Gas to Diesel conversation info

[Kevin Goodwin]

So, with the unplanned recent demise of one engine in our 34 sedan, and the fear of the other not being too far behind it in lifespan I can't help but ponder the conversion from gas power to diesel. I understand there will be a good amount of extra expense in this. But has anybody done this somewhat recently? 

I would like to pick the collective brain of the Tolly world before I spend more time planning this out. Buying another Tolly with diesels already in it really isn't a solution I am willing to adopt. Either it is done for Sandee or we stay with gas power and all that comes with it.

Thank you in advance,

Kevin 

[Bob Clos]

Kevin, 

In my opinion, it depends on how long you plan on keeping your boat. If you plan to keep it for 15-20 years, then bite the bullet and switch to diesels. You will be very happy and never sorry. If not 15-20 years, than just fix the engines you have. Although, where you cruise may be an overriding factor. If you plan to cruise to Northern BC or Alaska. more than once, I would recommend diesels. In both Northern BC and Alaska you will find that fuel docks are few and far apart. Diesels give you twice the range and you can run at higher, more efficient speeds. It's comforting to have plenty of boat speed and range when you have to cross large bodies of water in short good weather windows. 

Most of my cruising has been in Northern BC with one three-month trip to Alaska. The Alaska trip was on the gas engines. I had to keep the speed under 8 knots so I had enough fuel to get to the next fuel dock and not all fuel docks carry gas in Alaska. I switched to diesels right after the Alaska trip. 

I switched to diesels (Cummins 6BTA 5.9M3 - 370 HP) 25 years ago in my Tolly 37. They still run fine today. Maintenance has been far less than the 454's they replaced. Further, with the immediate thrust of the diesel compared to gas, docking the boat is much easier. 

Call me if you want to hear more.

Bob Clos

425-772-2062

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From: tollycraft-boa...@googlegroups.com <tollycraft-boa...@googlegroups.com> on behalf of Kevin Goodwin <z06g...@gmail.com>
Sent: Tuesday, July 2, 2024 1:46 PM
To: Tollycraft Boating Club Forum <tollycraft-boa...@googlegroups.com>
Subject: Gas to Diesel conversation info

 

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[Kevin Goodwin]

Well, had started down the path of going to a diesel but the recent emissions rules changes make going to anything less than a late model engine not possible. Yes, we plan to keep the boat for the next 10-15 years. 

At any rate, I reached out to some reputable businesses about converting and the price point is nearly $200K at this time. I can't justify that type of expense for what really equates to a water toy. 

So, I guess staying with gas is going to be the go forward solution. Now I'm torn between continuing to trust the old technology with the Reman 7.4L route or if opting for the latest 6.2L Direct Injected engines (420hp/440tq) will propel Sandee at reasonable speeds (10-12 knots) cruise without having to spin the engines too high because I don't want to replace them anytime in the foreseeable future (like not ever again) :)
Thanks for the insight Bob, but I can't drop that much funds into her these days.

[Trevor Lewis]

We repowered our 37 and after doing all the math we went with rebuilt 454s out of Florida.  $5000 for standard rotation and $5500 for reverse rotation blocks.  The 6.2s put out great horsepower but at much higher rpms.  Our 7.4s put out great torque below 2000rpm,  that's what we fealt was the most cost effective route for us.  Cheers and hope you're out on the water sooner rather than later.
Trevor

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[Jeff]

I have an ‘88 34 sedan with it’s original crusader 7.4s still performing well.

For future consideration though:

Replacing with 454s would certainly seem to be most cost effective as no other changes would be required and performance would be predictable.

I’d wonder about the longevity and performance of the small block stroker engines or 5.7s running at higher rpms.

Diesels would be great but I think  they’d have to come with a whole boat.

On Jul 15, 2024, at 1:43 PM, Trevor Lewis <tel...@shaw.ca> wrote:



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[andrew eykel]

You can buy a lot of gas and a lot of engines for $200k!

The 6.2’s you mentioned are great engines, smaller, lighter, more efficient than the older big blocks but they like more RPM. 

8.1 injected big blocks are a great fit for 37’s and I believe they can still be purchased new. 

Bob Clos is 100% right about diesels being more efficient and a good fit for 37's if money isn't an issue. My boat was repowered with injected 454’s in 2000 and the person I bought it from had water intrusion and seized them both. I pulled them out and had them overhauled, cost was $3800 each in 2015. That’s 52 engine overhauls for $200k. 

Just my opinion and experience with my gas burners. 

Sent from my iPhone

On Jul 15, 2024, at 1:42 PM, Trevor Lewis <tel...@shaw.ca> wrote:



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