The Stovebolt Site Forums The Shop Area Engine Shop "Hyperthetically"

Hyperthetically; If someone were using the adapter plate, to place an early water pump on a later 235, and they bolted the plate on the block as instructed, used the 27/64 drill bit to start the holes, then removed the adapter plate, used the 5/16 drill, to drill the holes to tap, tapped the holes, then when bolting the adapter plate with water pump attached, to the block, found out that the left hole (looking at front of block), was too far to the left (becouse they did not realize the drill bit slid down the raised part of the block where the adapter plate bolts on). Again, hyperthetically, could one tighten a bolt (grade 5,or 8?) with locktite in this hole, cut it off flush with the block, reattach the adapter plate, drill a new whole (while keeping the adapter plate attached this time} tap and go on? Hyperthetically of coarse!
Bryan

Hypothetically could the hypothetical formentioned said owner possibly have reversed the plate on said block so that said boltholes became misaligned? Hypothetically speaking?

YUR SCREWED come to mind Hypotheticaly ?
as long as the Hypothetical bolt is still accesable to do the forementioned, i would locktite the pooh outta said fictional bolt let it cure & cut an grind it clean .
After that just drill the new hole as you said with lottsa prayers an maybe RUB SOME ROSARY beads for good measure that the bolt hole wont wander an all that ..NOW THIS ALL HYPOTHETIC .

Two options.
Stretch the clearance hole in the adapter plate to fit the new incorrectly placed hole in the block.

Drill the incorrectly placed hole in the block in the right place for a Heicoil only if it is close enough to correct with this method.

A possible 3rd method would be to put a bolt in the hole flush and start over. I don't like this one because the new hole will be partly in this repair, if the "plug" loosens it could jam and the bolt won't want to come out. I also think that it may not be as strong as it could be, depending on how much overlap, about 1/2 a diameter would be better than less.

Good luck,
Grigg

Yes, plug the hole and redo the drill/tap job, but first enlarge it to about a 5/8" thread and install a big plug into the hole. Loctite the plug into it with the strongest stuff you can find, and let it cure thoroughly before doing anything else.

Now, when you redo the drill/tap for the adapter plate, you're not overlapping the repair, you're tapping into a solid piece of steel. It makes a stronger bolt hole than you could get by directly threading the cast iron.
Jerry

I would consider using a cast iron plug to fill the hole. Its done a lot in machining to fill holes in blocks and heads. The iron plug will move at the same rate as the block when it heats and cools, a steel plug will not. Do as Hotrod lincoln said, drill it out to bigger size pipe thread hole so that the new hole is inside the old one. Use a solid iron plug and really get it tight. Cut it flush, sand or file it smooth, and all will be right with the world! Joe

Thanks guys! I apologize for the hyperthetic wording, my embarrassment had gotten the best of me, I will re-drill & plug.
Thank you all.

Using the pump as a drill guide will help restore position. Find the biggest drill bit that will slip thru the adapter/pump and cut it off so it only has about 1/2" of flute length and repoint. Then mount the pump/plate and put a bit of grease on the drill shank and go straight and slow. Then remove the pump and measure the size you need to restore a round hole and select plug size there. Don't go too tight with a pipe plug as you could crack the block. Good luck.

I know that this advice may have been more appropriate before the original hole drift but this may be helpful with the second attempt. When I installed my plate I was so concerned about the possibility of drift and alignment that I did things a bit different from the instructions. First, I built up the area on the block under the plate with a bit of JB weld and filed it down so that I had a flat area for starting the hole. Second, I found a piece of thin wall steel tubing about a 1 ½” long that fit snugly into the water pump/adaptor plate. I tapped the tubing into the water pump/adaptor plate and bolted up as per instructions. With this in place, the tubing provided a drill guide that kept things straight, centered and allowed me to use a smaller diameter drill (smaller then the tap size). I initially used a drill that just fit in the tubing. After the initial drilling, I followed up with the larger appropriate tap size drill enlarging the hole in the tubing and the block. I removed the tubing tapped the hole and was good to go with perfect alignment. Worked for me but maybe it was just dumb luck on my part. Sounds like you got the bad luck part.