Timber or steel for engine mounts

[captmikem]

Originally Posted by RaymondR

Nay mate, neither wood or steel, alloy is the only way to go, doesn't rot or rust.

I used 75 x 10 x 30 alloy angle which I bolted the engine mounts to with countersunk bolts tapped through the angle from the bottom. The two alloy rails then sat inside the old rails and were located by pins welded into the old rails. I could remove two large retaining bolts and lift the engine out without disturbing the alignment. Drop her back in wiggle over the pins, two bolts and the drive flange and she was ready to go.

I did exactly that 10 years ago with a KP 46 replacing a VW pathfinder with a Yanmar. It worked great and I have had zero problems with it.

M

[peter loveridge]

I used aluminum angle ( mine was 2x2 but engine only 200 lbs). 30 years later it is fine and zero corrosion, stainless bolts like new

[davenrino]

We made a wood mockup of the engine for placement etc. Ironwood beds epoxied and lag bolted to the fiberglass rails and 1/2" Stainless lag bolt through all. Engine mounts mounted via drilled/tapped holes in the SS.

[slug]

Originally Posted by RaymondR

Nay mate, neither wood or steel, alloy is the only way to go, doesn't rot or rust.

I used 75 x 10 x 30 alloy angle which I bolted the engine mounts to with countersunk bolts tapped through the angle from the bottom. The two alloy rails then sat inside the old rails and were located by pins welded into the old rails. I could remove two large retaining bolts and lift the engine out without disturbing the alignment. Drop her back in wiggle over the pins, two bolts and the drive flange and she was ready to go.

Yah. Ive had good luck with aluminum

Keep electricity off it and observe proper craftsmanship

[Reefmagnet]

My current boat has used the aluminium angle bolted alongside the original beds to narrow the mounting width (installed about 2 engines ago) and it's still serviceable so this is definitely a solution. Having said that, galvanised builder's lintels are as cheap as chips and would work fine and are probably available at Bunnings. One thing I do suggest, however, is to make sure the additional height introduced won't screw up the shaft alignment as the base of the mounts need to align with the horizontal centre of the shaft and engine mounts have a limited range of adjustment in some designs (about 15mm for the Beta IIRC). If this is likely to be a problem, builders lintels, angle grinder, welder and cold galv will quickly solve that problem.

[charliehows]

my 40 yr old eng mount plates are 5-6mm angle steel, bit flaky in places but I'm not thinking of replacing them anytime soon. But I would consider using 12-15mm marine grade aluminium if I was doing a replacement.

[CarinaPDX]

Given the size requirement for the OP's project I doubt he would be interested in my approach, but I want to mention it for general interest. My bedlogs need to be raised by 2" for the new engine. The front mounts will be easy as they just need a 2" thick pad, which I have made out of commercial G10 fiberglass, drilled and tapped for the hex mounting bolts of the engine mounts. The rear mounts will require some shaping to the hull. In both cases they will be firmly attached with epoxy and glass to the old bedlogs and the hull itself. The downside is cost: IIRC I paid about $250 for four of the 2" x 10" x 4.5" blocks. These should be plenty strong and inert - no corrosion issues - and offer a perfectly flat surface for the engine mounts (an issue with the current bedlogs).

Greg

[GILow]

Well, lots of happy aluminium users out there. I will put it in the mix. I can see some benefits.

I really liked the builder’s lintel idea too.

Thanks all.

[Uncle Bob]

Originally Posted by GILow

Well, lots of happy aluminium users out there. I will put it in the mix. I can see some benefits.

I really liked the builder’s lintel idea too.

Thanks all.

Builders lintel is what a PO had installed when repowering mine.

[mercater]

Gilow-I used 316 stainless angle iron, can not fault it. Then high density poly ethylene (HDPE) pads that the mounts sit on. Isolates the de-similar metal contact.
Just a note: watch your water line as the reduction in weight will likely lift your prop too near the surface. I ended up using ballasts to compensate when I put my Yanmar in.
Best of luck.

[Lake-Effect]

Several years ago, when I was working as a marine mechanic's assistant, we used painted 3x3" steel angle on top of some chewed-up wood rail. The one thing worth mentioning is that we drilled and tapped the steel rails for the engine mounts. The mounts were then a breeze to bolt on.

[Davo1404]

Originally Posted by davenrino

We made a wood mockup of the engine for placement etc. Ironwood beds epoxied and lag bolted to the fiberglass rails and 1/2" Stainless lag bolt through all. Engine mounts mounted via drilled/tapped holes in the SS.

Nice set-up.

[GILow]

Hmmmm... I simply cannot source aluminium angle that would be remotely strong enough for this job. A pity, since it did sound promising. Likewise, stainless steel would be a bit tricky.

I’ve got a good local source of galvanised lintels in sizes that feel right though.

I’ve taken a day away from the engine to do more enjoyable tasks, I’ll see how it looks tomorrow in light of the suggestions here.

[Q Xopa]

Originally Posted by RaymondR

Nay mate, neither wood or steel, alloy is the only way to go, doesn't rot or rust.

I used 75 x 10 x 30 alloy angle which I bolted the engine mounts to with countersunk bolts tapped through the angle from the bottom. The two alloy rails then sat inside the old rails and were located by pins welded into the old rails. I could remove two large retaining bolts and lift the engine out without disturbing the alignment. Drop her back in wiggle over the pins, two bolts and the drive flange and she was ready to go.

I assume you are talking about aluminum alloy?

It doesn't 'rust' but it certainly oxidizes, corrodes (pick a word).

[GordMay]

Originally Posted by GILow

Well, lots of happy aluminium users out there. I will put it in the mix. I can see some benefits.
I really liked the builder’s lintel idea too.
Thanks all.

What, exactly, are you (pl) referring to, when you say "builders lintel"?
Concrete?