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I want make myself a set of solid engine mounts for my little 3 cylinder 70hp evinrude.
The rubbers in my top mount look as if they are about to fail, and my spares engine (same year same model)
mounts were total bad.

I was toying with the idea of making some solid inserts to go straight into where the rubber bushes were
but then thought maybe best to make a complete unit as it would be stronger.

what I propose to do is to use either alloy, stainless steel or solid steel bar.
Stainless would be harder for me to work with and find the side I need
ordinary steel could obviously corrode and cause a problem in the future
and with alloy it would need to be billet for cast would be total crap strength wise.

[b If using alloy billet what grade would I need, at the moment I am thinking 6082 t6 !!
does this sound right or do I need a different type ?[/b]

below is the type of thing I want to make, mine will be a lot uglier than that of course as
I am not an engineer and don't have a milling machine.
But I do have a good strong industrial pillar drill to get all the holes precise.

these are not mine they are taken from the net, but almost what I want.

6061 T-6
Contact Hevi Kevi. I think he's already made these. He can probably make & ship you one faster then you can make it yourself.

Thanks Northbase,
I have a drawing for the uppers but I only have solid lower mounts for the short shaft. Never made any for the longshaft yet. There was a guy on S&F that was making them I think. Pretty sure they are the same as the V4's and V6.

I can make them, but just not sure about what to use.
I can get 6061 t6 and can get 6082 t6, just wondered what is the strongest.
or would stainless be even better ?
for the bottoms I will do an easy way with a plate on outside and plate inside, seen a very simply way to do that.
its the top I am more worried about as don't want to be taking powerhead off again to put it right, or worse have the mount break.

I cant believe how crappy the original mount is, they use minimum amount of CAST alloy, its a bit of a joke realy how thin the wall of
the mount is, no way would I ever dreamt its so thin walled, and CAST alloy too.

my problem buying stuff from Canada and the states is postage and customs duty, its a real killer is the uk tax system.

is the 6061 t6 stronger than 6082 t6 ?

from what i saw there is only a 5% difference in strength between 6061 and 6082. I would use 6061 as that is what I think the majority of aftermarket mounts are made from.

Steve

well I looked up about the difference myself, it seems that ineurope the 6061 has been substituted for the 6082.
a couple of stockist both told me the same thing that the T-6 designation is what refers to the strength and both are the same ???

but either way I asked both about what I am making and they both say that either would be fine and plenty strong enough ??

so I think ill probably go with whatever I can get now, but I do know that if using stainless I would have to use 316L or get too must rust.

someone else at a steel stockist told me they put a piece of stainless 304 in a bucket of salt water for a test along with a piece of the
exact same size metal in just mild steel. !!!!
the result was both showed around the same amount of rust over a 1 week period, now that did shock me.

I did think about using just steel as that's what the steering arm is made of. ( just one of those daft idea moments )

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T-6 designation is the heat treat process.

In regards to the difference between the two alloys that i have found available to me I looked on a few sites.

I got this bit information from aalco ( largest uk metal stockholders)

Aluminium alloy 6082 is a medium strength alloy with excellent corrosion resistance.
It has the highest strength of the 6000 series alloys.
Alloy 6082 is known as a structural alloy.
In plate form, 6082 is the alloy most commonly used for machining.
As a relatively new alloy, the higher strength of 6082 has seen it replace 6061 in many applications.
The addition of a large amount of manganese controls the grain structure which in turn results in a stronger alloy.

when I asked around a few cnc and engineering shops they all said 6061 t6 is a bit old hat and they don't use that
anymore as the 6082 is superior for strength.
when I asked about saltwater applications they gave me blank stares !!!

so it seems 6082 t6 is stronger than 6061 t6.
I think either will be fine for what I want to make (top motor mount).

just have to go and get a couple of bits now, as my first attempt is bound to be crap
so enough for a second try is what I will get.

.

Well I went ahead and ordered some 2x1 6082t6 billet alloy for my mounts.
not too bad on price £15 ( $30 Canadian ) for 16 inch long by 2 inch by 1 inch block..
top ones will be dead easy as just a couple of cuts round the little ridges and drill 5 holes .

the bottoms I will be making and drilling and tapping a thread into them to take original bolts.
what I aim to do is just make a nice big chunk to go inside with a stainless plate on the front outside edge.
I will be posting pics of them once they are done.

my first ones will be all done by simple hand tools, but a friend I spoke to has told me he will be making
outboard engine solid mounts in the future once his new milling machine turns up in a couple of months.
will look forward to seeing what he makes and from what I gather he will be very cheap.

so I need to make mine look good or he will take the piss out of me something rotten.
That means I will be rounding off the edges and making it shine on one side.

High guys quick update on my latest bodgeneering attempt with the solid mounts.

So far so good, well good ish .slight cock up but never mind. i know about it.

here is a couple of pics of my solid top mount so far, remember I dont have a milling machine and I bodge stuff like this.
I have made a cock up, in that the two holes for the steering bar are both off by 1 mm to the left .
when I connected up the steering bar and bottom mounts I cant see any difference with my eyes (mr magoo ).
with the original rubber mounts the top could go either way by a few mm due to engine vibration so I am hoping this
wont matter too much.
this is only the mk1, I probably wont get it right until about mk 8 ha ha ha

the pics are not good and it all looks way off square, but infact it fits in the top perfectly and dead square.

I still have a small section to cut away at the front of the mount where the main drive shaft comes up, this will be done
next time its dry enough for me to have electric to my garage.
( we have had so much rain in the UK , even today I had to pack away quick)

I am thinking of cutting a bit out where the bolt heads go to make them sort of captive, and just ram a piece of rubber
down the back so they cant come right out the slots if I was to loosen the nuts , why I am thinking this I have no idea,
just thought it might come in handy if I need to take engine away from bracket for any strange reason.
anyway to those who are machinists please close your eyes, coz this aint too pretty . ( Bloody brilliant for me though )





this one shows what I have yet to cut out.



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