Discussion in 'Downeast Projects and Boat Building' started by leaky, Apr 8, 2016.
That’s not uncommon.
Once the engine bed stuff got all straight, after much debate and reckoning I cut a slot in the steering bulkead because the center of gravity on the engine is basically 1 inch forward of the bulkhead and it was going to make it a bear to easily put in place given the clearance needed for the lifting rig - in my install process I want to lower and lift it a few times to get shims right and mark/drill holes, so didn't want to be grinding the chain against the bulkhead and sliding an engine round. Am going to make a bolt on cover to re-join this area versus glassing it back together, such that the engine can easily be put in/out of this boat in the future.
We built a tall gallows behind the boat, a gallows in the boat, set an I beam atop it, rented a little trailer to get the engine out of the garage (which was a bit of a challenge on it's own there ), wheeled the engine under gallows, lifted, set it down into boat.. Original plan was to rent a Lull for this whole part but upon attempting to rent one at least the first place I called said I needed some certification (WTF ?) so went with what I know - build stuff.
Upon getting the engine set in the boat we cut down the gallows in the boat, and built a similar structure using the steering bulkhead, moved the I beam, and now I'm ready to roll it in - just fussing over how to hold the shaft aligned within the shaft tube at the moment (another thread and thanks again for the help there guys!). In the process of setting the engine, will snap a pic later, I've built a shoebox full of aluminum shims in 1.25 inch down to 1/4 inch, that are cut and drilled to fit the engine mounts - with my mount adjustments centered, I'm going to select a shim combination that basically aligns the engine and use the adjustment in the mounts only for final fine tuning.
This is a big step, glad to be here.
Ya if you look at how close the mounts are together it's almost gotta be the only way to do it with a V8 gas; the engine is so short not much room between the two sets of mounts as is.
My dad has that set up on a 6BT with a Borg Warner gear.
Engine is sitting in place now, working on alignment by adding and removing different shims, getting close to being able to drill mounts.
Everything went smooth as far as the engine bed and cutout, engine sits on the mounts right and lines up with the shaft.
Another pic of the whole contraption and bulkhead, cradle for the shaft to center it etc..
One problem I ran into was upon trying to initially lift the engine off the platform and get it into place I did not have enough space for the 2 ton trolley and 3 ton chainfall I was using between the engine bar and the I beam - I ended up getting the 1 ton versions of both (Harbor Freight stuff) just to lift the engine up initially and get it off the platform then I snatched it up with the heavier versions and am using those to set it...
I highly recommend anyone who is doing this with Harbor Freight garbage to use the heavier stuff if you can, the 1 ton version - particularly the chainfall, felt sketchy - very small chain and a ratio that makes you really have to pull on it to lift even this 1300 lb load - even kinda gets jammed up a little when you change directions...
The 3 ton chainfall on the other hand, very smooth, piece of cake to make small adjustments, and is very obviously in it's safe working load.. Well other than the fact that last night the cover for it became loose and was jamming the control chain - I found 2 missing nuts for the cover, at that point I quit and got replacement nuts for it today.
Old boat yard guy I used to know had a right that rode on the overhead beam and was about 5’ long with a shackle at each end. Chainfall would hang horizontally overhead attached to one shackle and the hook would go to a chain that went through a pulley and down to do the lifting. Just took the whole length of the chainfall out of the way but limited the overall travel so you had to lift/block/choke up on the chain but it allowed the overhead beam to be close to the load if you follow me.
Sucks you had to cut the dash... progress.
Ahhh maybe I could've gotten away without it by doing goofy stuff (ie swinging engine into place a bit, it's basically centered on the bulkhead) and if the builder set the engine they would've put it in before the top went on to avoid this, but to me it's how it should be - straight forward to maintain. I'll use the cutout to make a bolt on cover, will look fine, won't be very hard, and some day I'll be able to pull that engine right out if I want in a couple hours no sweat.
Got the engine really really close now, stepped away for night - what I'm reckoning though is these motor mounts are going to compress a lot upon actually through bolting them down, once I'm real confident with these aft mounts starboard to port going to drill the holes and mock bolt them to see, got a feeling they seat down at least 1/16 if not 1/8 and it's just going to throw alignment off all over again. They also do not have much adjustment. Forward mounts are different, rubber is on center and the bolts are just clamping metal to metal, so that will not change - might punt and over-shim them, worst scenario just will be removing a shim.
It comes down to what you have on hand for rigging, and experience. We have a section of I-beam, my gantry, hundreds of jack stands, and a 3 or 4 of us that have several repowers under our belt. Not to mention a crane.
When we repowered my brother ‘s 32 Holland we took a 502 Chevy out and put a John Deere 6.8 in. We used 4x4’s and built a railway of sorts. Then using come alongs made the engine slide slowly down into the hole.
Leaky I think you did fine with the resources at hand. Don’t be surprised if in a couple days from now you go “oh $hit I could have done it that way”.
I could be wrong but would think torquing down on those mounts might not be what you want to do. I would find a bolt that fits the inside diameter of the holes in them, drill and tap the aluminum mount you made and thread the bolt in once the engine is aligned just until the rubber compresses slightly (like maybe 40 lb-ft of torque) and then stop and put a nylock nut on the tip of the bolt under the mount to keep it all from spinning. Mounts would then just be very carefully located by the diameter of the bolt rather than the clamping force of the head on the rubber etc..
Don’t recall if my mercruiser mounts were similar but that engine is much bigger than my 6.2 was.
We were going to move the engine ahead in ours to do some stringer and mount work. I was thinking of some sections of big angle iron for the mounts to skid ahead on. Kind of the same idea I guess with the railway thing.
If you are going to do it in a month or something just borrow my setup.
This is actually a boggling area - no torque spec on them I can find but when I look around it does sound like in a repair manual someplace they call for about 40 lbs on them, which is about the standard torque on a 1/2 inch 316 stainless bolt.
Thanks, ended up picking it up with some 4x4 posts and come-alongs.
Agreed but I think its just for us one timers. Guys that do it every day have a way. For me taking the slop out of the bolt connection is a must and from there there is no reason to do more than just compress things a bit so that is how I arrived at my line of logic...
Got the rear mounts drilled and tapped, engine set back in and everything lines up nice. Tomorrow will tighten down those rear bolts, fine tune for alignment again, then mark and dril front mounts probably one side at a time using a similar process.
Are you going to weld or bolt all of those shims to the angles? I would suggest doing so
I had the thought of either using 5200 or epoxy to help lock things in place, or if it seemed sloppy I'd machine one ~2 inch shim to that height but what I found with those bolts threaded is it's a very tight fit before you even crank the bolts down, actually it's a tighter fit than you would have if the motor mounts were sitting on the bracket directly because the holes are not perfectly lined up in the spacers so the whole thing ends up being a sort of interference fit. I feel good about the setup so am going to run it.
Also would like to leave options as open as possible if say I find these Merc factory motor mounts suck and I go to a different style where something changes, any unnecessary welds or holes I add in the brackets might be a WTF moment performing a simple task down the road.
Glad you mentioned the threading idea, really worked good and was not much process at all. Definitely makes a difference doing it that way.
I wouldn't lock any of those shims down until she has been in the water for a few days and alignment final check. Add fuel and water prior to check