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Topic: Need help changing points...

in Forum: C3 Electrical


Need help changing points...

Posted: 8/10/04 9:21am Message 1 of 10
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Marion, IA - USA
Joined: 4/24/2004
Posts: 317
Vette(s): 1969 Corvette Stingray Convertible. Just bought it from my uncle who owned it since 1971. Fathom green, green interior. 350/300, T400.
OK guys I feel dumb even asking for help with this, but I've been working on it for 1 hour now with no luck. I cannot find a way to get the feeler gauge between the points! Not only that, but there is a little detent on the dist that fits into a little hole on the points, when it's engaged I can't adjust the points. I've changed a lot of points over the years, but never had anything like this.
Thanks,
Matt


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Need help changing points...

Posted: 8/10/04 10:16am Message 2 of 10
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Frederick, MD - USA
Joined: 9/8/2003
Posts: 3398
Vette(s): 1969 convertible L71 427/435 4-speed black interior
You don't need a feeler gauge to adjust points on a Delco V8 distributor. You use an allen wrench...the proper one often comes with the points. Install the points, condensor and rotor, then re-install the distributor cap. You have that little metal window that slides up. Insert the allen wrench and seat it appropriately and turn it clockwise until it stops, then back off one half turn (I believe...maybe one turn. It's been years since I've done this.). That should get you close to your 28-32 degrees of dwell. You should be able to start the car and use a dwell meter to finish setting the dwell then set the timing.

I would set the dwell closer to the 32 degrees end of it's acceptable range to account for wear as the car gets driven.


Need help changing points...

Posted: 8/10/04 10:24am Message 3 of 10
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Marion, IA - USA
Joined: 4/24/2004
Posts: 317
Vette(s): 1969 Corvette Stingray Convertible. Just bought it from my uncle who owned it since 1971. Fathom green, green interior. 350/300, T400.
Thanks! It makes sense now. This is my first old GM, I'm used to working on Fords. I got the dwell set at 30 degrees, runs good now.
Once again, thanks for all the good advice, and thanks for helping a "Vette novice" out.

Matt


Need help changing points...

Posted: 8/10/04 10:32am Message 4 of 10
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Frederick, MD - USA
Joined: 9/8/2003
Posts: 3398
Vette(s): 1969 convertible L71 427/435 4-speed black interior
Help is what we're all here for. I had to really think about it since it's been so long since I've done it.

The Delco points and how easy they are to adjust made so much sense it always amazed me no one else used the concept instead of always using feeler gauges. Maybe GM wouldn't license it to anyone else, I have no idea. I know AMC used it, but I think they bought their distributors from GM.

I remember using much colorful language years ago setting the dual point with a feeler gauge in the Studebaker Avanti I owned. It wasn't much better on some other cars where access to the distributor was limited or a stretch.


Need help changing points...

Posted: 8/10/04 6:58pm Message 5 of 10
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Hot Springs, AR - USA
Joined: 4/24/2004
Posts: 3236
Vette(s): 69 Conv #'s match 427, TKO-600/.64, 3.36HD-Posi, HT, T/T, PS, PB, PW, SP, Leather, Comp XE264HR & Roller Rockers & Lifters, Air-Gap RPM intake, Holley St Av 770 VS, MSD 6AL+Dist+Blaster SS, K&N, Jet-Hot Hooker Side-Pipes, Steeroids, Al Rad, Spal Fans
points.... yuck!!!

but gm definitely has the easiest ones.

I still keep my dwell gauge around just in the rare case I have to touch points.. I hope I never have to again..

in a pinch you can adjust your points with a vacuum gauge as well.. just guestimate .019 and then tune to peak vacuum.


Need help changing points...

Posted: 8/10/04 8:06pm Message 6 of 10
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CUYAHOGA FALLS, OH - USA
Joined: 12/2/2003
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Vette(s): 1975 C3 Red, T-Tops, Black Interior. All I need is time and money! Getting there!
On a V-8 point gap is usually .017 Ben you're close enough. But the change in gap or dwell cannot be set with a vacuum gauge. What you are actually doing is changing timing, that's why vacuum changes. For every 2 degrees of dwell change, you change timing 1 degree. Timing should always be rechecked after setting points.


Need help changing points...

Posted: 8/10/04 9:59pm Message 7 of 10
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Hot Springs, AR - USA
Joined: 4/24/2004
Posts: 3236
Vette(s): 69 Conv #'s match 427, TKO-600/.64, 3.36HD-Posi, HT, T/T, PS, PB, PW, SP, Leather, Comp XE264HR & Roller Rockers & Lifters, Air-Gap RPM intake, Holley St Av 770 VS, MSD 6AL+Dist+Blaster SS, K&N, Jet-Hot Hooker Side-Pipes, Steeroids, Al Rad, Spal Fans
 kstyer said: On a V-8 point gap is usually .017 Ben you're close enough. But the change in gap or dwell cannot be set with a vacuum gauge. What you are actually doing is changing timing, that's why vacuum changes. For every 2 degrees of dwell change, you change timing 1 degree. Timing should always be rechecked after setting points. 


I should have clarified.

thats what i meant by in a pinch...

it will get you close enough to get down the road.. a dwell gauge is harder to find these days then a vac gauge..

ive been stuck on the side of the road with melted points too many times and no tools.. assuming your timing was set right (by vac) then adjusting back to peak will get you back to the correct spot.. then get it home and do it right..

ive hitched down to the nearest parts store bought two sets of points and a cheap vac gauge (dont think ive ever been caught without a screwdriver in the car) a few times and have always been remarkably close.. this of course does assume that your timing was set with point dwell correct before the failure.

if you had your timing at peak vac.. then changing dwell either way (from your correct baseline) will either increase or decrease timing and therefore decrease vacuum... so back to peak will get you "close" to the dwell your points were at when you last timed the car.

again.. this is just a road side fix.. ive changed points road side this way.. (ive also changed head gaskets road side 4 times in my life.. I am definitely no stranger to road side repair.)

(btw... my haynes says .019 gap) and according to

http://autorepair.about.com/cs/generalinfo/a/aa052502a_2.htm

Most cars had a point gap of about 0.019", or the thickness of a matchbook. Some were set higher or lower so check your manual to be sure. To measure the point gap, you need a set of feeler gauges. Adjusting the point gap is a simple process, but it takes some practice to get the hang of doing it properly. First, make sure the rubbing block is on the high point of one of the cam lobes. If it isn't, you will have to turn the engine a little bit in order to turn the cam.

i found this by searching matchbook and points.. as I was taught to guestimate with a matchbook....

not arguing.. just disagreeing.

and the reason i never just guestimated with a matchbook and got home was that my distributor was old and had worn lobes.. cant remember if this made the gap smaller of larger to get it back to 30 degrees but it was significant.

I drove from sweetwater texas to ruston la in a 390/3spd 64 galaxie (which also needed generator bearings and brushes replaced roadside on the way to AZ) with my points set using the method I described above. no problems and remarkably close when I got home..

|UPDATED|8/10/2004 9:59:54 PM (AZT)|/UPDATED|



Need help changing points...

Posted: 8/11/04 8:13am Message 8 of 10
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CUYAHOGA FALLS, OH - USA
Joined: 12/2/2003
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Vette(s): 1975 C3 Red, T-Tops, Black Interior. All I need is time and money! Getting there!
Ah, the clairification. Knowing that it was set properly before. That makes a big difference. After being in the business as long as I have I NEVER make the assumption that it was okay before that point in time. With someone who has worked on their car themselves, and actually know what they were doing, it makes a difference. I would look at it that way if it was my car, but not someone else's car. So Ben, from your view point, I agree. But from my viewpoint of the unknown being there first, I go back to my statement.

As far as the matchbook, it does work. I have used it before. It's only until I can put a dwell meter on the car. Once again the difference. On anything with points, it usually has some lobe and distributor shaft wear. In many cars the points do spec at 17, some spec at 19. I go with the 17 to offset the wear factor, and shoot for the correct dwell.
Why some at 19 and some at 17? Design of the distributor and shape of the point lobes on the dist shaft. Not all are the same from OEM, and many aftermarket performance distributors have a lesser gap. This prevents the points from bouncing as much at high rpm. An extream example is a friend of mine with a GTO and an aftermarket dist. When set to the correct dwell, the gap was only 14.
So my answer was law of averages based on many cars with many setups.

Granted I get very specfic much of the time. But having worked on hundreds of different cars over many years, I somtimes use the generic answer.

Sometimes it depends on my listeners, as to which approach I take. I am more specfic here than I am with a general group. This is a focused group. I know I need to very specfic focused with Ben due to his knowledge base and experience. Generic background knowledge answers are not good enough. Ben take that as a huge compliment. |thumb|


Need help changing points...

Posted: 8/11/04 11:03am Message 9 of 10
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Hot Springs, AR - USA
Joined: 4/24/2004
Posts: 3236
Vette(s): 69 Conv #'s match 427, TKO-600/.64, 3.36HD-Posi, HT, T/T, PS, PB, PW, SP, Leather, Comp XE264HR & Roller Rockers & Lifters, Air-Gap RPM intake, Holley St Av 770 VS, MSD 6AL+Dist+Blaster SS, K&N, Jet-Hot Hooker Side-Pipes, Steeroids, Al Rad, Spal Fans
 kstyer said: Ben take that as a huge compliment. |thumb| 


I did.. thanks..

I really need to learn to clarify my explanations..

I make the assumption that someone would start at the same point I did in doing something..


Need help changing points...

Posted: 8/16/04 1:46am Message 10 of 10
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BRADENTON, FL - USA
Joined: 8/4/2002
Posts: 669
Vette(s): 1972 convertible 350 auto trans, delux int, air, ps, pb, t/t wheel, pw, 79,000 org miles Rare one year only color
i remember using a match book cover to get them set close enough to run and put a dwell meter on them


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in Forum: C3 Electrical


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