Engine mount lag screw broke - how to remove?

[JASinIL2006]

Re: Engine mount lag screw broke - how to remove?

Frantically Relaxing, what are those called? I think that's an interesting idea and would maybe be a nice alternative to lag screws.

I have both epoxy and poly resin on hand, so I'm OK with either, I just want to use whatever is strongest and will bond the best.

If I'm bedding studs or lag screws in new fiberglass or epoxy, how much penetration do I need into the engine mount? Is 2 1/2" enough? What sort of fastener material should I be looking at? Zinc-coated? Stainless steel? Galvanized?

Thanks,
Jim

 

[bruceb58]

Re: Engine mount lag screw broke - how to remove?

I would think the only problem would be corrosion on the threads.

 

[JASinIL2006]

Re: Engine mount lag screw broke - how to remove?

I would think the only problem would be corrosion on the threads.

Do you mean the only problem with the lag screw that was stuck or are you talking about one of the solutions for replacing it?

The other lag screws that came out WERE a bit corroded. Not enough that I would expect one to snap, but they were a but rough-looking.

Jim

 

[Don S]

Re: Engine mount lag screw broke - how to remove?

Just grind off the old lag bolt below the surface and fill the holes. Turn the mount a little and redrill both holes. Job done.

 

[mr300z87]

Re: Engine mount lag screw broke - how to remove?

Why not just rotate the motor mount a couple of degrees and drill 2 new holes for the lags and bolt it down. Fill in the old hold with 4200 or 5200 before bolting it down and call it a day. Just my 2 cents.

 

[mr300z87]

Re: Engine mount lag screw broke - how to remove?

I see Don S beat me to it. We must have been typing at the same time.

 

[smokeonthewater]

Re: Engine mount lag screw broke - how to remove?

ding ding ding..... that's the answer you would have done well to hear much sooner.... if you decide to continue on the current route, use 2 part LIQUID epoxy... not putty... ans yes mix it up your pb just the same as you would with poly resin.... you don't need to bell the hole... the jagged rough hole from all of the grinding and drilling will provide PLENTY of grip....

My point about drilling some more was specifically to enlarge the hole next to the remains of the lag enough to allow you to knock it loose and pull it out, either whole or in pieces.

 

[JASinIL2006]

Re: Engine mount lag screw broke - how to remove?

Rotating the mount a few degrees and drilling two new holes sounds a heck of a lot easier than the drill-and-fill method!

Any thoughts on types of screws and length? I think the old ones were about 4.5" long. Seems a bit much to me...

Jim

 

[Don S]

Re: Engine mount lag screw broke - how to remove?

I have always used 3/8" Lag bolts and sized the length to have 3" of threads in the stringer. So 3" plus any spacers under the mount, plus the thickness of the mount.

 

[JASinIL2006]

Re: Engine mount lag screw broke - how to remove?

Great, sounds good. Thanks for the help!

Jim