O/T- Drilling 6.25 Deep Engine Oil Galley

crusty1007 · Mar 27, 2018

Feedback & knowledge request.
Block 225 Buick v6 "oddfire"
Oil galley diameter from pickup tube mating face to timing cover/oil pump .440"
Depth 6.25" on horizontal, 2" on vertical - Integral 90 degree blind intersection .
Wanting to enlarge oil galley to .625" or close (casting wall thickness is suspect)

Here is what I am understanding from reading threads on drilling cast iron.
Use a "Core drill"
Cut dry
Low speed
High feed

Now, the questions
How large should I increase the drill bit size each pass, 1/32, 1/16 +/- or just go after it, taking into consideration desired finished hole size for reamer?
Is the Core drill the proper bit to control wander or blow out? - Is there a better drill bit or operation for this that will follow current bore path?
Can I get away with doing this with a hand drill or do I need to bolt it down to a drill press or mill?

TIA
Thean

edwin dirnbeck · Mar 27, 2018

crusty1007 said:
Feedback & knowledge request.
Block 225 Buick v6 "oddfire"
Oil galley diameter from pickup tube mating face to timing cover/oil pump .440"
Depth 6.25" on horizontal, 2" on vertical - Integral 90 degree blind intersection .
Wanting to enlarge oil galley to .625" or close (casting wall thickness is suspect)

Here is what I am understanding from reading threads on drilling cast iron.
Use a "Core drill"
Cut dry
Low speed
High feed

Now, the questions
How large should I increase the drill bit size each pass, 1/32, 1/16 +/- or just go after it, taking into consideration desired finished hole size for reamer?
Is the Core drill the proper bit to control wander or blow out? - Is there a better drill bit or operation for this that will follow current bore path?
Can I get away with doing this with a hand drill or do I need to bolt it down to a drill press or mill?

TIA
Thean

Your 440 hole is about6 inches deep .You want to enlarge it to .625. It is horizontal ,what does the 2 inch vertical dimention have to do with anything? If it is an oil gallery hole,why would you want to ream it?I think a hand held long length drill would do it in one shot.HOWEVER,tHE DANGER IS AT THE INTERSECTION of the cross hole.If the cross hole doesn't go all the way across and into the opposite side your .625 hole might be forced to one side because of the unbalanced cutting pressure.When you start to hit the cross hole,it would be nice to resharpen your drill into a flat bottom drill.When you get past the inter section,you could go back to the regular drill point or finish drilling with flat bottom ,depending on how much deeper you must go.. Once again,not enough information. Use a hand held electric drill with a 3/4 inch chuck. I would wrap one turn of .005 brass shim around the drill shank and don't over tighten. Better the drill slips a little than break the bit or your arm. .Edwin Dirnbeck

crusty1007 · Mar 27, 2018

edwin dirnbeck said:
Your 440 hole is about6 inches deep .You want to enlarge it to .625. It is horizontal ,what does the 2 inch vertical dimention have to do with anything? If it is an oil gallery hole,why would you want to ream it?I think a hand held long length drill would do it in one shot.HOWEVER,tHE DANGER IS AT THE INTERSECTION of the cross hole.If the cross hole doesn't go all the way across and into the opposite side your .625 hole might be forced to one side because of the unbalanced cutting pressure.When you start to hit the cross hole,it would be nice to resharpen your drill into a flat bottom drill.When you get past the inter section,you could go back to the regular drill point or finish drilling with flat bottom ,depending on how much deeper you must go.. Once again,not enough information. Use a hand held electric drill with a 3/4 inch chuck. I would wrap one turn of .005 brass shim around the drill shank and don't over tighten. Better the drill slips a little than break the bit or your arm. .Edwin Dirnbeck

I guess I should clarify. There are two holes, as you suspect, that intersect in the block. one is 6+" deep, the other is 2+" deep. They both need to be opened up. The bores do pass each other, not by much. Id say that there is additional material removed of less than a 1/4" passed outside of intersection.
It sounds like you are of the idea to just go at it with the final size drill and call it good.
As far as a ream is concerned, I assumed it would clean up the bores, for better flow and remove any material that might be hanging on.

Great idea on the insert to allow slippage! Thanks

Limy Sami · Mar 27, 2018

crusty1007 said:
As far as a ream is concerned, I assumed it would clean up the bores, for better flow and remove any material that might be hanging on.

Reaming of oil galleries was discussed quite recently on PM, with the general consensus being it was snake oil (I'm being polite here

) .....both drilled and cleaned properly there shouldn't be anything left hanging on!

edwin dirnbeck · Mar 27, 2018

I think reaming is a bit of overdoing it as far as oil flow is concerned. Especially in the short distance that you are talking about . It could help with minimizing burrs. I think that I would try to get a pressure washer wand down in the holes and squirt one way and another for a half hour or so. Good luck Edwin

RC Mech · Mar 27, 2018

Limy Sami said:
Reaming of oil galleries was discussed quite recently on PM, with the general consensus being it was snake oil (I'm being polite here ) .....both drilled and cleaned properly there shouldn't be anything left hanging on!

But...but...but, the oil pump requires power to rotate, and less resistance for the output flow of the pump = more power to other things, like the wheelz!*

*Fully realizing that any 'gains' would likely be offset on any given day by the mass of the driver's breakfast.

Bill D · Mar 27, 2018

If the hole is not reamed it will be ever so slightly rougher thus allowing more surface area for the oil flow to remove heat faster thus cooling the engine immeasurably.
Bill D.

crusty1007 · Mar 27, 2018

Limy Sami said:
Reaming of oil galleries was discussed quite recently on PM, with the general consensus being it was snake oil (I'm being polite here ) .....both drilled and cleaned properly there shouldn't be anything left hanging on!

Thanks, that's one topic I had not specifically searched for. Ill have to track down the thread and give it a read.

edwin dirnbeck said:
I think reaming is a bit of overdoing it as far as oil flow is concerned. Especially in the short distance that you are talking about . It could help with minimizing burrs. I think that I would try to get a pressure washer wand down in the holes and squirt one way and another for a half hour or so. Good luck Edwin

I guess my take was, that was the best controlled manner to take it to final dimension after drilling, along with those other reasons. Ill track down and read the thread Limy Sami has referenced.

RC Mech said:
But...but...but, the oil pump requires power to rotate, and less resistance for the output flow of the pump = more power to other things, like the wheelz!*

*Fully realizing that any 'gains' would likely be offset on any given day by the mass of the driver's breakfast.

Any horsepower gain is still horsepower! Parasitic loss is a thing. :shrug:

Bill D said:
If the hole is not reamed it will be ever so slightly rougher thus allowing more surface area for the oil flow to remove heat faster thus cooling the engine immeasurably.
Bill D.

Cant tell if you are serious or being sarcastic like the Canadian above you.

Bill D · Mar 27, 2018

crusty1007 said:
Thanks, that's one topic I had not specifically searched for. Ill have to track down the thread and give it a read.

I guess my take was, that was the best controlled manner to take it to final dimension after drilling, along with those other reasons. Ill track down and read the thread Limy Sami has referenced.

Any horsepower gain is still horsepower! Parasitic loss is a thing. :shrug:

Cant tell if you are serious or being sarcastic like the Canadian above you.

Saracastic I do think it will be ever so slightly rougher and thus will have more surface area but the difference in heatflow will not be measurable. I bet the color of the paint on the hood will have more effect on engine temperature on a sunny day.
Bil lD.

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