Oil Analysis for high-hour 4.5L 250 HP

[Lou C]

No they are Merc produced engines not GM based. the 4.5 bears no resemblance other than number of cylinders to the 4.3..

It is confusing on the 6.2, Merc did use a GM bases 6.2 up until like 2015 ( stroked 5.7) the new Merc 6.2 other than displacement has no commonality with GM made engines.

I think where this will hurt guys like us is if you ever need an engine you can only get it through quicksilver/merc. Not sure if the aftermarket will start supplying machine shops with rebuild components but the days of getting a relatively off the shelf GM marine new base engine or reman are likely over.

Scott take a look at a Merc parts diagram
you'll see that the 4.5 has many features of the old 4.3
1) 90* included angle between cyls, why would you design a brand new V6 with a 90* angle instead of a 60* angle which is normal for V6s
2) same split journal crank
3) same balance shaft set up
4) cast iron block and heads
looking at it pretty carefully I'd say maybe Merc bought GM's old tooling lol.
The biggest difference is that the modern 4.5 has fully integrated electronic control systems not add ons like the old 4.3. The head castings are somewhat different, and it is big step forward in smoothness vs the old 4.3.
Now the issue for people who keep them a long time is, the parts cost a fortune. To the point where, cost wise, it has no advantage vs an outboard.

 

[Lou C]

No they are Merc produced engines not GM based. the 4.5 bears no resemblance other than number of cylinders to the 4.3..

It is confusing on the 6.2, Merc did use a GM bases 6.2 up until like 2015 ( stroked 5.7) the new Merc 6.2 other than displacement has no commonality with GM made engines.

I think where this will hurt guys like us is if you ever need an engine you can only get it through quicksilver/merc. Not sure if the aftermarket will start supplying machine shops with rebuild components but the days of getting a relatively off the shelf GM marine new base engine or reman are likely over.

I spoke with the guys at Michigan Motorz about this and they hardly ever get a core to reman. That might be good news, maybe Merc did a better job than GM.

 

[dubs283]

maybe Merc bought GM's old tooling

They did

Mercury, or Brunswick/someone in the family bought GM's foundry in Mexico along with the rights/specs/proprietary info for the 4.3, 5.7, and 7.4L engines

Dunno the specifics of the deal but possibly an agreement is mercury cannot "reissue" any of these engines or the epa won't allow it

WAG is mercury used all of GM's history and info for the engines and developed re-engineered designs seen in the 4.5, 6.2, and 8.2L engines. Also, these are the only sterndrive/inboard engines mercury is producing

Seeing as how sterndrive and gasser inboards are becoming a thing of the past my other WAG is mercury will slowly phase out the mcm/mie line and focus only on outboard engines.

I think right now the biggest market share for inboard gasser engines is the surf/wake industry which has multiple engine manufacturers to choose from. Aside from the bravo 4s mercruiser hasn't had much to do with that style of boat.

 

[Scott Danforth]

the 8.2 is just a GMPP 502 motor. nothing special about it. same motor that you can order from GMPP or Summit or Jegs or your local GM dealer.

the early 6.2's were built in-house at brunswick in both stillwater and fon-du-lac with GMPP parts, including the stroker rotating assembly and crane cams.

then GM pushed the 377/6.2 as a standard long-block offering to all the marine marinizers

the industrial/marine motors kept the SBC alive for nearly 15 years after the SBC was replaced with the LS motors on the automotive front.

GM moved the industrial product line to LS motors, which VP, Indmar, Ilmor, and a bunch of others jumped on. Mercruiser de-tuned the 8.2 to fill in the 425hp slot for the 8.1 in 2009 and continued their parts-bin motors with the SBC based 4.3 and 6.2 when the rest of the industry went to the LS and LT motors.

Then brunswick bought the plant to keep the technology lacking Gen 1 SBC based family alive on life support. the rest of the world moved on to the LT motors in 2015. like the VVT 4.3 putting out 280hp or the VVT 6.2 LT motor putting out 430hp or even the LSA that put out well over 700hp.

as to migrate to only outboards. doubt it. they will look to make a buck where they can cheaply and without any significant risk.

However gone are the days where the marine offering came out of the same plant as the truck offering. EPA has put a stake in the heart of simple marine motors starting back in 2012.