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.

[Larry Hill]

Upon further inspection it looks like the tap drill was larger than spec leaving the thread form short for 7/16- 14 NC. Who or what to blame, I will take responsibility I had a torque wrench that was not true, and I payed the price. Measuring the thread pull out it was about 20 % undersized.

Y’all have a good July 4th weekend.

[Larry Hill]

Block is cleaned well enough to take to the machine shop next week to be honed. The manes are installed with protector bearings and torqued. Honing plates and gaskets are installed and torqued. It has taking a while to get the gaskets to be large enough to go to the next size overbore if it is necessary. A steel gasket hanging in the bore will eat up a set of stones.

Most if not all machine shops appreciate receiving relatively clean stuff and sometimes you can save some money by cleaning it yourself.

Time to clean up my shop its a wreck.

[Larry Hill]

A tip of the hat to Mahle Pistons. I checked the next size +.005" over pistons for the engine and size varied .0003" and weight of the eight pistons varied by less than a gram. I forgot to check weight of small piston to larger piston for balance. The bores checked OK just not very straight. With us going to the next size Jeff Taylor Performance will have it round and straight. Honing
using a Profilometer assures the values of RVK and RPK are closely observed. New equipment is always plus for any shop.

[goinbroke2]

Originally Posted by 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

Perfect explanation, got it, thank you.

[Larry Hill]

Yesterday was a good day at Jeff Taylor Performance we got a lot of stuff done and got some stuff ordered. I learned a little more of the things to look for on my combination and how to check for potential problems.

Time to go to work!