claening up the adaptor omc 56

[phillnjack]

Ok I have an adaptor off my spares omc 56 ci that I use for making solid mounts, and I have noticed it has lots of alloy casting marks
that I will be getting rid of.
But in the adaptor where the transition of the exhaust from powerhead to tuner runs, it has two what I think are major casting flaws.
they run from top to bottom and opposite each other ....
These may or may not be meant to be there to help with exhaust swirl or whatever I dont know.
just wondering if anyone has ground these out and polished the exhaust in this area. I am thinking better flow with these 2 horrible
looking casting flaws gone..
They are pretty sharp on the edges, and to me anything that interrupts in the exhaust path is not good idea.
if this was on a 2 stroke bike I wouldn't hesitate and just grind it out straight away and polish the exhaust as much as possible,
but sometimes I hear some very different idea's on outboard tuning due to the exhaust being so different.


here is a couple of pics to show what I mean.

[FORBESAUTO]

Subscribed to see what others have to say. Me, I would remove and blend all transitions from plate to tuner and ph with them bolted together. Then polish. the small port Mercury two piece plates have a similar but larger casting in them. I've only noticed positive increases in power through out rpm range by doing so and each time I have relieved more backbressure by opening up exhaust. And believe me my boat will let you know in a hurry if I loose any bottom end. I know this is against the grain and not what is supposed to be. But my ph is no where near stock and could be reason for my results. I'm even running the larger rectangular port configuration now and again has helped all the way around. A stock motor may yield different results. My 1st mota was the normal 260 port, with mild lake chest and was the weakest motor I've built out of the hole, even had to go to 2-1 gears. As I kept experimenting and changing motor to gain top end, I kept picking up low and top end by relieving exhaust until I'm currently running the strongest motor I've had yet through out rpm with a supper high flow low restricted exhaust chest, mid, and porting.

[phillnjack]

sounds good, you think like me , get rid of any restrictions and get it all as smooth as possible so it can escape easy..

with the adaptor off I have found so many casting marks, even in the water ways its realy crap.
my little die grinder is definitely going to get warmed up on this.

[flabum1017]

Those are made with lost foam castings, that's just where they glued the foam together. I bet if you looked at a hundred of them, they would all be similar. They shouldn't cause any back pressure but there's no harm on grinding them off either, so go bananas

[phillnjack]

yeah its the lost foam casting on the block, think its the lost foam everywhere else too.
so many casting marks it makes everything ugly.
on the outside of the adaptor you could cut yourself if not careful due to the amount of crap that is left from casting.
bit by bit I ma getting rid of it though, just every time I pick something up I whizz over it with a grinder.

I think on the sst60 they cleaned up a lot of the marks, not all of them though as even they have crap in behind the sleeves that
needs to come out.

arethe newer e-tecs like this , or have they been cleaned up before the customer gets his paws on it.