OK, I attacked the issues today and here are the results:

Fuel bowl and filter: Clear, clean and good flow

Idle speed: 650+- measured on a Snapon Dwell/Tach meter

Timing (vacuum line off at carb and plugged going into distributor):
Originally was 8 (4 marks above 0 on balancer. Reset to 4 (2 marks above 0.) Set by using a Sun timing light (old, heavy relic)

Dwell: Was 32 but reset to 28 (using Snapon Dwell/Tach meter)

Coil resistance: I bought a new coil at NAPA and test resistance, 1.9 ohms. Old coil tested at 1.8 ohms. I did NOT replace original coil for 1/10 ohms difference.

Ceramic Resistor (mounted on engine side of fire wall). With the battery disconnected, the resistance was .8 ohms. The resistance on the new resistor from NAPA was right on spec at 1.9. I replaced the resistor because the material inside the wire coil was broken. The wire coil itself did not appear to be broken.

After doing the above adjustments and replacing the resistor, I ran the car with several starts and stops over approximately 15 miles of local driving and 30-45 minutes of driving time. Result was NO BACK FIRES. Additionally, the sound, the voice of the engine is different. It sound smoother. It never sounded bad, but now it does not have the same scratchy edge as before. Something I will keep in mind for the future.

OK, here is where I lay myself out naked before one and all. I know some will want to make fun of a 65 year old 'newby' but at least I am willing to admit I don't know much, but am willing to learn! So mock me as you will, but I hope the true HELPERS/TEACHERS will come through in the end.

1. What is the purpose/function of the ceramic resistor? How does it cause/affect backfire? I thought its function was to control voltage going to gauges, etc.

2. If dwell is set at the high end of spec's (32) and timing set at 8, how do either or both of these cause back fire vs. when set as 28 and 4?

And finally, to all the fellow uniformed veterans of CF, I say thank you and salute you for your service. GO NAVY! (from a Tin Can Sailor and SeaBee)

Regards,

Bob

 

My dad was a Tin Can Sailor, he's still active in the tin can sailor associations.

Thank you for your service.

 

I for one will commend you for asking questions, for I am in the same boat as you as are a lot of members here. There is no such thing as a stupid question if you don't know the answer. That is why I like this forum. Most of the guys here are there to help. There are a few who feel you should know everything already but they are few and far between. Keep asking and you will learn alot as I have.

Shemp

 

the resistor is called a ballast resistor and it lowers the voltage from the 12 volt system to the coil to 5-7 volts after the mill has started, while cranking, it is bypassed so a full 12 volt shot is used....

as far as your timing and dwell query, they are both related and after the dwell is set the timing should also be set or reset......it sounds like at first blush, with a cracked resistor you were not getting enough voltage or intermittent voltage to the coil for optimum performance in the secondary side of the ignition....i do not know what timing specs are correct for your engine but it must be set with the vac can hose removed and plugged for initial timing..then plug it back in and you should see over 14 deg of advance or a higher number depending on the vac can at an idle....i hope you found your problem..good luck...

ps...don't be surprised if your coil is bad....you can test them all day with a meter but i have seen a coil that tested ok be a dud in real world running..jmo

 

My 62 Owner's manual says 8 degrees advanced at 475 RPM for a Powerglide. It doesn't discuss the specs for a standard.

 

You say,Timing (vacuum line off at carb and plugged going into distributor): It should be off at the distributer and plugged going to the carb. You don't want to set your timing with a vaccum leak at the carb.

 

With the vacuum line plugged going to the carb, you should have something like 4-8 degrees. When you reconnect the vacuum hose to the distributor, you should have about 24 degrees of timing. If you still have 8 degrees, then either your can is defective, the wrong one, or your not connected to a manifold vacuum source. At idle, when you pull that hose off of the vacuum can, your idle rpm should drop, and the motor will idle rough, or stall. As Midyear said, always set your dwell before your timing. You then can mess with the timing all you want, and it won't change the dwell. However, if you set your timing, and then mess with the dwell....it will change your timing. Keep us posted.

 

Agree.

 

Thanks to all for continued help. We are heading out of town and will not be back until late Sat. I will re-do timing and remove vacuum hose from the distributor and plug going into carb.

Several put in comments on coil testing. I tested my coil against a new one. The DIFFERENCE in ohms is .1 (One coil read 1.8 and the other 1.9) I did not consider this significant and reinstalled by original coil. As I indicated yesterday afternoon, the car drove very well and did not have any backfires. Should I install this new coil now or keep in ready stock for the future?

Finally, for now, what do you recommend should be in the first aid kit for Ol' Red that is kept in the trunk for on road emergencies?

Points
Plugs
Condenser
Rotor
Cap
Coil-?
Ballast resistor-?
Fuel filter
Tools to install any of the above.

Thanks again. I will report results of timing changes late Sunday

Bob

 

Looks like a good first aid kit, hold on to the coil to see if the problem comes back up. Sometimes coil intermitent problems are temp related.

 

Bob, Given all that you have done, I'm guessing it's your distributor. Before you try and set the timing and dwell, check the distributor inner shaft for play (wobble back and forth) and vertical movement. Either condition will cause the points to operate erratically. I had a 67 GTO with a worn inner bushing that allowed the shaft to wobble on acceleration and deceleration and cause a backfire or noticeable miss. It can drive you nuts! If there's too much clearance in the inner shaft bushing, the shaft will open and close the points erratically depending upon the load on the shaft. This will cause plugs to fire out of sync with the actual rotation of the engine. Good luck.

Mark

 

Might not need to carry the plugs but the rest are a good idea and they basically will fit inside the cap for storage.

 

A famous Corvair malfunction. They will start and idle but lack enough power to even move the car.

SOP on my Corvairs is a new dist. housing in the first batch of parts ordered.

 

Update:

I re set dwell, timing and idle speed. I removed vacuum line from distributor and plugged the line (not the distributor).

Dwell = 28
Timing = 4 deg
Idle sp = 575

If I hand accelorate engine to approximately 1,500 rpm, the timing advances to approximately 2 marks past last one on indicator.

Book calls for dwell of 28 to 32. I can set engine to any of these degrees. What is the significance of setting at 28, 30 and 32? Is this just a range or is there a time when one would be better than another?

What is the benefit of a timing advance of 4 deg, 6 deg and 8 deg when engine is at idle? When is one better than another?

No backfire since re-setting timing earlier last week and replacing ballast. So, to all who contributed.

Regards and a to our uniformed vets.

Bob

 

good news, glad the backfire is gone..i think you should play with your timing a tad.....try going up 4 more deg. adv., and take it for a ride, it may wake it up.....listen for detonation and you know you went too far.....jmo.......

ps.... the dwell figures are just a range for good coil saturation, optimum spark and point life...28-32 is fine.....

 

Everyone is thinking timing..It could be excess gas..running rich ..gets into the exhaust manifold and ignites. Anothe cause could be a burnt exhaust valve. Did you do a compression test? My best guess...

 

the backfiring is already fixed....were' just trying to dial it in a little better....

 

I have not done a compression test. Since the back fire was originally intermittent and now seems to have gone away after replacement of resistor, would doing a compression check tell us anything? If an exhause valve is burned or even slightly burned, would the back fire have been more frequent?

 

a compression test would give some indication of the condition of the mill and would show a bad valve although i think you are fretting over nothing..a leak down test is a better barometer....i suggested more timing to maybe give you better performance.....you could also re curve the dizzy....

 

OK, understand not doing a compression test.

Pls explain your suggestion 'recurve the dizzy'. Is this just another way of saying to advance the timing 2 to 4 deg as previously suffested?