Motor Mount Boss

[Menace Marine]

What is wrong with the current mount setup that put so much stress on the corner of the block?

[WESTERNAERO]

My opinion on how it broke to begin with is the the holes drilled in the motor plate were not quite in the right place. Probably drilled with a 7/16 drill and no clearance. When the bolt was run it it was putting a side load on the casting and popped that piece off. The aluminum is stronger than the cast iron right there so something had to give.

[78Southwind]

When this was Greg's engine he drove his Spectra from Site Six to Laughlin then back and then to Havasu Landing (over 100 miles), the mounts got loose and one of the loose bolts did the damage. It is a Merlin II block and when this happened he had different plates on it that only had 2 mounting bolts per side. His fix was to change out the plates to 4 mounting bolts per side utilizing the water ports. Everyone that I have talked to seems to think that running it with it's current set-up (4 mounting bolts per side) is strong enough and I should not have any problems.

I am just a little different when it comes to doing things and if the block can be welded without creating other problems then that's what I want to do. However, Barry has brought up some good points that welding the block may create other problems.

[WESTERNAERO]

When this was Greg's engine he drove his Spectra from Site Six to Laughlin then back and then to Havasu Landing (over 100 miles), the mounts got loose and one of the loose bolts did the damage. It is a Merlin II block and when this happened he had different plates on it that only had 2 mounting bolts per side. His fix was to change out the plates to 4 mounting bolts per side utilizing the water ports. Everyone that I have talked to seems to think that running it with it's current set-up (4 mounting bolts per side) is strong enough and I should not have any problems.

I am just a little different when it comes to doing things and if the block can be welded without creating other problems then that's what I want to do. However, Barry has brought up some good points that welding the block may create other problems.

Well that could break it too.
Just drill and tap it thru. That's what I would do, but what do I know.

[obnoxious001]

It could be through bolted, but I looked at a regular GM block and a GM bowtie block that I have sitting here (sorry, no Merlin to verify on), and looks like there may only be 3/8" of iron to drill through, might be just a marginal fix.