81 FJ-40 - Hesitating / bucking under acceleration (2 Viewers)

[pb4ugo]

Following/ Watching...

I've got the same problem, but have not started the process of investigating it. My problems started after a mechanic "fixed" / changed the breaker in my distributor. Its never been the same...

My thought process :

1. Change the vacuum piping from the Carburetor. Just noticed it is fairly loose, dont think its doing anything. I will try to put a gauge on it.
2. Check the distributor cap / electrodes and the "coil" inside.
3. I also have some concerns on the fuel pump; might change it. Same mechanic put that doubt in my head, but I dont trust him. I will change the fuel filter first; that's a easy fix.
4. Check / adjust spark plugs, valve spacing; then do a compression test.

If he just replaced the points, I'd 1st check the dwell, then go from there. Timing, idle mixture, etc. I wouldn't mess with stuff he didn't touch.

 

[AYM707]

If he just replaced the points, I'd 1st check the dwell, then go from there. Timing, idle mixture, etc. I wouldn't mess with stuff he didn't touch.

sorry, but what's the dwell?

 

[pb4ugo]

It's an electronic way to adjust the points. You'll need a dwell meter. It's a more accurate than using a feeler gauge. The point gap effects timing.
Spark is generated when the points open.

 

[MatthewMcD]

sorry, but what's the dwell?

Dwell is the measurement of the angle that the points are closed. For a '40 2F it's 41* (+/- 1*). It's another (more accurate) way to measure the impact of points gap.

 

[pb4ugo]

I've set points many different ways. When your in a pinch you'll use anything handy or by sight. Use the old match cover if you can find one or you could use a test light. Adjusting points by Dwell is my preferred way. Hookup the meter crank the the starter and adjust the points. Or go with some sort of hei.

 

[ceylonfj40nut]

I've set points many different ways. When your in a pinch you'll use anything handy or by sight. Use the old match cover if you can find one or you could use a test light. Adjusting points by Dwell is my preferred way. Hookup the meter crank the the starter and adjust the points. Or go with some sort of hei.

Also a cheap regular business card

 

[charliemeyer007]

What ever works for you. You need to check/set valves and breaker points, a set of feelers gauges is cheap enough to leave a set in the glove box. I grease penciled the #'s on the inside of the hood along with the last dry compression check

 

[pb4ugo]

Back in the day, when I was knee deep in a water hole with a wet distributor and drying out the points, I'll use anything.

 

[Chungas Revenge]

@pb4ugo
“When you’re in a pinch you'll use anything handy or by sight. Use the old match cover if you can find one.”


Hoss, I don’t know how to tell you this but, “we’re” old.

 

[65swb45]

@pb4ugo
“When you’re in a pinch you'll use anything handy or by sight. Use the old match cover if you can find one.”


Hoss, I don’t know how to tell you this but, “we’re” old.

 

[AYM707]

Dwell is the measurement of the angle that the points are closed. For a '40 2F it's 41* (+/- 1*). It's another (more accurate) way to measure the impact of points gap.
View attachment 3874122

Using a multimeter, my dwell is at 36 degrees.

It appears the only way to adjust it is trail-n-error. What feeler gauge thickness should I use?

 

[MatthewMcD]

Using a multimeter, my dwell is at 36 degrees.

It appears the only way to adjust it is trail-n-error. What feeler gauge thickness should I use?

You need to increase decrease the gap. Measure the current gap and add subtract a few thousandths. You can run the starter and measure the dwell without starting the engine.

Edit: Fixed

 

[pb4ugo]

This is sort of hard to describe. Take the cap. Rotor, and dust cover off, so the points are exposed. . Get 2 screwdrivers. Leave the dwell meter hooked up. With one screwdriver loosen the screw holding the adjustng side of the points to the plate. Loosen it enuff so there's a some resistance during adjusting. Use the other screwdriver to adjust the points. Have someone crank the engine while you are watching the meter and you are adjusting the points. Once you get the desired reading tighten the screw holding the points to the plate. I usually keep one screwdriver on the screw holding the points while adjusting the points with the other. It might take a bit of practice, but that's how it's done.

 

[65swb45]

You need to increase the gap. Measure the current gap and add a few thousandths. You can run the starter and measure the dwell without starting the engine.

Negative. Decreasing the point gap increases the dwell.

It also increases the rate at which the points will burn.

Try a point gap of.015”.

For general reference, If you get down to .012 or less to get dwell within tolerance, it’s time for a new distributor…or an electronic ignition conversion.

 

[MatthewMcD]

Negative. Decreasing the point gap increases the dwell.

It also increases the rate at which the points will burn.

Try a point gap of.015”.

For general reference, If you get down to .012 or less to get dwell within tolerance, it’s time for a new distributor…or an electronic ignition conversion.

RIGHT! My bad, I was looking at the image I posted and failed to read that they are adjusting the Rubbing Block Gap.

 

[AYM707]

This is sort of hard to describe. Take the cap. Rotor, and dust cover off, so the points are exposed. . Get 2 screwdrivers. Leave the dwell meter hooked up. With one screwdriver loosen the screw holding the adjustng side of the points to the plate. Loosen it enuff so there's a some resistance during adjusting. Use the other screwdriver to adjust the points. Have someone crank the engine while you are watching the meter and you are adjusting the points. Once you get the desired reading tighten the screw holding the points to the plate. I usually keep one screwdriver on the screw holding the points while adjusting the points with the other. It might take a bit of practice, but that's how it's done.

Negative. Decreasing the point gap increases the dwell.

It also increases the rate at which the points will burn.

Try a point gap of.015”.

For general reference, If you get down to .012 or less to get dwell within tolerance, it’s time for a new distributor…or an electronic ignition conversion.

So I finally got some time to pull apart the distributor...and overcome my fear.

I am assuming screw 1 is the locking screw while screw 2 is the adjusting screw. I tried to turn the engine to maximize the gap but struggled to get it at the maximum opening ( the top of the point for the cam). I did check the gap, in most cases it appeared smaller than 0.015 in; ie the breaker was pushed out when I inserted the feeler gauge in.

@65swb45 - you mentioned I need to decrease the gap to increase the dwell angle.

Can I adjust the dwell without manually positioning the engine at max opening? just using a dwell meter?

I also want to clean the distributor cap & sand down the connector points and the top of the rotor. there was a lot of carbon / roughness there.

 

[pb4ugo]

Screw 1 holds the points to the dist plate, it should be tight. It's the stationary side of the points. If your going the adjust the points with a feeler gauge you must have the points rubbing block on the high point of the dist cam. You can use a wrench on the crank, or try to use the belt to rotate the engine, or put the vehicle in 4th gear and rock the vehicle to rotate the engine.

Screw 2 is loosened to adjust the point gap. In the pic below I circled about where there's a slot for a straight blade screw driver to fit and allows you to adjust the adjusting side of the points. Its hard to tell where the notch is in your pic, because of your circle and residual grease. There's a slight notch on the edge of the adjusting side of the points and a corresponding raised portion or notch on the dist plate to sort of pry/twist with the blade of the screw driver. Loosen #2 so there's a slight resistance in moving the points and use the slotted screw driver to move the adjusting side of the points. If you use a dwell meter, have some one crank the engine while your adjusting the points. You'll have 1 screwdriver on #2 screw and 1 slotted screw driver on the adjusting notch and you'll be watching the dwell meter. Once you have adjusted to the desired dwell tighten the #2 screw. Then remove the screwdrivers and crank the engine to confirm the dwell is where you set it. Then start the engine and confirm once again.
By the way, your screws are in pretty bad shape, you might want to go to ACE hardware or somewhere and find replacement screws. ACE usually have a pretty good assortment.

 

[AYM707]

I'm jumping back on this after a few weeks of "other" things.

I did do some preliminary investigations; opened it up, cleaned / sanded the copper connectors. I have also increased / overcome my fear with "playing" with the distributor. I also experimented with starting / turning the engine with the distributor open / disassembled. Problem is the dwell meter is always reading. When the engine is off, the meter shows ~60 degrees, but when you start / turn the engine, it drops to 36 degrees. This means....this is a 2 person job.

My distributor cap is also chipped where the cable #4 connects. Not a big issue, but ordered a replacement.

@pb4ugo / @65swb45 / @MatthewMcD

I re-read all the threads, so just to confirm what I'm doing one last time...my dwell angle is 36 deg and I need to increase the angle to min 40/41 deg. This means I have to decrease the gap; ie using a slot screwdriver in the slot near screw 2; move the points slightly closer to the cam shaft. I am assuming this is a hair's width adjustment.

Gap decrease = dwell angle increase?

Apologizes, I'm asking baby steps; but dont want to screw this up. Appreciate your confirmation / support.

 

[pb4ugo]

Yes, typically it's a 2 person event. It takes a little practice, because you have to watch the meter and adjust without looking at what your doing.

 

[MatthewMcD]

move the points slightly closer to the cam shaft.

With the points rubbing pad on the peak of a cam lobe the gap is opened. Decreasing that gap will increase your dwell.