Dumbo The Flying Elephant

[Larry Hill]

Hindsight is always clear. If I knew to listen, the block was trying to tell me something. All of the outside studs had to have more force to remove them from normal. What normal is I can't define, but something changed. Part of the problem as I see it is the outer main studs are non ARP and the OD of the rolled threads are .006-.007" smaller than the ARP studs with the same thread form. To correct for the small studs I made the tap drill size a little smaller then carefully taped the hole for the insert. I did a test in an aluminum practice piece before I repaired the first hole. The end result was the stud fit better in the block. I did have to make some stuff to drill hole straight and something to keep the tap straight.

[Larry Hill]

The block maybe be made from bubble gum aluminum but the machine work is very good. I?ve collected some destroyed blocks that I rob parts or cut up to better understand what I?m working with. To drill and tap the block I used old main caps that fit my block amazingly well. Front to back, left to right (they are cross bolted and doweled), and housing bore is close.
Made a concentric sleeve for the cap. OD of the sleeve fit ID of cap ID of sleeve fit tap drill. The second cap was drilled just under the the OD of the threads of the tap. While the second cap was in the mill after drilling, a center was added to support the end of the tap to keep it straight and centered during the tapping operation.
By having the cap loosely taped it forced the tap to tap the hole straight and perpendicular. I had to modify a insert tap to be a bottom tap to use all of the insert. I did not want to give up the last two threads.
All drilling was done with a hand drill on the block. The only things I had to observe was speed, feed, and depth.

[goinbroke2]

I know it's a pain but pictures would be awesome. Sometimes it's hard to comprehend what a person means until a picture and then it's obvious.

The second reason I do it is to remember what I did. "where did I ...oh yeah, I used the other tool" etc.

Great thread, thanks, Jim

[Larry Hill]

As Jimmy Bridges once said all of the experts don’t live out of town Jim I used a junk cap for an aluminum block bolted down with a reduction sleeve to guide the tap drill and keep in the center. The depth was determined by a mark on the flute of the tap drill. A second cap was drilled the size of the OD of the thread form of the insert tap. Without moving that set up I installed a center in the drill chuck to keep the tap centered while I taped the cap. Both outside ends of the cap were drilled and tapped. After the block was tap drilled I installed the tap guide cap and taped the hole for the inserts. Installed inserts and tested each stud for performance.
I ain’t to good with pictures.
Mr John would be great help.
Hope this helps

[Larry Hill]

I have all the main studs assigned and checked for Bullet nose contact. While making protective bearings from old main bearings I noticed an aluminum bearing that all of the aluminum was worn away it was difficult to see at first glance but steel and aluminum are almost the same color. A pocket knife can tell the difference. Block is ready to go to the car wash to be cleaned before installing gaskets and honing plates. Before we have it honed we will check ring gap and bore size and tension of oil ring.