Merc V6 History

[rckid74]

The first several sandcast engines were built using hardware that was very minimal in detail features. They’re only purpose in life - at least initially - was to show power level, fuel economy, vibration level, cooling characteristics, and basic durability. Once these were determined to be good, upper management gave the go-ahead to finish up the design and head for production. I’m guessing now, but I’d say this point was reached about 12 to 14 months into the program.
In order to get some boat performance data we had to adapt the new powerhead to the in-line 6 undercarriage. While not ideal, that was the best we could do short term. Boat and dock endurance proceeded. Additional sand cast units were built. Design of the production undercarriage, engine accessories, and cowl proceeded with all haste. Sand cast parts were made. Hand-layed-up fiberglass cowls were made. By early ‘72 we had a complete sandcast prototype unit. Testing proceeded, changes were made and retested time and time again. Later that year we felt ready to start production tooling.
Now production tooling rarely ever produces parts that perform just like your previous prototype parts. For one thing, vendors and our own production people are always asking for changes to facilitate their making of the parts. Making and testing these new parts with all these changes is what we spent most of our time doing for the next couple years. As an example, I recall that the production cylinder liners did not give as good flow patterns as what I had developed on the “Jante Fixture”. We made some changes and improved the patterns a little but they never were as good as the originals. This was just typical of the hundreds of new parts. This engine used almost no parts from any of the then in production engines. The spark plugs are the only part I can think of that weren’t new. So this was a major, major undertaking for Mercury.

[Mark75H]

At about this time Merc unveiled the last of the inline 6 race motors, the T2X which used the mid section that would be later used under the V-6 and had the not yet released V-6 base pattern with an adapter for the inline powerhead.

Would you say this was because V-6 development was behind or that the mid section with the V-6 pattern was just built in anticipation of the V-6 coming in the future?

[rckid74]

I'm not familiar with the T2X mid section. My guess is that it was a special sand cast unit used only for racing. The V6 engine was developed well ahead of its' mid section. As I indicate above, we had to make a special adaptor plate to mount it to the inline mid section just to get some boat testing done. The production V6 mid section came somewhat later.

At about this time Merc unveiled the last of the inline 6 race motors, the T2X which used the mid section that would be later used under the V-6 and had the not yet released V-6 base pattern with an adapter for the inline powerhead.

Would you say this was because V-6 development was behind or that the mid section with the V-6 pattern was just built in anticipation of the V-6 coming in the future?

[stace911]

Thanks Jerry for the great history lesson! I was just a small kid in the late 70's who spent summer days at Lake Sam Rayburn in east Texas and remember the infamous name "Black Max" on boats that had a sound like no other. My childhood dream was to someday own one. Just one year ago my dream came true!

Stace

[99fxst99]

I remember those drilled bolts well, especially crawling into the bilge of a bass boat to hook them up. Cross threaded a few of those!
How was it that the early engines had the oddball transom bolt pattern?
GREAT thread! Thanks for all this info!

[rckid74]

I’ve been pondering just how to approach this next entry, that is, the introduction by OMC of their 200 HP V6. A lot of this will just be my opinion as I don’t have a lot of facts about that. So, here goes.


We, Mercury, had made a 50 unit pre-production run of our V6 sometime in early 1975. However, problems developed which prevented us from making a mid-summer introduction. I forget just what those problems were, they may have been either engineering or manufacturing in nature, most likely a little of both. We spent the better part of that summer correcting those, aiming for a second run that Fall. It was during this time that OMC introduced their V6. I, for one, was devastated, deflated. I had no idea that was coming and I doubt anyone else at Mercury did either. True, I had seen evidence several years before which proved that OMC knew about our V6 and in fact had detail knowledge of it, but I had no idea they were proceeding with their own. Perhaps they were already working on it before they found out about ours but, in any case, that knowledge would have spurred them on to complete it before ours came out.


Here’s what I think actually happened. OMC finds out sometime in the early seventies about our 2 liter V6 and decide they have to do something. The easiest, quickest, and most effective counter play would be to just add 2 more cylinders to their V4. True, it would still be a cross flow engine but they would more than make up for that with displacement (150 ci. to 122 ci.). If they kept the same 90° bank angle they could machine it on the V4 line, and could use the same rod-piston assy. and all the inlet system from the V4 also. This was a very much easier thing to do than what Mercury was trying to accomplish. One problem they faced was just how to handle the crankshaft configuration. If they kept two rods on one pin like in the V4, the firing order would be uneven (90-30-90-30-90-30). If they made the firing order even, they would have to offset the pins which would require a thicker web between pins. Then that would require greater bank offset and that would screw up the machining line. They made the obvious decision to go with the uneven firing order. I don’t know of any problems they experienced due to that. It might have had a funny sound at idle but at higher speed would hardly be noticed. The cycle to cycle torque peaks would be somewhat higher but not nearly so bad as if 2 cylinders were firing at the same time.
They pulled it all off and came out ahead of us. It was a brilliant solution and I give them full credit for it. They accomplished what they set out to do. I don’t know just how many years that engine stayed in production, probably less than 10. So I guess we get to have the last laugh since “Black Max” is still in production 39 years later.
I think this might be a good time to take on questions about the 2 liter and then I'll talk a bit about the V4 and the X12.

[Rotary John]

I’ve been pondering just how to approach this next entry, that is, the introduction by OMC of their 200 HP V6. A lot of this will just be my opinion as I don’t have a lot of facts about that. So, here goes.


We, Mercury, had made a 50 unit pre-production run of our V6 sometime in early 1975. However, problems developed which prevented us from making a mid-summer introduction. I forget just what those problems were, they may have been either engineering or manufacturing in nature, most likely a little of both. We spent the better part of that summer correcting those, aiming for a second run that Fall. It was during this time that OMC introduced their V6. I, for one, was devastated, deflated. I had no idea that was coming and I doubt anyone else at Mercury did either. True, I had seen evidence several years before which proved that OMC knew about our V6 and in fact had detail knowledge of it, but I had no idea they were proceeding with their own. Perhaps they were already working on it before they found out about ours but, in any case, that knowledge would have spurred them on to complete it before ours came out.


Here’s what I think actually happened. OMC finds out sometime in the early seventies about our 2 liter V6 and decide they have to do something. The easiest, quickest, and most effective counter play would be to just add 2 more cylinders to their V4. True, it would still be a cross flow engine but they would more than make up for that with displacement (150 ci. to 122 ci.). If they kept the same 90° bank angle they could machine it on the V4 line, and could use the same rod-piston assy. and all the inlet system from the V4 also. This was a very much easier thing to do than what Mercury was trying to accomplish. One problem they faced was just how to handle the crankshaft configuration. If they kept two rods on one pin like in the V4, the firing order would be uneven (90-30-90-30-90-30). If they made the firing order even, they would have to offset the pins which would require a thicker web between pins. Then that would require greater bank offset and that would screw up the machining line. They made the obvious decision to go with the uneven firing order. I don’t know of any problems they experienced due to that. It might have had a funny sound at idle but at higher speed would hardly be noticed. The cycle to cycle torque peaks would be somewhat higher but not nearly so bad as if 2 cylinders were firing at the same time.
They pulled it all off and came out ahead of us. It was a brilliant solution and I give them full credit for it. They accomplished what they set out to do. I don’t know just how many years that engine stayed in production, probably less than 10. So I guess we get to have the last laugh since “Black Max” is still in production 39 years later.
I think this might be a good time to take on questions about the 2 liter and then I'll talk a bit about the V4 and the X12.

OMC was working on the cross V-6 long before in infamous blueprint issue. Most of your other assumption are fairly accurate, except different firing orders weren't considered. Time and cost to introduce dictated the current V-4 with 2 more cylinders. Strang went so far as to have 150HP decals made for it to confuse Merc about the real 200HP. If my memory is correct he even certified a 150 HP version with the Merc people in attendance. The 200HP certification came later.

[powerabout]

v6 crossflow seemed like a quick and dirty solution to me, although the crossflow makes a great workhorse and that was proven all over the world.
Not a perfect solution as a race engine though
Surprised me knowing that OMC had production and race loopers ( inlines) prior to the V6 ( which didnt make good work horses when worked hard)
I assume bass boats were the largest market then as they are now so clearly it was all the other fishing markets they had in mind?
I have seen that Rick McChesney has a patent on an etec crossflow, now that would be a perfect workhorse.

[FUJIMO]

I think this might be a good time to take on questions about the 2 liter...

Thanks for remembering(lol), and putting to print everything so far Jerry. Much appreciated. Question. Were any of the first 1750's produced with a "square" crankshaft "female" hole end. These would have been assembled as a complete engine, with a square lower-unit(gearcase) driveshaft top, to fit up into the crank bottoms square reciever. This would have replaced the traditional male/female spline marriage. That you know of, that is?

[194268]

When I was at Marine Engineering (OMC) in the year of '76, they where comparing their 200 to the 1750. I was informed that the 200 was slightly better on the top end and as the load went up the 1750 proved to be increasingly better. I asked why and was informed that the Mercury prop's where better.

[rckid74]

Thanks for remembering(lol), and putting to print everything so far Jerry. Much appreciated. Question. Were any of the first 1750's produced with a "square" crankshaft "female" hole end. These would have been assembled as a complete engine, with a square lower-unit(gearcase) driveshaft top, to fit up into the crank bottoms square reciever. This would have replaced the traditional male/female spline marriage. That you know of, that is?

I'm not sure how good my "remembering" is these days but I try.
No cranks were ever made with a square coupling end that I'm aware of. I can't imagine why anyone would want to do that anyhow. The spline would be stronger.

[rckid74]

When I was at Marine Engineering (OMC) in the year of '76, they where comparing their 200 to the 1750. I was informed that the 200 was slightly better on the top end and as the load went up the 1750 proved to be increasingly better. I asked why and was informed that the Mercury prop's where better.

Mercury always had good props but it could also have been due to a fatter torque curve from the engine.

[rckid74]

OMC was working on the cross V-6 long before in infamous blueprint issue. Most of your other assumption are fairly accurate, except different firing orders weren't considered. Time and cost to introduce dictated the current V-4 with 2 more cylinders. Strang went so far as to have 150HP decals made for it to confuse Merc about the real 200HP. If my memory is correct he even certified a 150 HP version with the Merc people in attendance. The 200HP certification came later.

It would be interesting to know when OMC did start working on their V6?

[John Schubert]

It would be interesting to know when OMC did start working on their V6?

From Rotary John's post above:
OMC was working on the cross V-6 long before in infamous blueprint issue. Most of your other assumption are fairly accurate, except different firing orders weren't considered. Time and cost to introduce dictated the current V-4 with 2 more cylinders. Strang went so far as to have 150HP decals made for it to confuse Merc about the real 200HP. If my memory is correct he even certified a 150 HP version with the Merc people in attendance. The 200HP certification came later.

[John Schubert]

ry John

What do you think about Lars Strom's quote from another thresd?

The BRP management asked for a new aggressive design so you can tell it is an Evinrude outboard from long distance.

The engineering department went back in the Evinrude history book and looked at the successful racing rotary.
You can see many similarities here.