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  #1  
Old 09-30-2006, 05:09 PM
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progress report...how set points gap?

Ok, so acquired an engine analyzer to check dwell, its at about 31 deg. manual shows it should be 39-41 and reccomends reducing points gap. unfortunately nowhere in the manual (Haynes) does it say how to accomplish this. seems like it should be .3mm. I guess I need a quick primer on how to set these?! Any help would be mre than welcome s I can move on to timing....

Thanks!

Marc

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  #2  
Old 09-30-2006, 07:43 PM
t walgamuth's Avatar
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ok. generally you will have to take off the cap, remove the rotor and probably a dust cover as well. this will expose the points. reach in with a small screwdriver and pull the point contacts apart to see if they show wear. if they are pitted you should replace asap.

there willbe two screws. one that holds them onto the base plate and one that is in an arced hole which you loosten to adjust them. there will also be a slot and a pivot point where with a flat screwdriver you can move the point base a bit to adjust the gap. you will need to get the point at its maximum opening on a rotor hump. then put in a feeler guage so that it is a snug fit and tighten the adjusting screw back down. to adjust it you want to loosten it just enough so that it will slip when you lever it with the tip of the screwdriver but not so loose that it slips on its own.

now you can also set them with a dwell meter but i dont really know how to do that.

while in there i would check the spring advance and weights for free operation and the vac advance. also remove the felt plug in the center of the rotor shaft and drop in some 10w30 oil and fill the felt plug with oil too. dont get oil on the points though.

good luck

tom w
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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.
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Old 09-30-2006, 08:43 PM
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Hey t walgamuth,

Not sure what you mean by setting the points with a dwell meter, but the meter is used to see what the dwell is.

Dwell is the lenght of time the points are open while the engine is running.

This is done by trial and error until you get it just right. It's taken me anywhere from 2-45 minutes.

New points should be set to the maximum range so they last the longest. In your case 41'
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Old 09-30-2006, 11:59 PM
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Quote:
Originally Posted by ggenovez View Post

<>

<
New points should be set to the maximum range so they last the longest. In your case 41'
>>>

Dwell is the amount of degrees the distributor shaft/cam turns while the points are CLOSED. Which is why it is called "Dwell Angle"..


Points should be set at the min. dwell angle spec.. b/c as the gap decreases, the dwell angle increases ..so, as the points cam block wears , the points gap will decrease..
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Old 10-01-2006, 12:11 AM
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I stand corrected. Thanks Arthur,

It's the gap should be set to the max so the dwell is the lowest.
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  #6  
Old 10-01-2006, 12:16 AM
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Correct....
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  #7  
Old 10-01-2006, 09:01 AM
t walgamuth's Avatar
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now i know.

thanks arthur.

tom w
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[SIGPIC] Diesel loving autocrossing grandpa Architect. 08 Dodge 3/4 ton with Cummins & six speed; I have had about 35 benzes. I have a 39 Studebaker Coupe Express pickup in which I have had installed a 617 turbo and a five speed manual.[SIGPIC]

..I also have a 427 Cobra replica with an aluminum chassis.
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  #8  
Old 10-01-2006, 01:29 PM
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Well I got lucky, no feeler guages, so I just set them by trial and error and checked with the dwell meter, got them right the first time! nice to see something go right! Will add the oil to the rotor today.

Oddly enough when I hooked up the timing light (Positive lead to battery, black to ground, and clamp part to spark plug wire 1 as per directions) I got nothing out of the light itself. Broken right out of the box or did I miss something? Its a craftsman inductive timing light, basic model, figured it should work...

Thanks for the help!
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  #9  
Old 10-01-2006, 01:32 PM
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Some models require you hold the trigger, some have a sequence. press the trigger several times with a 5 second delay in between. Also some have trouble running at high speed.

Any of those don't work bring it back
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  #10  
Old 10-01-2006, 03:15 PM
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<>

Clamp has an arrow on it .. must be on the plug wire w/arrow facing plug direction.. They are polarity sensitive.
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  #11  
Old 10-01-2006, 03:29 PM
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The basic gap adjustment for points on a benz is one of two things.
- With an transistorized ignition system use a match-book cover. (piece of thin cardboard)
- Without a transistorized switch box, do twice that (fold the cardboard).

These are just rough estimate settings to get the thing close. I learned that 20+ years ago and it's pretty close to spot on usually.


After you set it, you net to test it with the dwell meter and adjust accordingly. When dealing with used points, the gap is meaningless, since the points are pitted a bit and near impossible to measure accurately.


-CTH
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  #12  
Old 10-01-2006, 03:46 PM
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< >>

True... which is why a dwell meter reading is better.. it measures electrical conduction/closed circuit rather than an air gap, so the pitting does not show up in the reading.
Also. most decent dwell meters have a point resistance test feature.. if they do not pass this, don't bother setting them as they are pitted to the point of poor conductivity and are useless.........
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  #13  
Old 10-01-2006, 04:29 PM
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Out of curiossity what is the life span of a set of points and the condensor
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  #14  
Old 10-01-2006, 05:10 PM
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So, to keep things interesting, and me crazy, after getting it to at least idle yesterday, went out this am and started it up, idled along nicely for about 5 minuutes then cut out, now wont hold an idle at all by itself. I can run it, but as soon as I stop or slow down enough, it dies. restarts fine, but backfires and hesitated at first. Got new points although the dwell meter which has a test function showed them as ok. leaving nothing to chance at this point. Not altogether sure how to remove and reinstall, the manual indicated removing a circlip from the contact breaker arm pivot. looks like it makes sense, but I can't see a circlip there.

Will try the timing light again and look for the arrow, thanks. Would have never guessed that one.

Back out to mess with it some more...at least I'm learning!

Marc
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  #15  
Old 10-01-2006, 06:26 PM
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Ok, got the dwell set correctly, and now it will idle without help, at least at the curb. There is a louder than normal hissing sound coming from the aft carb, and looking down the barrel, it seems quite wet, the fwd carb is dry. also notices that if I cover the aft carb with my hand, the engine rpm's speed up!? not so with the fwd carb.

No arrow on the timing light to indicate direction, still no clue on that one.

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