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drilled oil gallery

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spoon12342002 Avatar
spoon12342002 Eddie S
Milton, VT, USA   USA
1976 Triumph 1500 "Blue Bomber"
Engine is at the machine shop, I want to have them drill out center oil main gallery to 5/16. Just looking for some specific details to pass along to the machine shop.

Thanks,
Spoon

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colodad Avatar
colodad Silver Member Calvin Williams
Grand Junction, CO, USA   USA
1979 Triumph Spitfire 1500 "Spitty"
Ed, use the search to find information about that.
Andy had posted one a short time ago.
http://www.triumphexp.com/phorum/read.php?8,1509075

Fictioneer Avatar
Fictioneer Doug Hirt
Colorado Springs, CO, USA   USA
Calvin, don't you have a good youtube video on this?
Doug



"Mr. Filby, do you think he'll ever return?"
"One cannot choose but wonder. You see . . . he has all the time in the world!"

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clshore Carter Shore
Beverly Hills, FL, USA   USA
Although opening up the passage diameter is a great improvement, there is also the matter of the intersection between the two passages.
Fluid flow is sensitive not only to the change in direction, but also the abruptness of the transition, the sharpness of the edges,
the changes in effective cross sectional area, and the effects of the drillings that may extend past the point of intersection itself.
There is an enormous body of work, research, observation, experiments, and approaches to optimizing such passage intersections.
Not only do all the above create a larger pressure drop through the joint, but promote turbulence, and in the case of heated pressurized oil,
often yield cavitation and dissolution of gasses that can seriously affect the load carrying capacity of highly loaded bearings.

I plan to drill my passages just to the point before they intersect, and then use a 5/16" ball end mill with 4" shank, inserted from
each end to machine the last 5/32" to create a spherical junction between the passages.
If the existing 1/4" drillings already extend past the intersection, I will plug them with filler first, either iron plugs or brass.
(I don't trust JB Weld to be durable enough to hold up to the heat, pressure, and oil; some epoxies are not great with motor oil)
Then the sharp edge at the inner perimeter of the spherical joint will be rounded and radiused as much as I can manage.
Perhaps a long shanked 7 mm ball end carbide burr, followed by a piece of rope liberally saturated with abrasive compound,
drawn through to smooth and polish.

Finish up with a suitable ball hone to polish the passage surfaces:

https://www.ebay.com/itm/5-16-8mm-Flexhone-flex-hone-valve-guides-180-grit-315/232544549877?epid=1411795764&hash=item3624bc3bf5:g:MEAAAOSwfcVUJELd

I have a .22" borescope to help me assess and inspect the stock setup, and the remediation efforts.

And of course, while you are at it, the sharp T intersections between the main oil gallery and the bearing feed passages should get the edges radiused and smoothed as well.

HTH

colodad Avatar
colodad Silver Member Calvin Williams
Grand Junction, CO, USA   USA
1979 Triumph Spitfire 1500 "Spitty"
In reply to # 1513118 by Fictioneer Calvin, don't you have a good youtube video on this?
Doug
yup, it's on that thread Andy did that I posted the link to.
I didn't machine the bushing when I was drilling, I could next time I have reason to remove the dizzy.



Edited 1 time(s). Last edit at 2018-02-13 09:42 AM by colodad.

clshore Carter Shore
Beverly Hills, FL, USA   USA
In reply to # 1513120 by colodad
In reply to # 1513118 by Fictioneer Calvin, don't you have a good youtube video on this?
Doug
yup, it's on that thread Andy did that I posted the link to.
I didn't machine the bushing when I was drilling, I could next time I have reason to remove the dizzy.

I'm not convinced that machining the 'waist' is that important.

The oil gallery is 7/16" ID, yielding a cross sectional area of 0.1503 sq in.
The 'waist' on the bushing is about 1" wide x 3/16" deep (approx.)
That yields a cross sectional area of 0.1975 sq in.
But multiply that by 2, because the oil flows in both directions around the bushing, giving 0.375 sq in.

I'm more interested in (wait for it ... you know what's next) the sharp edges of the holes.
Chamfer and/or radius & smooth (on all 3 holes) to promote laminar rather than turbulent flow.
Or machine a flat in the 'waist' (not too deep!) where the entry and exit holes are to create a more gradual
flow transition. You would have to mark the bushing and ensure that it was pressed back in with the flats aligned.

BTW, the oil gallery axis does not intersect the bushing center axis, it is offset to one side.
You can peek down the hole with the bushing removed, see the attached pic.
On the left side, 3 holes, the smaller center one is the oil passage to the #2 main bearing,
the two larger are the entry and exit for main oil gallery.

Carter


Attachments:
SpitfireOilBushingBore_IMG_0883.jpg    26.1 KB
SpitfireOilBushingBore_IMG_0883.jpg

spoon12342002 Avatar
spoon12342002 Eddie S
Milton, VT, USA   USA
1976 Triumph 1500 "Blue Bomber"
I watched the video that will help alot. Question, why dont you drill the bushing hole too?

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colodad Avatar
colodad Silver Member Calvin Williams
Grand Junction, CO, USA   USA
1979 Triumph Spitfire 1500 "Spitty"
In reply to # 1513131 by clshore
In reply to # 1513120 by colodad
In reply to # 1513118 by Fictioneer Calvin, don't you have a good youtube video on this?
Doug
yup, it's on that thread Andy did that I posted the link to.
I didn't machine the bushing when I was drilling, I could next time I have reason to remove the dizzy.
I'm not convinced that machining the 'waist' is that important.
Carter
please excuse not posting the full directions (just saving space here), I was wanting to comment on machining the waist, and something I discovered in 2016.
I was interested in the oil pressure change after drilling to 5/16s, so I connected 2 senders/pressure gauges to the galley. before and after the bushing.
I found a pressure drop of 9 lbs on the rear tap. I believe the dizzy bushing is slowing flow, and if I machine the waist a bit I can eliminate that 9 lb drop.

corrected waist not 'waste'



Edited 1 time(s). Last edit at 2018-02-13 11:17 AM by colodad.

spoon12342002 Avatar
spoon12342002 Eddie S
Milton, VT, USA   USA
1976 Triumph 1500 "Blue Bomber"
Machine the waist? Sorry i dont know that your referring to.

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colodad Avatar
colodad Silver Member Calvin Williams
Grand Junction, CO, USA   USA
1979 Triumph Spitfire 1500 "Spitty"
In reply to # 1513139 by spoon12342002 I watched the video that will help alot. Question, why dont you drill the bushing hole too?

the hole lets oil to the oil pump shaft, when the shaft is in it gets oil as needed.

spoon12342002 Avatar
spoon12342002 Eddie S
Milton, VT, USA   USA
1976 Triumph 1500 "Blue Bomber"
OK got it, no need to drill bushing.

colodad Avatar
colodad Silver Member Calvin Williams
Grand Junction, CO, USA   USA
1979 Triumph Spitfire 1500 "Spitty"
In reply to # 1513142 by spoon12342002 Machine the waist? Sorry i dont know that your referring to.

Carter's photo, and Steve's photo images they posted on another thread about this.



Edited 1 time(s). Last edit at 2018-02-13 11:19 AM by colodad.


Attachments:
Carter Shore SpitfireOilBushing_IMG_0881.jpg    45 KB
Carter Shore SpitfireOilBushing_IMG_0881.jpg

Steve Jackson 1500 oil pump bush_3.jpg    35.3 KB
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grumpicus Steve Jackson
Leicester, Leicestershire, UK   GBR
Just to clarify - the reason I machined the waisted section of the oil pump bush was simply to clean up the rough 'as cast' surface that was there originally. I'm not claiming that it will provide a remedy to the oil pressure drop along the gallery, but maybe it might help to reduce turbulence as the oil flows round it towards the rear of the engine!

clshore Carter Shore
Beverly Hills, FL, USA   USA
In reply to # 1513141 by colodad
In reply to # 1513131 by clshore
In reply to # 1513120 by colodad
In reply to # 1513118 by Fictioneer Calvin, don't you have a good youtube video on this?
Doug
yup, it's on that thread Andy did that I posted the link to.
I didn't machine the bushing when I was drilling, I could next time I have reason to remove the dizzy.
I'm not convinced that machining the 'waist' is that important.
Carter
please excuse not posting the full directions (just saving space here), I was wanting to comment on machining the waist, and something I discovered in 2016.
I was interested in the oil pressure change after drilling to 5/16s, so I connected 2 senders/pressure gauges to the galley. before and after the bushing.
I found a pressure drop of 9 lbs on the rear tap. I believe the dizzy bushing is slowing flow, and if I machine the waist a bit I can eliminate that 9 lb drop.

corrected waist not 'waste'

I concur with the pressure results you observed through the bushing, I've observed similar drops but less precision.
But I disagree with your conclusion that the size or surface roughness of the 'waist' is the cause of the pressure delta.
But the experiment you propose should help to uncover what is actually happening, by supporting/disproving your conclusion.

I'd like to instrument a Spitfire oiling system.

Copper capillary tubing is easy to obtain, 0.026" ID x 0.072 OD is the smallest common size, a 16 ft roll is $17 on Amazon.
Fittings or bolt seals used on the oiling system can have a #49 hole drilled into the center, so that a length of capillary tubing can be soldered in place.
The inner length can be 'snaked' into the passages, cut to length to place the open (sensing) end deep inside the motor.
This enables actual running pressure readings in areas of interest, perhaps even right where the passage delivers oil to the main bearings.
The outer length can be soldered to a connection fitting, for attachment to gages or to pressure measurement sensors.

Could hook up a 4 channel Data Acquisition like this one for $59

https://www.dataq.com/products/di-1100/

Using 4 pressure sensors like these:

https://www.mouser.com/ProductDetail/Honeywell/ABPMLNV150PGAA3?qs=sGAEpiMZZMvhQj7WZhFIAIc6zRP3uSZW4YfvQBxlQvwGGBtuQHUmKw%3d%3d

And capture the datastream on your PC, for review and analysis.

Hmm, am I obsessing again?

Roy Avatar
Roy roy o
Marietta, GA, USA   USA
Didn't someone claim to solve this problem by feeding the center main cap from the oil pump ? CRS

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