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SO I was just wondering, what would a 6.5 be like as a swap in an inboard ski boat? I know a lot of them have small and big block v8's so size would work nice. Also I know the 6.5 is a very popular marine engine. I am sure the 3600 rpm redline would be a problem. I know nothing about boat transmissions, or even if they really have them. What do yall think?
I think it would perform well in a ski boat, if you can manage the weight. The rapid torque rise (compared to gassers) would allow for a steeper/larger prop. You may not need more than 3600 RPM, but they'll turn higher if you need them to (pump modification up to around 5K is possible). A 2 (or variable) speed prop would negate that need, though. I don't think it would work well for a jet pumper, without a speed increaser. If I had a ski boat in need of an engine, I'd do it. If nothing else, the cool factor would make it worth while.
There were some inboards sold in Europe that had diesels. The transmission in a true inboard is like a simple automatic transmission. If you find one with a Chevy V8 it would be nearly a bolt in. I have thought about that swap in my old Correct Craft. I swapped out the Chrysler 318 for a Chevy 350 many years ago.
Years ago, when I was involved in circle racing, many of them used the Powerglide tranny. A torque converter wasn't needed, as the water served that purpose. It really improved the hole-shot and exiting turns. We opted for more HP, but the real winners got away with small blocks and the Powerglide because they had several hundred RPMs over the BB's, and also due to the weight and weight distribution. A 6.5L with a tranny or gearbox would be VERY heavy.
www.peninsularengine.com created a business out of producing marine 6.2L diesels and 6.5L diesels. I remember hearing from the owner about his sales to Europe for use in ski/pleasure boats. I was told that the diesel, with its low rpm torque, was great for pulling skiers out of the water. All this plus about 50% fuel consumption when compared to an equivalent power/tq gas engine. You would need a prop and gearing designed for the diesel as DmaxMav mentioned, due to the lower overall engine rpm.Quote:
Originally Posted by Kmehr
Jim
My Dad has a 2002 malibu that has an LS1 in it. I think it would be a really great/cool project. So tell me more about the transmissions in these things, what type of tranny would that malibu have?
To clarify I would not be chopping up my Dad's boat I would be looking for an older one. Also, I think it would be an ideal swap because you could use WVO, blend, or at least off road diesel to save some coin!
I have been using inboards for waterskiing for 29 years now. Still at it even today. I cannot see where a diesel engine would be practical or beneficial. Maybe for other applications but the inboard ski boats are in need of quick acceleration. The Velvet Drive transmissions provide a 1:1 or 1.5:1 gear ratio and use the horsepower for desired acceleration, in lieu of a (primarily) slower responding torque force.
That said, if there would have been a usefulness for a diesel powered inboard (within the context of this thread of small boat applications, as it has evolved), there would have been that available by. I have spent 29 years with Mastercrafts and have had more inboard boats than I can remember. I like the gas powered acceleration for all entities of skiing. That Ford 351 Windsor is bullet-proof. The Chevy 350 or the LT1 are good engines as well (other than the aluminum heads on the LT1 Corvette engine).
Just my $.02 from many years of satisfied gas-powered skiing.
Happy dieseling to all...
I am thinking it would be hard to beat gas acceleration as well
Yea, but it has been discussed here before and I will say this, I always enjoy seeing someone with a vision. You seem to be having fun. Good deal...... :DQuote:
Originally Posted by Kmehr
Now to talk skiing is another thread and a lot of talking to do....
Most have a Velvet Drive 1:1, 1.23;1, or a 1.5:1 (aka Power Slot). The 1.23:1 were used in Correct Crafts mostly, and rotate the opposite direction as most other manufacturers. Mastercraft used the 1.5:1 (Power Slot). There is a torque disk between the engine and transmission, but I can't remember the proper name for it.Quote:
Originally Posted by Kmehr
ZF also builds a direct drive boat transmission.
Any boat with a gas Chevrolet engine should be basically a bolt in.
Not sure what transmissions were used by the diesel ski boats sold overseas. May want to talk to Peninsular Engine in MI. I think you can buy a crate engine from them.
I am going to keep looking into this i think it would be a sweet project
I was involved in boats years ago and we always ran BB Chevies of 454 to 500 Cubes in our racers
We used a retired race boat as our weekend warrior to ski behind.
The pleasure boat had a 396 chevy with a 671 Huffer up top and some huge Carbs to flush the fuel though the thing :eek:
The idea of a 6.5 diesel is not a bad one. The 6.5 with a couple turbos would be sweet.
Run dual turbos and turn the IP up to the limits.
The 6.5 will spin fairly well and it will grab revs plenty fast enough for any pleasure needs.
Stay away from Bronze/ brass props though. Go with a tri blade stainless.
As daddy always told me, when they shed a blade it never goes out or
down. This = WET butt. :(
Depending on the size of the boat and the prop,the proper gearing can put the little 6.5 right in its sweet spot.
No reason at all that the 6.5 can't spin along at near governed speed for periods of time.
The thing with a boat is that there is no coast, the prop is loaded all the time that there is power to the shaft.
Now what would be cool is a Drag boat type hull with a well chromed up and painted 6.5 with a set of wild chrome over the transom exhaust coming off the turbos. :D:D:D
Definately have some fun with this beast. Cruise by the beach with all the folks watching and belch forth a cloud of black smoke on their picnic :eek: Ohhhh Yes you will be the life of the party.
Be sure to use longer tow ropes so the little cuties back there wont get their Bikini's all sooted up. :rolleyes:
I want to see this when its finished
Best
Robyn
This project is still very much in the weanling stages, but I will be sure to keep all posted on the progress!
Several people installed 6.5 engines in ski boats. They report that fuel usage is about half of what is used by a gas engine.
I put a 6.5 in my 21 foot fishing boat and just got it running October 2011. I removed the inboard Perkins diesel and converted it to Mercruiser Bravo One Outdrive. The old engine pushed the boat at 13mph for 2 minutes until it overheated. We got 38mph out of the 3rd test and feel there is more power available as soon as we get rid of the temporary 1/4" fuel lines.
There were only minor problems. The batteries had to be moved to the bow for better trim. It has glycol coolant and a big heat exchanger, 180 degree T-stat. There is an oil cooler with T-stat control as well. I ran the engine hard and there were no heating issues. It is nice to feel the power of the engine and hear that turbo. Here is a link to the second test:
http://www.youtube.com/watch?v=nHPtNYtnP-k
Third test: http://www.youtube.com/watch?v=J9bGyO2aWXk
Did anything ever come of this? I was thinking of doing the same thing.