Re-setting lag bolt front engine mount holes

[jimrockireland]

The lag bolts holding in my front engine mounts on my 1983 Wellcraft 196 Sunhatch don't really hold very tightly. What is the best way to refill/re-drill these holes to get the lag bolts to hold better.

 

[Scott Danforth]

Remove engine, rebuild motor mounts, reinstall engine, align engine and go boating

 

[chevymaher]

First question is why it happened is the wood wet? Cut the wood out and replace is the right way to do it.

 

[jimrockireland]

When you say "rebuild motor mounts" do you mean drill out the existing boles clean - then fill them with something like wood filler mixed with epoxy?

 

[chevymaher]

Cut the fiberglass. Remove the wood. Grind the nubs down. Replace the wood and glass it back in.

 

[tpenfield]

What 'we' are saying is that the wood core of the engine mount stringers are probably wet and rotting so the lag bolts are loose. If that is the case, then not an easy way to fix it other than what has been described. Maybe you can take out one of the lag bolts and see if you can get a sample of the wood from the hole.

 

[Scott Danforth]

When you say "rebuild motor mounts" do you mean drill out the existing boles clean - then fill them with something like wood filler mixed with epoxy?

Unfortunately no. Most likely the wood core is wet and gone like Ted mentioned. Only fix is cut out, rebuild / replace and do it right

 

[jimrockireland]

I think the boat is solid. I've had it for 6 years. I've taken the lag bolts out several times and I can only guess how many times previous the bolts have been removed and re-installed. The bolt holes can only take a finite number of times before the holes become oversized for the bolts. I was looking for a simpler way to just repair the holes to where the bolts would bite again. I once used wood filler mixed with epoxy to build a kayak and the result is something you can drill and bolt. .Has anyone tried using wood filler with epoxy to fill in holes or is there another product that works better?

 

[TommyRocker]

Sounds like you've already decided what you're going to do, but since I'm apparently ignorant, what would be the reason to remove the bolts over and over again?

 

[jimrockireland]

When I install the engine I have to use the bucket on my tractor to lift it in place. It requires some pushing and shoving to get it aligned if I leave the front engine mounts in the boat and try to line up the holes on the engine brackets with the motor mounts. It's just a whole lot easier to attach the motor mounts to the engine and then drop the whole thing in place. The other advantage is if I have to reposition the tractor it's easier to set the motor down inside the boat if it has the motor mounts attached.

 

[tpenfield]

So, what you are saying is that the holes have become oversized because you have removed and re-installed the engine several times. :noidea: OK, but just to be sure, check the holes for wetness and rot. If the wood is perfectly dry then try some epoxy to close up the holes a bit, then install the lag bolts.

If the wood is even slightly wet, then the epoxy will not work and you are more on the track that the previous posts have mentioned.

You could also drill a test hole on the side of the engine mount stringers, low near where it meets the hull, to see if you get water coming out.

 

[Scott Danforth]

You are using the alignment bar, correct?

Test drill into the motor mounts, dry light-colored wood shavings and you may be ok. However if the shavings are damp and dark-colored, replace the mounts

 

[jimrockireland]

Not sure what you mean by using the alignment bar. I use that to align the engine coupler to the gimbal bearing.

 

[bbook83]

Those who have advised you to remove the rotted (if it is) mount area are correct. I finally had to do that recently, but I bought several years by drilling the hole larger and driving in lag bolt "shields" like you would use in concrete and then using the appropriately sized lag bolts. If the mount wood is truly solid, you can also drill to size for wooden dowel that you have cut slots in and drive them in along with epoxy.

 

[Woodonglass]

If in fact the motor mounts are dry and solid and Only the holes for the lags have wobbled out to oversize holes, Here's how I'd recommend repairing them. fill them with a piece of wood as best you can and then center a 2" spade bit and drill em out to this size. Once the oversized holes are drilled fill them with 2" wooden plugs using epoxy. Then drill the Plugs to the correct size for the lag bolts and reinstall using 3M 4200 sealant. That's how and Old Dumb Okie would do it.

 

[jimrockireland]

Thanks for all the advice. I was really just interested in how an experienced boat restorer would tackle the problem I have without major reconstruction surgery.

 

[Scott Danforth]

We would test drill, look at the shavings and then proceed from there. If the shavings are wet we would replace the mounts and fiberglass accordingly

 

[jimrockireland]

Thanks for all the advice. I'm going to try the lag shield idea first. It can't hurt and does not preclude the other ideas if it does not work.