Something new everday at Bubbas??

BUBBAS IGNITION

BUBBAS IGNITION

Well-known member
Something new at Bubbas every day. We have done quite a few hundred of the 42-46 crab distributor and thought we had heard and seen everything. Customer called me a few weeks ago having a problem with a crab unit we had built 7000 miles ago. Car had ran well for a long time and then was running rough etc. A spare distributor fixed the problem! Wanting to see one of our rebuilds after 7000 miles of happy driving i asked him to send it in.
Got it yesterday and inspected it this morning.
WOW it has a shorted rotor button!!! Over the years there were quite a few factory units from different oems that sometimes had rotor blow thru but never a crab that i had seen. Inspection shows rust under rotor and splash voltage marks top and bottom. Been sparking direct to ground!!!
NOW what would cause this??? and the answer is "cheap rotor" ( Been pretty quality NAPA/Echlin unit , maybe but i doubt it. ) OR:

1- Open coil wire , the open gap in the coil wire would step up the required voltage making it higher than ever ! A bad connection at the coil or cap would do the same thing.
Old gas station trick to start a flooded car was to loosen the connection at coil wire , leaving a gap and then try to start the car , worked like a champ...

Beats me but i will ask customer to check the coil tower and connection as well as the coils condition etc.

Will replace the rotor, clean and adjust/replace points on a machine and return to customer .

Along with some dielectric gel for connectors etc .:eek::eek:

Connection from cap to carbon button checks good !!!
 
"Will replace the rotor, clean and adjust/replace points on a machine and return to customer ."

Now THAT'S away above & beyond ! I've never heard of a warranty on an electrical unit, especially after 7,000 miles and when the culprit was a vendor supplied part. Lots of thumbs up (and I'm ALL thumbs!) to Bubba !!
 
How about some pictures???
 

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Hey Jim: I've done a lot of work with high energy ignitions (mags, MSD, ProMags, etc). The rotor tang and conductor on your picture sure looks like something was getting really hot - like maybe the coil wire was not all the way in and it was arcing and heating up the cap and rotor.

Would also be interesting just to check the air gap for the Hell of it between the rotor and the cap terminals - because it seems that for some reason it was "easier" for the spark to jump through the rotor (into the shaft), then it was to jump the rotor air gap and spark plug gaps. You might also check to see what coil he was running, what type of plugs and the plug air-gap. Could just be a bad rotor, but I've only seen this type of stuff when there was another 'lurking' issue that I needed to know about.

Side Note: A couple years ago I didn't "time/clock a rotor" correctly on a crank-trigger driven juiced up magneto setup at Bonneville . . . cost me a record in that it fried the rotor at the starting line of my backup run (next morning) -- learned a lesson the hard way on that one! Too much air gap - caused a big-*** spark and a meltdown!
 
Let me see if I get this. A coil wire not all the way in the terminal will cause rotor melt down. I ask because I just had rotor melt down on an original crab distributor and i am trying to figure out why.
 
I had the tower for the coil wire on the distributor cap on a 8BA MSD unit disintegrate for what was probably the same reason. What fails probably depends on where the easiest path for the stray electrons is.
 
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I've had 1 or 2 crab caps fail between one of the terminals and the wire clips that hold it on. I also had a rotor just like that where it had blown through to the shaft. I will also look at the ht side of the coil, and make sure all is hunky dory.

I also make sure the plug gaps are set not too wide. .025 max for me.

Mart.
 
Hello, the distributor that Jim is working on came off my truck. 7,000 mile 239c.in., Max-1, single 94, Fentons. After over coming a few initial start up problems, the motor would fire up at the touch of the starter button, as the miles accumulated it got harder and harder to start and there was a noticeable stumble when accelerating(i thought it was the carb). I changed the dist. With another Bubba's dist., starts easy and the truck accelerates smoothly. The plugs were gapped @ .025", so maybe it was the HT lead(just checked both ends now) or rotor to cap dimension or defective rotor. I know when Jim gets finished with it, it will be 100%.
Tom
 
Bored&Stroked said:
Hey Jim: I've done a lot of work with high energy ignitions (mags, MSD, ProMags, etc). The rotor tang and conductor on your picture sure looks like something was getting really hot - like maybe the coil wire was not all the way in and it was arcing and heating up the cap and rotor.

Would also be interesting just to check the air gap for the Hell of it between the rotor and the cap terminals - because it seems that for some reason it was "easier" for the spark to jump through the rotor (into the shaft), then it was to jump the rotor air gap and spark plug gaps. You might also check to see what coil he was running, what type of plugs and the plug air-gap. Could just be a bad rotor, but I've only seen this type of stuff when there was another 'lurking' issue that I needed to know about.

Side Note: A couple years ago I didn't "time/clock a rotor" correctly on a crank-trigger driven juiced up magneto setup at Bonneville . . . cost me a record in that it fried the rotor at the starting line of my backup run (next morning) -- learned a lesson the hard way on that one! Too much air gap - caused a big-*** spark and a meltdown!
Click to expand...


YEP to all the above.......:eek::)
 
hotcoupe said:
Hello, the distributor that Jim is working on came off my truck. 7,000 mile 239c.in., Max-1, single 94, Fentons. After over coming a few initial start up problems, the motor would fire up at the touch of the starter button, as the miles accumulated it got harder and harder to start and there was a noticeable stumble when accelerating(i thought it was the carb). I changed the dist. With another Bubba's dist., starts easy and the truck accelerates smoothly. The plugs were gapped @ .025", so maybe it was the HT lead(just checked both ends now) or rotor to cap dimension or defective rotor. I know when Jim gets finished with it, it will be 100%.
Tom
Click to expand...


UPS picked it up yesterday.........on the way....:eek:
 
Jim, the distributor was delivered yesterday, it looks terrific and i'm sure it will function as good as it looks. What you did was above and beyond, Thank you!
Tom
 
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