Engine Block Problem (Mounting Studs Are Broken)

Re: Hole In The Engine Block

More than likely its time to buy a new one and use that one for spare parts. The good news is that you can just buy the motor instead of a whole new kit and save a few bucks. Just for s*&ts and giggles you could go to the local hardware store, pick up a couple of studs or some goos all-thread and the BEST high heat epoxy that they have and try to hold the studs in that way. It should also seal your hole, if you don't put on so much that it drips into the engine. Its worth a shot.

Try using a center punch and punch the seam in the second bolt at the same spot you drilled the other one. Put some masking tape around the drill so you know how deep your getting. Figure out what size grade 5 or 8 studs you can get at the local hardware and get the tap and nylock nuts to match. Get some JB weld. Tap the new holes. You may need to tap them till the tap bottoms out then either use a bottom tap or grind the end of the tap off till there's just a little taper on it to turn it into a bottom tap and thread the holes to the bottom. Install the new studs with the JB weld. Now get new metric studs for the intake, exhaust, front motor mount. Take the originals out put the new better studs in with Lok-tite blue. If you can't find studs use metric bolts. Don't wait for the same thing to happen all over your motor.

The hole that’s been drilled off center is your biggest problem. I would pull the lower end apart and JB weld the hole from inside. When drilling out a stud start with a small bit and keep getting a little larger with each drill. The stud is slightly softer in the center so buy opening it up a little at a time the bits will gradually try to center in the stud. On the stud that hasn't been drilled, spend a lot of time center punching the stud, then drill it out to about .040 and set a std. 6mm nut(or ¼-20) on top of the stud. With a wire feed welder, spot-weld through the nut and onto the end of the stud. Weld the nut to the stud and after letting it cool a short time, try unscrewing the nut. If the nut brakes off weld on another nut until you get the stud out. I would drill out both holes (front mount, Ex studs and intake studs) with a #7 drill and tap with a 1/4-20 tap. Next get some good studs to replace the soft china ones. The one nice thing about the stud you drilled is that you can open it up to a 8mm if you have to. Next time take more time with the center punch. I drill all the 6mm out to ¼-20 as soon as I get a motor. The other nice thing is a replacement case is jut over $20.00. Have a Nice Day. Center Photo shows 6mm then 1/4-20 and bottom 8mm. Right showe 6mm , Broken Stud Drilled off center and lower is 1/4-20 American stud. Vic

mxchris727 said:

That's what I did, I started with a small size bit then continued to go bigger. Eventually I was at a perfect size and was able to screw the studs in tightly. BUT.... After I did this, I realized that I had drilled too far and now there is a hole in the cylinder! I don't think I could epoxy it because there is too much pressure in the block.

I will try to upload pictures soon...

Click to expand...

Counter sink the hole from inside, Install stud and then fill countersunk hole from inside. This way the JB weld will hold 10 times the inside pressure. Vic

The hole that’s been drilled off center is your biggest problem. I would pull the lower end apart and JB weld the hole from inside. When drilling out a stud start with a small bit and keep getting a little larger with each drill. The stud is slightly softer in the center so buy opening it up a little at a time the bits will gradually try to center in the stud. On the stud that hasn't been drilled, spend a lot of time center punching the stud, then drill it out to about .040 and set a std. 6mm nut(or ¼-20) on top of the stud. With a wire feed welder, spot-weld through the nut and onto the end of the stud. Weld the nut to the stud and after letting it cool a short time, try unscrewing the nut. If the nut brakes off weld on another nut until you get the stud out. I would drill out both holes (front mount, Ex studs and intake studs) with a #7 drill and tap with a 1/4-20 tap. Next get some good studs to replace the soft china ones. The one nice thing about the stud you drilled is that you can open it up to a 8mm if you have to. Next time take more time with the center punch. I drill all the 6mm out to ¼-20 as soon as I get a motor. The other nice thing is a replacement case is just over $20.00. Have a Nice Day. Center Photo shows 6mm then 1/4-20 and bottom 8mm. Right Photo 6mm top, Broken Stud Drilled off center and lower is 1/4-20 American stud. Vic

You could buy a new lower engine block from one of the site sponsors; that is, if all else fails.

I had the very same problem If you can work the stud out you can redrill the same holes
with an "f" drill then tap for a 5/16-18 thread I used 4" cap screws and added an 1-3/4 alum.spacer but I needed room for the reed valve mod I was doing anyway. so far so good. dont drill any place else or you will have to repair case with jb as mentioned or replace cases or engine.