Gm 140 3.0 motor reliability ???????

[Cowboyhick]

I'm have been researching buying another boat for my family. Have seen the
GM 140hp 3.0 in a few boats i have looked at. Can anyone tell me the reliability
on these motors. The pros and cons kind of. i had a 1972 Starcraft super sport with the gm 120HP motor in it. but i don't know any thing about the 140HP. The boat i'm serious thinking about getting is a 1972 Tom Sawyer 18ft with the GM 140HP 3.0.

 

[CharlieB]

Re: Gm 140 3.0 motor reliability ???????

The 3.0 has been around for a looong time, because it is a reliable workhorse.

As long as you religiously perform scheduled regular oil, filter(s), and water pump maintenance, it will serve you well in a small craft up to 19 ft, over that I would recommend the 4.3 V6 for a bit more power.

 

[Bondo]

Re: Gm 140 3.0 motor reliability ???????

Ayuh,... The 140hp is the Big sister to your 120hp,... Fine little motors...
As long as their not dressed as an OMC.....

 

[JimS123]

Re: Gm 140 3.0 motor reliability ???????

I read somewhere that the 3.0 liter was the longest run production motor in history. Not just for boat engines, but autos as well.

That surely is a testimony to its reliability.

 

[Howard Sterndrive]

Re: Gm 140 3.0 motor reliability ???????

I read somewhere that the 3.0 liter was the longest run production motor in history. Not just for boat engines, but autos as well.

That surely is a testimony to its reliability.

except the 3.0 referenced in this thread was never used in cars.

a few US Postal vans in the late 1960's, but not cars

 

[JimS123]

Re: Gm 140 3.0 motor reliability ???????

except the 3.0 referenced in this thread was never used in cars.

a few US Postal vans in the late 1960's, but not cars

I knew someone would say that after I typed it. Let me rephrase! The 3.0 was the longest running model of any car or boat engine.

GM designed it for the Chevy II in 1960. But, when Ford came out with the L-6 144 in their Comet and Falcon, GM panicked and put a 6 in their "compact" cars to be competitive. With no use for their development, they marketed it to the marine industry, and the rest is history.

Coincidentally, I had 2 of Ford's L-6's - one in a Merc and the other a Falcon. I also had one of the original Camaros with the L-6. I think it was a 200, but I forget now. Anyway, I'll take my old "Iron Duke" any day.

(That's what the 3.0 L 4-banger is affectionallly called by many)

 

[Bondo]

Re: Gm 140 3.0 motor reliability ???????

(That's what the 3.0 L 4-banger is affectionallly called by many)

Ayuh,... Depends on the crowd yer in,...
It seems Iron Duke could be about Any 4 cylinder motor ever built outa Cast Iron.....

 

[fishaman]

Re: Gm 140 3.0 motor reliability ???????

I am not completely sure, but I remember helping a friend of mine long time ago with his late 70s/early 80s Citation, and his engine looked quite like the Iron Duke I had in my first boat... It definitely was not a 3.0, it was something like 2.4 engine.

 

[Fordiesel69]

Re: Gm 140 3.0 motor reliability ???????

Pro's:
-Very durable
-Very common, almost 1 in 7 people will have the same engine in your local marina.
-Parts are easy to find and source.
-Cracks externally in almost every case when not winterized so your internal parts are usually re-usable to transfer over.

Con's:
-Very underpowered.
-Consume more fuel than a V6 and even some V8's in comparable hulls at same speeds.
-A lot noisier as a result of having to operate at high RPM to acheive same speed.
-Most I have test drove had an engine rattle that develops and stays the same for the life of the engine.

 

[Fishermark]

Re: Gm 140 3.0 motor reliability ???????

Ayuh,... Depends on the crowd yer in,...
It seems Iron Duke could be about Any 4 cylinder motor ever built outa Cast Iron.....

Boy ain't that the truth!

"Iron Duke" is a phrase I have learned not to use at all. Someone, somewhere will certainly correct you if you apply it to any engine. The problem is that phrase is hard to define - you can get about as many opinions on it as you can with asking about what oil to use!

 

[IES99]

Re: Gm 140 3.0 motor reliability ???????

Very reliable, sturdy. One mantra: maintenance, maintenance, maintenance.

 

[rodbolt]

Re: Gm 140 3.0 motor reliability ???????

the iron duke was a moniker given to the pontiac designed 151 CID inline 4, NEVER marinized.
the original 120 was a 153 CID and was used in the chevyII and postal jeeps,jeeps into the mid 70;s.
the 3.0 is a 181 CID that is similar to the 2.5l 153 CID but there were some changes.
both the 153 and the 181 have extensive use in the industrial engine application.

 

[JaseBosto]

Re: Gm 140 3.0 motor reliability ???????

Pro's:
-Very durable
-Very common, almost 1 in 7 people will have the same engine in your local marina.
-Parts are easy to find and source.
-Cracks externally in almost every case when not winterized so your internal parts are usually re-usable to transfer over.

Con's:
-Very underpowered.
-Consume more fuel than a V6 and even some V8's in comparable hulls at same speeds.
-A lot noisier as a result of having to operate at high RPM to acheive same speed.
-Most I have test drove had an engine rattle that develops and stays the same for the life of the engine.

uh, I completely disagree with your "cons"
1.While it's not a powerhouse, I firmly believe my 3.0 has adequete power.

2. The 3.0(Mercruiser or Volvo penta)is up there with the most fuel efficient propulsion systems out there. It definitely shouldn't be compared to v6 and especially v8 fuel consumption. Hull design plays a major role in that.

 

[45Auto]

Re: Gm 140 3.0 motor reliability ???????

The 3.0(Mercruiser or Volvo penta)is up there with the most fuel efficient propulsion systems out there. It definitely shouldn't be compared to v6 and especially v8 fuel consumption. Hull design plays a major role in that.

What do you consider to be the most fuel efficient propulsion systems? Your 3.0L is barely competitive with the V6, much less something like a diesel or a sailboat!

I'm also curious as to exactly why you think that you shouldn't compare the fuel consumption of the 3.0L to a V6 in the exact same hull?

JimS123 1984 Stingray (I've never seen his data, this is what he claims)

Sea Ray 185 from Boattest.com: