Crab-ie patties ??? Ford Distributor

[BUBBAS IGNITION]

After doing the helment distributor build i was asked to do another post on the two bolt, got one in today from a 1948 Ford and got er done tonight with some helpfull pictures....
Going to try to load all pics and then discuss...

A qick dip in our Cuda water jet machine at 185 degrees get the basic crud off the distributor.
Take all parts off , the inside was nasty with crud and what was left of the leather vacuum brake assembly. ( hadnt worked for years !!)
Cam assembly has a small and a large snap ring remove and clean and polish the rusty areas etc.
Relube with spray lube , be carefull here as some lubes are too thick and will set up pretty stiff. I like the liquid wrench product...
Just clean er up and reassemble the unit....
I like the VHT temp paint goes on really thin after cleanup and drys fast and nice "almost orginal looking" ..

 

[BUBBAS IGNITION]

Almost got all twenty , hate those "time outs "...
Napa CS47 contacts, lubed up good . " I soak them in marvel oil for days, seems to prevent premature wearing on the cam blocks ??"
Note , this set wouldnt adjust on one side had to bend and realight the contact bottom to get the setting i wanted . .016....
Now on the machine ( more about actual testing below).
The leather belt is where i get my leather for the vacuum brakes ( also soaked in marvel for days)
As this custome rhad some interesting problems i checked his coil and the distributor with lab scope , current probe and secondary waveforms etc.....

 

[BUBBAS IGNITION]

And this one takes some explanation !! Interesting stuff here for all !!

The blue line is a low current probe watching the build up, rise and fall of the primary ignition current.
The red line is the secondary ignition( spark) waveform of the distributor and the spark actually jumping the spark gap.
We are testing a 3.5 ohm coil with all internal resistance ( my favorite for these cars) and the coil rise time is handled as a factor of design ( resistance ) and allowed time etc. The current is peaked at 2.3 amps using a 12 volt battery at 12.2 volts.
The coil shows a good clean build up an a clean cut of at end with a very consistant drop .
No problems ....
The red shows a spark line ( upward) and averages 9,000 volts ( i am using a adjustable spark tester and have it adjust for a 3/8 inch gap). The spark line ( horizonal line) indiactes the spark stepping of the gap and jumping to the other side. The almost flat line shows no real problem in getting this duty done. A upward/downward sloping line would show resistance at the plug gap in regards to spark requirements etc.
The ocillations show a diminishing magnetic field with the coils final spark and once again show no adverse ignition coil problems as well.
The small ocillations at the end is the contacts closing for coil saturation and the upward line at the end ( spark line again) shows a good clena off signal as well.
I use a very good .40 mfd condensor for these systems and this area is where a defective or weak condensor would show up.
This unit was ran for a hour or two this afternoon with the lap top based on customers problems over the last couple years.
Looks great to me.....
This tes was done at approx 2000 rpm and the coil needed 20.56 ms of buildup time at idle to fire the plug etc. ( example : A new 2009 Ford Focus fires the plug three times in 2.6 ms !!!!! at 7.5 amps !!!)

Questions any one ?????? Always glad to help... Bubba

 

[jdl]

Great info & pics. Thanks for posting. you do great work!

 

[JM 35 Sedan]

Hey Bubba, that's one very nice Tech job on the '48 distributor. That one will definitely get downloaded into my saved files if you don't mind.

 

[JWL]

I do not see that the wick material has been attended to?? Any rebuild should include a proper cleaning or replacement if long term service is the intention.

 

[Matt in Alameda]

Outstanding report Bubba,...thank-you very much....Matt in Alameda

 

[BUBBAS IGNITION]

I do not see that the wick material has been attended to?? Any rebuild should include a proper cleaning or replacement if long term service is the intention.

I didnt take any pics of the wick material, i will add those as thats the magic that makes these old crabs live forever. I usually just clean with brake clean , oil and replace.
Good catch.......

 

[RBaker]

Your post will really come in handy for me and other members here, thank you!

 

[jerry grayson]

Almost got all twenty , hate those "time outs "...
Napa CS47 contacts, lubed up good . " I soak them in marvel oil for days, seems to prevent premature wearing on the cam blocks ??"
Note , this set wouldnt adjust on one side had to bend and realight the contact bottom to get the setting i wanted . .016....
Now on the machine ( more about actual testing below).
The leather belt is where i get my leather for the vacuum brakes ( also soaked in marvel for days)
As this custome rhad some interesting problems i checked his coil and the distributor with lab scope , current probe and secondary waveforms etc.....

How do you handle the vacuum seal on the back of the unit?

 

[JM 35 Sedan]

I didnt take any pics of the wick material, i will add those as thats the magic that makes these old crabs live forever. I usually just clean with brake clean , oil and replace.
Good catch.......

Bubba, I'll be watching for the addition of the wick info so I can download that to everything else on this post that I have already downloaded in a separate file for easy ID and retrieval.
Have you ever done a tech write up on rebuilding an Harman & Collins Model 14 dual point, dual coil distributor? I'm getting ready to tackle one now and could sure use some guidance. Let me know if you can help on that one.
Thanks again for for putting this post up for everyone to learn from.

 

[rotorwrench]

Graphing the oscillations really shows how the capacitor builds a charge and then discharges with the corresponding inductive reaction of the coil. Some folks have said that the spark from the coil lasts as long as the condenser is discharging but that graph shows that is peaks instantaniously then just oscillates with the current flow until the points close. The condenser charge sort of deflates like a balloon. If you took the condenser out, the secondary voltage peak would look a lot different. Most likely very weak and erratic.

Thanks for posting this.
Kerby

 

[hbleadsled]

BUBBAS IGNITION after seeing all you do in rebuilding the ford distributor ,I would send my dist. to you for a rebuild for sure ,thans for posting,great photos .Harold central coast Ca.

 

[Tim Ayers]

Bubba did one for me as well. The bonus was the awesome hot sauce included in the box!

 

[BUBBAS IGNITION]

How do you handle the vacuum seal on the back of the unit?

I replace the oring with a new oring if the old one is defective..on this one it was ok.
Another good point as many of the vacuum brakes are inop ( this one was ) and the owners have no idea what that does to the engine etc........

 

[BUBBAS IGNITION]

JWL has a really good point that i missed in the build.
The crabs have a hollow shaft and engine oil can wick ( small amount) thru the threads in to a wick . This would allow a slight amount of lube to be "wicked" to the outter bushing.
I cleaned the wick with brake clean dryed it off and soaked it in marvel mystery oil. Then reasembled the unit and screw...........

 

[Bruce Lancaster]

And...if you clean the innards without addressing the wick, the wick will still be saturated with dirty solvent when you reinstall the shaft. The solvent will emerge more rapidly than oil would go through and deposit mysterious dirt. And it will be a while before the forward bushing sees anything resembling oil.

 

[BUBBAS IGNITION]

And...if you clean the innards without addressing the wick, the wick will still be saturated with dirty solvent when you reinstall the shaft. The solvent will emerge more rapidly than oil would go through and deposit mysterious dirt. And it will be a while before the forward bushing sees anything resembling oil.

I agree Bruce , this one was nasty with rusty residue from oil fumes etc. The end hole was stopped up , had to use a piece of small wire to clean out the shaft hole....l

 

[BUBBAS IGNITION]

Kinda a finish to the build above.
Customer drove the 48 Ford to the shop today with the distributor installed, he had a small pop in the exhaust. A quick uncrossing of two plug wires made it right.
I also built him a Holley 94 when i did the distributor , may write up a couple of those builds as well in the future. Rebuilt the carb and ran it on my test engine ( 1951 Chevrolet 235 on a stand). Adjusted it and checked the flow with flow meter etc.

Nothing starts like a flathead in proper tune!!!!!

 

[JM 35 Sedan]

Bubba, any words of wisdom on rebuilding a Harman & Collins distributor? Reference my question on post #11 above in this thread from yesterday. As you say "If it Makes Spark, you do it" So I'm hoping you have some good pointers on doing an H&C. Thank you!