Technical Distributor wobbling with engine running, seems weird...

I have a built 347 small block Ford using a Pertronix HEI III distributor. That thing is pretty top heavy but still, with the engine running, distributor hold down good and tight, the distributor has a noticeable wobble.

I've never seen this before, I'm wondering if it's a problem; I'm mostly worried about the gears meshing between the dist and the cam. I have no misfires that I can detect, or anything like timing jumping etc.

Thank you for the help

 

Does the whole distributor wobble or just the cap? If it is your cap, check for rotor contact on the inside of the cap. If it is the whole distributor, your hold down bolt is most likely bottoming out in the bolt hole before it is putting clamping force on the hold down.

Good luck, -Abone

 

The whole thing wobbles :/
That's the thing though, the bolt isn't bottoming out (I've tested it without the hold-down clamp on and it threads fully in)

 

Set up a dial indicator on the housing and rotate the engine by hand. If indeed it is wobbling, I would say either the housing does not fit in the block well, or the shaft is bent.

 

@BamaMav got one for his 302 that did the same thing. don't know if it was a pertronix or not but is a hei. took it out sent it back and got another, no problems after that. i hope i remembered that right.

 

Jimbo, also check that the drive gear is bored on center. We had one that did that, and the gear was off center. Would have eventually wiped out a bunch of stuff. Mike

 

I put a HEI converted distributor in my 235. Wobbled like hell. Pulled it apart and the shaft had a “wow” in it.

Won’t know till you pull it and take it apart.

 

@AccurateMike how would I check that the gear is on center?

@Budget36 I'm sorry I'm still wet behind the ears with hot rodding, what's a "wow"?

@Elcohaulic The HEI was recommended to me by someone more experienced :/ I also wanted a simple, no coil setup.

I'll try to pull it and get a few pictures, see if that helps

 

Both the stock points distributor AND the Pertronix have a distinct wobble in my Chevy 250 inline. I've checked everything and still wobbles,,,so I'm running it till she pops. Good luck, Mitch.

 

If your "hold down" is snugged down well, try and 'wobble' the distributor with your hand. If it doesn't, you can eliminate that from the possibles.
Next, pull the distributor and strap or clamp it down horizontally on your workbench. Turn the shaft and eyeball the bottom gear to see if it oscillates at all. You can also set an object on the bench lightly kissing the gear, then turn the gear/shaft to see if you have a gap between your gear and the reference object that opens and closes with each revolution.
If you can see an obvious problem, since it's "new", don't fix it..... exchange it.
Good luck and have fun spending some quality time in the shop.

 

Jimbo, it was a Pertronics for a SB Ford. We pulled it to check the shaft and the gear was visible to the eye. We took it off the shaft and it was .040" off center. We had another gear and just swapped it out. I think Mitch might have a cam gear issue. I have seen both gears all wiped out and knife edged from bad mesh issues. Hi-vol/hi-pressure oil pumps and thick oil can aggravate this. Bad alignment between oil pump and distributor can happen too. Not as likely to cause a wobble on a hex as a slot though. Mike

 

Love this forum, thanks so much for the input!

I'll do all the checks and report back. Any chance at all this could have damaged the gear on my roller cam? I really don't want to have to pull it....

 

I was leaning toward the cam gear, the engines got 60,000 + original on it so its just a matter of time. Jimbo, I hope you can get this fingered out . Mitch

 

Sounds like a bent shaft in the distributor to me.

 

Jimbo..

Don't know where you are located..
I'd be happy to spin it up in my distributor machine for you.
I live in the Boise area..

Dave

 

Mine is one of the small cap HEI off of eBay. Like Odie said, my first one danced a jig. Contacted the seller and they sent another, it works perfectly. I think the first one has a warped shaft, I kept it for spare parts.

 

Will a bent oil pump driveshaft cause this ?

 

It’s possible,,,,but most likely the distributor,,,,,something machined off center,,,,or a bent shaft .
Things sometimes get out of hand in assembly,,,,,dropped,,,walked over,,,even run over .
Yes,,,that does happen sometimes ,,,really !

Tommy

 

@Jimbo Nettles a “wow” is just a term used for a long bend, not straight anymore.

Speaking of dropping stuff…

Was writing some numbers down after mic’ ing some bearings, I heard a “clunk/clang” turned around and took a step. Seems my bore gauge fell off the block, landed cocked on the engine stand leg.
No, it didn’t support my weight when I stepped on it…

 

@dave lewis very kind of you! I'm in South East Texas though... I did find the problem however, followed advice here and chucked the distributor in a vice, rotated it and.... Bent shaft :/

Thanks everyone for the help. I just hope it didn't mess up the cam gear too bad.

 

i bought a dizzy for my 318 dodge motor off of egay and it wobbled too. i just went and bought a rebuilt one from Autozone and put a Pertronix in it. works fine. never looked at the other dizzy and don't care. cheap chiny junk.