Mid 90's 3.0LX vs 2000's 3.0L engines

[mark1905]

While hunting down a viable candidate motor to replace my shot 1997 3.0LX, I've been running into a number of 2001-2002 "lightly used" 3.0L motors.

I was under the impression that after Mercruiser switched from the "L" designation, that all motors were then "LX"? What is the difference between my 1997 3.0LX and these early 2000's 3.0L motors?

From what I'm gathering, the only difference is that in 2000 they moved from a 12.75" flywheel to a 14" flywheel? Any other differences?

The valve cover and subsequent shift/throttle cable connections look to be different as well.

Am I compatible?

 

[fishrdan]

Re: Mid 90's 3.0LX vs 2000's 3.0L engines

As far as I know the 3.0L is the normal (base) engine, while the 3.0LX is the high output version. The main difference between the 2 is the high flow head and manifold on the LX. Going down to a 3.0L, I think you are going to notice a difference in power, 20HP or so. Pull up a parts catalog for Mercruiser and see if the LX was available in later years, 2000+, I'm pretty sure it was.

The 12 3/4 flywheel was used in early GM 4cyl marine engine's, 70's & 80's.

Valve cover shift linkage anchor points, just swap over the valve cover and ditch the shift plate that bolts to the head. Though you will have to accommodate for the starter's slave solenoid and coil that bolts to the shift plate, probably all ready located fine on you 97.

You are close enough in years that I think you can easily swap the engines over without fiddling with mis-matched parts too much.

 

[mark1905]

Re: Mid 90's 3.0LX vs 2000's 3.0L engines

The 12 3/4 flywheel was used in early GM 4cyl marine engine's, 70's & 80's.

According to PPT and Michigan Motorz, 2000 was the change in flywheel size..(http://www.perfprotech.com/store/pr...Ignition-1991-to-current-GM181BASE,24318.aspx)

Also, the block and head seem to be the same from 1991-up. On all the new 3.0 engines that I see advertised, it's either pre-1991 or post-1991 which was the switch from L to LX. I actually just got off the phone with Michigan Motorz and he swore that there is no difference whatsoever in the actual engine itself.

http://www.michiganmotorz.com/marine-engine-1967current-p-69.html - "If you have a 1990-2010 3.0L marine engine, then this is your exact engine."


Still gathering details..

 

[Bondo]

Re: Mid 90's 3.0LX vs 2000's 3.0L engines

On all the new 3.0 engines that I see advertised, it's either pre-1991 or post-1991 which was the switch from L to LX.

Ayuh,.... Isn't that when it went from a 2 pc. rear main seal to a 1 pc.,..??

 

[fishrdan]

Re: Mid 90's 3.0LX vs 2000's 3.0L engines

I could be wrong on the flywheel, you'll have to verify it through the Mercruiser parts catalog. (check the flywheel P/N across the years)

The heads are definitely not the same on all 3.0 engines after 1991. The one pictured at Michigan's website is the high flow design, it has the small intake ports. (opposite of what you would think)

There were 3.0"L" and 3.0"LX" engines built in the same year, the X designated the high performance version.

 

[mark1905]

Re: Mid 90's 3.0LX vs 2000's 3.0L engines

The heads are definitely not the same on all 3.0 engines after 1991. The one pictured at Michigan's website is the high flow design, it has the small intake ports. (opposite of what you would think)

There were 3.0"L" and 3.0"LX" engines built in the same year, the X designated the high performance version.

Wait wait.. are you SURE about that? I think that this is entirely wrong information.

Pre-1991 there was only one head.. the normal L model. Post-1991 there was only one head.. the HO LX model. Check your Mercruiser part numbers. The same exact PN for the cylinder head comes up for a 2000+ L model as it does for my 1997 LX model.

1997 LX: http://www.perfprotech.com/store/assembly/Cylinder-Head-and-Rocker-Cover,2330-100.aspx

2000+ L: http://www.perfprotech.com/store/assembly/Cylinder-Head-and-Rocker-Cover,4893-180.aspx

1990-1994 L: http://www.perfprotech.com/store/assembly/CYLINDER-HEAD-AND-ROCKER-COVER,1604-200.aspx


Aftermarket: http://www.flagshipengine.com/catalogpages/23/page23.htm


I move that there are no differences whatsoever on the actual engine itself from 1991 to 2010.. as is stated on the Michigan Motorz page.


Now.. there are some carb differences according to years.. that is listed out in the service manual. As far as the internals though, I think we're comparing apples and apples..

Ayuh,.... Isn't that when it went from a 2 pc. rear main seal to a 1 pc.,..??

Yes, this is correct.. http://www.perfprotech.com/store/articles/3liter-upgrade.aspx

 

[fishrdan]

Re: Mid 90's 3.0LX vs 2000's 3.0L engines

Wait wait.. are you SURE about that? I think that this is entirely wrong information.

Eh, use what ever information you want. I stand by what I said. Don S (I/O guru) seems to think the same thing as I from this thread post #64

Owners manuals were noted for misprints. They don't get updated like service manuals do. Even the OEM service manuals have mistakes in them. Dealers get changes and updates for service manuals, not something that happens with owners manuals.
Oh, and the 3.0LX had a different head on it than the 3.0L

The Vortec/HO/high performance head was only used on the LX, or high output engines, it was not used on ALL 3.0 engines

Check out the intake gaskets used on GM 4cyl marine engines, the small intake port gasket (head) was ONLY used on the LX/HO/high performance engines

Good luck with the engine swap.