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offset on dizzy gear

Posted: Wed Feb 15, 2012 10:38 am
by chitwnvw
What is the function of the offset on the dizzy gear and the way it meshes with the bottom of the dizzy? If I follow the Bentley and get my 12% angle will that then give me a rotor that points roughly at cylinder one when it is at top dead center? I mean is the purpose of that offset to get the plug wires in a good position. Because it seems to me that no matter where you put that gear that its purpose is to spin once for every two crank turns and so allow a spark ever 90 degrees of turning, and you really could put it in any way you want and find TDC #1, turn the dizzy body so that the rotor points to your notch in the body and you would be ok. Just curious...

Re: offset on dizzy gear

Posted: Wed Feb 15, 2012 10:47 am
by sped372
Think about the vacuum can on the side of the distributor...

Re: offset on dizzy gear

Posted: Wed Feb 15, 2012 11:39 am
by chitwnvw
sped372 wrote:Think about the vacuum can on the side of the distributor...
Do you mean that if you don't have a great enough angle on that offset, that the vac can will bottom out on the fan shroud and you won't be able to turn the dizzy enough to line up the rotor with the tdc #1 notch? 8-[

Re: offset on dizzy gear

Posted: Wed Feb 15, 2012 12:45 pm
by RSorak 71Westy
The only thing to think about is if the vac can doesnt hit anything in the needed range for timing adjustment. Besides this anything goes as long as it set to fire on #1 and the rest of the wires are positioned to follow suit in the proper order.

Re: offset on dizzy gear

Posted: Wed Feb 15, 2012 8:31 pm
by SlowLane
Well, there's also Bob Hoover's piece on distributor orientation to consider: http://bobhooversblog.blogspot.com/2006 ... an_24.html

Feel free to form your own opinion. Some folks don't think that matching the oil groove with the oiling window is all that important and say they've have had years of running successfully with a mis-aligned groove. Personally, I think Bob "knew his onions" far better than I do, so I put up with having my vacuum can crowd the cold-start valve just to make sure that the dizzy oiling groove is properly lined up with the window.

Re: offset on dizzy gear

Posted: Thu Feb 16, 2012 5:37 am
by vdubyah73
yep the orientation is about oiling the dizzy, enough room for the vac advance to rotate is secondary. you do have some wiggle room built in. if you are a bit off you may have enough wiggle room to time it anyway. if you run out of room to time it but you are soooo clooose, you can, but not always bump your plug wires one nipple and still have oil. ya gotta study the crankcase oil passage orientation to the dizzy's oil passage. the passage in the case is shaped to provide oil to the dizzy in a range of postions within an arc of movement to allow proper timing. you can be one nipple off on the cap and still have oil if the oil passages still line up when timing is set.

Re: offset on dizzy gear

Posted: Mon Feb 20, 2012 6:12 pm
by ruckman101
Dang it, ya got me in a panic, but whew, drive done right.


neal

Re: offset on dizzy gear

Posted: Mon May 27, 2019 10:19 am
by Sawspa
I had to turn my pertronix flamethrower distributor until the vacuum can was on the opposite side of the csv from the factory placement of the can. Not sure if the oil passage still lines up after timing, but its got to be close. Thank you all for this thread. I had no idea about the oiler holes..

Re: offset on dizzy gear

Posted: Mon May 27, 2019 3:55 pm
by Amskeptic
Sawspa wrote:
Mon May 27, 2019 10:19 am
I had to turn my pertronix flamethrower distributor until the vacuum can was on the opposite side of the csv from the factory placement of the can. Not sure if the oil passage still lines up after timing, but its got to be close. Thank you all for this thread. I had no idea about the oiler holes..

Why? You can rotate engine until #1 is TDC with rotor facing your current #1 spark plug wire

loosen distributor clamp and move distributor in discrete 90* movements until the can is lined up with the breather bale (I think you have just one 90* movement counterclockwise). The distributor rotor will still be exactly where you found it. But now, you must get the cap on, and it will require taking the wires out and moving them one position back so #1 is still directly at the rotor position under the cap, then 4-3-2 around the circle, time, and yer done.
Colin

Re: offset on dizzy gear

Posted: Mon May 27, 2019 5:34 pm
by Sawspa
Thats what I did. It put the vacuum can to the left of the csv. I did it that way so the oil hole in the side of the dizzy shaft, just below the seal, lines up with the oiler hole in the distributor hole of the engine. As explained in bob hoovers blog. Yes getting the cap on was hard. Also i stuck points in my new pertronix dizzzy. The pertronix module kept sputtering terribly when it got to full temp.

Re: offset on dizzy gear

Posted: Mon May 27, 2019 6:38 pm
by Amskeptic
Sawspa wrote:
Mon May 27, 2019 5:34 pm
The pertronix module kept sputtering terribly when it got to full temp.
Was it a new purchase or an old Pertronix you had laying around?
Colin

Re: offset on dizzy gear

Posted: Mon May 27, 2019 7:01 pm
by Sawspa
I had purchased a new pertronix module to put in my stock bosch 205p distributor. It worked great on 5 minute trips. I took it to a car show that was a half hour away. Again, it worked great. After the show I drove another 40 minutes and when I pulled off the freeway it would idle ok but when I pulled out in first gear, it was all stumbles until i was able to get it up to speed. Next day it did the same on the way home. (1hr). I had then discovered my vacuum advance can held zero vacuum. So, after reading about how much those cans can be, i just decided to get a new pertronix distributor with a new module preloaded. I adde grease to the new distributor in a few spots( no instructions) and installed the dizzy. I am not sure of the first way i had it in but I was able to get the motor timed. Again, it ran great until it got hot. Then stuttered all over itself. For shits and giggles I put my points back in it, in the new pertronix dizzy, and no more problems. When it was stuttering my ts2 registered 62 ohms. Maybe pertronix dont like them that low?

Re: offset on dizzy gear

Posted: Mon May 27, 2019 7:17 pm
by Sawspa
So yes. Two new pertronix modules total. Both stuttered terribly when the motor got hot. I have ran pertronix before without this problem, but a mechanic told me the pertronix was giving an intermittent miss, so it’s been on points since. I have a new vacuum can coming from c1p. The bosch distributor will be going back in tomorrow hopefully . 1978 2.0l FI, no egr, bigger hoffman heads and a bigger cam. 76 exhaust.

Re: offset on dizzy gear

Posted: Mon May 27, 2019 8:24 pm
by Amskeptic
Sawspa wrote:
Mon May 27, 2019 7:17 pm
So yes. Two new pertronix modules total. Both stuttered terribly when the motor got hot. I have ran pertronix before without this problem, but a mechanic told me the pertronix was giving an intermittent miss, so it’s been on points since. I have a new vacuum can coming from c1p. The bosch distributor will be going back in tomorrow hopefully . 1978 2.0l FI, no egr, bigger hoffman heads and a bigger cam. 76 exhaust.

I have had a couple of Pertronix units misbehave when hot. Nobody wanted to believe me, so deeply had they committed to "your problems are over with Pertronix" ad copy.
I will not run a Pertronix engine in the desert southwest. Points! Cuz they're good.
Colin