Drilling out 1/4 for 5/16 style distributors

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62Cometman
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Drilling out 1/4 for 5/16 style distributors

Post #1 by 62Cometman » Tue Oct 10, 2017 5:03 pm

So after scouring the internet it looks like other than vintage inlines no one that I could find carries a 1/4 drive "performance" distributor for our cars so it would see that the easier option would be to drill out and swap oil pumps for a later 5/16 drive unit and it looks like the spec for a later 5/16 hole for the end of the shaft is 0.525-0.530 which without a mill wouldn't normally be possible to machine, but a 17/32 drill bit is 0.53125 , do you guys think that's close enough? Would the extra .001 would be too much play? Also if anyone has done this swap already please let me know if I might have any obstacles to overcome
1962 Mercury Comet 170 ci, 2.77 Trans, 3.10:1 7.25 rear.
She ain't fast but she's fun. 8)

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Re: Drilling out 1/4 for 5/16 style distributors

Post #2 by woodbutcher » Tue Oct 10, 2017 5:57 pm

:hmmm: IIRC,those drive shafts are Allen wrench shaped,not round.You would also have to change the oil pump also to have the same size drive on it.Not to mention changing the distributer too to match the larger drive shaft.
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Re: Drilling out 1/4 for 5/16 style distributors

Post #3 by bubba22349 » Tue Oct 10, 2017 7:29 pm

There are severial ways to do this type conversion! If you have your engine apart already for rebuilding or don't mine tearing it down to do the swap than yes machining the block Distribitor lower pilot hole makes real good sense. Drilling it out probally isn't a good idea most drills will tend to leave you with a much bigger hole than you would expect. Plus you need to also set the block up so the existing Distribitor pilot hole is perfectly straight up (vertical) in all axis too, with a very good drill press to be a bare minimum and a vertical milling machine the best way along with an accurate sized reamer to finish and control the final hole size. Another way if your engine is good runing and still assembled is to make a 1/4 to 5/16 oil pump drive adapter (or a custom oil drive shaft that's 1/4 inch on bottom end and is 5/16 inch on the other end). Then have the distribors lower shaft that fits into the block pilot hole, machined down to match your current 1/4 inch drive Distribitor. Good luck :thumbup: :nod:
A bad day Drag Racing is still better than a good day at work!

I am still hunting for a project car to build but with my current low budget it's not looking so good. My Ex- Fleet of Sixes these are all long gone! :bang: 1954 Customline 223 3 speed with O/D, 1963 Fairlane project drag car with BB6, 1977 Maverick 250 with C4, 1994 F-150 a 300 with 5 speed.

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Re: Drilling out 1/4 for 5/16 style distributors

Post #4 by frozenrabbit » Tue Oct 10, 2017 7:49 pm

Not 100% sure, but I think you can swap shafts between OEM distributor bodies, or swap the guts into a 1/4" distributor.

I'm running a '65 200 head and cam in a '63 170 block, I just swapped the internals to get the springs and advance curve the '65 distributor had.

No idea at all about aftermarket.

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Re: Drilling out 1/4 for 5/16 style distributors

Post #5 by 62Cometman » Tue Oct 10, 2017 8:11 pm

I guess I could ask my machinist if he could enlarge the block hole, my biggest worry about making a custom shaft is that its still being driven by a 1/4 drive but honestly that's only a 1/16 bigger, also if I had a machinist make such a shaft or I attempted to make one myself id have to find a way to harden it, also don't the 65 and later dizzys have a larger diameter that goes into the block?? and I was looking to do the swap so I could go to a DUI or a DSII style system to match the 32/36 weber I have, with out paying the $500 for a DUI from VI, sorry matt
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Re: Drilling out 1/4 for 5/16 style distributors

Post #6 by bubba22349 » Tue Oct 10, 2017 8:50 pm

The differance in an early 144 or 170 block Distribitor holes is located only in the lower, or pilot bore. These early ones that use a 1/4 oil pump drive pilot hole is 0.490". The later model 200's of about 1965 and up that use a 5/16 oil pump drive shaft the pilot hole is 0.530". So it's only a difference of .040 this is the amount that would needed to be either machined in the blocks pilot hole or from off the distribors lower shaft (below the drive gear) see below picture. In any case a competent machinist should be able to do either of these operations for a relatively low cost. Good luck :nod:

In an old post by Aldo there is also one more option you can choose the Aussie Electronic Distribitor too.
"Easy; there are a few solutions. Whichever you choose will require a 66-up oil pump for a 200, and the 5/16" hex drive shaft. You can't avoid these two parts.

Now you can buy an Aussie electronic distributor which will drop in with a little grinding to reduce the mount tab.

Or, pull apart a Duraspark and machine down the pilot section of the shaft, below the gear. This is machine shop territory but quite feasible and very straighforward.

Both options are easier than altering the block.

Regards, Adam."

In a post by Jammers
"Here's a pic of a '62 Load-O-Matic distributor from the NAPA website:

Image

And a Duraspark (II?) from a '75 Maverick 200, same source:

Image"
A bad day Drag Racing is still better than a good day at work!

I am still hunting for a project car to build but with my current low budget it's not looking so good. My Ex- Fleet of Sixes these are all long gone! :bang: 1954 Customline 223 3 speed with O/D, 1963 Fairlane project drag car with BB6, 1977 Maverick 250 with C4, 1994 F-150 a 300 with 5 speed.

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Re: Drilling out 1/4 for 5/16 style distributors

Post #7 by 62Cometman » Tue Oct 10, 2017 10:33 pm

So it would seem that it would be easiest to get a new pump and hex drive then buy which ever distributor I want and have it machined down by a competent machine shop which honestly should be quite easy for them if I had a metal lathe id do it myself
1962 Mercury Comet 170 ci, 2.77 Trans, 3.10:1 7.25 rear.
She ain't fast but she's fun. 8)

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Re: Drilling out 1/4 for 5/16 style distributors

Post #8 by frozenrabbit » Wed Oct 11, 2017 2:55 am

I don't think there is enough material to machine down a 5/16" shaft to fit the block.

I had a cracked 1/4 shaft at the hex, I wouldn't trust a 5/16" machined down at all.

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Re: Drilling out 1/4 for 5/16 style distributors

Post #9 by rbohm » Wed Oct 11, 2017 7:02 am

actually FR there is plenty of material to machine down the shaft. the aussie distributor that bubba mentioned uses a 5/16 oil pump drive shaft, but fits the older block with the smaller pilot hole. i have one somewhere that i bought from addo a number of years ago.
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Re: Drilling out 1/4 for 5/16 style distributors

Post #10 by frozenrabbit » Wed Oct 11, 2017 10:56 am

Yeah.....but not.

1/4" distributor shaft o.d. is 0.450", 1/4" hex is +/- 0.275" hex point to point. Resulting in 0.0875" of material at hex point to o.d.

5/16" hex is +/- 0.350" point to point. Resulting in 0.05" of material at hex point to 1/4" shaft o.d. with hardening gone after machining.

As I said, the pictured 1/4" shaft cracked at 0.0875" thickness(clogged lower shaft oil passage on high mileage block), and I would never trust 0.05", even with re-hardening. It's almost half as much remaining material after machining. If 62Cometman has upped his h.p. even a little, this isn't a good solution.

Physically yes, practically no.

After looking at my distributors, I need to correct my earlier post, the shafts can't be swapped between bodies, but the upper internals can be on OEM distributors. '63 1/4" to 65 5/16", but I have no idea of aftermarket or Duraspark into an early 1/4" distributor.

I'm sure 62Cometman has more money in his engine than the cost of 2 distributors to swap internals.

Pertronix maybe with a hotter coil?
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Re: Drilling out 1/4 for 5/16 style distributors

Post #11 by 62Cometman » Wed Oct 11, 2017 12:40 pm

I don't know if were talking about the same thing or not FR I want to machine down the end of the distributor where it enters the block and leave the 5/16 shaft whole now I would be taking about .040 or so off so I don't think I'd be doing any major structural damage here, if the 1/4 inch setup that's in my car can last as long as it has I don't see any reason why a slightly machined down unit ment for 5/16 couldn't.

I understand what your getting at and yes this would not be my first choice however I want / need to get away from the SCV style distributors because I'm going to a Weber so I need something that is going to play nice with that carb now the Aussie style DS might be the way to go without having to machine anything and still have a performance dizzy, hard part is finding one
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Re: Drilling out 1/4 for 5/16 style distributors

Post #12 by frozenrabbit » Wed Oct 11, 2017 2:13 pm

I think we are talking about the same thing.

I just measured with calipers, 1/4" distributor shaft is 0.450" o.d., 5/16" distributor shaft is 0.515" o.d., you would need to machine off 0.065" resulting in 0.0475" of material remaining between the 5/16" hex points to the machined o.d. Almost half as much material.

Personally, I wouldn't trust that at all.
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Re: Drilling out 1/4 for 5/16 style distributors

Post #13 by bubba22349 » Wed Oct 11, 2017 2:22 pm

frozenrabbit wrote:I don't think there is enough material to machine down a 5/16" shaft to fit the block.

I had a cracked 1/4 shaft at the hex, I wouldn't trust a 5/16" machined down at all.


Not sure what you mean in your statement, but here goes. By using the later 200 oil pump with 5/16 inch hex drive so there is no need whatsoever to mod the 5/16 oil pump driveshaft it's used as it was made so it's hardening stays intact.

As to the block pilot holes (cast iron) this could be remmed out .040 to .530 there isn't any hardening here at all. As to the the Distribitors shaft size being reduce .040 causeing weakness I doubt that it would matter much this is only .020 per side. It could also be rehardened if it changed its surface hardness though I don't know that it would if machineing was done carefully (i.e. Not to over heat it) it for sure wouldn't affect the broached hex part (drive shafts hole). As I stated above probably the best choose is to machine the block itself if it's being rebuilt anyway. This would be my perfered choose or had access to one of the Aussie Distribitors building up an early block. Good luck :nod:
A bad day Drag Racing is still better than a good day at work!

I am still hunting for a project car to build but with my current low budget it's not looking so good. My Ex- Fleet of Sixes these are all long gone! :bang: 1954 Customline 223 3 speed with O/D, 1963 Fairlane project drag car with BB6, 1977 Maverick 250 with C4, 1994 F-150 a 300 with 5 speed.

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Re: Drilling out 1/4 for 5/16 style distributors

Post #14 by frozenrabbit » Wed Oct 11, 2017 2:28 pm

Not reffering to the hex shaft, talking about the distributor shaft.

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Re: Drilling out 1/4 for 5/16 style distributors

Post #15 by bubba22349 » Wed Oct 11, 2017 2:33 pm

Okay but your calculations in your above picture would be wrong, there would only be a .020 differance in the wall thickness per side. This should be insignificant. Good luck :nod:
A bad day Drag Racing is still better than a good day at work!

I am still hunting for a project car to build but with my current low budget it's not looking so good. My Ex- Fleet of Sixes these are all long gone! :bang: 1954 Customline 223 3 speed with O/D, 1963 Fairlane project drag car with BB6, 1977 Maverick 250 with C4, 1994 F-150 a 300 with 5 speed.

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Re: Drilling out 1/4 for 5/16 style distributors

Post #16 by frozenrabbit » Wed Oct 11, 2017 2:39 pm

I'm correct in the math. There is a 0.065" difference in shaft diameters. 0.040" won't get it there.

Both have 0.08" of material from the points of the inner hex to the o.d.

0.515" - 0.45" = 0.065" (to machine 5/16" down to 1/4" o.d)
0.065"/2=0.0325"
0.08"-0.0325"= 0.0475" (material remaining between points of inner hex and o.d.)

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Re: Drilling out 1/4 for 5/16 style distributors

Post #17 by bubba22349 » Wed Oct 11, 2017 5:12 pm

Okay I guess we have a differance of opinions then. I believe it's not a big problem and the fact that the Aussies used this very meathod on their inline six'es instead of boring out the block pilots to the US size should be of some evidence.

As a side note I once repaired a 1962 or 63 Ford Galxie 390 that that was towed into my shop, had lost oil pressure again after another shop had just repaired it severial weeks before. They had replaced the oil pump and oil pump drive shaft. When I tore it down found that the oil pump driveshaft (the end fitting into the bottom of the Distribitor) was rounded a bit on the hex points and was slipping. Replaced the distribor which had the hex drive totally worn out and installed another oil pump driveshaft and problem was solved. I don't think there is any or very much harness in the Distribitor shaft to speak of. Good luck :nod:
A bad day Drag Racing is still better than a good day at work!

I am still hunting for a project car to build but with my current low budget it's not looking so good. My Ex- Fleet of Sixes these are all long gone! :bang: 1954 Customline 223 3 speed with O/D, 1963 Fairlane project drag car with BB6, 1977 Maverick 250 with C4, 1994 F-150 a 300 with 5 speed.

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Re: Drilling out 1/4 for 5/16 style distributors

Post #18 by frozenrabbit » Wed Oct 11, 2017 5:22 pm

Vintage Inlines may be your best bet 62Cometman. Pricey side at $390.

144/170 1/4" shaft DUI

https://www.vintageinlines.com/product- ... 44-170-cid

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Re: Drilling out 1/4 for 5/16 style distributors

Post #19 by xctasy » Wed Oct 11, 2017 5:56 pm

Hey there, frozenrabbit

What bubbaxxxx said

That's right.

"Stabbing the dizzy" is sadly also way of potentially turning a hex drive if you don't be gentle.

Turning a hex drive

Image

in to a macorini drive

Image


They really should put stickers on this stuff in the price check section


to stop an international "knot in wood" gnocchi incident....

https://www.youtube.com/watch?v=Gg_yzRWy9HM

https://www.youtube.com/watch?v=VX128MzM64s

Although they are hardened, and machining will leave exposed unhardened end, its not an issue unless its been burred or miss directed.


viewtopic.php?f=1&t=72783&p=559468#p559468
/viewtopic.php?f=3&t=9798&start=0

Sizes:
for US 200 after 1964, all the same 5/16" drive 65 to 1983
for 250 US, the 5/16" drive is 0.393" too short for a Aussie 200 log after 1970, or any 200 or 250 cross flow
for 351W 8.19" length by 5/16"
for 302C/351C/351M/400 9.34" length by 5/16", and you have to cut it to fit a US 200 or US 250

You'll find any hex drive won't even be close to a 52 rockwell harness, these things were spat out of the susage machine with the strength in the manufactoring, not in the materials design.

Its only under load, when the edges are rounded, or the wrong drive is placed in the distributor, that it'll chuck a mental.

That happens a bit, as there are both 200 and 250 hex drives, with different lengths.

Some times, a guy in Australa or the US might tick an ebay supplier, and get the tall deck or short deck 200 hex drive, which is application specific. The lenght varies on the hex drives.

The Aussie stuff was designed to integrate the existing US inventory into the existing Australian made inventory, so if you have, say, a hex drive for a 1983 Ford Fairmont i6 six, you could end up with any one of the US or Australian in line six parts.

The Aussies down graded the out side hole pilot diameter in October 1980 back to 485-490 thou from 525 to 530, basically pre 64-1/2 Ford style.

The so called "Duraspark" Australian distributor is actually based on a 1959 Dodge Truck in line six part, which was also used in Holdens and Falcons, then converted to electronic in 1973 by Chrysler Australia for the Hemi 215/245/265, and then, for both the XT5 2.85/3.3 Holden and the late 1980 3.3 and 4.1 liter X flow engines.

It reverted back to the pre 1964-1/2 US pilot size.....

This was so the GM Holden and Ford Falcon/F100/Cortina six item could be sourced from the same "white box" Robert L Bosch Australia supplier.

Australia is a small market, so quite often, Chrylser, General Motors, Ford and even AMC Australia used to use the same white box supply, and just change the hard dimensions to suit the parts.
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Re: Drilling out 1/4 for 5/16 style distributors

Post #20 by bubba22349 » Thu Oct 12, 2017 12:14 am

:beer: Lol Xctasy those skits are hilarious, I got my eye on you!

One last way this can be done! One of our site members awhile back (sorry can't remember his name to give him the credit), turned down his DSII Distribitor shaft to fit his early block then used a drill diver socket as an adapter to go from the 5/16 inch to drive a shortened 1/4 inch oil pump driveshaft. This was because he had a new early Melling 1/4 inch drive oil pump and driveshaft. He's been running it successfully to the best of my knowledge. Good luck :nod:
A bad day Drag Racing is still better than a good day at work!

I am still hunting for a project car to build but with my current low budget it's not looking so good. My Ex- Fleet of Sixes these are all long gone! :bang: 1954 Customline 223 3 speed with O/D, 1963 Fairlane project drag car with BB6, 1977 Maverick 250 with C4, 1994 F-150 a 300 with 5 speed.

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Re: Drilling out 1/4 for 5/16 style distributors

Post #21 by 62Cometman » Thu Oct 12, 2017 10:54 am

Thanks for the info X, so if i was to look for a distributor for my pre-64 block i want a 81 or later aussie dis? or would a search for Australian duraspark work?
1962 Mercury Comet 170 ci, 2.77 Trans, 3.10:1 7.25 rear.
She ain't fast but she's fun. 8)

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Re: Drilling out 1/4 for 5/16 style distributors

Post #22 by wsa111 » Thu Oct 12, 2017 7:42 pm

Any competent machine shop should be able to ream out the small shaft bore to comply with the larger 64 1/2 & up blocks size. Then you can use the DS11 & HEI distributors. Note i did not mention the DUI cause it has housing design problems & the over priced DS11 with a full length bushing which also has vertical movement & is just a reman. distributor with a generic curve & has a non adjustable vacuum advance plus a non hardened distributor gear.
Other wise some of their products are very good.
How do i know cause i fix those mentioned above every week. Bill
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Re: Drilling out 1/4 for 5/16 style distributors

Post #23 by xctasy » Fri Oct 13, 2017 10:01 pm

62Cometman wrote:Thanks for the info X, so if i was to look for a distributor for my pre-64 block i want a 81 or later aussie dis? or would a search for Australian duraspark work?


Yes, the Aussie Bosch made Duraspark or even the TFI, both have a really nice F150 4.9 style spark curve which is perfect with a mild to wild in line six.

But a good machine shop is better, IMHO.

And another thing....


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FAZER 6Bi (M112 & EEC5) or FAZER 6Ti (GT3582 & EEC5) 425 HP 4.1L/250 I-6
FAZER 6V0 3x2-BBL Holley 188 HP 3.3L/200 I-6 or 235 HP 4.1L/250 I-6
X-Flow Engine Components Ltd http://www.xecltd.info/?rd=10

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