Engine choice on Grand Banks 42 - Page 2

bayview · 09-26-2019, 12:22 PM

I also do all my own work and prefer inline engines. They also have fewer wear parts such as heads, exhaust, turbos, cooling tubing. Easier to access the outboard side as well

rslifkin · 09-26-2019, 12:23 PM

Quote:

Originally Posted by bayview

inline engines. Easier to access the outboard side as well

That one is somewhat engine specific. Depending on the manifold layout, a fully assembled inline can be just as wide as a V block, at least for a crossflow inline (where the intake and exhaust manifolds are on opposite sides).

T210DRVR · 11-09-2019, 05:18 PM

So far I’m seeing 7.5 to 7.7 knots at 1500 RPM with Lehman 120’s. I can get a bit over 8 knots at 1800 RPM but the engines seem happiest at 1500.

jdscott3 · 11-10-2019, 05:01 AM

I'm late on this one, but my two cents. My 1982 GB Classic 42 has been repowered with a naturally aspirated single John Deere 6086. She hums along at 7.5 knots burning 1.5 gph fuel, at 8 - 8.5 knots I'll burn about 2 gph. I love my powerhouse, I found I had enough torgue to get me out of some crazy currents in tight spots heading up the inside passage last summer. She is not underpowered thats for sure.

Nomad Willy · 11-10-2019, 05:41 AM

Quote:

Originally Posted by T210DRVR

So far I’m seeing 7.5 to 7.7 knots at 1500 RPM with Lehman 120’s. I can get a bit over 8 knots at 1800 RPM but the engines seem happiest at 1500.

That dosn’t have much meaning unless one is privy to the WOT rpm.

diver dave · 11-10-2019, 07:42 AM

Quote:

Originally Posted by jdscott3

I'm late on this one, but my two cents. My 1982 GB Classic 42 has been repowered with a naturally aspirated single John Deere 6086. She hums along at 7.5 knots burning 1.5 gph fuel, at 8 - 8.5 knots I'll burn about 2 gph. I love my powerhouse, I found I had enough torgue to get me out of some crazy currents in tight spots heading up the inside passage last summer. She is not underpowered thats for sure.

4nm/g is awesome for a high windage, 17 T powerboat.

sunchaser · 11-10-2019, 07:59 AM

Quote:

Originally Posted by jdscott3

I'm late on this one, but my two cents. My 1982 GB Classic 42 has been repowered with a naturally aspirated single John Deere 6086. She hums along at 7.5 knots burning 1.5 gph fuel, at 8 - 8.5 knots I'll burn about 2 gph. I love my powerhouse, I found I had enough torgue to get me out of some crazy currents in tight spots heading up the inside passage last summer. She is not underpowered thats for sure.

Those fuel numbers equate to a horsepower draw of approximately 36 HP at 8.5 knots on the JD 6068. How do you measure fuel used?

Pete Meisinger · 11-10-2019, 08:30 AM

Although brokers "should" be very knowledgable just like realtors should know real estate and car salesmen should know cares, the truth is that some are strictly salesmen and will tell potential buyer anything he/she thinks they want to hear.

Some supposedly nautical people really don't know the difference between knots and mph. If someone tells them a boat can obtain 8 -9 knots which is "sort of" 10 or 11 mph it may become 12 + knots in the retelling.

Twin F.L. in that boat is about the best engine/boat combination you could dream of. Buy it !!

pete

hollywood8118 · 11-10-2019, 09:35 AM

Quote:

Originally Posted by jdscott3

I'm late on this one, but my two cents. My 1982 GB Classic 42 has been repowered with a naturally aspirated single John Deere 6086. She hums along at 7.5 knots burning 1.5 gph fuel, at 8 - 8.5 knots I'll burn about 2 gph. I love my powerhouse, I found I had enough torgue to get me out of some crazy currents in tight spots heading up the inside passage last summer. She is not underpowered thats for sure.

You have one of the best motors made for a boat, we saw very similar #s over the 9 years we had the same motor in Volunteer. I tracked the fuel consumption with a 100G day tank that was very accurately marked. We ran 8kts in no current and burnt 2.2-2.3 gph including about 4 hrs a day of 4kw gen time on non travel days. Either that motor or the famed Gardiner would be my go to engine in a trawler.

HOLLYWOOD

jdscott3 · 11-10-2019, 11:37 AM

I've a Floscan flow meter. I've not checked the accuracy of this meter but I had a similar one on a fishing boat that burned gasoline, it was accurate in that application. I know flow meters can be affected by viscosity, and other variables and to be sure should be calibrated. I have a diesel generator and heater so doing a simple gallons burned divided hours on the engine will give me a close approximation at best.

Xsbank · 11-10-2019, 01:31 PM

GB is a semi-displacement hull and will plane with enough horsepower. The theoretical top-speed is infinite.

The difference is fuel burn. If it took 45 litres to get somewhere in 3 hours or 45 litres to get to the same place in one hour (sadly, its not linear) its the same thing...

The best GB42 I have seen had a single 6 cal Gardner that idled at 400 rpm and came with a drum of Brasso.

catalinajack · 11-11-2019, 03:01 AM

Quote:

Originally Posted by T210DRVR

So far I’m seeing 7.5 to 7.7 knots at 1500 RPM with Lehman 120’s. I can get a bit over 8 knots at 1800 RPM but the engines seem happiest at 1500.

My 56,000 lb DeFever 44 with Lehman 120s goes about 7 knots at 1,600 RPM. Lasy year doing the Loop, we consumed 3.5 gallons per hour for all conditions, including generator time. That equates to 2 nautical MPH which I think is pretty good for a heavier boat.

dz1drwww · 11-13-2019, 08:42 AM

I have Cat 3116 straight 6s in my 1993 GB42. I typically cruise at about 1800/2000 RPM, 70-80% rated RPM at about 10K speed. Get about 1.2 NMPG at that speed. I don’t work on the engines (only let Cat mechanics turn those wrenches) other than oil changes but I do all the other support/systems repair & maintenance with room. It’s tight sometimes, but I’m not a small guy either!!

I looked at boats with all different engines, happy with my choice as it provides good economy and engine room space. Oh, and you can’t beat the sound of a CAT engine!!!

Nomad Willy · 11-13-2019, 08:53 AM

dz,
What’s the power and displacement of the Cat 3116’s?

dz1drwww · 11-13-2019, 10:15 AM

I don’t have the spec sheets with me (boats is in storage in Wisconsin) but if I recall, the displacement is 6.6L and 305 HP. If needed, I can pdf you the spec sheets (including fuel burn chart) when I’m visiting the boat next week. Just let me know....

John R M · 11-20-2019, 09:48 AM

Quote:

Originally Posted by dz1drwww

Oh, and you can’t beat the sound of a CAT engine!!!

I read somewhere that CAT engines are somewhat noisy. Is that what you're suggesting?

dz1drwww · 11-20-2019, 09:54 AM

No, not at all.... I’m my opinion they sound like an engine should sound.

**slowgoesit** · 11-21-2019, 09:33 AM

Quote:

Originally Posted by John R M

I read somewhere that CAT engines are somewhat noisy. Is that what you're suggesting?

Nicknamed "Clatterpillars"! but I've personally not found them to be that loud.

FoxtrotCharlie · 11-21-2019, 10:31 AM

We have the twin Lehman 135's in our 42' CHB Present Sundeck - semi-displacement. At 1800 rpm we cruise at 8.7-9.0 mph and burn about 3.5-4 gal per hour. Love those engines - as has been stated they are very easy to work on and they run fairly cool at 175 degrees consistently (especially after I installed two new water pumps

). But I did pull a bone-head issue a few weeks ago on the TN River - checked the strainer on the starboard engine, and then promptly forgot to re-open the sea-cock - burned up a brand new impeller

But again, pretty easy to repair.

dz1drwww · 11-21-2019, 02:46 PM

Those Lehman’s are proven marine engines and easy to work on. In addition they have a very favorable footprint!!!!