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Valve adjustment question on sbf 302

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I couldn't get it steady at 8degrees. So i took the distributor apart and there's a thin spring which looks good and a tick spring which is a bit loose (see video).   Don't know if it should be loose.

I'll be checking for vacuum tomorrow with a mini propane tank.

in the picture i have these 2 sets of springs from an msd distributor that i removed last year (left & center) and don't know if i can or should use those.  The right pair of springs are from another autolite distributor and look pretty rough

20200322_183254.jpg

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The big spring that is loose is supposed to be slightly loose. Yes, I know it seems off, but that is the "technology" Ford used 540 plus years ago. The outer spring tab is designed to be bent as needed to adjust the timing curve.

To check the vacuum advance, simply push inward on the rod after it is disconnected from the timing plate. It should be moderately hard to push in due to the spring inside it. If you can move that rod in and out freely, the advance unit is bad.

If the advance unit is good, as a experiment in your case, you could remove your light spring in the left side of the photo and install one that feels just slightly stronger and try that. The correct spring will slow the ignition advance down some so it will not suddenly jump to 20 degrees when you advance the timing at idle from 8 to 10.

From what I can tell, the second springs down are close to stock but may be slightly stiffer, and the first springs should be stiffer than the ones below it, so compare  one of the second springs down to the smaller/thinner stock spring first.

You can rotate the rotor a few times with the stock springs to get a feel of how much resistance it has, then install a different small spring and do the same test to compare both.

All the other springs are going to be too stiff.

Also, there should be a little tension on these smaller springs when they are installed.
 

 

 

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Thanks for the follow up.

The vacuum advance works fine.

Just to be clear, when i advanced the distributor by literally a hair, the timing jumped from 8 to 20....and stayed there.

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1 hour ago, signorc said:

Just to be clear, when i advanced the distributor by literally a hair, the timing jumped from 8 to 20....and stayed there.

yup, i understand. seen that many times.

does the engine speed increase a lot also when it jumps to 20 degrees?

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1 hour ago, signorc said:

Thanks for the follow up.

The vacuum advance works fine.

Just to be clear, when i advanced the distributor by literally a hair, the timing jumped from 8 to 20....and stayed there.

If I were you, I would chart my vacuum and mechanical advances before trying to adjust/change them.

For vacuum, I attach a handheld vacuum pump with vacuum gauge to advance canister (with the vacuum line on carb or manifold plugged), set the idle speed to about 750 rpm and after that set the advance to about 10 degrees. Then apply 2 hg vacuum to canister and measure the advance reading. Increase the vacuum to 4 and measure the advance. Do this all the way to 24-25 hg vacuum and record the readings (hg vacuum applied vs advance increase which is advance reading minus your initial 10 degree).

For mechanical, remove and plug the vacuum to canister. Start the car, set timing to 8 or 10, and rpm to 500 (check and make sure advance is still 10 or 8). Increase the rpm to 750 and record the advance, increase the rpm to 1000, record the advance, do this all the way to 3000-3500 (till advance stops increasing). Record the rpm vs advance increases advance reading minus initial advance). 

Make 2 tables or charts, one for vacuum vs advance increase, other for rpm vs advance increase.

I would check the mechanical advance curve first as it looks like it may need adjustment.

Now you know how your distributor is set up and make the necessary adjustments (spring changes, stop limits, vacuum adjustment etc) needed for your engine.

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Good morning Mustang lovers from sunny "lock down" Italy!  if you wanna google it, I live in a small town called Vicopisano near the Leaning Tower of Pisa.

Today is a glorious day cause after 20 years of owning my 69 convt Mustang and not driving it frequently which is the way I wanted  (cause it would stall and not start when hot), YOU have seemed to have helped me solve the issue!!!!  Barnett, your list of 9 things to do to set the timing seems to have been the magic trick!!! THANK YOU!!!!  

Once I changed the original Ford thick distributor spring to an MSD medium one the engine ran at idle without jumps or fluctuations.  I then followed your 9 steps and the car's temp stays at 180 and never stalls (even after 90 min of idling in the driveway) and now the timing properly set :)

I went back and adjusted the entire carb (choke, cam, fast idle, choke cap, curb idle screw & 2 idle mix screws).   fast idle at 1600, curb idle at 550 rpm while in D !!!!

I used to barely get to 14 inHg with the vacuum test not I'm at a steady 16.5 :) 

My only issue now is that the second hand on my clock ticks only when the doors are closed.  If I open either door the clock stops.  Also, the courtesy lights no longer turn on when I open either door and the cigarette lighter doesn't work :(  

Hopefully everyone in the chat is safe and staying at home in order to avoid this virus to continue to spread

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2 hours ago, signorc said:

Today is a glorious day cause after 20 years of owning my 69 convt Mustang and not driving it frequently which is the way I wanted  (cause it would stall and not start when hot), YOU have seemed to have helped me solve the issue!!!!  Barnett, your list of 9 things to do to set the timing seems to have been the magic trick!!! THANK YOU!!!!  

Once I changed the original Ford thick distributor spring to an MSD medium one the engine ran at idle without jumps or fluctuations.  

I then followed your 9 steps and the car's temp stays at 180 and never stalls (even after 90 min of idling in the driveway) and now the timing properly set :)

I went back and adjusted the entire carb (choke, cam, fast idle, choke cap, curb idle screw & 2 idle mix screws).   fast idle at 1600, curb idle at 550 rpm while in D !!!!

I used to barely get to 14 inHg with the vacuum test not I'm at a steady 16.5 :) 

My only issue now is that the second hand on my clock ticks only when the doors are closed.  If I open either door the clock stops.  Also, the courtesy lights no longer turn on when I open either door and the cigarette lighter doesn't work :(  

 

1. I'm glad it has improved, so you are saying that it no longer stalls when it is hot and it also now restarts easily when it is hot?

2. I wanted you to remove the THIN spring in your distributor, not the thick one. Even though your car has improved, your timing "curve" is probably not as good as it could be, and an incorrect timing curve can cause the engine to run hotter than it otherwise would, and cause it to have less power than it should, and will cause it to get worse mileage.

3. What was the results of the timing test I posted?

4. That's very good, and is a noticeable improvement. A typical engine with a stock camshaft, should have around a minimum of 18 hg. Does your engine have a performance camshaft?

5. Remove the fuses that are for the clock and lighter and see if the tabs in the fuse block that holds them are rusty. This is the first place to look because they often are after 40 years, and if they get rusty, they can cause odd problems. You can clean the tabs with a small sharp pick or a small bit on a dreme tool etc.

 

 

 

 

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9 minutes ago, signorc said:

Got it! One of the fuses wasn't making proper contact.  Time to swap the tube fuse box to a blade fuse box

I just posted about the fuses, lol. No need to switch to a different box, and that is way too much unnecessary cost and labor.

If you simply clean the tabs on the box that are corroded, it will work for many years if you live in an area that is dry like the Desert, and if you live where it is humid or are near the ocean, you can put a little Dielectric grease on the tabs with a Q Tip or small tip screw driver after you clean them, and this will help protect them from the humidity. The Dielectric grease is available at most auto parts stores, and is a silicone base, and is hard to wash off your hands or other surfaces it gets on. Also, avoid getting it on any painted surface.

 

 

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this is weird....all is good with the electrical till i push the cigarette lighter in.  Then the courtesy light & clock stop.  no fuse blows. but when I move the #6 fuse it all resets and the lights and clock work again........till I push in the cigarette lighter again

422061246_ScreenShot2020-03-25at11_59_11AM.png.3c774a8f0394de07f6303f290b33dbcf.png1453715867_ScreenShot2020-03-25at11_59_52AM.png.2f837746197bd93ca2c25ea4d67c2867.png

 

To answer your questions Barnett: I have a stock camshaft but have NEVER been over 14inHg....so 16.5 is great.

When the lockdown here in Italy ends, I'll bring it for a drive and see what results I get by having changed the thick spring.

The results of the 9 step timing you sent me:

1. removed vacuum to dist

2. set to 8degrees

3. advanced 2 degrees and then adj the curb idle till it got back to 8

4. did #3 again

5. adjusted curb idle and the timing stayed on 8 degrees (.....here I got excited I gotta tell you!)

6. increased curb idle to 2000 and advanced timing 4 degrees

7. repeated #6

8. timing was finalized by putting curb idle to 550rpm while in "Drive" and timing was set at 8 degrees

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3 hours ago, signorc said:

this is weird....all is good with the electrical till i push the cigarette lighter in.  Then the courtesy light & clock stop.  no fuse blows. but when I move the #6 fuse it all resets and the lights and clock work again........till I push in the cigarette lighter again

422061246_ScreenShot2020-03-25at11_59_11AM.png.3c774a8f0394de07f6303f290b33dbcf.png1453715867_ScreenShot2020-03-25at11_59_52AM.png.2f837746197bd93ca2c25ea4d67c2867.png

 

To answer your questions Barnett: I have a stock camshaft but have NEVER been over 14inHg....so 16.5 is great.

When the lockdown here in Italy ends, I'll bring it for a drive and see what results I get by having changed the thick spring.

The results of the 9 step timing you sent me:

1. removed vacuum to dist

2. set to 8degrees

3. advanced 2 degrees and then adj the curb idle till it got back to 8

4. did #3 again

5. adjusted curb idle and the timing stayed on 8 degrees (.....here I got excited I gotta tell you!)

6. increased curb idle to 2000 and advanced timing 4 degrees

7. repeated #6

8. timing was finalized by putting curb idle to 550rpm while in "Drive" and timing was set at 8 degrees

These are not results. These are just the steps of the test.

I need to know exactly what the engine did as far as changing rpm and running smoothly or running rough when you advanced the timing.

The purpose is to run as much advance as the engine will tolerate. If the engine does not have enough timing, the engine rpm will increase as the advance increases until the engine gets as much advance as it should have.

Once the engine has as much advance as it should have, the rpm will either not increase much more if you continue to advance the timing, or the rpm will not increase at all, or the engine will start to run a little rough.

The higher vacuum at idle suggests that it did not have enough timing at idle if the engine rpm is the same at idle as it was before the test. If this is the csse, it is good, however, it still needs to be determined if the engine has enough advance at around 2000 to 2500 rpm or too much advance at that rpm,  or just the right amount of advance at that rpm.

Typically, it should have around 30 degrees of total advance at around 2500 rpm. If it only has 20, I can guarantee you it will run better at high rpm with more advance.

If it needs more advance at high rpm, you will need to check the position of the rotor in the distributor. There are 2 different positions it can be placed in. One position gives it more advance at high rpm only . Neither position will affect the amount of timing it has at idle.

Basically, you can set the engine rpm to around 2200 to 2500 rpm, then start advabcing the timing until the rpm stops increasing very.much as you give it more advance. In other words  the rpm may increase by 300 if you give it 4 more degrees of advance  but may only increase by 100 if you keep turning the distributor to give it another 4 degrees of advance. When this happens, it shows that 4 more degrees of advance is what it wants and 8 degrees of of advance is a little too much.

If you try this method, do it a few times, meaning that you leave the engine running, and retard the timing after each time after you advance the distributor until the engine finally no longer increases much in rpm. Basically slowly twist the distributor back and forth until you think it runs the best, then tell us how much advance it has.at high rpm and at idle. This info will tell us what you need to do with the distributor.

Also, again  you changed the wrong spring.

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thank you for the detailed explanation. i wouldn't be able to give you the results because I don't have a tach and did not record the results.  What I will do is change the spring and redo the test again.  why does the 1969 Ford Mustang manual say that it should have 16inHg? you and i both agree that it should have 18 but it doesn't. maybe i'll get there after redoing the test.

also, any suggestion about the fuse and cigarette lighter?

also (again), were you (are you) a teacher?  I was and gave it up.  you explain quite well and are very precise (which i like).

best, paul

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Quote

If it needs more advance at high rpm, you will need to check the position of the rotor in the distributor. There are 2 different positions it can be placed in. One position gives it more advance at high rpm only . Neither position will affect the amount of timing it has at idle.

Say what about 2 possible positions of the distributor rotor????

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56 minutes ago, Midlife said:

Say what about 2 possible positions of the distributor rotor????

In the example below, the mechanical rotor/advance unit is positioned in the 15L slot. This will provide more advance than the 10L slot. This rotor unit can be removed and rotated 180 degrees so it will then be in the 10L slot.

 

CpmHlItvtcZW7adTeYCqaWVzy8UxEuF7hmVtqQzJ

 

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1 hour ago, Midlife said:

Ahhh...terminology.  I was thinking of the actual rotor (the thingy that goes into the top of the distributor) having only one way to go in. 

Oh there's definitely more than one way the thingy can go in, and they even have books on the subject.

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I'm not sure if you have resolved your electrical issues, but if not: Fuse #6 should be 14A. Despite what your drawing says, It runs the following items (but you may not have all of these) map light, cigar lighter, clock, trunk light, and courtesy lights. The lighter takes the most amps in this circuit. Since the problem is when you push it in, either you have a problem with the lighter or perhaps the fuse is undersized. The lighter draws 5.6A so it should have 2.14 ohms- you can check it will an ohmmeter, or the socket may have a short. On my Mach1 the lighter is in the console and is fairly easy to get out. Stay well. I look forward to visiting your amazing country when this is all over.

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To Barnett: I replaced the springs. As you can see in the pic the 13L has the ticker spring and the 18L has the thinner one.  Is this the correct placement that you suggested?

To Mach1 Driver: The fuse on #6 reads "SFE 14".  Would this be different than a 14a?

20200326_201538.jpg

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43 minutes ago, signorc said:

To Barnett: I replaced the springs. As you can see in the pic the 13L has the ticker spring and the 18L has the thinner one.  Is this the correct placement that you suggested?

The thick spring is supposed to stay in its original location and you should use the original thick spring.

The original thin spring was the one I wanted you to replace with one of your new, thin, silver or blue springs.

 

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55 minutes ago, signorc said:

To Mach1 Driver: The fuse on #6 reads "SFE 14".  Would this be different than a 14a?

 

The fuse is good so it must be the lighter. If you have an ohmmeter check out the resistance. I found this on line: https://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=2&cad=rja&uact=8&ved=2ahUKEwj6uIW9j7noAhWEiOAKHZ9wDLIQFjABegQICRAB&url=https%3A%2F%2Fwww.cjponyparts.com%2Fmustang-cigarette-lighter-element-knob-set-1967-1969-installation-instructions%2Fa%2F408%2F&usg=AOvVaw3g9wJuqCny_t_ak0Av9D-D

 

 

image.png

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