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distributor gear install
#1
Hello fellow 7173 enthusiasts ,
I have been pondering the 351 c distributor gear install for roller cam and would like to know what others have done.
I will be using duraspark distributor.
currently both my end play and gear installed dimensions are correct.
as some of you know one can purchase a distributor gear for roller cam, (0.531'' steel) either drilled or un drilled.
Personally I am not a huge fan of having a SECOND hole drilled thru the distributor shaft for the means of locating the distributor gear, will be using STANDARD volume oil pump and will be using installed distributor to locate the oil pump prior to torqueing of the oil pump mounting bolts.
My question is this
Could/ can one use an undrilled distributor gear and line it up with the original removed gear on a perfectly flat table and use the drill hole as an alignment device to drill a pilot hole in the new gear to be used ?
One could then install that gear getting drill hole to line up and then drill the second hole.
would also keep gear teeth aligned while drilling the first hole to ensure rotor phasing.
What ya all think ?
Pretty sure buying a pre drilled gear and expecting it to line up and or the installed dimensions to be correct would a recipe for failure.
Boilermaster
  Reply
#2
(02-03-2018, 10:25 AM)boilermaster Wrote: Hello fellow 7173 enthusiasts ,
I have been pondering the 351 c distributor gear install for roller cam and would like to know what others have done.
I will be using duraspark distributor.
currently both my end play and gear installed dimensions are correct.
as some of you know one can purchase a distributor gear for roller cam, (0.531'' steel) either drilled or un drilled.
Personally I am not a huge fan of having a SECOND hole drilled thru the distributor shaft for the means of locating the distributor gear, will be using STANDARD volume oil pump and will be using installed distributor to locate the oil pump prior to torqueing of the oil pump mounting bolts.
My question is this
Could/ can one use an undrilled distributor gear and line it up with the original removed gear on a perfectly flat table and use the drill hole as an alignment device to drill a pilot hole in the new gear to be used ?
One could then install that gear getting drill hole to line up and then drill the second hole.
would also keep gear teeth aligned while drilling the first hole to ensure rotor phasing.
What ya all think ?
Pretty sure buying a pre drilled gear and expecting it to line up and or the installed dimensions to be correct would a recipe for failure.
Boilermaster
 You're right, trying to drill and then line up to a pre existing hole is close to impossible. Huge chance that the hole through the shaft will not be dead centered. The only way it could be done would be on a mill with a very good digital read-out. You would have to pick up the hole dimension from the solid edge of the vice, then do a load of math to figure out where to drill the gear to get it exact. Damn near impossible!! I do agree that a second hole in the shaft is not the best, but it will have to be done. If you buy a remanufactured dizzy, it will likely have two holes in it. The load on the shaft should not be that great I would think.
Personally, I would not attempt to do it at home unless you have the equipment to do it. This is a high precision operation. Take it to a machine shop if you can.
Geoff.
  Reply
#3
(02-03-2018, 11:13 AM)Stanglover Wrote:
(02-03-2018, 10:25 AM)boilermaster Wrote: Hello fellow 7173 enthusiasts ,
I have been pondering the 351 c distributor gear install for roller cam and would like to know what others have done.
I will be using duraspark distributor.
currently both my end play and gear installed dimensions are correct.
as some of you know one can purchase a distributor gear for roller cam, (0.531'' steel) either drilled or un drilled.
Personally I am not a huge fan of having a SECOND hole drilled thru the distributor shaft for the means of locating the distributor gear, will be using STANDARD volume oil pump and will be using installed distributor to locate the oil pump prior to torqueing of the oil pump mounting bolts.
My question is this
Could/ can one use an undrilled distributor gear and line it up with the original removed gear on a perfectly flat table and use the drill hole as an alignment device to drill a pilot hole in the new gear to be used ?
One could then install that gear getting drill hole to line up and then drill the second hole.
would also keep gear teeth aligned while drilling the first hole to ensure rotor phasing.
What ya all think ?
Pretty sure buying a pre drilled gear and expecting it to line up and or the installed dimensions to be correct would a recipe for failure.
Boilermaster
 You're right, trying to drill and then line up to a pre existing hole is close to impossible. Huge chance that the hole through the shaft will not be dead centered. The only way it could be done would be on a mill with a very good digital read-out. You would have to pick up the hole dimension from the solid edge of the vice, then do a load of math to figure out where to drill the gear to get it exact. Damn near impossible!! I do agree that a second hole in the shaft is not the best, but it will have to be done. If you buy a remanufactured dizzy, it will likely have two holes in it. The load on the shaft should not be that great I would think.
Personally, I would not attempt to do it at home unless you have the equipment to do it. This is a high precision operation. Take it to a machine shop if you can.
Geoff.

EDIT: It occurred to me that there may be a way to not drill that second hole, but it would mean using a 5/32" roll pin instead of the 1/8". Essentially, you need to set it up in a mill and use a 4 flute end mill to re-cut the predrilled gear and shaft. Again not easy to do as it may push the dimensions off. Using just a drill bit would be a bit risky imo. Everything would depend on how close it looks to begin with. It ain't goin to be easy!!
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#4
Geoff,
Not exactly sure I am on the same page as you:
once the distributors end play and gear location are verified as correct, I would pull the exhisting gear off the distributor and use the bottom of the gear (machined surface) as a pilot to drill one hole in the new gear (no holes in the new gear as of yet)
then using a lathe or horizontal drill press with the used gear thru the drill bit, align the bases of the gears to the table and drill ONE hole thru the new gear .
I would then press on the new gear (still one hole in it) and align it to the existing hole in my distributor shaft.
I would then drill the second hole in the new gear using the previously drilled hole in the new gear AND the existing hole in the distributor shaft as my pilot.
If I am reading you correctly are you saying that the drillings of the existing gear and shaft can be off in Two planes ?
Thus making the first drilling of the new gear to be incorrect and to alter the installed height of the gear ?
please reply
If that is the case I guess I would be forced to drill 90 degrees from the existing hole.
Boilermaster
  Reply
#5
(02-03-2018, 12:03 PM)boilermaster Wrote: Geoff,
Not exactly sure I am on the same page as you:
once the distributors end play and gear location are verified as correct, I would pull the exhisting gear off the distributor and use the bottom of the gear (machined surface) as a pilot to drill one hole in the new gear (no holes in the new gear as of yet)
then using a lathe or horizontal drill press with the used gear thru the drill bit, align the bases of the gears to the table and drill ONE hole thru the new gear .
I would then press on the new gear (still one hole in it) and align it to the existing hole in my distributor shaft.
I would then drill the second hole in the new gear using the previously drilled hole in the new gear AND the existing hole in the distributor shaft as my pilot.
If I am reading you correctly are you saying that the drillings of the existing gear and shaft can be off in Two planes ?
Thus making the first drilling of the new gear to be incorrect and to alter the installed height of the gear ?
please reply
If that is the case I guess I would be forced to drill 90 degrees from the existing hole.
Boilermaster

 Yes, I get what you're saying. That would work if the hole in the shaft is not too far off center and straight through. You may be ok doing it that way. I have one shaft in my junk box that the hole is about a 1/32nd off on one side, meaning the hole wandered when drilled. I doubt they worried about it too much as the gear and shaft would be drilled as one, I'm thinking.
**Starting the hole in the gear could be tricky as the flute may push the drill off location**. You would need to center drill it first and for that you'd need either a mill or a good drill press and vice to stop it wandering.
Honestly, I don't think you'd have a problem with a second hole in the shaft, but if you can do it with the existing hole, that would be perfect. 
Let us know how it works out.
Geoff.

**      **. Sorry, I had a brain fart here. The hole is NOT through the flutes, but a center drill would still be necessary or at least a very short drill bit to get a dead centred start. sorry for the confusion.
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