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Tach drive housing eccentric

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J

jcsb

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Part of my rebuild was to replace the original distributor with a Mallory, because I was going with fuel injection. Anyway I bought a new gear for the shaft on the Mallory distributor and installed it. Put it into the tach drive housing and the offset dog (slot) was very tight. I started removing material on one side of the slot in the gear only to find the real problem. The bore in the tach drive housing was eccentric to the dog shaft. I found a good used tach drive housing and bought it only to have the same problem. The PO or the factory had opened the slot up to adjust for the eccentricity. The problem with that is about half of the rotation there is a looseness in the engagement and the other portion it is ok.

So I decided to fix this for good. Having owned a machine shop and still having several machines I decided to machine the housing. First I machined a set of soft jaws, indicated the housing in and it showed the housing was eccentric by .004" tir. So I machined the housing so that I could install a brass insert. I pressed in the insert and then machined it back to the right dimensions. Now everything is concentric and the distributor fits great.

John photo (43).jpg
 
You must've just got unlucky (twice)! I've never noticed any binding like that in the ones I've swapped__or I was just lucky!
I too put a Mallory in my car, but probably used the eccentric from a spare/parts distributor unit.

Nice job, you do good work; which leads me to wonder how people can own Healeys without having lathes, mills, welding machines, etc., etc. They seem so vital to their continued existence...
 
Thanks Randy. Yep, I'm used to making a lot of parts since the old ones need some degree of rehabilitation or the new reissued parts are of such poor quality. Plus with all the mods I'm doing making parts are really the only way to go.
John
 
I don't have a chance, why have I owned a Healey for 33 years?
 
TimK said:
I don't have a chance, why have I owned a Healey for 33 years?
Click to expand...
Some guys get by on luck alone :cheers

But I think Greg's got the right idea: imagine when you can load the "ink" cartridges with aluminum, copper and iron powders. It can't be too many years off, can it...?
 
That has been around for several years, but I don't see that technology taking off. Basically, it's a three step process, whereas direct metal printing can be done in one or two steps. Plus the precision of direct metal is much greater.
 
GregW said:
That has been around for several years, but I don't see that technology taking off. Basically, it's a three step process, whereas direct metal printing can be done in one or two steps. Plus the precision of direct metal is much greater.
Click to expand...

Do you know what the price is on those? Not that at this stage I would ever buy one (meaning age). The price of the 3d printers when they first came out were pretty pricey, but have come down in price significantly over the years.

John
 
I don't have a clue on price (are you asking about the machine?) Here is a link to get a quote for the different models they have. https://www.3dsystems.com/3d-printers/production/overview I'd imagine there would be 6 numbers before you saw a decimal point. Oh, I found where they talk about tolerances.
"All 3D Systems' DMS printers create chemically pure, fully dense metal and ceramic parts, and they deliver accuracy compatible with EN ISO 2768 (fine) machining tolerances and a repeatability of about 20 microns in all three axes."
 
Before I retired my shop had the a broad range of capabilities. Unfortunately I never found the requirement for something like this or the 3d printers. Everything I had needed to make money, but I did have some exotic inspection equipment, such as several CMM's including a large Zeiss CNC Cmm. While they didn't directly make money they sure kept me from loosing money. :eagerness:

John
 
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