How good were racing the OMC lower units

[Skoontz]

In `67 or `68 we received from Bruges one of the first 55hp loopers with a racing lu which externally looked the same as the GT115 ones. A hot works SE engine, received in `69, was unable to grenade a like unit within the 40 hours, during which we used it for testing on the Rhine river, as well as the Liege and Berlin 6 hour races, which Helmut Tinscher and I won in that year (Jimbo won ON).
We never had water in the oil or noticable radial shaft play. Only, I cannot remember ever having used a shifter on those motors.

It is quite possible that the OMC back room boys installed a spacer where reverse gear was and you in fact had the X115/GT115 unit on the three banger.
Spacer kits to replace reverse gear were routinely sold for the manual shift pointeed gear cases that Powerabout is referring to, and they would get you marginal incements because the drag of reverse gears flipping through the lower unit oil robbed power.

We were considering extending the lower pice on the pointed cases once so we could get more prop diamter, but nixed the idea when the gear ratio was what it was.

We did have a 75HP V-4 running a 17" 2 blade cupped bronze Johnson-Oakland prop on a 14' Yellow Jacket. It loved eating big black grain silos but we are talking river racing here, not any sanctioned events.

[JohnsonM50]

[QUOTE=Roy Hodges;84634]

Would this type of gearcase have been used in the 36 class?
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nope ! the only omc's allowed in "36" were the 25 &30 horse "Big Twins". The only big twin that had a "pointy" lower unit was the 40 horse electramatic, not allowed in 36 class , because it was about 43 or 44 cubic inches .

Yup those were 43ci & the pointed case wasnt a big advantage over the mechanical shift [bullnose/club foot HD] split case for the same motors.

[Dave S.]

Was trying to take apart one of the pointy cases apart.....hitting the prop shaft with a big hammer to get the bottom part off the top part. The prop shaft BROKE like GLASS. I do not think it would like to be surfaced in water with hammers. If I were to run one I would sneek in a Merc prop shaft. I think it can be done. Powerabout needs to ask for more info but also needs to say what his intentions are.

[JohnsonM50]

I think the pointed ones [not the split case round nose with screws up thru the bottom] are dis & reassembled from the rear like Mercs

[Powerabout]

Ok

The higher horsepower ones are split above the pinion bearing, the lower horsepower ones split the propshaft line.

Having the water pickup behind the prop you could run them quite high without any mods i would guess?

My question was I was interested to know as these were stock cases on the engines and assuming the stock engines were raced in the 60's, how did these boxes survive when surfaced compared to modern stock boxes that flog the bearing carriers out?

cheers

[Mark75H]

Quite simple, they were not surfaced. People raced Mercs and fished with OMC's

[Powerabout]

you could have at least lied!
lol
Cheers

[JohnsonM50]

you could have at least lied!
lol
Cheers

Im of the mindset that all can be improved. How?, another thing for another . What you would run into is prop availabiltiy, gear ratio limits, RPM limits..weight, etc. & on. Not that you cant get speed outta the old OMC, just that the old Merc manufactured the 'good stuff' ready to go, hard to beat. Good Luck with it.