Diesel Repowering Series 2 36 Footer

[cjd]

I made it thru this season with ethanol issues so
I love the boat. She's a keeper so I dont want to press my luck. I am pretty much set on repowering my gassers to Cummins.
I know alot of folks on this site have just gone thru repowers. I was looking for opinions/advice on which is the best fit. The first reputable mechanic I talked to said the 330 recons is a perfect fit and said the 370's are overkill and would have to up the exausts to 6", others said to spend the few extra for the 370's so the power is there when you have a full load.
I got a quote for just over 70k for the 330's, ZF220 gears, filters, controls, installed fully turn key plus another 11k for a kohler genny( Which i thought was high). My questions are these.
Reasonable price?
Go with 330 or 370's?
Get the Recons or new?

thanks
CJ

 

[41-Hatteras]

I repower my 41 with 450 cummins and 270 ZF gears.
You may contact Roy Flood, his may can give you some advice and a great deal on engines. 516 378 7331. Tell Him I said hello. Ron in Houston.

Captain Ron

 

[Maynard Rupp]

We have a 1986 36C with Crusaders. I have the engines running so good that we have put off the re-power. Here is what we have found. I would only consider the 370 Cummins 6BTA. The newer boats are quite heavy and seem to love power. Yes, the exhausts have to grow to 6" and that ain't cheap. The sea water inlets have to go to 2", although the thru hull part is already that size, I believe. Those Groco strainers are too small, but everyone is installing the "wedge strainers" on the outside. No muss, no fuss, and a ton cheaper than the huge Groco units. All you see on the inside is the ball valve shutoff. The water intake location is perfect.The shafts are 1 3/4" Auqamet 22 so they are great as is. We also found that the recomended prop size is what we already have. The installer needs to buy 4"aluminum angle and some 3/8" and 1/2" aluminum plate stock to fabricate and weld the new mounts. You just unbolt the whole existing rails and replace them. pretty simple. I think the cheaper ZF trans is OK at 8 degrees down. I think it is a 220A. The 280A is tougher, and has a 7 degree down angle, but it is pricey and I determined not necessary. We were quoted $23,000 per engine with the ZF 220A gear. We were quoted $8000 for an 8kw. Northern Lights Genset, but the soundshield was another $1100. The exhaust is not cheap. We figured it would take $6,000 to get that done. With labor, new cutlass bearings, the whole job comes to about $80,000. Not cheap but worth it for these boats as the value of the diesel powered boats is a bunch more than the gassers. Of course, right now isn't the time to be selling. Prices are all over the map and I see boats on YW that were there 3 years ago. Like homes in the Detroit area, the only ones that are selling are the ones that are very cheap and very good.

 

[Banshee36]

I sold my 36 hatteras this spring , But I had repowered with the 330 b derated to 315 hp with TD 1.5:1 gears. The performance was awesome as well as the fuel consumption. In my opion I would use the same set up inanother 36 hatteras, I saw way to many of the 370 b blow up way before there time.
My rig would run 33kts gps in the corner and cruise 25kts at @2300. But once i loaded upall the fishing gear and put 6 head on her normal cruise was 23-24 kts at 2250-2300, burning about 17-20 gph.
If I still ahd the boat and had to repower I would put the QSB engines in her along with the twin disc gear, and de-rate the motor and go happily on my way.
I did the full repower mostly my self, I did hire a guy to bed the engines and align the engines. I had the time and know how and probably saved thousands of dollars.
I will tell you that you will need new rudders, the old ones just do not cut the higher cruise speed.
Just my two cents worth.
JW

 

[ADaily3224]

I have a 1988 36 and Maynard is right. When I hauled mine a few weeks ago it was tipping the scales at 28,000 plus pounds. Those newer 36's need a lot of power. Mine has 350HP Cat diesels. I wish it had a bit more, but do enjoy the good fuel economy. Cruise is about 17 to 18 MPH in fresh water. Add a mile or a mile and a half more in salt. The 36 is a good candidate for a repower, everything Maynard said is right on. Don't forget the upgrade in battery capacity and cabling, and you will probably need a new instrument panel. My boat has side dumping exhaust so the installation was easy but the system is complicated and expensive. I don't know when Hatteras went to side exhaust but I think it was around 1987?

Tony D

 

[cjd]

Thanks everyone for the advice.
Maynard & Tony - T.Athens over on the boatdiesel forum just emailed and said the 5" exhausts should work just fine if properly set up. This is what he said

"I have yet to find a 330 / 370 Diamond or a QSB 380+ need a six inch exhaust as long as the wet elbow or riser and the rest of the system is designed correctly. Your might read the article on the home page from about 3 months ago......Build your system like plumbing a house with sewer pipe and you may need 6", but if you follow a few simple rules and plan, 5" is all you need...In some applications we can even use 5" on the 450 Diamond and easily meet specs...It's all in the design....So if space is at a premium, it is easily done"
What are your thoughts on this?

Thanks Banchee- Thats the first time anyone said to replace the rutters. I will look into it.

 

[BUSTER]

I sold my 36 hatteras this spring , But I had repowered with the 330 b derated to 315 hp with TD 1.5:1 gears. The performance was awesome as well as the fuel consumption. In my opion I would use the same set up inanother 36 hatteras, I saw way to many of the 370 b blow up way before there time.
My rig would run 33kts gps in the corner and cruise 25kts at @2300. But once i loaded upall the fishing gear and put 6 head on her normal cruise was 23-24 kts at 2250-2300, burning about 17-20 gph.
If I still ahd the boat and had to repower I would put the QSB engines in her along with the twin disc gear, and de-rate the motor and go happily on my way.
I did the full repower mostly my self, I did hire a guy to bed the engines and align the engines. I had the time and know how and probably saved thousands of dollars.
I will tell you that you will need new rudders, the old ones just do not cut the higher cruise speed.
Just my two cents worth.
JW

The 6bt@ 315 horse would be my choice as well,with very little power loss,the duty cycle of the engine is much better and so is the engine longevity. A thoughtful choice.

 

[Maynard Rupp]

Just a couple of thoughts. I am not sure that everyone is on the same page here. This boat is a series 2 36 convertable. These are not anything like the early boats and I don't think they would even plane with 315 hp. These are a Jim Wynne design and are huge and heavey for a 36' boat. Jim Rosenthal told me that we might be able to put his early 36 inside ours. The other thought is the 5" exhausts. I am sure that these boats had 5" exhausts regardless which engines they were delivered with. Besides gasers, you could get 370 hp. Cat 3208s or 390 hp DD 6-71s. The problem is meeting the Cummins guys tests after the job is done. If they don't meet the flow test, he won't validate the warranty. 5" sure seems big to me, but it does have a lot to do with how much water you push through with the exhaust. The trick that Tony uses is to send most of the cooling water out through a seperate thru-hull fitting. He only alows enough through the exhaust to keep the parts cool.

 

[Akyla]

If you look at the cost of upping the exhaust it really will be a small portion of the overall refit expense. Vetus makes a very flexible 6" exh hose that will be easy to run and cost you around 500 (maybe less) for what you would need. Increasing the diameter to 6 is a significantly bigger tube and diesels lke nothing more than air flow. The big pia in this is the access to the space the tube flows through. I dont know the series 2 hull as well, but in the series 1 it is a tuff fit for anyone to get to the outboard side of the tanks. In the yard the exhaust goes in through the transom when the flange is out, but you have to get in bedded in supports etc.

Also, in both boats bigger HP is better...

Just my opinion, worth only what you just paid for it.