Drill bit for HVX modification..

[JLaw]

Hi all,

I am currently preparing a crankcase and would like to carry out the Bob Hoover mods which include drilling the lifter bore oil gallery. I am having a bit of trouble finding the correct drill bit for the job. Could anyone who has done this before point me in the right direction.

Thanks,

John.

[spanners]

There are pitfalls to this work, they often break out in the case under #2, I do a fair few, but they are for circuit or rally cross dry sump motors were the right head has oil centrifuged away in right hand turns, the push rods define how much oil goes up to the valve gear with dry sump, wet sump gets more than enough oil slosh in the heads, and in normal use this is certainly plenty, run with a valve cover off to see how quickly it runs the sump dry, but to answer your question, the drill I use is about 11"1/2 x 7m. [ Attachment: You are not allowed to view attachments ]

[spoolin70]

Morning Spanners.

The area you mention where the break out can occur, is this accessible enough to fill back in with weld ?
Or even plate over if the wall thickness is small ?

Thanks
Darren

[spanners]

Spoolin, yes, either, you need a piece of like material to plate over it, go again with the drill if you just plug weld the hole, less heat like that too.

[JLaw]

Hi,

Thanks for the reply. I was planning on using a 5.5mm diameter drill bit which is closest to the recommended 7/32'' bit. Where do you get your drill bits from at that length (11.5'') I've tried MSC industrial supplies but no luck..

Cheers,

John.

[spanners]

Hi,

Thanks for the reply. I was planning on using a 5.5mm diameter drill bit which is closest to the recommended 7/32'' bit. Where do you get your drill bits from at that length (11.5'') I've tried MSC industrial supplies but no luck..

Cheers,

John.

Yes, do check my drill info on the web, mine was just a quick week end guess from the memory banks, it's years since I sized the job, same old bit I've had probably 15 years now, it was then you could just walk in and walk out with almost what ever you wanted, machine tool stores were in many high streets, alas no more, but the web should turn it up, I'm in the shop tomorrow and will run the rule over the bit. Regards spanners.

[brian e]

Hi,

Thanks for the reply. I was planning on using a 5.5mm diameter drill bit which is closest to the recommended 7/32'' bit. Where do you get your drill bits from at that length (11.5'') I've tried MSC industrial supplies but no luck..

Cheers,

John.

http://www.mcmaster.com/#
search for part # 2955A13   

I also use one of these stop collars to hopefully avoid any accidents. 
Part # 8865A11

[delroyb]

I ended up brazing a drill onto the end of a piece of rod that I trued up in the lathe. Worked well.

[andy198712]

I ended up brazing a drill onto the end of a piece of rod that I trued up in the lathe. Worked well.

impressive!  when i drilled mine i aimed it towards the safe direction a little (as the bit will move in the hole ID a little

[JLaw]

Hey guys thanks for the replies. I managed to get a drill bit in the end but one of the cases I drilled broke through. No biggie, just got some magnesium filler wire to plug it.