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My B31 has twin 1981 454 Crusaders remanufactured on 2004....running smoothly.....Gas price rocketing I need to move to diesel or I'll be back fishing on my kayak be this time next year........have saved about $15K with a goal of $40,000 to get new twin Yanmars 6cyl.............However, I've seen people buying and redoing Cummings and other engines with $15,000 or less............If I were you......what would you do? and what choices you recommend

I cannot tell you how pleased I have been with Cummins 6bt's. Basically very simple engines. If you don't over HP your boat, you can keep your 1 3/8" shafts, one serpentine self-tensioning belt, inexpensive parts, you can live with straight exhausts (no mufflers). Uncle Vic probably has the perfect combo 250 hp, 1.52:1 transmission. Factory rebuilds are available if I am not mistaken. My opinion of course.

Although I only have 33 hours on the Steyrs, I highly recomend them. Same gear ratio tranny and re-used same running gear. There should be some posts on here about the Steyr. They are not the cheapest but quality looks pretty good. Can't speak for performance becuase mine is a 28. Not sure if any 31's have tried the Steyrs yet. Would be curious to hear results for a 31 with the 256.

Hang in there and wait for Bill Beardslee's reply. He put these in his Otter (B31) and would be a good person to talk to. I have to call him right now so I'll mention your post.

I did the conversion with two 496 Fuel Injected Crusaders and I'm told I'm going to get 14 gallons per mile at cruise. They were only $15K each!

That's just me...

Hueso,
Look at price but look at service and parts availability. I hear good things from the yanmar guys and I love the cummins in our boat. Hind sight being what it is, I'd probably look at a pair of 270 6B's, less maintenance with fairly good speed 25-27kts @ cruise.
But if Cummins has no support in your area I'd look at the manufacturer that does. Nothing hurts more than saving a bunch of money on the cheapest package then being broke with nobody to fix it.

Hueso,

Its going to be hard to find anything factory reman'd or rebuilt properly under 8k an engine.
That will not include a gear most times.

Under that price you will be looking at used which can be good or very bad depending on how well they were taken care of.
Even a complete engine survey cannot spot potential problems at times.

Someone who has complete maintenance records on a set of used engines most likely took good care of them.

Most diesel engines when replaced are worn down and need rebuilding.
It doesn't mean they won't run, but in most cases are tired and in need of major work otherwise they would not be up for sale.

Rebuilding is an arbitrary term that can mean a whole lot of things from a balanced and blue printed engine to a spray can.

Getting an older pair of diesels can be a parts nightmare so keep that in mind.

More common engines like Detroit can be much cheaper and most parts are plentiful and cheap.

To keep the costs down, a lower hp diesel can reuse 1-3/8 shafts and some can reuse a 4" exhaust system that most big blocks use which if you do your homework will allow you to put those associated costs into the engines.

Hueso,

In my opinion I totally agree with Walter. If you want to follow the progress on my boat ( Short Circuit) that is whats happing. I had 87' model 454 Crusader's in my boat for 17yrs installed new and ran them until 2004, gas was cheap then! But now diesels are the way to go if it is within your budget.

Sold those and purchase a used set of 89 model Cummins 250hp 6bta's and had those rebuilt and put ZF220a 1.5:1 gears on them with 21"x 22" wheels with 1 3/8" aguamet 22 shafts. Installing those now in my boat, UV has the same setup that Walter was saying. I have pictures on a post below of some of the progress. Will be posting more next week on more modifications I'm doing. So you can see first hand if that will work for you.

But you can purchase already rebuilted by Cummins for about as much as I spent to rebuild the 89 models I have.

R,
DQ

Hueso-

Unless you need the range, do the math on the fuel burn/cost. It'll take alot of hours over alot of years to justify a gas to diesel switch if your gassers are fine.

John F.

14 miles per gallon! The period must be broken on your keyboard! Or my eyes are getting really bad, but I did shoot mostly headshots at the range so my eyes are pretty good.

There's a post by Charlie referencing a pair of 300hp 6V53's for 10K. The DD are older engines but there's a bonus when you rebuild them, you basically get a new engine because those old engines are wet-liner sleeved engines....I believe, I know all the 71 series DD's are. The rebuild kits include; pistons, rings and new cylinder sleeves.

Typical bottom end kit for that engine is about 1K. Of course you would want to go throught the heads and turbo's but you could end up with a pair of engines that would more than likely never wear out or let you down.

Injectors are under a $100 bucks ea.

One more bit of info, the DD are two strokes. Also if you run out of fuel it's no big deal. Put some more in and it will prime itself.

They are heavy, smoke a bit and will burn some oil, but hey there are more DD's in service than any other diesel ever built, world wide.

DD's may be one of the only engines that I wouldn't hestitate to buy used and have rebuilt. I sent 7 years working in the Gulf and EVERYTHING ran on DD's.

Food for thought.

I became a bit curous about the 6V53's after posting and went to the baotdiesel.com site and read some of the 53's owner post.

Yes; they are wet liners.

Here's a post from a guy that spent a lot of time with 6V53's in the military;

"Far as a 6V53N goes, I run & worked them things both in the USN and the USCG, and we beat the shit outa 'em in both branches. 2800 RPM's wide open all the time, and all the time usually meant all day and all night, and we never had a failure, or a bunch of leaks. I think the last pair I overhauled in the USCG on a 44' motorlifeboat had around 15K on 'em, and the heads had never been off. 235 HP in the USCG boats, 218 in the USN PBR's. Run 'em propped, run 'em water jets. Run 'em upside down and every other point on a compass. "

I think he like's the DD's. Most of the postings concurred that the 6V53's will last forever up to 300hp, the 400hp versions is not so lucky.

The engine never went out of favor except with the EPA! That's why they are not produced anymore...read 2 Stroke.

cough cough ive got a set of 6v53's 400hp supercharged twin turbos that have to go!

Yah that would be nice huh? I had a couple glasses of wine when I wrote that. Still 14 gallons per hour isn't bad for gas!

Get Capt Mike inn the fray on this. He did what you're talking about and seems most pleased.

Whaler1777,

There's no denying that a gas mask is always a good idea when living with DD's. The "cabin cruiser" back draft effect of a 31 FBC makes this even worse.

I would not try to make a case for them, that's a 60 year old design, but they are No.1 in the affordability category and extremely dependable.

Hueso,

John F. has the right line of thought (in my opinion) - do the math, and I think you will be hard pressed to make the decision now to switch to diesel.

IF you have your heart set on repoweing to diesel, go with one of the simpler engines - DDs or Cummins. I have Yanmar 6LPs. The engines are great, but I have had some issues with the electrical. Were I to do it again, I would take a harder look at Cummins.

Bill B.

Hueso,

I have 240 HP 4 cylinder Yanmars. I love them. They are the perfect engine set up for this boat in my opinion. As of yet, I have had no issues at all. They run reliably and extremely efficiently all day and night long.

11 gph is hard to touch. At 24 knots.

I made the choice to replace dead gas with new diesel. It ain't a game where something as critical to the reliability and performance of your boat is worth trying to save the minor dollars. If you want to march in the parade you need to wear the uniform. Go and do it right, and don't half ass it with rebuilt anything. I did that, and payed double what I needed to.

As Vic says so well, the enemy of good is better. There are cut and dried formulas to prove what works and doesn't in the B31. Follow them, and you will be really happy.

I also agree that you are throwing away good money by replacing pretty new gas if they are running well. In your case, to go diesel and justify it that you will do it because you want to. Unless you put serious hours on the boat regularly, it is hard to run the numbers and make them come out in your favor without assigning an emotional number.

In my case as I said the 440 Chryslers were dead, and it was repower right or have a 31 foot floating deck that dad would pull out in front of the beach anytime I wanted to go for a "boatride". What the hell was the point in that.

Think it over. That be my advice.

Dug

I gotta agree with Scot that if you have short runs and budget, it is hard to beat the DD. The entire fleet (15 of 'em) of B31s at Tropic Star are powered with identical DD 4-53 naturals at 140 hp, but the manager says they have the governors set at 100 hp. Boats have no tachs. Wide open to run, I'd say about 17 kts or troll, use your ears and eyes to get the speed right. The 6-53s, while a factory option in the later B31s like the 4-53s, are a little big, but ask Capy, they run good and produce a lot more speed than the 4-53s.

As Scot points out, parts and service are available anywhere in the world and they last forever and sip fuel. For your budget and location Fellow Counsellor, consider the DD 4-53 as a diesel option. You can use the same shafts, props, water intakes, exhaust, etc. I see good running 4-53s all over for 1500 each with gears, and again as Scot says, a rebuild is a real rebuild since you get sleeved cylinders.

I was very impressed with the de-tuned 4-53s at TSL in Panama, but buy some ear plugs as they are pretty loud, not so much the exhaust, but the clatter from the motor boxes. And another plus, they never rust since they lubricate themselves both internally and externally, after all they are not called "oil slinging dump truck motors" for nothing.

UV

Run the gassers till they die and then get the desiels and do it the way you want at that point. Just my 2 cents.

Based on where UV boats I know he's heard the awsome sound first hand that a 120' aluminum crewboat makes with (3) 16V71's DD's hammered.

I truely loved riding those boats and miss the experience greatly.

Pure horspower and extremely addictive to run 23kts in an 80 ton boat. After a few years of that you'll have a place in your heart for DD's.

Hueso,

If you decide to keep the Crusaders you can make them more efficent by replacing the intake manifold's with Eldebrock TII performer intakes for around $300 ea. They will match your intake ports much better than stock ones and improve fuel milage and performence. Look up Eldlebrock on the internet for there phone or e-mail them, they are in California and talk to there people about your engine an they will guide you.

On my 87 model 454's Crusader's, I had Eldebrock intakes & marine carbs by them, by the flowscans with full tower at 21kt.s cruise burning 9.2 gals per engine with 18"x15" wheels w/#2 cup on them. Just another option for you to chew on.

Doug

Doug-

I've thought about trying Edelbrock manifolds on my 454s--what carbs did you have?

John F.

John,

For one thing you will shed about 125# of weight just by changing intakes.

The Carbs were Eldebrock Marine carbs 650cfm/4brl which very simple & easy to work on.

The secondaires did not open till 3100-3200rpm but everything was matched perfectly as far as the ports were concerned, almost like it was blueprinted, compared to stock. I also had electronic ignitions. I guarantee they worked for me for the way it was set up with props and everything else.

I had a friend that wanted to see first hand data, Boat he had was a 36' Pacer, 89 model Crusader 454's, installed intake & carb on (1) engine and left the other as is. Did test trials with 3gal difference burn per engine at 3000rpm on the floscans. He made the switch!

Doug

Hueso, first, welcome to the board. Your posts have been very interesting, and the pictures stimulating. I am assuming you are serious about the diesel swap, not just daydreaming. I did it a few years ago, using Cummins truck engines converted to marine use. Same 6BTA engine, just saved money in some areas. By the time I changed shafts, props, shaft logs, engines, gears, and added a diesel genset - and paid a larger yard bill than i should have due to delays - I probably had $25,000 invested. Since then I have done a lot of prop tweaking, recalibrated injector pumps, and some other stuff to maximize performance with the engines I have. Right now I top out at 25 knots, cruise 20 - 22, and mine is a heavy 1962 express. I am very happy with the way the engines run, economy is where I want it, dependability is great. Right now, guys near me are converting the 24 valve Cummins Dodge truck engine and the newer common rail engines. If you shop around, it is possible to find these new in crates for low prices. What you won't get is a warranty. If you choose to use Detroits, maybe 453's, at least you will be converted to diesel, so if you want to try a more modern engine later, the switch will be much easier.

Doug-

I converted over to the Edelbrock 650 marine carbs and electronic ignition a couple of years ago. I looked at the Edlebrock site, and then Summitt Racing. Is the manifold you're referring to the Performer part # EDL 2161 at Summitt?

John F.

Yes that is the part# John, you've got everything else on there just add the those manifolds and away you go. Those carbs are sweet compared to the others out there.

You will hear and notice the difference in the way the engines will be running. Thats the sweet set up for gas 454's. Let me know how it goes if you do it.

What size are your props and pitch?

Doug

Doug-

Definite possibility for this winter. I got the 4-blades that are on her now from Dug. I think they're 17x15 w/#5 cup. I get pretty much the same numbers I got from what was on her when I got her--18x18 3-blades w/no cup (I think). She cruises 21-22 knots at 3000, 20 or so at 2850, and I can get her down below 2 knots on one motor for slow trolling for rock. Thanks for you help--its been something I've been thinking about.

Also meant to ask: Did you have to rejet your carbs? I used mine straight out of the box, and the plugs look good. I can't exactly do what was suggested--take her to the track and run timed quarters with a consistent launch until I get the jets right. Any advice on jetting would be appreciated.

John F.

Repowering with diesel is great if you love your boat,but pricy, i am in the middle of repowering my 68 31 when I got it it have 440 in it and I replaced them in 97 with ford 460 which ran good until no more manifolds,and they burned gass 1.5 gpm, the new Caterpillars I figure will give me .5gpm at cruise speed, and at 40knt about 44gph we will see, nothing like a sea trial, but this is very expensive I paid $28,000.00 for new cats and new 1.5 twin disc 5061, this was cheaper than yanmar they wanted $34,000.00 per eng and Volvo wanted $33500.00 per. I did have to go to 1.5 shafts and a new mantex back deck the whole project will be in about $130,000.00 to $140,000.00 so like I said you must LOVE your Bertram, and I am a marine diesel mechanic with no figuiring my labor but it is a labor of love, I have had Busted Flush for 20 years and am now going to take it to Costa Rica for the next 20 years of fishing

Busted Flush

GOOD FOR YOU. I bet there's 100 guys on this board that would love to be takin their 31's to CR to fish for the next 20 years. Good luck, everyone's root'in for you.

I did the conversion with two 496 Fuel Injected Crusaders and I'm told I'm going to get 14 gallons per mile at cruise. They were only $15K each!

What speed would be your cruise? And that is per motor or total fuel burn? Prior to my port motor biting the dust I was getting 12-14 gals per hour per motor at 2800rpm and 21kt cruise.

I was thinking of having my friend's shop re machine my motors, bore them out to 462 cu in. Change mainfold, cam, carb, and have both engines balanced. End result would be 425 hp. Yard has put a minor cabash on the deal since they want to do the job themselves, so it looks like I'm just gonna rebuild the bad heads for now and see what I can swing in the future.

Hi capt mike, not just daydreaming was not to be taken personal was it? not long ago I posted and was looking into going diesel [and somewhat still am], but gas engines are cheap and I'm not sure that the 28 SF is the boat that I will keep for many years. With the few hours that I do at this time diesels will never pay for themselves.

Daydreams,

"I'm not sure that the 28 SF is the boat that I will keep for many years"

Find the model BERTRAM that you can live with forever and spend your money there. I have made that mistake in the past, twice. Glad to say I've finally found my last boat and don't mind putting the money in it. When it's the right boat for YOUR needs/wants you won't even think twice.

hi Scot, this boat is a total rebuild, I always the boat but I 've never been in one. What boat did you decide on? Thanks daydreams [Gary]

My brother put Yanmars in his early 70's 31 about 15-20 years ago. He was one of or the first. Yanmar used his boat to advertise their engines. It was the muff diver in seaford LI NY. The engines were great, good fit, quiet, not spoke. The only problem I hear is that their not rebuildable to the level of dependability you want from a diesel..

I ended up with a 25 Bertram. One of the original Ray Hunt designed boats, looks and rides similar to a 31....but comes home with me on a trailer. This was a must for me, I like doing all my own work, it's a hobby. A marina boat would be hard on me. I find myself outside working on my project at all hours of the day and night.

Daydreamer, no offense meant, forgot about your boat name - which is a good one, by the way. Spent the best times of my life daydreamin', sad to say.

Hueso: If the boat is running GOOD now and you do not have ANY engine issues, I would keep it that way and do the Yanmars ONLY when you start having issues with present engines.

Capt Mike, thanks for the reply it was great to hear from you.

Scot, I know the 25' [same rounded sides, etc, as the 31] i wish you many great years of boating in & out of the water. .

As usual, your comments are most appreciated......many things happening in the marine engine industry...................We are witnessing that the industry is taking it to the next level, specially in diesels........for example Styer and Yanmar/BMW producing lighter and faster power plants........this is a very difficult decision to make.........I believe Miami's Boat Show will be a good venue to continue the research.......keep it up....I'm reading

I am running Michigan 18x18 quads with high proformance spark plugs and air filters. 3000 RPM means 23 knts for the boat. No doubt I loose on the top end but the cruise @ 19 knts is good.

If I were to repower, I would buy two 454's from the junk yard. They go for $400/800 per engine for two bolt mains. Four bolt mains are harder to find and would be more. I would stay with the Velvet drive 72c's(1.5 to 1). The Eldebrock intake maniflods and the marine carbs are a must have.


The payback for me just isn't there with the diesels. And if I did go diesel, there would be no financing. Having a family and a big mortgage nut as I did when I wore a younger mans clothes, if I couldn't buy for cash, I wouldn't buy.


And another thing ... with the weather being so warm in New York, maybe I won't go to the Keyes in Febuary. I'll keep my Yankee dollars and pis it away on fuel next season!

Hey daydreams

I was leaning towards 4-53's untill I spoke with one of the mechanics I deal with.
He agreed with the advice given here that the engines are too heavy, too big and sling too much oil. He also thought they would under power boat and the noise and vibration could may be a bit too much. He also agreed they would sip fuel and last longer then I would want them and they are easy to fix.

I was still Okay with most of the downfalls mentioned, but then he said what I found to be the deal breaker, you can't get parts, the few you do find are now $$. Most notable the heads are prone to cracking.

Wondering if the same rings true with the 6-53's.

The 6V53's are getting older but I still see parts on line for them. By many accounts this may be the best little engine DD ever produced. that I know of they have no leak link. Weight around 1800-1900 lbs, 300hp twin turbo is a good power level, 318 cu. a bit on the small side for the weight.

But they will live longer than you will want to live with them.

Mike, I thought about marinizing truck engines, but figured the marinization kits were about 4G's @. Not including starters, alts. bell housings, flywheels, etc. What did you do for all the marine parts needed to complete the packages? Mitch

Sim,

I currently run 4-53's and I'm repowering this spring with Cummins. I ran the 4-53's for 8 years and I can attest to everything that's been written here about them, with the exception of availability of parts. Parts are readily available and are very affordable. Johnson & Towers still continues to support the 4-53, and will do so in the future. So, if that is your only objection, that shouldn't affect your decision.

For me, I could live with the noise and the lower cruise speed, but I couldn't deal with the "oil slingin" any longer. It's bad and was uncontrollable for me. Believe me I tried everything. Email me if you want any other info.

Sounds like I may have ruled the DD out too soon. Thanks.

Mitch, the company I worked with is no longer in business, but contact HS Marine Services - Lee Holt, lholt@hsmarine.com - or call Lee at 979/849-3088 if you are still interested. I think the marinization kit does run $4K or better per side, that includes everything you'll need - bell housing adaptor, heat exchangers, exhaust manifolds, wet elbows, aftercooler, damper plate, etc. No need to replace starter and alternator - mine have been in the boat 7 years with no problems, and if they need replacing, I can go to the auto parts store to get them. Go to Lee's web site - www.hsmarine.com - and look at pictures of completed engines and installations they have done that are very, very slick. These guys have this process fine tuned, and can help you find engines, get better pricing on transmissions, or build the whole engine for you.

Thanks, Mike

whaler1777 hi neighbor Im by the riviera catering hall.