Drilling oil passage

Can anybody explain how you go about drilling out the middle bearing oil passage on a Spitfire engine. Obviously the one from the bearing side is easy. But I cannot figure out how the passage from the oil galley over to the dogleg is to be drilled. Callums site says there is a distributor bushing in the block that must be driven out from the bottom. But I cannot get anything to move. Also, it looks like you would have to drill throgh one of the exterior oil galley plugs. Is this correct?

I was thinking about doing this on my 1500 engine that I am about to rebuild.

Hello Bill,

what are you trying to do, drill out an existing passage?
From the exterior you would remove the gallery plug (it could be very tight and you will probably destroy it removing it.)

What are you trying to achieve?

Alec

Yes, you're drilling from the outside of the block. There's already a plug in that hole. Remove it or drill through it, and replace it when done.

Look closely and you'll see the bushing in the block. It's right in the way of the passage and the drill holes. I can't remember if there's a plug at the bottom that lets you push the distributor bushing out, or if you need to use a fingered puller and pull it out from the top.

Piman, the Spitfire has the #2 and #3 bearings sharing a common passage. It's the same size as the #1 and #4 passage. So, #2 and #3 get half the oil. That's why when a Spitfire blows its bottom end, invariably it's either #2 or #3 that let go.

The intent is to drill the passge out to 5/16 inch to allow more oil to flow to #2 & #3 Foxtrapper has stated.

I've popped on the bushing a few times, but I'm scared to hit it too hard. I also could not get the one out of my 1147 years ago.

Bill, the bushing comes out from the bottom, but if hammering on it, chances are 50/50 you will break it when you punch it out. The bushing is cast iron, and has a "waisted" portion in the middle. Once the bushing is <span style="color: #CC0000">pressed</span> out, you drill the passage from the crank side. Then, press the bushing back in place. The orientation of the groove on the top side doesn't matter.
I've done many of these.
Jeff

I thought pressing would be best. That's why I didn't hit on it too hard. I just knew pressing it out wouldn't be slam dunk easy because its not perfectly vertical. I may try to get the machine shop to press it out.

Thanks all.

Hello Foxtrapper,

I'm sorry but that is not how hydraulics work, what limits the amount of oil is the clearance in the shells (and the available pump capacity). I can't believe that the original designers under sized an oil gallery.

Alec

billspit, i know exactly what you are talking about kas kastner did this on the tr6 engines. on my tr6 engine i took an old long socket extension and a socket and then hammered it from the bottom of the block. hope that helps you out. i drilled the main bearing passages and i only hammered this part out for cleaning the block.
Randy