370 CUMMINS

smanni · Post by **smanni** » Thu Nov 08, 2007 12:20 pm

IF I repower - or rather- If I get to the day that I can afford it - The cummins 370 would be my first choice. Unless someone comes along with a comparable, non-yanmar, non volvo 370+hp, non higher than 3100 rpm engine - this is my choice. (SORRY to the Yanmar and Volvo guys - I just dont like them and I'm Stubborn!!)

Post by **dougl33** » Thu Nov 08, 2007 1:25 pm

quote:Originally posted by smanni I'm Stubborn!!) Not to worry Sean. I think its a trait common in most bertram owners (myself and nearly every other owner I've ever met included). Regards, Doug L. 1986 33 Bertram FBC Queen Elizabeth Marblehead, MA [img]http://www.bertram33.com/photogallery/p ... sabeth.jpg[/img]

smanni · Post by **smanni** » Mon Nov 12, 2007 10:02 am

Are MIKEFRITZ and michael the same person posting with 2 names? If not - does MIKEFRITZ have a performance update?

smanni · Post by **smanni** » Mon Nov 12, 2007 10:03 am

NEVERMIND. I clicked on their icons and saw they are in fact one in the same!. I was confused with the thread being answered by both. Sorry.

smanni · Post by **smanni** » Fri May 30, 2008 8:23 pm

Did we ever solve the mystery of the B33 with Cummins 370b that cruises slower than the B33 with 300's? I reread this thread and Im as confused now as I was then.

michael · Post by **michael** » Mon Jun 02, 2008 1:42 am

Sean Somewhere along the line when I created my name I must have forgotten my password or something and created a new name.? can the admin change mike fritze to michael on the previous posts. As far as performance I had my engines phototached last week. My tachs were 30-40 rpm's lower than actual depending on how you are looking at the gauge. No load rpms were 3330 rpms which is where cummins said they should be. 3300 min 3400 max. Loaded full of fuel,water,tackle,2 people and everything else I keep on the boat the engines topped out at 3020 rpms and 32 kts. At 2400 the boat ran at 25 kts. Tomorrow will be my 1st Bass trip this year so I will see what it does with 5 people and all of their gear. In the fall I will send the props back to ACME to have 1/2 of the cup taken out which will give me another 80-100 rpms. Michael 33sf

smanni · Post by **smanni** » Mon Jun 02, 2008 7:19 am

2400 rpm and 25 knots is great. Cant those engines be safely cruised 3-400 below max. So even at a cruise of 2600 rpm - you will be flying!

michael · Post by **michael** » Mon Jun 02, 2008 7:36 am

Cmmins says 10%off the top which would be 2700 but I am very happy to do 25kts at 2400 which sounds like the engines are just chugging along

Gonzalo · Post by **Gonzalo** » Tue Dec 23, 2008 7:02 am

Anybody running 2:1 ratio on 315hp 6bta? That's what I have and I'm very slow compared to the numbers I've seen here so I'm trying to figure out if I have the right props. Thanks

IRGuy · Post by **IRGuy** » Tue Dec 23, 2008 8:17 am

Gonzalo... Several of us have the Cummins 315/330HP engines, and use a 1.5:1 transmission ratio with props in the neighborhood of 21"D x 23" P.. Buzz K has the same engines but I believe a 2:1 transmission ratio, but I can't recall his prop data. He is here regularly and I am sure he will answer you. Frank B - IRGuy@aol.com The weak will inherit only whatever the strong are willing to let them have! "Phoenix" 1983 FBC Cummins 6Bs - 315HP Wilmington, NC

Post by **dougl33** » Tue Dec 23, 2008 9:04 am

Buzz actually has 1.75:1. I know Brian Davin (370 yanmars) is running 2:1, and I think Syd (315 yanmars) is also running 2:1. What size are your props?

buzzk · Post by **buzzk** » Tue Dec 23, 2008 12:43 pm

My engines are 315/330 Cummins. I have 1.75:1 transmission. I'm running nibral 23x25x3 blade props 1-1/2 shaft. Depending on the current I'm close to square 2100=20.5 kts, 2200=22.5 kts.,2400=25.2 kts.,2700=27.6 kts., 2950=30kts. Buzz

lwrenn · Post by **lwrenn** » Tue Dec 23, 2008 2:26 pm

Do I trade up to larger cockpot boat or re-power for the speed? Does any one have trolling valves for slow trolling? 25 knot cruise at 20gph would be a dream during dolphin season, scream out twenty miles and fish all day with sixty gallons of fuel used! The more I think about it I really like my 33 fbc and six guys will crowd almost any cockpit.... Any one got any low cost 370 hp cummins with gears and valves Captain Larry Wren 305-360-4900 www.apirateschoice.com [img]http://www.bertram33.com/photogallery/p ... Choice.jpg[/img]

franklyprice · Post by **franklyprice** » Tue Dec 23, 2008 3:24 pm

Larry, "Low cost" is a very subjective thing. I can tell you it's very hard to get a deal on any decent diesels but if you want to do something like what I did and save maybe $20K on the total job, I'd be happy to share any advice I can with anyone here. I continually look around for deals on Cummins stuff and they do show up once in awhile but you have to be ready when they do come up.

JohnD · Post by **JohnD** » Tue Dec 23, 2008 5:25 pm

Larry, I know everybody says, so I'll apologize in advance. Go with good local support from the supplier to installer. I went with CAT 3126's because of the local yard and local rebuilder. I was all set for the cummins 370's and still like them a lot. I know the regional rep we've discussed the best setup is 370's with 1.75:1 220A's, he finds that combo gives the best performance in B35's (and probably b33 as well). Good luck.