Busted motor mount bolts

[Biggyniner]

Hey all,

I successfully removed my engine from my bayliner ciera 2655. On my port motor mount I busted the two lag bolts that go into the stringer. Now I've removed busted bolts before, but never from the hull of a boat. Anyone have any ideas or special tricks to get them out?

My plan was to soak the holes with penetrant oil and then try and drill them. I'm skeptical at how successful this will be since these lag bolts are pretty beefy...

Thanks for any ideas...

 

[Mad Props]

I would get a 3/4" hole saw like this one... take out the center drill and drill around the lag and then take a hammer and bang on the side of the broken lag until the wood and everything breaks loose and pull them out... Then epoxy in new dowels that match the drilled hole size... drill new holes for new 5/8" lags.

 

[Biggyniner]

That is not a horrible idea.... What do you mean by banging on the side of the lag? The bolt broke off about an inch and a half in the stringer, so nothing is sticking up above it...

 

[Mad Props]

Didn't know if it broke sticking up or down inside... If theres nothing sticking up, then use a chisel/screwdriver/punch and hammer to smack the top of the plug sideways to try and get the wood to break down at the base of the plug so the whole thing comes out. check out a video on cutting plugs... same idea.

Check out around 2:30

 

[harringtondav]

That's a tough one. It happened to my pal. He used Mad Props method. His broke off flush. He chiseled and beavered enough wood away to get a narrow jaw vise grip on the stub and worked it out. Then his oscillating tool to remove the rest of the wood plug. Then he expoxyed in a section of oak dowel. You may need a large hole saw and dowel to get access down that deep.

I had the same issue on my lags. One thing I considered that should be workable was to hang the mounts from the engine, rough align it, then rotate the mounts just enough so you can mark new drill spots next to the stubs. I decided on a different fix shown below.

When you redrill, use SS hanger bolts. These have a machine thread on top so you can use nuts to retain the mounts, and easily remove them next time. https://www.boltdepot.com/Hanger_bolts_Steel_plain_finish_3_8-16.aspx Buy 3/8-16 X 6" to get enough wood screw length (3 -31/2"). You may need to cut off some of the machine thread to clear the engine mount feet.

This is an aluminum plate, through drilled for the hanger bolts clear of the broken stubs, and tapped for SS cap screws to bolt the mount to the plate. I didn't have enough mount adjustment thread to account for the plate's thickness, so I routed out a pocket to accept the plates, and glassed over it before installation.

 

[kenny nunez]

Get a 2”X5” X 3/16” or 1/4” strip of stainless or aluminum. Drill 3/8” holes to line up with the motor mount bolt holes using 3/8”X 1.5” stainless bolts washers & self locking nuts and with the bolts from the bottom up, drill holes on the outer part close to the motor mount and into the stringer using stainless lags. Usually 3/8” X 3” will do the job. Another option is to use a piece of angle metal bolting the lags from the side. I have used both methods with good results.
The above method was posted while I was posting mine, his is also a very good method. Good luck.

 

[harringtondav]

The above method was posted while I was posting mine, his is also a very good method. Good luck.

Dang. I thought I had an original idea. Gotta get up early to beat Kenny

 

[Bt Doctur]

The aluminum angle would work ONLY if you dont raise the height of the mount too much and lose the height for engine alignment. With the engine out use a hole saw to remove the glass and wood to try and grab the broken remnent .
Absolute worst case cut away the glass , drill a 2 inch hole , epoxy in a oak dowel/hand rail/banister/ etc, reglass the top. locate and drill new holes

 

[achris]

Once you get all this mess sorted out, and the next time you need to remove your engine, just remove the top nut off the mounting and lift the engine. Much easier and save all that unnecessary mucking around with lag bolts.

Chris.......

(Remove 'b', not 'a')

 

[harringtondav]

Once you get all this mess sorted out, and the next time you need to remove your engine, just remove the top nut off the mounting and lift the engine. Much easier and save all that unnecessary mucking around with lag bolts.

Chris.......

I got into this mess because my port mount nut was hopelessly frozen to the stud, which was turning in the rubber. The lags twisted off. The other side had one lag screw broken off (???). So I was 3/4 in trouble. ..don't know why the builders don't use hanger bolts. So easy to remove the mounts if necessary.

 

[achris]

I had over-tightened, under greased mounting nuts on that 350 MPI... I have to take the exhaust manifolds off so I could get a socket with long extension onto the nut before it would release. Needless to say, they got greased when they went back on!

. ..don't know why the builders don't use hanger bolts. ....

Because they cost a few cents more. :facepalm:

Chris......

 

[Biggyniner]

Thanks everyone for the ideas. I have a bit of time before I can have a day to put the engine in. I will first try soaking and then drilling and attempting to remove with an easy-out.

Barring that, I will move on to the more extreme methods... Sigh, its always something...

 

[Biggyniner]

Actually I may just drill around it, dang it... Was hoping this would be easy. A lot of the easy out literature I have read basically states the same... If it's broken off more than an 1/8 inch below service, drill around the outside of it....

 

[Scott06]

When I pulled the factory engine from me searay it was surprised to see the motor mount was about 25-30 degerees off the centerline of the boat and lagged in that way.

My advice when when you go back in grind existing lags flush seal with 5200& just tweak the mount off center so the holes are just adjacent to the original ones with the busted lags. I used a 3/8 x 18” long but to drill new holes with the engine in place and aligned on mine as I was swapping a 4.3 to a 5.0 and holes needed to be 4” farther forward

 

[Mad Props]

. ..don't know why the builders don't use hanger bolts. So easy to remove the mounts if necessary.

Even better is, why dont they use thru holes with a cavity under the mount.. this is how I rebuilt me restorations mounts. Nowhere for water to pool if it gets around the mount holes... plus stainless bolts and nylok nuts are easier to find than stainless lag bolts.

 

[achris]

Even better is, why dont they use thru holes with a cavity under the mount.. this is how I rebuilt me restorations mounts. Nowhere for water to pool if it gets around the mount holes... plus stainless bolts and nylok nuts are easier to find than stainless lag bolts.

Most tin boats do. It's not so easy to do in 'glass.

Chris....

 

[Mad Props]

Most tin boats do. It's not so easy to do in 'glass.

Chris....

I'll drink to that! Lol

I had my body in all kinda contortions glassing those mounts in.

 

[Biggyniner]

When I pulled the factory engine from me searay it was surprised to see the motor mount was about 25-30 degerees off the centerline of the boat and lagged in that way.

My advice when when you go back in grind existing lags flush seal with 5200& just tweak the mount off center so the holes are just adjacent to the original ones with the busted lags. I used a 3/8 x 18” long but to drill new holes with the engine in place and aligned on mine as I was swapping a 4.3 to a 5.0 and holes needed to be 4” farther forward

I'll see if this is feasible. I don't have a lot of lateral room on the stringers, but that might work.

 

[Biggyniner]

Here are some pics... Do you think if I epoxy the holes, I have enough room on that stringer to bolt the motor mount to it, ****-eyed at a bit of an angle? Pardon the dirty bilge, I just got her and have yet to deep clean it...

 

[achris]

From those pictures, looks like well enough room for the mount to be bolted in at about 30 degrees off...

JMHO,

Chris.....