Just found a shredded bolt in my engine bay.

[vyv_cox]

Certainly a fatigue fracture. Multiple origins, typical with a cut thread or groove in round components. The final fracture area is very small indeed, showing that it was carrying little load when it failed.

 

[Rhylsailer99]

Certainly a fatigue fracture. Multiple origins, typical with a cut thread or groove in round components. The final fracture area is very small indeed, showing that it was carrying little load when it failed.

Big job broke out now. Replacing all the engine mounts. I got these brackets about 5 years ago and now they will be of use. Would it be wise to replace all the bolts as well?

 

[Stemar]

Would it be wise to replace all the bolts as well?

I would. The additional cost is negligible, and the peace of mind invaluable.

 

[vyv_cox]

Big job broke out now. Replacing all the engine mounts. I got these brackets about 5 years ago and now they will be of use. Would it be wise to replace all the bolts as well?

I would. You can buy high tensile bolts, 8.8 galvanised at Screwfix, very cheap.

 

[Rhylsailer99]

I am worried how to do the 2 front mounts because I have had issues with the front ones becoming loose. You can see that they have been bent as the bearer is not quite long enough.
I do not like the idea of bending new mounts to fit.
It looks like one of the previous owners drilled an extra hole in them.

 

[Seastoke]

you could drill mount and put in say 6 mm coach bolt as well .

 

[Rhylsailer99]

you could drill mount and put in say 6 mm coach bolt as well .

I just notice the original bukh engine mounts are round. The ones on my boat do not look original as they are rectangle. Will be interesting to see if the holes match when I get the new mounts.

 

[Seastoke]

I just notice the original bukh engine mounts are round. The ones on my boat do not look original as they are rectangle. Will be interesting to see if the holes match when I get the new mounts.

Will you have to have boat lifted to align shaft.

 

[Rhylsailer99]

Will you have to have boat lifted to align shaft.

I will attempt it in the water first.

 

[Rhylsailer99]

I would. You can buy high tensile bolts, 8.8 galvanised at Screwfix, very cheap.

Would the bolts in the pic be ok or is 8.8 the correct spec. I bought some 10.9 soec.

 

[Plum]

Would the bolts in the pic be ok or is 8.8 the correct spec. I bought some 10.9 soec.

The 10.9 will be stronger but must be tightened to a higher torque otherwise it's more likely to come loose. I would stick to the correct spec.

 

[vyv_cox]

Would the bolts in the pic be ok or is 8.8 the correct spec. I bought some 10.9 soec.

Sorry, I don't know what the spec is but I would use stronger than basic 4.6 or 6.8. 10.9 are stronger than 8.8 but can have a tendency to be brittle.

 

[Rhylsailer99]

The 10.9 will be stronger but must be tightened to a higher torque otherwise it's more likely to come loose. I would stick to the

Sorry, I don't know what the spec is but I would use stronger than basic 4.6 or 6.8. 10.9 are stronger than 8.8 but can have a tendency to be brittle.

I think I will go with 8.8. I have read the harder screws need to be tighter, and not sure about going so tight into the alloy gearbox casing.

 

[ontop]

Engine is a Bukh dv20 and the bolt was sat right next to the back right sided engine mount.
Will have to wait for the water to go as the boat is rolling so much in the east winds.
Must have sheared someehere as it has red paint on it.

Engine is a Bukh dv20 and the bolt was sat right next to the back right sided engine mount.
Will have to wait for the water to go as the boat is rolling so much in the east winds.
Must have sheared someehere as it has red paint on it.

Clean the top of the stud, hold a nut over the top of the sheard bolt & with an arc welder weld the inside of the stud to the nut, leave to cool then gently unwind & replace the bolt.

 

[Rhylsailer99]

Clean the top of the stud, hold a nut over the top of the sheard bolt & with an arc welder weld the inside of the stud to the nut, leave to cool then gently unwind & replace the bolt.

By the luck of god it came out with mole grips .

 

[Rhylsailer99]

Getting there slowly kness are killing me going up and down without ladders.