Cat 3126

wmachovina · Post by **wmachovina** » Jun 18th, '09, 19:05

got a lead on some new 3126 cats w gears. Need to repower Seachele and was wondering what the faithfull have to say. These are the mechanical 370's. Lots of horespower, may need trolling valves and I'm wondering about size and weight. Bill

scot · Post by **scot** » Jun 18th, '09, 22:16

I can not comment on the fit. I have never investigated the dimensions on that particular CAT. That series of CAT is longer than the 3208s or the 6B Cummins. Length could be an issue. The new C7 & C9s moved the heat exchanger tank to the side of the engine vs the 3126 tank which is up front ( I think).

The engine has a solid reputation and the weight is not a problem for the hull. If fact it's a bit lighter than the 3208s (which came in some 31s) You would have a nice quiet ride.

If they check out, and if you can make them fit, I would not hesitate, but that's just me.

bob lico · Post by **bob lico** » Jun 18th, '09, 22:36

are you sure they are not 385hp? anyways great engine and perfect hp for 31 bertram however due to the large displacment and piston diameter there is no way in hell you will ever get rid of the vibration.the cockpit deck will vibrate unbelivable .on the otherhand you get relocate the eletrical box at rear of motor to shorten lenth but still to long for stock engine box.don`t believe any other post on to much hp that is ridiculas every boat made in the us has at least that hp in a 31 like cabo for one . even outboard power oem. is twin 350hp yamaha on a 31'. you will have to use barry mounts and cross braces between stringers .great engines my first choice have to pay attention to total weight balance and shaft angle pm.with me and i will help you put all that torque to good use with off the wall props .31/32 knots with first five feet of boat completly out of water .capt patrict rudders are essential due to raked props.

JohnCranston · Post by **JohnCranston** » Jun 19th, '09, 00:43

Bob,
I like the way you think! Realighn, redefine, re-think the whole 31 power layout! Well done, sir.

wmachovina · Post by **wmachovina** » Jun 19th, '09, 05:57

Bob,Scot, And John, thanks for the info, going home tomorrow and will check out dimensions, etc and$$ We glassed the cockpit (Alan Whitiker) to hullsides and transom and made it one piece so maybe that"ll help vibes somewhat. Being an old Phantom driver " speed is life" is an anthem!!

Carl · Post by **Carl** » Jun 19th, '09, 06:28

On the "flip side" if you can get them at a "great deal"..."Flip " them for motors you could just drop in.

CaptPatrick · Post by **CaptPatrick** » Jun 19th, '09, 06:39

sim wrote:On the "flip side" if you can get them at a "great deal"..."Flip " them for motors you could just drop in.

Amen..........

scot · Post by **scot** » Jun 19th, '09, 08:37

What's your saying Capt Patrick...."the money is in the iron"
So if the iron can be had cheap, he may actually end up with equity in a BOAT, rare indeed.

Bob, l dig large displacement engines, it's just plain "manly". Harleys vibrate and we love it.

CaptPatrick · Post by **CaptPatrick** » Jun 19th, '09, 08:53

After 10 years of buttin' my head against this wall, and with my views on the topic reasonably well known, I respectfully decline to get involved again... Just about anything is possible if you throw enough time and money at it.

Don't know who claims the "The money's in the iron." statement, maybe Uncle Vic.

But, in any case, cheap ain't necessarily right.

My story and I'm stickin' to it...

Harry Babb · Post by **Harry Babb** » Jun 19th, '09, 09:32

Capt Patrick wrote:... Just about anything is possible if you throw enough time and money at it.

Its amazing what you can do with an "Old Boat" or an "Old ______" (pick your poison) and $200,000

BUT AIN'T IT FUN! ! ! !

Harry

Carl · Post by **Carl** » Jun 19th, '09, 11:24

Harry Babb wrote: Its amazing what you can do with an "Old Boat" or an "Old ______" (pick your poison) and $200,000

BUT AIN'T IT FUN! ! ! !

Harry

If it ain't fun and it ain't cheap and it won't run any better or more economical and you can't sell it for what you put into it...then why?

Harry Babb · Post by **Harry Babb** » Jun 19th, '09, 11:43

Carl wrote:If it ain't fun and it ain't cheap and it won't run any better or more economical and you can't sell it for what you put into it...then why?

I think a few beers and several hours of conversation might begin to give us some insight into this situation.

I generally buy high and sell low.......and they say that I am Lysdexic....Ha

Harry

Carl · Post by **Carl** » Jun 19th, '09, 12:45

LOL, your on. When we finally get to meet, I'll buy the beer and we will sit down and go over all the particulars.

scot · Post by **scot** » Jun 19th, '09, 13:08

Sorry Captain Patrick, I thought that was yours. But I do like the statement, seems to always be true on my projects.

wmachovina · Post by **wmachovina** » Jun 19th, '09, 15:58

Didn't mean to start a political post (?)but I was just getting opinions on the motors. My mech found out about em $40k w gears(dont know which). it seemed to me to be basically the same as 330 Cummins w/o gears. Now my intention was to go lower hp, slightly better fuel economy to run the Bahamas. Just lookin for technical insight from those in the know, just learning guys.

JP Dalik · Post by **JP Dalik** » Jun 19th, '09, 18:52

The wheel the way it was invented works just fine.
I have 330hp Cummins in our boat and love the performance that comes with this power.
You will need to do more maintenance to the engines (heat exchangers- after coolers) You will need larger exhausts. This all adds expense to the repower. I have gained roughly 3 kts at cruise and 2 kts at top end over the 270hp Cummins ( I attribute the top end reduction to the beginning of bow pushing)
The extra speed at cruise is a great thing. The added cost vs. the added maintenance is yet another. If you can do it yourself........rock on. If you can afford to pay for it..........rock on. If neither of the above work for you stay a little slower at 270hp.
There are some that would have you attempt to reinvent the wheel to maximize horsepower and speed out of the B31. If you have the pockets or the desire to take on this project I will say again.......rock on.
If however common sense runs in your family and you actually realize that the boat is 31 ft long and a 2.5ft chop actually hurts at 30kts AND that the ocean is typically rougher than that every time you go out you'll be happier (and your crew will be thankful) that you used your head and slowed the boat down they will forever pee without blood (praise you).

We played the hand we were dealt when we bought this boat. The bottom line is that 95% of the time the boat is forced to run the same speeds as the 270hp boats or slower.

The Cummins power is recognized as the most reliable and will therefor provide the best resale.

If you plan on dieing with this CAT powered project then I say again.........rock on.

JohnD · Post by **JohnD** » Jun 19th, '09, 20:59

Let me state for the record, I own 420hp 3126's and really like them so far. I've got a B35 and the fit was not easy. In hind sight the extra money for 6bta's at 370 hp would have been worth it. But you can't change what's done and I like these motors. they're taller and longer and than Cummins and not worth it for a B31.

The 3126's had some problems but were straightened out and are damm fine motors, but not for a B31 and that's my .002 (decreased due to being out of work in a recession ;)

br,
JohnD

bob lico · Post by **bob lico** » Jun 19th, '09, 21:05

jp don`t you have cpl. 0970 1992 or earlier vintage cummins ?
the question here is are you doing your own installation and is the deal on the cats a steal ! if the installer did 4,560 installations i don`t want him i just want you to go in your garage and tear off a piece of shelving
(1x12) 3' long then throw this on the bilge floor just aft of the bulkhead this is the distance the rear of the gear will be off the bilge floor if you can understand this concept then your on if you ever look at the stringers forget they won`t be there!! your only problem will be plenty of coffee you will fall a sleep at the wheel in 3' seas . with 370 hp waste gated cats it just takes a 5 minute trick to make 380 hp. we could make that boat prop walk with all that torque . you could back off to supert economy mode at 2100 rpm and still fly totally differant concept of a stock bertram so do not refer to has been ideas! or go back to detroit 4-53 and be one of the boys

JP Dalik · Post by **JP Dalik** » Jun 19th, '09, 21:42

Bob,
I have CPL 1975's built Feb 2003. Near as I can tell as good as they get.

Unless you've been offshore over a dozen times in the last year in a B31(yes that's only a poultry 12 times per year 50 miles or more) there is no way you can debate me regarding the real world application of these engines in this boat .

I've driven this boat for 6 hours going 100 miles in one direction trying to keep everyone comfortable enough to be human when its time to fish in the morning.

I've driven the boat 110 miles home wishing it would stop blowing 30kts in my face and just blow 20 like the weather man said it would.

Oddly enough in these conditions I've never been able to do more than 16kts in either direction before a crew member is pissing blood or bouncing off of the ceiling. For sure I am not using the available horsepower or for that matter the down angle shafts or any of that crap because the f'ing boat is only 31ft long and typically the ocean is 10% of the boats length or larger.

I've never been afraid of what the boat could handle. The bottom line is that for 95% of the time I've been part of this boat I've used the power available to come home only once or twice. If you want to race Sea Rays in the bay then go nuts with the big power. But if you want to really Fish day in and day out just shut up and live with a lower cruise speed, less maintenance and great fuel burn of the 250-270hp engines. Really I don't want to hear about what could be when its flat. Where I live its never flat enough and those numbers only work in the Bay.

I can run 29 kts all day long at cruise and beat the boat and crew to and from the offshore runs but I really need the crew to be alive and well when I get there. The bottom line is its a little boat in a big ocean and the little red knobs need to be pulled back when a team is expected to perform at the end of your long run. The last time I checked there was no money in any tournament I've fished for first one on the spot or first one home, just biggest or most.

bob lico · Post by **bob lico** » Jun 19th, '09, 22:28

WHOA hold on jp i have no clue what you are getting at with sea rays ---what the fu-k over . speeding in the bay ??? huh . my only application is offshore but i could not agree more on the microwave falling out of the cabinet and take 10 waves in a row and the 11th one is two feet larger and sents the crew crashing against the ceiling.yes is sure feels good to span 3 waves at a time like in a 47'viking last week. my weekly chores put me on quite a few differant boat during the season .next thurday 60 miles offshore in a 30' grady white/twin 250hp yamaha . i compile all my time offshore as a learning lesson both good and bad.i been completly surprise buy supposely great boats like 28' parker that are unsafe at more then 2' waves and really surprised by a 35 everglades that took the waves better then a 31bertram.(head seas).i am just saying you can alter the trim angle of a 31bertram to make a softer ride in 2' to 3' waves not gale warning! of course you have to slow to 13 knots but at least the boat will ride bow proud and you will burn more fuel then nomal but what is the alternative 47' viking burning 65 gallons a hour ---deep pockets man cost you about $1800.00 for one 35lbs bluefin tuna.

JohnCranston · Post by **JohnCranston** » Jun 20th, '09, 01:10

Cool...

Buju · Post by **Buju** » Jun 20th, '09, 07:57

Turning out to be a great thread... a little heated, but thats because everyone believes in the points they bring up. And they're all good to take into consideration.
One thing I've noticed (and often do myself) is that folks assume that others will be using their vessel the same way as they do, whether that be hardcore offshore fishing, or pleasure boating w/ the family, or what have ya...

I think perhaps the key is:
What are the attributes that Bill (wmachovina) wants to accentuate & acheive in his repower?

Fuel Economy?
High top end speed?
Low initial cost of repower?
Weight decrease/increase?
Resale value?
"unique-ness"?

I'd say the reasons to not attempt to squeeze the 3126's in the B31 clearly outweigh the reasons to try... especially if John had a hard time getting 'em in his B35.
And it's also pretty safe to say that the low purchase price on these engines will be quickly over-ridden by the amount of customization, downtime and the mountain of labor needed to make 'em work in the B31.

On the other hand, Capt.Bob did successfully pull off some pretty unique things with Pheonix.

Only Bill knows what he wants out of SeaChelle... But if it's simply good fuel economy, reliability, ease of repower, and resale value- then it's a pretty good bet that all of this could be better obtained by going with the tried and true powerplants.
If he wants a unique (already is- she's an awesome boat Bill), fast as snot, and much heavier B31, then maybe it's worth pursuing.

Brewster Minton · Post by **Brewster Minton** » Jun 20th, '09, 08:25

I have the 315 lp6s in mine and she runs 29knts all day. That being said out of the 25 times last year that I ran 100miles offshore fished for two or three days and came back there was 5 times I got to go that fast one way. I tell the guys in the 32 foot Regulators who go 55 how much fun it is to pass them at 40 fathoms in 6 footers at 13 knots and they and getting killed at 8 knots. Up here JP is right you cant go that fast.

Carl · Post by **Carl** » Jun 20th, '09, 08:40

Always seems one of us comes in to moderate...

Buju has a real good point, these boats are lots of things to lots of people with different backgrounds.

JP- Die hard fisherman like Brewster, and these boats are well know in fishing circles as one of the best fishing boats.

You have those such as Bob who relish in the fact they can really boogey in less then perfect conditions, although not know as being a fast boat by todays standards, we need to realize the fact these hulls where racing boats in days gone by and are the foundation of the go-fast monohulls of today. Lots of racing heritage that Bob has brought back with some tweaks here and their.

Then you have me, I fall in the middle and off to the left. I used to fish her weekly, take her on a yearly vacation, fill the back with lots of my dock friends for night of dock, dine and tikki bar stops as they would not fit on any other of the boats. Last couple of years she has been a playpen with a pool in the cockpit for the kids...

As someone said, throw enough money and time at it and you'll get the motors in and I'm sure if done right she'll run just fine.

Is it the easiest project, doubt it...
Least expensive way, doubt it...
Will it add to the resale value, hardly...
Worth doing...the beauty is in the eyes of the beholder.

Didn't someone convert the 31 to a single screw with a 671 for power, now thats a project I'd like to look over. Not sure if I heard it here of from someone I spoke to. Possible just a rumor or bad memory.

bob lico · Post by **bob lico** » Jun 20th, '09, 09:04

buju you have covered the topic very well and my intention was not to have arguments about the adventure of going offshore at 32knots . the subject of puting a 3126cat in a 31 and the results. i put 3126 (385 hp)cats in a 32 blackfin after removing 3208 at 375hp and the results were amasing.only 20hp more but 2000 lbs less weight.fuel economy increased was dramatic after putting trick props in combination with these great engine, and performace was up 4 knots cruise.i drop the engine to the bilge and changed shaft angle as well as rudders.no changes to engine boxes at all .i belive in answer to buju`s post if you are doing your own work and get the engine real cheap the 3126 installation is a go but if you are sitting back having some marina do it forget it. the use of the boat after installation is not the topic.you may be a "fair weather sailor" or you may be brewster/jp day in day out fish for a living then you have to weight the validity of a 32knot boat when you can only go 20knots most of the time.i myself don`t care what day it is i chose my offshore days by using 4 sources of weather information one being the furumo nav net weather with instant update.most people can`t drop with there doing and go offshore on a weather break. most of all we have to be open minded many this application is on a south sea island that really never seas heavy seas .lets keep in mind we are pulling 370hp out of 734 cubic inches as oppose to a yanmar 315 hp out of 327 cubic inches.the cats are purring away at 28 knots while a high speed diesel is at 3800 rpm at 28knots.the 3126 with there "b" engine hydralic injection pump produces fantastic fuel economy in a light boat.

jspiezio · Post by **jspiezio** » Jun 20th, '09, 09:54

What do you guys think of a conversion to a sloop rig? Talk about economical.

wmachovina · Post by **wmachovina** » Jun 20th, '09, 19:30

well that put the kabosh on

scot · Post by **scot** » Jun 20th, '09, 20:52

One point not made is that running too hard is ignorant, and not reserved for boats that CAN go fast. Just because it could, don't mean it should.
The boat would however ride better with the added weight.

I agree it's a DYI type project and a costly deal if you have to pay for ALL the mods to make-um fit.

It would be a nice engine for my single diesel B25 project. BTW, I'm building the engine box currently...and it would fit nicely. I have read SO MANY discussions about all the issues surrounded repowers that I set the boat up for ANYTHING I want to stick in it. From a 6BTA to a C9.

The down side is I will never be satisfied, and forever on the look out for the "next" engine!

wmachovina · Post by **wmachovina** » Jun 21st, '09, 07:53

Scot, good point about running hard. Between here and West End there are summer days where its glass , so the ability to pick it up is nice. In 40 years of driving boats, cars, and highly powered aircraft I haven't made anyone bleed yet. Now to use an engine that is understressed as oppossed to wound up like a suzuki sounds reasonable to me. I haven't checked out the engines yet, and am tied up for a week (Bahamas with gas 454s $$$) but am considering all the advice given here.I'm still dealing with weight concerns as the boat sits 1/2 inch deep above the chine (and exhaust) when loaded heavy. If you are interested in a motor I will certainly give you the info.

scot · Post by **scot** » Jun 21st, '09, 08:39

to use an engine that is understressed as oppossed to wound up like a suzuki sounds reasonable to me.

That is correct. An under propped, under utilized diesel or gas engine will always have a longer and happier life than one on the edge. Although "most" of the engines installed into these boat are not on the edge IMHO, but your diesel theory is sound.

bob lico · Post by **bob lico** » Jun 21st, '09, 10:15

bill it should be noted here some of us who play "victory at sea" more offten then not should also be aware of areas in the world don`t nomally see 6' oceans on a average day as a matter of fact 95% of the time the wave height is 2' or less. that being said as clearly as possible and don`t want to represent myself as a reckless maniac .the discussion is solely base on the use of a 3126 cat at 370hp in a 31bertram . the person driving the boat should know his own safety margin . i use my boat to go to fire island with family and grandchildren about 4 times a year. never exceed 20knots and this is in the bay!!! my first concern is 4year old children so with 660 hp i still idle out and take my sweet time going on plane . getting back to the subject the cats will drive the boat to a sweet 32 knots know i know you have been on 8,256 31 bertrams but this is the 8,257 31 bertram and does not have the trim,plane angle,turning radius,or entry as the others! lets think about this for a minute in a laymans way.no centroid of gravity or other mathmatical theorys.lets say you rope yourself to the light chock in in 6' seas you would get pounded next you sat in a bean bag on the cockpit floor at the stern with your back to the trasom wall you would be real coftable (aside from the water spray) now lets look at the other possibilities; a fbc with tower and 4 cyl. 805 lbs engine as opposed to a bahia mar with no tower and 2000 lbs cat power.from the worst to the best ride in the same 6' seas.it is not just weight ,most important is that the weight is as low in the bilge as possible and the weight is far enought back to counter balance the thrust from the included oem shaft angle without outside help from trim tabs. this would be the optimun ride at cruise speed .brewster`s boat approaches this with 1500 lbs of ice in the bilge on a bahia mar, and 950hp engines and 1000 lbs of gear.this example is not the norm. for a 31 bert but it works. now we can put these 3126 cats in a 31 and no outside weight (like ballast, ice,etc,)and obtain the same trim angle thus a faster cruise without the undesirable bow ruddering or terrible steering.no we are NOT reinventing the wheel or endagering passengers just using a differant approach to a repower .the key here is the 3126s are real cheap and you are doing the work .best to have friends that are shoe saleman,doctors anything but marine engine installers because this is thinking out of the box.

Tony Meola · Post by **Tony Meola** » Jun 21st, '09, 21:42

Like the dealer who sold me my 270 Cummins said to me, if this was Florida and not NJ then I would tell you to go with the 330's.

Just look at what JP and Brewster have said, up here in the Norhteast the days to use the full potential of the larger engine are rare.

bob lico · Post by **bob lico** » Jun 21st, '09, 21:57

brewster has 315hp and jp has 330hp it is not like they were under powered tony . like bringing a gun to a knife fight "it`s there is you need it" you could always back off the thottles if weather worsens but you could get out off dodge much quicker.

scot · Post by **scot** » Jun 21st, '09, 22:40

Where it will be used is critical, as mentioned. I will have a 1 hour ride to the Gulf from my new marina (once the boat hits the water) and extra speed would be nice. Cutting the time down to 40 minutes crossing a large bay when your sun burnt, dog tried and have fish to clean is good.

Occupants are also a consideration as Bob mentioned. If they don't understand what can happen to them at 32 kts while they promenade around the aft deck and cabin, break out the first aid kit. The center console has an advantage here. Everyone on board is typically holding on tight and mindful of the pounding, because they expect it. A larger boat can pound them just as hard, but they don't expect it and typically don't see it coming at them before it's too late.

Reminds me of when I first started taking my daughters boating. When a wave would knock them around...they would scream at me, as if I did it!! lol.

I believe the old saying is "one hand for the ship and one hand for yourself"

I am currious why your boats sits as deeply as you stated with 454s? Seems to be about 2-3" too deep?

Rawleigh · Post by **Rawleigh** » Jun 22nd, '09, 09:34

It should also be remembered in this discussion that Bob has experience and boat handling skills from his racing days that most of us lack. Odds are he can run run faster more safely and with less stress on the boat than your average person could.

Capt. DQ · Post by **Capt. DQ** » Jun 22nd, '09, 10:06

Good point Rawleigh about Bob, which he likes going fast as we all do at sometime or another depending on the conditions. But I can say that in the Gulf of Mexico that my B31 with a full marlin tower a 250hp 6BTA Cummins under normal conditions that a 21kt - 24kt cruise is about all you want comfortably. As seas increase the throttles are coming back to about 18kts - 20kts. In which I love my low fuel burn and great speed over the water and easy to get to & work on Cummins. Even with 250 hp engines the 21' wheels will push the bow over at about 27-28kts and any faster is not good for safe control of the boat in my opinion.

Just another opinion,
DQ

Tony Meola · Post by **Tony Meola** » Jun 22nd, '09, 20:45

Bob

I realize we have had this discussion before, and I know you did one heck of job getting Phoenix finally tuned, but for those of us that can live with a couple of knots either way, the extra 10 grand for the pair of Cummins the next size up, plus the extra money to redo the exhausts (I was lucky, for some reason my big blocks had the larger exhaust) the extra couple of knots for the few times I could do use it just was not worth it.

Plus, the maintence factor for a boat I can really only use 8 months out of the year just did not seem to add up for me.

Trust, me if I hit lotto the old girl will really get a major face lift.

bob lico · Post by **bob lico** » Jun 22nd, '09, 21:48

you got it brother and i would be the first to help you.

bob lico · Post by **bob lico** » Jun 22nd, '09, 22:20

tony bear in mind when pulling back the thottles they is a big differance in fuel burn .the 330hp go into its powerband around 1900 rpm at 6.7 gph ,at 2100 your at 8.4 gph and pedal to the metal your at 16gph so you run into bad weather and back off to 2100rpm and the 330hp are getting real good economy . now here is the differance for the 270 hp cummins to keep the same speed you would increase rpm over the 330hp like 2300rpm the attain the speed of its big brother around 24 knots for a conventional prop/shaft angle fbc.hp is hp a certain amount is needed to power the boat a given speed. i hope i made myself clear.

Tony Meola · Post by **Tony Meola** » Jun 23rd, '09, 21:22

Bob

Believe it or not I actually new that when I made my decision. The differance in fuel burn was not enough to make me go increase my cost and future maintenance. I figure if all goes well I will get offshore maybe 5 times a summer the rest will be inshore, so the burn difference should not really effect me.

wmachovina · Post by **wmachovina** » Jun 30th, '09, 16:36

To Scot,Bob and all, decided the 3126 option won't be worth the mods, thanks for the tips,info et.all, learned alot. but if anyone, wants the leads (Scot) I got the number of the seller. pm Bill

bertram31.com

Cat 3126

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