Remodeling engine bed - advice needed

[jimbunyard]

Originally Posted by arecuk

Guys, your advices are very helpfull, especialy down here in guatemala where one must improvize. Also my budget is tight.

So what i did - removed the old plates, grinded the thing to fit the new plates. I would rather have the steel plate for mounts, rather then mount them directly to fiberglass bed. See picture, i thing its going well so far.

Regarding engine mounts - the only ones i can get here are bushings df-100. I hope its fine for my small perkins.

Looks good so far.

The DF100 mounts should be fine. They're rated to 850 lbs for a four point mount, so they may be a little stiff with a 400 lb motor/transmission, but they will be much better than solid mounting.

If I understand correctly that your intention is to mount both front and rear mounts on each side to a single plate, and then bolt or screw that plate to the bed after positioning the engine as closely to true as possible, well certainly that will work. In my opinion though, securing the plates to the engine bed should be done solely by screws or bolts through the plates into the bed. Covering the metal plates with fiberglass is probably not a good idea, the differing expansion rates of fiberglass and steel will tend to break any bonds you may initially achieve, also the inevitable condensing of water on the metal because of temperature differentials will trap water between the glass and the metal plates, though in the tropics you may have less of an issue with this.

From your pictures it seems that you intend to glass the blocks you've added to the top of the bed to the original bed. This is very important, whether you go over the plates or not. If it were me I'd glass the blocks in first to ensure I had a good structure to mount the plates and motor mounts on.

Originally Posted by reed1v

1. would advice against gluing(epoxy) the lags into the bed. Down the road you will want to remove the engine and may not want to destroy the bed in doing so.
2. Nothing wrong with aluminium except its a soft metal. The racing boats are not built to last very long. Also aluminum needs protection against corrosion due to stray currents, galvanic reactions, and certain chemicals. That said, makes a fine hull as long as you stay away from currents which can disintegrate aluminium quickly. It basically becomes an zinc anode. It also can get stress cracks(think airplane wings) from repeated flexing. Doubt if that would be relevant to your situation.

The engine mounts should be firmly attached to the engine bed. To remove the engine for overhaul one normally removes the top nut from the stud shown in the picture below. If one has to remove the mounts, the wax or light oiling one used before installing the bolts or lags allows one to remove them (though usually one can remove them without waxing or oiling, I think because they come from the manufacturer with a light oily coating anyway)...