engine mount stud height

I need to verify the dimensions of the stud for the engine mount. I have a 1987 21ft larson cuddy. The previsous owner made a platform, would like to verify the dimensions. They made a box as the pic shows. Theres is a piece of aluminum I think for the mounts to sit on. There is no access hole to use bolts and nuts. Underneath the top cover is void. There is only 2 pieces of starboard underneath the plate running port to starboard. There is no wood underneath either. Is this enough or should I add wood and glass it into the box. I really need to know the diminsions of the stud. I want to put in a 305 or 350 engine in.

Thanks for any help

Re: engine mount stud height

Ayuh,... I think yer Right, those mounts suck...
I build 'em outa solid laminated plywood, so the lag bolts have something to bite into...
To set the height, 'n distance, I hang the motor off the rear mounts, use my alignment bar to set the alignment, 'n meassure from there...

Post up in the Mercruiser I/O forum, 'n maybe Don has an installation manual to give ya an Idea of where ya gotta build 'em...

Re: engine mount stud height

Yes, that starboard and aluminum really will not adhere to glass Yes as stated above....Don S. probably has access to a proper installation manual. On a different note...... starboard was a nice idea but will not last since the stress will pull through it. I would not use it as a spacer either. I would investigate what is below it and see if it is covering some old mount that was pulled through.

Re: engine mount stud height

Ayuh,... Top o the mornin' to ya Bob...

How 'bout you just move this thread to the I/O forum...

Re: engine mount stud height

Like that!! Good Morning!!

engine mount stud height

I already posted this on another forum and Bondo and Bob_VT suggested to post it here. I need to verify the dimensions of the stud for the engine mount. I have a 1987 21ft larson cuddy. The previsous owner made a platform, would like to verify the dimensions. They made a box as the pic shows. Theres is a piece of aluminum I think for the mounts to sit on. There is no access hole to use bolts and nuts. Underneath the top cover is void. There is only 2 pieces of starboard underneath the plate running port to starboard. There is no wood underneath either. Is this enough or should I add wood and glass it into the box. I really need to know the diminsions of the stud. I want to put in a 305 or 350 engine in.

Thanks for any help

Re: engine mount stud height

that is a pretty bad pic, can't really tell what you are trying to explain there

but, the front engine mounts will sit on top of whatever plate you have on either side there

getting to the motor height adjusting nuts does not look to be an issue for either merc or volvo

Re: engine mount stud height

Check out the replies from Bondo. I originally posted this under Nonrepair I/O and inboards.

Re: engine mount stud height

Approx measurements are 21 -1/2 for the mounting holes, overall width of my 350 with 4 inch risers is 30 inches. Your engine box looks to be for a 4 cly. motor. Regardless of what your installing , you will need some wood stringers installed or sufficiant strength in the side walls for 4 inch aluminum angle to bolt the mounts to.

Re: engine mount stud height

okay - i would get rid of everything you have there and start from scratch

you are going to need to build solid core mounting blocks for the engine mounts - those boxes aren't gonna have the support you need

as far as the height, there is a dimension you need and it probably includes first mounting the transom plates and measuring height and distance - what those dimensions are i do not know

as stated in the other forum, there are folks here who may have access to that info

what i would do is:

- remove what is there now
- install the transom assy
- hang the engine in the bilge and attach the rear mount with the mounting bolts
- use the hoist to gently raise/lower the front of the engine until you can easily slide the alignment bar in/out
- note the height of the front mounts and build solid mounting blocks to fit - prehaps a template of some sort would help??

Re: engine mount stud height

Bob_VT said:

Like that!! Good Morning!!

Click to expand...

Uhhhh, hate to tell you this Bob, but you forgot to move it over.
I'm going to move it over and merge the two posts together so all the information is in one post.