dear Optimist, Pessimist, and Realist.

While you guys were busy arguing about the glass of water. I drank it!

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The opportunist.
Lost in the 60s


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I was going to say, you need and "advancing" timing light. I just bought a digital one a couple months ago since my 40 yr old light quit last summer too. I haven't used it yet.



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Chris R


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Scott Parkhurst wrote:

To really dial in the advance, you have to pull the dist and get it on an old-school Sun machine. They're still around if you look a bit, and it's the best-possible way to make sure it's right.

 Thats what I would do. Your still running the old school no electroncs stuff so thats what I would do.

 



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Chris - Ramsey, MN.

Dear Optimist, Pessimist, and Realist.

While you guys were busy arguing about the glass of water. I drank it!

Sincerly,

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SShink


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Chris R wrote:

How about the guy Stan went to?

 Yep, Competition Engines in Eagan (sort of south metro).   They're about 10 min. from Kevin's too so you can stop in for a cup of coffee if he's around.

Ask for Randy.  He's a great guy, has the Sun machine, and tweaked/tuned my disty for $20! 

 

3925 Cedarview Drive
Eagan, Minnesota 55122
(651) 688-6351

 



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jim larson


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Thanks everyone. Just printed out the map to CE. Looks like it is easy to find, just up old Cedar Ave from County 42 by Jeff Belzers Chev. But first the new timing light will arrive next Tuesday. That should give me an idea of how much my distributor is adding and at what rpm all the advance has been added. Then if I change the base to add more advance to get the engine to run better and cooler this summer, I will know if I have to reduce the amount of advance the distributor is adding.

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Jim L

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