Adding Extra Engine Mounting Brackets. How do these look.

[1965GTFB]

This is a 1967 MerCruiser 120 in a Astro Marine Starflite 18. While performing the first running after having the original head rebuilt I noticed a lot of movement from the front mounting point before I got the idle adjusted. This obviously an older boat but it is in great shape. But the floor of the engine compartment was flexing more then I liked and some small cracked in the paint on the floor have started, that likely has allowed water(from skiers/boarders) that would normally stay in the engine compartment and be pumped out by the bilge, to get into the lower hull area. I did notice last year when draining after several days on the lake that the lower hull had been holding more water then is good. I have plans in the next year or two to pull up the floor to add reinforceing and foam so that the old girl won't be killed by all the stupid huge wake board boat wakes out there.

So I fabed up a couple of bracket to mount on the original GM mototr mount holes to take some of the twist out of the engine. What do you think. They will be bolted to the floor, just had not yet drilled and painted(Phantom Black of course) the brackets when I took the pics.

 

[ziggy]

Re: Adding Extra Engine Mounting Brackets. How do this look.

Re: Adding Extra Engine Mounting Brackets. How do this look.

well, it's not oem. though i've seen one other set up (here on iboats, by bond-o's buddy) that had similar mounts. ya gotta have alignment spot on when ya bolt it down as you loose that adj.
have ya tried some holes in the sole/stringer for your new mounts. if the ft. mount wood is rotted. maybe that area is too? might not be too. drilling will tell.

nice fab.

my guess is your gonna need to be doing more than just add some foam next year when ya tackle the job. i'd think more like stringers and transom and sole. just a guess. i've got a boat 4 years newer than yours, the only thing good about mine is the hull. and that's not sayin to much.

i'd think the mod will add stabilty to the engine to some degree. but i think you have underlying issues that these brackets won't cure...

good luck with brackets though, i hope they work like ya want them to..

 

[Don S]

Re: Adding Extra Engine Mounting Brackets. How do this look.

Re: Adding Extra Engine Mounting Brackets. How do this look.

Nice fab job, BUT. Knowing how a 3.0L acts cold, and when doing a tuneup and you first get them running and still need some adjustments. You really need some rubber motor mounts in there. You bolt it solid with a single bolt on the engine, and you are going to have a bolt break or a broken block.
Look here what Volvo did with their side mounts.
http://www.volvopentastore.com/Moto...*****.502736270--store_id.366--view_id.774096
#17 thru #24 is rear mounts and different from Merc.

 

[1965GTFB]

Re: Adding Extra Engine Mounting Brackets. How do this look.

Re: Adding Extra Engine Mounting Brackets. How do this look.

I am actually planning on elongating the block holes to allow for alignment adjustments.

You bolt it solid with a single bolt on the engine, and you are going to have a bolt break or a broken block.

I did think about if it being solid would create any problems. A couple of thoughts were: Some rubber to insulate between the bottom of the brackets and the floor, and or not bolting to the floor and just letting the brackets minimize the movement.
Maybe I should span a bar across both holes on each side and have the bracket I made bolt that bar. That woudl give two mounting points on each side of the block. Also the bolt in the pick was just for mock-up, would go with a grade 8 hex head.

 

[1965GTFB]

Re: Adding Extra Engine Mounting Brackets. How do this look.

Re: Adding Extra Engine Mounting Brackets. How do this look.

Nice fab job, BUT. Knowing how a 3.0L acts cold, and when doing a tuneup and you first get them running and still need some adjustments. You really need some rubber motor mounts in there. You bolt it solid with a single bolt on the engine, and you are going to have a bolt break or a broken block.
Look here what Volvo did with their side mounts.
http://www.volvopentastore.com/Moto...*****.502736270--store_id.366--view_id.774096
#17 thru #24 is rear mounts and different from Merc.

I am actually planning on elongating the block holes to allow for alignment adjustments.

You bolt it solid with a single bolt on the engine, and you are going to have a bolt break or a broken block.
I did think about if it being solid would create any problems. A couple of thoughts were: Some rubber to insulate between the bottom of the brackets and the floor, and or not bolting to the floor and just letting the brackets minimize the movement.
Maybe I should span a bar across both holes on each side and have the bracket I made bolt that bar. That woudl give two mounting points on each side of the block. Also the bolt in the pick was just for mock-up, would go with a grade 8 hex head.
What do you think of tose ideas Don?