Facts about Evinrude/Johnson racing outboards made my OMC

[lars strom]

Offshore racing. Not sure but looks like Second Effort - Limited Edition production Johnson V8 engines.
Picture credit: unknown

[lars strom]

Billy Rosko huffed & puffed, but his Merc V-6 couldn’t blow the OMC V-8’s away..!!


http://svera.se/blogg/billy-rosko-hu...omc-v-8s-away/

[FMP]

I'm starting to get the impression that you favor OMC.

[Rotary John]

Well I certainly wasn’t there when any of this happened. I would be interested in seeing a parallel timeline of OMC vs Merc v6 development. Still, the crossflow v4 that the omc 6 was based upon went into production in ‘69. The Merc V6 was a clean sheet starting in the early 70’s and used a much better layout (60* vs 90* odd-fire). I’m not really trying to start a pissing contest, but let’s be real...

The OMC V6 was designed to give a production expedient answer to the V6 everyone knew was coming from Mercury. The Mercury V6 was a clean sheet design that eventually saw up what - 280 hp in basically it’s original form? Can you crush that power with an OMC V6? Sure, if you’re Stoker or Monty. A 2.0 Merc an be stretched to 300 hp too if you’re the Capt or T-Rex. 10,000 RPM’s!!!

The OMC production V-6 didn't go into production until 1974. 2 hand built 2l engines raced and won in Paris in 1973 against the merc V-6. The OMC design was indeed the V-4 with 2 more cylinders. This was because of production transfer line tooling already in existence. Merc didn't have any V engines and as such had to do a clean sheet design. And if you recall is was designed as 150HP. The Hp race continued for years there after including the ill fated 300 HP Merc. and the OMC V-8

[lars strom]

Evinrude E-TEC V6 225 H.O.

[nitro_rat]

The OMC production V-6 didn't go into production until 1974. 2 hand built 2l engines raced and won in Paris in 1973 against the merc V-6. The OMC design was indeed the V-4 with 2 more cylinders. This was because of production transfer line tooling already in existence. Merc didn't have any V engines and as such had to do a clean sheet design. And if you recall is was designed as 150HP. The Hp race continued for years there after including the ill fated 300 HP Merc. and the OMC V-8

IIRC the original Merc V6 was 175 hp. The 175 came later. Merc did originally intend to share some tooling from the inline with the new v6 (rods/pistons?) but the idea was scrapped to better meet the design goals of the v6 project.

[lars strom]

Well kind of difficult to use a direct/cross-flow Merc piston from the in line six to a looper V6

[nitro_rat]

Well kind of difficult to use a direct/cross-flow Merc piston from the in line six to a looper V6

Re-reading and the spec was actually to use the same bore as the inline (2-7/8”) to facilitate sharing of the ring package. Also part of the spec was sufficient bore spacing to accommodate an overbore to 3” in the future.

I’m not really interested in continuing a pissing contest though. What I am interested in is the development of OMC’s V6. I’m interested in hearing any info from those who were there regarding the impetus for the project and design goals, setbacks, etc.

[lars strom]

Evinrude E-TEC V6 225 H.O.

[Instigator]

IIRC the original Merc V6 was 175 hp. The 175 came later. Merc did originally intend to share some tooling from the inline with the new v6 (rods/pistons?) but the idea was scrapped to better meet the design goals of the v6 project.

Their inline 4 was two 2 bangers stacked, their mighty �� Inline six was three 2 bangers stacked.
Same rods, pistons (cross flow by the way), carbs and reeds.

[nitro_rat]

Their inline 4 was two 2 bangers stacked, their mighty �� Inline six was three 2 bangers stacked.
Same rods, pistons (cross flow by the way), carbs and reeds.

I’m all for economy of production! It just wasn’t the BEST way to make the V6 platform work in my opinion. Those of you with larger hulls than 17’ Hydrostreams May appreciate the grunt of the extra displacement...

[lars strom]

I'm starting to get the impression that you favor OMC.

...



...and YES..this is a thread about Evinrude/Johnson outboards.

[lars strom]

Evinrude E-TEC V6 225 H.O.

[lars strom]

Evinrude E-TEC V6 225 H.O.

[Rotary John]

Re-reading and the spec was actually to use the same bore as the inline (2-7/8”) to facilitate sharing of the ring package. Also part of the spec was sufficient bore spacing to accommodate an overbore to 3” in the future.

I’m not really interested in continuing a pissing contest though. What I am interested in is the development of OMC’s V6. I’m interested in hearing any info from those who were there regarding the impetus for the project and design goals, setbacks, etc.

The HP race was in full swing in the early '70's. OMC V-4 @ 135 hp was about as far as it could go in a production mode. The natural progression with the least amount of development and investment was to add 2 more cylinders to the V-4. A line of 150,175 & 200 HP would expand the line and keep the HP race going. When word came back that Merc was going to race their new V-6 at Paris in '73 and was successful in getting the rotary ban, a crash program to reduce the displacement to 2l and have it ready for Paris was started. Sleeving the 2.5l sand cast block was simple but there wasn't time to get the new crank from production tooling so V-4 cranks were welded together. Clarence Blanchard shepperred the program and should get the credit for getting the 2 engines ready for Paris. They took 1 & 2 beating the new Merc V-6. The following week the rotary won Windermere beating the Merc V-6 for a second time.