I just sheared a dist gear roll pin. When I slid the gear off I noticed...January 11 2009 at 9:49 AM
hollis franks (Login hfranks)
that one of the holes for the pin was elongated. It appeared that it had been redrilled to match the hole in the shaft. So I took 2 other gears to compare and neither had holes that would line up completely. When they built these units did they just slide the gear on and drill anywhere? If they did this would mean that you would have to keep the gear with that particular unit forever.
If the gear was only supposed to go on one way, I could see why they would drill off center, but still I would think they would all be off center by the same amount. It appears on mine that someone fitted another gear and redrilled to make it fit. But in that case the pin doesn't contact the gear properly on the elongated hole and all of the shear is absorbed by only one side of the roll pin. Maybe this is why mine sheared off.
So I put it back together with the same gear, but I want to replace with a bronze gear. Should I expect the new gear to line up or will I have to redrill also?
Black 63 1/2 XL R Code
Gray 65 289 Falcon Ranchero
Distributor gear installation
|January 11 2009, 10:01 AM |
(Select Login johnvermeersch501)
Re: Distributor gear installation
|January 11 2009, 10:29 AM |
Frank. pay special attention to the specs listed in the OHO newsletter...VERY common problem, will destroy cam teeth,while eating the dizzy gear.....I use a multi roll pin, .125 dia. vs. the single roll pin ( available at machine tool supply store )
|This message has been edited by johnvermeersch501 on Jan 11, 2009 10:32 AM|
Thanks, Rich. That's amazing, they ARE drilled randomly. Who would have thought...N/M
|January 11 2009, 10:45 AM |
Black 63 1/2 XL R Code
Gray 65 289 Falcon Ranchero
The OHO Spec is , Misleading
|January 11 2009, 12:02 PM |
The Spec I use is the same as MSD 3.045-3.050 AFTER ALL PLAY IS TAKEN OUT , or better said by pushing up and away ( it is naturaly pulled down by its design ) I shoot for .010-.15 end play , and the shim to take any play up ( if needed) go between the center shaft and the body, Not between the collar and the body , ( although I have saved a few worn setups by using both spaces )
|This message has been edited by Faron on Jan 11, 2009 12:10 PM|
Re: I just sheared a dist gear roll pin. When I slid the gear off I noticed...
|January 11 2009, 10:40 AM |
I couldn't tell you how many times I just pressed an old gear off and stuck a another one on just using the existing holes. Pretty lucky I guess.
|January 11 2009, 10:51 AM |
Several times I have swapped gears and distributors and vice versa.. never had a problem.
Although I did have a Mallory Distributor that could keep a roll pin to save it's life.
The Mallory is the exception
|January 11 2009, 12:16 PM |
They were not press fit and a 1/8 roll pin was not enough to hold , they can be drilled to 5/32, be sure to use a Quality Pin !!
I ditched the Mallory a decade ago!
|January 11 2009, 12:22 PM |
Couldn't stand that thing. IF it wasn't the roll pin it was the damn module.
Durasparked it and never looked back.
Re: I ditched the Mallory a decade ago!
|January 11 2009, 12:47 PM |
I have also had broken dist. roll pins on my old FE Mallory YL dual point distributors. I`ve never broke a pin on either an Accel or Ford distributor.
428 powered Fairmont drag car, Best ET:firstname.lastname@example.orgMPH, best 60 ft: 1.29
59 Meteor 2 dr. sedan 332, Ford O Matic
74 F350 ramp truck 390 4speed
You will need to heat the gear
|January 11 2009, 12:14 PM |
It needs to be pressed on ( NOT HAMMERD ) and will need to be heated , a propane torch and a shop press are the best way, Aftermarket Bronze gears are a press fit as well as utilizing the roll pin
Distance is important
|January 11 2009, 1:02 PM |
The installed distance is very important. Use the coiled type roll pin,not the stiff 3/4 type. Did you determine why the pin sheared? Oil pump locking up from debris is common. Many instances of old wires from a wire wheel getting caught in pump causing this. I would be very concerned about the reason. Each distributor gear is installed to a specific distance...the old drilled hole is not an accurate measurement. When you change gears, re-drill. Rotate approx 15 degrees from original hole.
Engines are like garages,never big enough! Check out my distributor restoration site! http://428cobrajetcars.homestead.com
Drilled after pressing
|January 11 2009, 2:46 PM |
MSD gears are driled on one side and pressed into position, then drilled through using the one side as a starter hole. They "might line up", maybe, sometimes. Usually not - so I just go 90 degrees off and redrill. If the pin fails it ain't unusual to "waller out" the hole on one side as it comes apart.
'Waller'? I haven't heard....
|January 11 2009, 3:22 PM |
waller since I was a kid. And that's flathead days!!!
Ken, as you
|January 11 2009, 3:44 PM |
may know, we still use the term waller down south. Also, did you know that RCH is a unit of measurement? Yes it is, I'll give ya the first and last words. figure it out. Red----Hair. This is used when tolerances are gettin' real close and ya need just a little bit more, Ex: move it a RCH, almost there. LOL, LOL Don
|January 11 2009, 5:12 PM |
Up north we use the BCH form of measurenment. Those RCHs are to tempramental and just plain DANGEROUS!!
|January 11 2009, 5:50 PM |
They vary in thickness from color to color, just like Plastigauge! LOL
Re: Drilled after pressing
|January 11 2009, 4:06 PM |
Approx 17 years ago I had a 427 side oiler in a 69 Cyclone. One playful day I was on hwy 1 near Abbotsford BC. and I had it buzzed up to near 7000 RPM in 2nd gear ready to ease the C-6 into 3rd when all of a sudden the engine died.
Less than a second later I heard a Bang like a 12 gauge shotgun going off close to my ears. There was dust floating freely in the car that had not been disturbed for over 20 years. It turned out that the pin from the distributor gear sheared off and the engine under full throttle loaded with fuel caused quite an explosion. It blew both mufflers wide open and my hearing has been selective since then.
I dont remember for sure but I think I was running a Ford distributor at that time.
Soon after I changed to a Mallory electronic.
Just a little side note: I sold my last FE in 1998 but read this forum every day and through you great FE people I relive the fun times I had in my years of playing with that old Merc.
You've been to SE MO, no doubt :-)
|January 11 2009, 8:43 PM |
Bernie, Malden,Sikeston, its all wallered out of the mud there.
I've been everywhere man, I've been everywhere.... n/m
|January 12 2009, 9:49 AM |