gearboxes and potential

Bobber a couple of things to ponder. There are things to consider when marinizing a car engine heat as mentioned above and electroliss. certain car engines have marine conversion kits available wich have the zinks built in to them. converting a motor that doesnt have kits available may take some engineering. but it can be done. I know a captain that had a mercedees diesel that his daughter totaled. he converted it over and installed it in his bay trawler and towed nets for atleast five years before he sold it. HE had a marine engine background wich helped. He took a heat exchanger off a ford lehman, so the core of the motor was still fresh water cooled. he had to get the xaust risers special made. The neet thing though was that most gas engines in my area use velvet drive transmissions., but he couldnt find a bellhousing that would bolt on the mercedees.. he was slick though he bolted a flat plate to the exising bell housing and took his time lining the the gear and bolted the velvet drive to that plate. THe boat was never designed for speed so she worked great for him about a third of the fuel consumtion of the gas motor that it replaced.

 

A 302 Ford with 260,000 miles on it that gets a 35' dive boat up "fairly quick" as he was told. We all know of the many 350 powered tugs out there, chugging along as they shove container ships into their berths. Come on . . .

This is a problem.

People come here to get advise they can count on, from folks with experience and expertise. What have we got here? A well used 302, any one not thinking a 302 dragging a Crown Vic around for 260,000 miles wouldn't be done please stand, happily picking a 35' dive boat up on plane quickly. Some body bought into some bull.

Car engines can, have and do get slammed into boats of all types, but suggesting it, promoting it and recommending it is the mark of amateurs, if not the fool hearty. Just because it has been done, it is being done or will be done doesn't mean it's correct, safe, wise or even legal.

The whole point is to provide a place to get things done, without endangering life and limb (doing it correctly). This isn't being served by listing all the ways to kid one's self into thinking you can stick your mom's Buick motor in the runabout and get by.

Folks suggesting you can "just" do this or "just" do that in regard to automotive applications being transplanted into a boat, haven't had their insurance company listed on the bill they've sent the client. It amounts to asking people to take their own asses for granted on the advise of an inexperienced, uninsured, keyboardist that has some knowledge about boats.

There is a reason why marine applications are so much more then repowering you car and it has little to do with mark up. The aircraft industry has the same reasons and problem with costs, for seemly the same application of engine uses.

If your car runs out of gas, tosses a piston or rod, you roll to a stop and get out. You use the cell phone and get a ride. If this happens in an aircraft or boat, you aren't getting out and walking to the next gas station or sitting on the curb waiting for AAA. Both aircraft and boats place the human in an unnatural environment, whereas issues arising must be dealt with on hand, on board or you will be at the mercy of the unnatural environment you are avoiding by being aboard. Cutting corners on propulsion systems by using automotive engines is unwise, unsafe and in some cases not legal. To preach anything else is unethical and frankly wrong and voiced by those whom have little experience and haven't the backing of any of the automotive engine manufactures or insurance companies blessings.

It has nothing to do with the "proper way of doing it" as you've implied, Bobber, but the safe way of doing it. I've seen what happens when it's done your way, they blow up, taking property and people with them.

I own a Dodge Rampage, a little mid 80's pickup. It came as front wheel drive with about 90 HP. It now is 412 HP with a V8 powered rear wheel drive. I shoe horned a 350 and 5 speed into the thing, fabed up a 9" rear (shortened 10") and put a suspension under it. It runs mid 10's, if I keep the front end on the ground and is a great beer run car. I know about making things work, and am willing to step well out on the limb, but not risk my neck to save a few bucks. This is why it has a blow proof bell housing and a bunch of other necessary goodies, because I like my limbs just the way they are and am not willing to follow the advise of ill informed, inexperienced floks, whom have little real knowledge of the tasks at hand in engineering the issues they are promoting advise for . . .

 

PAR, given the context of the thread, that is "experimenting with propulsion" is it so wrong to use a car engine in a mock up? Certainly even though I posted that I had done it I also conceded that I do not recommend it. In my boat I knew the waters, a shallow bay, and was never far from help if I needed. I would never suggest that anyone do as I did. As a simple experiment though I still feel it is a cheap alternative especially given the chance of success with a non-standard transmission as mentioned. Even so though a V-8 Gas marine engine is not much different from a V-8 Car engine. Certainly the durability issues could be adressed if one wished.

 

I use to have a cardboard and plastic small block Chevy and 350 turbo combo mock up I got from a car parts shop that was closing down. I wish I knew what I did with the thing (the other half probaly tossed it) as it was very handy. Short of that I've used short blocks mostly, slap on heads and valve covers and see if the engine box closes, etc. mostly I measure a lot.

The differences between automotive and marine applications is great. Very few of the internal parts (crank, cam, pistons, rods, etc.) should be used as they are generally cast pieces and not suited for the task of continuous duty cycles. The only type of engines well suited for easy marine conversion are stationary engines or fixed mount units, used to drive generators, pumps, aircraft and other continuous operation duties.

The car engine needs only to produce 20% of it's potently available power 90% of the time it's in operation. It requires but just a touch of the peddle to keep it tooling along at high way speed. Marine engines need to produce 80% of the available power 90% of the time they are in operation. If you roll back the throttle on a boat from "high way" speed to the just kissing the gas peddle needed in a car the boat comes to a quick halt and crawls along at the reduced RPM. Marine engines need to be stout, able to handle this power output requirement evey time it's used. This is why the internal parts are forged and much heavier duty then the automotive parts. They are made of much better metals, have thicker sections and generally much tougher to break.

The whole fuel system is different to contain gases that could escape into the bilge (read, loud kaboom) and the electrical components have special shielding to prevent stray sparks (look in the vent holes of your drill motor the next time you use it and imagine if that lived in a bilge full of gas fumes) and the connections have to be rock solid to prevent arcing. An automotive carb. will not have shaft seals or vent loops, though may look just like the car version of the same model carb.

The only way you can safely use a car motor in a boat is to have it very exposed to the environment where the fumes can vent naturally to the air, but this can and does cause problems as the fumes can collect in areas not as open (under motor mounts, transmissions and engine blocks for example) when a little poof of fire ball can be set off. A little poof isn't that much of a big deal, unless your luck is like mine and the little poof pops off a fuel line and the cascading effect of these type of mishaps begins.

Many studies have shown that big problems aboard are a result of a bunch of little ones that got over looked or unnoticed until the downward spiral was so steep, no relief short of major problem can be avoided. Insurance companies have headed the research for safer and required engineering to address issues they see cropping up over and over. They send out investigators and find the same things happen for different reasons. They then put big pressure on manufactures, politicians and the courts to get changes made. In a perfect world this would be their effort to help their fellow man, but in realty it's their effort to get more from their bottom line. If a single regulation makes boats less likely to toss it's cookies in the middle of nowhere they get to keep a higher percentage of the premiums paid in, rather then having to pay the clams made for the loss of another boat.

I love to play with things and experimental craft of any type would be wise to stay near home base, but these wild announcements of 260,000 mile car engines pushing 10 ton boats up on plane "quickly" and aunt "Millie's" used up beater dragging a dredge across the bay for several years stories that we've all heard most of our lives is foolish urban folk lore stuff best left for books, and bed time stories.

In defense of Captword, the transplanted Mercedes oil burner probably produced a bunch more power then the boat needed. A displacement vessel needs much less power then a planning craft and this engine may have made say 120 - 150 HP, but the boat only need 50 to work well and drive to hull speed. In this way you can use the cheaper automotive long block assembly, just way over rated for the service it will perform. There's a weight penalty, but if the cost is right and the conversion can be made . . .

Personally I'm a big fan of heat exchangers, they save blocks from rotting from the inside out. I prefer aircooled, but are a bit on the shy side on this side of the pond.

CVT's may be a way to go, but transmissions will not over come the laws of physics and a a lot of boats will max out or become very unstable, because of their hull forms, not the lack of power or effective gearing.

 

I assume this long post is to bolster your position and not to educate me. I am well aware of the intricate details and differences between a "stock" small block and a MArine version. Pistons, cranks and rods are on par with slightly HP pieces from the manufacturer. Well built aftermarket engines are much stronger than Marine units. Of course marine pieces such as starter, Alternator, fuel system whether Carb or injected as well as exhaust MUST be marine pieces. And for the record I did use a 307 chevy from a nova with 250,000 miles in my 26 FT trojan for many years. It pulled a skier quite well and nearly reached 30 MPH. It had a marine carb, exhaust and fuel pump. It had a summit racing cam and I simply got a left handed prop. I believe I was swinging a 13X11 cupped and the boat would reach 4300 RPM with a light load. Again I DO NOT RECOMMEND the use a car engine in a boat except in the context discussed here for and experiment or mock up.

 

this thread seems to have deviated a little from what it was intended.
I wasnt talking about anything commercial, or even produced, i was talking about the gearbox mainly, how to go about fitting a gearbox. the car engine was, as i think i pointed out earlier, mainly for mockup as mentioned earlier. i had a 2.0 calibra engine, which i was going to use to play around with, instead of forking out cash for a marine engine and then having to fabricate bell housings etc, before i could even see if it would work. the calibra engine was a mass produce, common 4 cylinder lump, which would be easy to match up to a gearbox, and allow more time and money spent on testing the gearbox idea instead of wasting time and money getting a marine engine to match up to a gearbox. thats all the car engine was for, if i made it sound like i intended to mass produce anything like that using car engines, then oops.

I agree with you par on the problems with car engines, and the risks and problems associated with it. and although i know a lot of people have managed it, at the end of the day, thats their call, if they want to risk it, thats up to them. im sure most go around quite happy with no problems, and based on that, tell others it works. the next person may not be so lucky.

As far as i know, granted i am not clued up on the inboard engines much, most of the boats ive been with have been outboard, and only inboards were the large mercruisers on Princess boats, but i believe they are GM blocks anyway arnt they? but with different heads and valves? thats what i always thought anyway.

you dont need a degree in marine engineering to know that vapours in an closed space is a problem, thats common sense. granted some people dont have that common sense, but still. IF i did go ahead and look more into it, then the car engine, as i said would be a test subject, if a suitable, improved idea came from it, then obviously it wuold need an engine that is more suited, or the engine modifying. seems everyone mainly talks about fuel and electrics though when it comes to safety. fuel system wouldnt be hard to make safer in a boat. only fuel parts in the engine bay would be the lines and the interns of an engine. since the calibra lump i had is injection, carbs arnt an issue. injectors can leak in a car or a boat, thats just a problem that happens. no internal combustion engine can be 100% safe and never fail. if you can make an engine that never fails and never has any problems, you would be a very rich man!. Id imagine, and im going off the top of my head now, but stainless steel fuel lines, and fuel rail, would be plenty safe enough. the fuel pump doesnt need to be anywhere near the engine or bay.
Electrics would need better shielding, but it has to be said that these days, most electronic components in a car engine are sealed units anyway and no longer do you have the spade connectors wrapped in electrical tape cable tied to the exhaust. anything thing like ECUs etc can be mounted outside the engine bay, away from vapours etc. spark plugs are sealed anyway, and on the calibra engine anyway, the ignition system is a sealed unit and doesnt use the old points system which would spark. Id say actually that the elctrics on this engine are as safe, if not safer than most older boat engines. Engine electrics are engine electrics, despite what the engine is fitted to. still needs to make a spark at the right time and run sensors etc, you obviously wouldnt use anything not relevent to a boat, thus reducing the wires down significantly anyway.
a heat exchanger would be used for cooling, which i mentioned in the first post, as obviously the internal waterways and water pump wouldnt cope with raw water cooling. Since the engine is a GM engine, and as far as a i know, mercruisers are GM blocks, then pistons etc that may need changing would fit into this block like a Mercruiser block, failing that, you can buy much stronger pistons and rods which would cope with the pressure. If they can handle a NOS injection and forced induction, then im sure a set could be forged to handle marine applications. and a water cooled exhaust can be fabricated from stainless with little trouble, and there was a guy in Wales that made his living by making water cooled exhaust systems for any engine you took him.

Im not saying it should be done, im just saying, the issues could be addressed if needed. i probably wouldnt go the effort, and would use a marine engine if the gearbox idea worked.

i think i am going to look into the CVT more, as i think thats going to be the way forward, but just wanted to clear up this thread a little and get back onto topic of the gearbox and potential, and not flood it with does and donts of car engines. The idea of using a 4cylinder is still an idea, and as loads have pointed out, would require some modifications, which i think is pretty clear now, but i really wanted to know about the gearbox not the engine. Engines have been done and already work, dont need to improve them, well ok, always room for improvement, but not what i was talking about.

aircooled engine pose problems too though, when your talking about enclosed engine bays etc, as getting the air too the engine to cool it is where air cooled engines have always failed. VW common example. nearly all campers or beetles running the old aircooled engine would catch fire, because air couldnt get to the engine to cool it properly. the engine itself is built to deal with it, but often the fuel lines arnt, and they either melt or expand so much they leak, and then you have a bonfire going on. I wouldnt fancy an aircooled engine in a boat, for the same safety issues you mention on car engines. fuel systems etc, i could see them maybe in outboard form though, must admit though, ive not seen many boats with aircooled engines in them, if any, but im sure they do exist.

but anyway, enough of the car engine stuff.

 

Air cooled engines are quite popular in Europe and other places around the world, just haven't caught on over here.

My favorite marine engine is the old air cooled 3 cyl. Lister. No electrical system at all, being hand started, though an alternator and starter could be rigged easily enough. Just flip open the compression releases and give it a spin, then close the compression releases. It has a lot fewer parts and systems to worry about, is near bullet proof and I wish I'd never sold the 50 HP 1958 I had. You couldn't kill the thing, just put new rings and bearings in it and she was good as new. Other owners of the older style slow turning diesels agree, and do they produce torque, globs of it and this is what makes boats go, not HP.

I like the idea of CVT and am wondering why it hasn't been tried commercially (or maybe it has and I've been sleeping) Seems to answer the problems more conventional gear changers have, automatic or manual.

If you could find a running FWD setup with transaxle and final drive attached, you could just weld a flange to the half shaft screw on a prop and give it a try. Certainly would prove or disprove the concept. Wouldn't have to run long, or even be the most healthy example of the breed.

I know of two different approaches for the type, one being mechanical and the other hydraulic. There may very well be other engineering angles used in this application of gear reduction. I just don't know enough about them to want to play with the idea, on the hard, though some research is warranted for sure.

I still think fuel to electric, fuel to electric to hydraulic or fuel to hydraulic would be the best transmission available and have some assurance of reliably. This is something else that hasn't caught on in this country, but has a strong following overseas. I'd guess if it isn't easily understood in this country then acceptance is difficult.

Ever watch a drywall hanger cut holes around the electrical boxes? They've been told they're dead, not hot etc., but they will walk well around a wire hanging out of a wall and cut well clear of the wires or just cover them over, just to avoid the shock they think they may get. Yet we all have added brake "fluid" to the master cyl. reservoir (we can't even call it the hydraulic oil it is)

Maybe Europeans and the rest of the world are a bit more daring with engineering then us, yet we are the ones with all the cool gadgets all around the workplace, home and shop. Go figure . . .

 

i wouldnt say us europeans are more daring as such (yes i am european, british), but i guess being the small island britain is, we tend to play around more with boats. instead of sitting down and thinking. well that works, so wont mess with that, we sit down and think, that works, but i bet i can make it work better.
I think it has long been a tradition with europe, italy and britain mostly, italy more recently, to advance with boat design. and the rest of the world tends to just follow along picking up the good ideas and ignoring the bad ones, which makes sense. but i wouldnt call us daring, just curious i guess.
of course the biggest pioneers in boat design is the RNLI. (royal national lifeboat institution) quite often they set out to improve on something and in turn, the leasure industry follows suit. the RIB for example wasnt intended as a pleasure craft, was intended as a fast inshore lifeboat. Everyone thought it was stupid. would never work. dont be daft etc etc, but yet now is probably one of the most widely excepted boat designs for offshore use where speed and stability are key issues, OK america seems to have kept away from it, but it is getting harder to avoid the RIB in american marinas.

As far as engines and stuff go. You have to remember also, europeans generally dont have as much money to throw around as america, and also dont have many engine manufacturers left (GM own most of them now). Aston Martin being the only british production car/engine company left, and somehow i dont think a V12 from an aston martin is the answer, so we tend to work on a budget. As my dad taught me from a very early age. if it dont fit, make it!, and thats kinda how its done. although the ideal solution maybe to use something different, often its home engineers inventing stuff who have to make cheaper alternatives work.

I dont know of any examples of the cvt being used, which is why i was kinda edgy around it myself, and asked if there was any known problems with it as to why it isnt used, but it seems the logical solution to many of the problems associated with gearboxes and boats.

i was wondering about what setup to test it with, FWD or RWD. my thought with the FWD gearbox was it has 2 drive shafts, comming from the side, and in order to get those shafts pointing backwards would require some kind of differential or CV joint in order to do it. I thought a RWD setup would be easier as it just has a single output which could drive a shaft straight out to the prop and just do away with the rear differential that would normally be present, at least just to see if it works.
Im tempted to also look at semi automatic gearboxes, as i think this would give more driver control over the ratios. select a good ratio for high speed cruising, and then a lower ratio for skiing etc. keeping the prop turning through gear changes i think i have solved, but the actual gearchange itself is where im tripping up. where as in a car if you miss a gear, oh well you dont stop, you just coast a little bit until you find the gear, but in a boat, if it missed a gear, for whatever reason, and your at speed, its going to be dangerous, also stalling would be a problem, although probably not as much of a problem.

 

"I dont know of any examples of the cvt being used" For that matter I have never seen a manual or automatic transmission in a boat only single gear ratio models. As far as the FWD tranny: it has to have some sort of differential. You should be able to open it up and weld the spider gears solid or some other similar modification so that both sides turn at the same rate and then just connect one. This is after all a simple mock up/experiment. As far as Americans, I think we are pretty innovative. After all we tend to do well on junk yard wars

 

ive seen one automatic in a racing boat, was a home made boat, running some large V8, seemed rather bodged together to be honest, dont think i would fancy doing the claimed 120mph or somthing like that in it, but that had a 3 speed automatic in it, but i never saw the boat running, so i dont know how well it worked, from what i understand though, it shared the same problems racing teams experienced with automatics. it would get to high gear and stay there, so taking turns etc actually was slower as the ratio was all wrong comming out of the turn. i think he uses this boat for drag or something though.

junk yard wars eh. my dad had a team on that show, but they didnt air it, they were "to good and didnt make good TV" seemed a little strange to me, but i guess TV is what its all about. but i didnt mean it as americans werent innovative, was just saying they tend to stick more to what they know works instead of playing around a bit more and seeing if they can improve on something, or make something do a job it wasnt intended to do at first, if that makes sense

theres a boat for sale down the road though, after saying all that, that looks home made, and has a very large chevy lump sticking up out the back. not sure exactly what lump it is, havnt looked at it that closely, but obviously a V8 and what looks like a supercharger bolted to the top, or a compression scoop of some form, boat itself looks like plywood, and looks like it is capable of scaring the pants of plenty of people. so obviously there are some fool hardy home mechanics around these parts, only wants $6500 for it, dont know where you would use it around here, lakes around here arent huge. cant see you having much fun in it, open it up and you will the out of lake in a couple of seconds and have to turn around again.

 

CVT gear boxes in cars are popular in Japan, I think they are more popular than regular autos, which is why most modern examples are in suabrus mazdas etc. they tend to only handle fairly low power though.

Despite what has been said in this thread, It is certainly possible to succesfully marinise automotive engines and transmissions, So long as you get good advice and use a some good engineering common sense. If you have not been put off you might want to track down, Nigel Warrens book "Marine conversions". Plenty of firms make a good living from this.

Some of the arguments against marinising are a bit strange, Especially with regard to marine use being different to automotive use, that is obvious you just have to spec the engine correctly. The argument that the marine engine works harder is irrelevant, If an auto engine is designed to run at a peak pressure/power/speed for x thousand hours, that is what it is designed to do, it will have been designed and tested to perform at 100% of those condistions for 100% of the time. Regardless of the fact that the normal customer will ony use it in those conditions for a fraction of the time. I have been involved in the design and stressing of these types of components for 15 years. There are still customers around who will use an engine at 100% of load for 100% of the time.

Also these components don't necassarily fail at peak torque/speed or power, the big killer is torsional vibration in a crank and that can occur almost anywhere in the load speed range.

Gareth

P.S. Aston is now owned by Ford, Reliant (Del boys 3 wheeler) is I think the only British owned and built car manufacturer

 

O.K. Folks, I see this is always a touchy subject, but here's my 2 cents worth. Before I fire away, let me just say that I've been working on engines/trannies/etc..., both automotive AND marine for 15 years now. Marine engines of the inboard or I/O variety are all production automotive engines, with a few relatively minor changes. Of course, as Gonzo and others have mentioned, starters, altenators, carbs, and fuel pumps are all marine versions, with flame arrestors, carb bowl vents directed back down the carb throats, double diaphragm high output fuel pumps plumbed to vacuum so the carb will suck up fuel from a ruptured diaphragm, and the list goes on. But the engine itself, the block, crank, heads, pistons, rods, etc., are automotive pieces. Usually from the high performance shelf, but automotive none the less. I have torn into Crusaders, PCM, Indmar, OMC, and Mercruiser, and they're all the same Chevrolet 350, Ford 302, Chrysler 318 or what have you that can be found in a Nova, Mustang, Charger......The point is they are car engines at the core. Unless they're raw water cooled (which is suicidal with a late model thin casting engine, and/or aluminum heads) which requires a marine head gasket, and cooling circulating pump with SS shaft and Bronze impeller. Even the old reliable Velvet Drive isn't a marine only piece, it's a FORKLIFT transmission!!!!! The fact is that the pleasure marine market just isn't large enough to warrant boat specific inboard engines, with the lion's share going to the outboard manufacturers. There's probably 10 outboard runabouts/fishing boats for every 1 inboard powered pleasure vessel of any kind, so the numbers just aren't there to develop marine inboards when converting automotive engines will do, and I believe does well. An inboard will last just as long, if not longer than an outboard, and is more efficient to boot, though they're closing that gap with 4 stroke and EFI outboards. But because the market is small, and they've done a lot of development over the years, outboards cost TWICE as much per HP as inboards. I can buy 2 brand new 330 HP Crusaders for a few thousand more than the price of 1 Mercury 225 EFI 4 stroke. See where I'm coming from? Anyway, I've rambled on enough. The point is, everyone here is a little bit right. They are in essence, car engines, with a few modifications for marine use. You can pull that 100,000 mile 350 out, put on starter, manifolds, etc... off that old Crusader and drop it in your old fishin' rig (but I hope you've got twins or a kicker for when it dies). Is it adviseable? That's up to you.

 

so i was correct, mercruiser is just GM engine. First time i really worked on one, i was given a crate, piled up with various engine parts, and told it was a V8 Mercruiser engine and has to be put together to go in a boat, which already had another one assembled.
Id never worked on a marine engine before that, but had worked on many Vauxhall cars (UK version of Chevy) and as i sorted through the pieces i was thinking this is just a Chevy engine, and managed to put the whole thing together, without instruction, going from what i knew of chevys, also a lot of the parts were stamped with GM anyway, block etc, ive not really worked with many inboards, and everyone was going on about cars and boats being different, so i wasnt sure if i was right or not.

 

It's quite correct that automotive blocks are used for marine applications, and it only makes sense to insure the combination of parts will survive the tasks asked. Marine blocks generally are the heavy duty versions of their land based counterparts (truck engines with different performance profiles)

You could build a real work horse of a motor with after market parts or race parts, but you'll likely spend much more then a prepared engine from a manufacture that produces or vends out the production of the necessary parts or rebuilding a marine engine. Most of the engine manufactures have continuous service parts available for their auto blocks as they are used in a wide aray of applications from running stationary generators and pumps to A/C compressers. I've even seen a natural gas fired GM 4 cyl. driving an refrideration unit for an ice rink! Many aftermarket suppliers also provide the same parts of lesser and much greater quality. Marine torque and HP curves are very different then typical automotive applications and short life can be expected from a stock auto engine producing the same HP as an equivalent marine engine. Most marine engines operate in two modes, idle and WOT, the engine performance profile need not be very flexible. This is a mostly a function of the cam profile and parts able to take the loads. Auto engines need a wide range of operation envelope and hence are poorly equipped to handle sustained high shock loads and sustained WOT operation.

This was my only point.

Several marine engine builders have purchased the right to make or lease the right to build many now out of use auto engines. Mercruiser owns the 165 and 181 CID GM blocks it uses in it's I/O setups. Those engines were in production and used in Novas and other similar sized GM cars in 1969 and 1970 only (in the case of the Nova anyway) It buys Gm V8's built to their specs directly from GM for use in their I/O's.

In the context of trying something out to verify an idea or rig up a different assembly, then it's an acceptable and easy way of testing a theory. Durability isn't an issue, as long as reasonable safety concerns are addressed.

CVT has been used in heavy output applications. Tractors now use them, a friend has a '55 Packard that has a Hydromatic trans in it. It is bolted to a 275 HP 352 CID V8. That's plenty of HP for most pleasure craft. Now that Packard has a 727 doing the gear changing, because it's very had to get parts or skilled folks to work on those old transmissions, but they do exist and can handle the power. I think Buick toyed with the concept in the 1950's or early 60's Huskavarna (sp?) has been installing them in garden tractors for years and International has been using them in tractors of all sizes. I'm not sure about John Deer, but it's worth further investigation. I have a Cub Cadet tractor with a spent engine, but sound (if a little leaky) hydro trans. It was mated to a 18 HP engine and could be had by anyone who will pay the freight to their shop. it's not real heavy, but I don't think UPS would pick it up on a hand truck, maybe UPS Freight. It has a power takeoff for the deck lift, but doesn't need be hooked up to prove the point. The best part is the shaft comes right out the back. A jack shaft, coupler, stuffing box, strut and a prop you'll be set. I'll bet a RIB that can plane with a 35 HP outboard will plane with a 20 HP inboard and have the hydro trans in the mix to boot . . .

 

Hi bobber,There must have been many hundreds of thousands of auto three speed gearboxes used in boats over the years bobber,because it is the easiest way to install an auto engine in a boat.You have choice of gear ratios and a good clutch assembly,the auto clutch being easier to use than the cone clutch and if used sensibly there are many advantages.Some people also modified the reverse to a higher ratio,and used cooling too.With the different gearing this gives more propeller options and a choice of running surface or subsurface props,using deep gear ratios,running motor faster in adverse conditions,the list goes on.Automotive automatic boxes have been used in many ways,such as adapting the auto transmission to the engine and a V Drive.The torque converter being replaced with a solid coupling and only using the two forward gears and reverse.Have you ever heard a boat change gear?There is plenty of research to do in this area,and lots of lost cash and fun.tom kane.