engine marinisation

Discussion in 'DIY Marinizing' started by PMI, Aug 13, 2007.

  1. PMI
    Joined: Aug 2007
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    Location: Tyrone, Northern Ireland

    PMI New Member

    I came across this forum while searching for information on engine marinisation, I am a car mechanic but know almost nothing about boats and the systems used in them. I have bought a 13 ft speedboat which is fitted with a 2.9 V6 engine out of a ford sierra/granada/capri. The engine is beyond repair and I am looking at alternative engines including some turbo diesel engines (petrol almost £1 per litre, red diesel less than 50p). I dont know how sensible this is. Performance is not a major factor as the boat in question is old and not worth much and only to be used for occasional fun use. Can anyone tell me what all the steps involved in marinising a car engine are and why they are taken?
     
  2. PsiPhi
    Joined: May 2007
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    PsiPhi Newbie

    I have no idea as to the answer to your question, but would be interested to know myself, but red diesel, isn't that for tractors and farm machinery only?
    I'm pretty sure a speedboat with a combine harvester engine is going to be a little 'difficult' to handle.
     
  3. PMI
    Joined: Aug 2007
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    Location: Tyrone, Northern Ireland

    PMI New Member

    "red" diesel is exactly the same as road diesel except that it is dyed to distinguish it, red is for use in applications other than road use where the fuel is subject to a lower rate of tax. The engines I have been considering are car engines, particularly peugeot 1.9td or toyota 2.0td (It has been mentioned to me that a diesel is no good for a speed boat as it does not rev high enough but with the extra torque at lower revs supplied by a diesel im assuming that this can be negated by using a more aggresively angled propellor?). I have been reading some information on the internet and might try to fit the cooling pipes used in the car but replace the radiator with a large heat exchanger, exchanging heat between the engine coolant and "raw water" pumped through by a belt driven pump, the intercooler also could be replaced by a heat exchanger which would be fitted immediately after the "raw water" pump but before the engine rad heat exchanger (also, is it necessary or just tidy to put the expelled water out into the exhaust as seems to be the done thing?). These are ideas which seem sensible to me after an evening of online research but im sure plenty of people before me have tried similar ideas so would like to know if im on the right track or not!! As previously stated I know almost nothing about boats, I know even less about combine harvesters but suspect that it may be ambitious to attempt to fit an engine from one into a thirteen foot boat!!
     
  4. USCGRET/E8
    Joined: Jul 2007
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    USCGRET/E8 Senior Chief

    Is the old V6 marinized? It may be easier and cheaper to get another engine.
    They are quite plentiful in the states. Or check for the conversion parts at Glenn L Marine or Barr Marine.
     
  5. USCGRET/E8
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    USCGRET/E8 Senior Chief

  6. CDK
    Joined: Aug 2007
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    Location: Adriatic sea

    CDK retired engineer

    Small diesels reach 4000 rpm easily and still have much more torque than the average gas engine. A merc 3,0 ltr does 4200-4500 at W.O.T. and consumes 50% more fuel that also costs twice as much as red diesel. I am at the present marinizing 2 VW 1,9TD engines. Not an easy job, but possible. A Ford FSD from a Transit would have been simpler, but at the time I could not find any with low mileage.
     
  7. Frosty

    Frosty Previous Member

    If you want some gut wrenching hp in a reasonably small package might I suggest the toyota 1Hd engine from the Landcruiser. It is 6 cylinder and is the cream of the small recreational boat engines offered by Yanmar. It is the same engine believe me I have two.

    I think they are 380 Kilo and can give out 300Hp in the 4 valve head option.

    Any diesel engine will convert to a boat engine ,I would choose something made for a hard life like something from a 4 wheel drive. Again Toyota!!
     
  8. Ike
    Joined: Apr 2006
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    Ike Senior Member

    Most diesels will work just fine in a boat. You need to think about noise suppression, getting enough air to the engine and what type exhaust, dry stack or water cooled. Also, how you are going to mount the engine.

    Marinizing a gas (petrol) engine is a whole different ball game. Read Marine Engines 101 at http://newboatbuilders.com/pages/fuel-2.html.

    There are exceptions. But generally speaking gasoline is a dangerous beast that can bite you really bad and should not be treated with a cavalier attitude. If you are going to do it, do it right. Marinizing a gas engine will probably cost about the same as dropping a small diesel out of the box (or a car) into your boat.
     
  9. CDK
    Joined: Aug 2007
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    CDK retired engineer

    I'm glad it's off my chest

    First of all, my Kia Sorento with state of the art 170 HP 2.5ltr common rail turbo diesel gets only red diesel and never complains. There are a lot of fairy tales circulating about sludge, sulphur and emulsified water in red diesel, but it is just diesel with trace amounts of a cyclic hydrocarbon combustible dye added to catch you evading taxes. The nasty stuff I just mentioned is also present in the high tax diesel, that's why car manufacurers cut their profits by installing filters and water seperators. Without these, there would be a warranty claim for every car sold.

    About marinizing, there are also many fairytales. While wrestling with my 2 VW engines I read as much as I can about the subject or as much as my heart rate can handle.
    Do not look at the large companies like Mercruiser to see how it is done. Their aim is buy cheap, sell expensive. Look at the GM Vortex product line to see where they come from. They reluctantly increase their standards now, but still sell a 1947 GM designed museum piece with an embarrasing valve lifting mechanism and a carburettor that is pouring your high tax gasoline away as if it were for free.

    Feeding seawater in your engine's cooling jacket is not a good idea, not with an aluminium head gasket nor with a golden one. The company I will not mention again because it isn't the only one uses a thermostat that is already wide open when it should still be firmly closed. As a result, the engine temperature is way to cold to allow full combustion. The coolant temperate should be near boiling point but if you do that with raw water cooling even an oldfashioned greycast engine is eaten away while you look at it.
    I've used up 1 Volvo Penta, 1 OMC and 4 of these black ones; believe me, a thermostat in seawater is asking for trouble. Immediately when the warranty period is over, it either stays closed or remains open. Marine growth does that.

    Look at www.mesamarine.com to find out for which engines a water cooled exhaust and heat exchanger are available. There may be other sites as well, but in my humble opinion they are the prime source for both US and foreign car engines.
    You will notice that the choice is limited, but dig a little deeper. My VW-150 manifolds were marked for 1,5 ltr engines, diesel or gasoline, but engine manufacturers tend to use the same hardware in several generations, so they are a perfect fit for 1.9TD's as well. A car mechanic knows more about that than I do.
    Use a modern, lightweight diesel if you can find one and can afford it. Operating temp. is reached quicker, saving fuel and polluting less. And all the lbs. you don't have to carry around will save fuel every mile and gets you into plane faster.
    Unless your application is a real workhorse with a 6 digit hours counter, engine life is no issue. Passenger car engines live very, very long, even in the average passenger car. Being in a boat is like a holiday for 'em: clean air, perfect cooling, steady rpm and -with the right props- no overload from hill climbing.
    B.t.w. you do not need the amount of horses commercial marine engines are rated with: these are commercial horses. A diesel with about half that, but real shaft HP will be more than enough. You may loose a few knots at WOT but than again, your diesel has no throttle at all and you started out with mentioning red diesel so you don't want to waste money....

    Your bargain diesel will not need a marine starter motor and no marine alternator. First of all the only difference between a car starter and a marine one is the price (3 times, sometimes more) and maybe a metal band around the area where the brushes are, but most starters I've seen in cars already have that. A marine alternator is different from a modern lightweight one because it invariably is an oldfashioned Motorola or Lucas with a steel casing and a sintered copper filter at the rear cover. The side where the fan is doesn't seem to need that. But you do not need it at all, your diesel fumes won't ignite, they just smell.

    What you also don't need are marine relays. From my own experience and the many summer guests looking for help, I can testify that they are the cause of nearly all electrical problems in a sterndrive's engine bay. Relays you do need because some actions like glowing or starting need a lot of current, but car relays (perhaps not aftermarket ones) are just as good or better and certainly cheaper.

    From the car engine's air filter, keep the housing and the wire mesh from the filter cartridge. Boat engines gets clean air that needs no filtering; the mesh will keep animals from building nests in the intake manifold.

    There are of course mechanical issues like making engine mounts (those from the car absolutely never fit), adapter plates for your marine gearbox, the engine coupler and the bracket you'll need for a raw water pump, but that's just a lot of cutting, drilling, bending and welding. You'll need a good friend or do it yourself. The only real problem I spent a lot of internet hours on was finding the right coolant hoses because in a car there is normally no plumbing at the exhaust manifold side, so you must improvise a bit. No big deal for a car mechanic I suppose. And of course the diameters from marinizing parts and car parts do not match, but adapters are quickly bought or made.

    I may have overlooked something, so keep reading what others will add.
     
  10. Jimbo1490
    Joined: Jun 2005
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    Jimbo1490 Senior Member

    The Vortek line of heads and intake manifolds were designed specifically with EFI in mind; indeed it had been nearly a decade since GM sold this engine with a carburetor when the Vortek line was introduced. But Merc uses them with a carburetor?? Shameful indeed.

    Your beef with pushrod engines is a little quirky, I think. OHC and especially DOHC does NOT save any weight in terms of unit weight/units displacement. It's only of use if you want to spin an engine very fast. Down below 7500 RPM there is just no advantage. Thus the motorcycle world is dominated by such engines.

    Ditto for pentroof heads. Two big valves with lower lift actually flow better and provide more low RPM port velocity. Pentroofs are very useful if you are racing in a class where displacement is stricly limited (all racing, really) because then you want to get every bit of power per unit displacement that you can get. But it will always be easier, cheaper and even lighter to just up the displacement a bit as long as nobody (like a race rule committee) is stopping you. The Mercedes racing pushrod engines certainly put the exclamation point on that during the '90's.

    None of this has anything to do with engine efficiency in the real world, either. The most efficient engine will be the one that can fully fill its cylinders under the widest range of operating conditions. A flat torque graph is indicative of such cylinder filling. Many large displacement pushrod engines have such torque graphs and are capable of delivering high efficiency.

    But carburetors on a Vortek head engine?? For shame, for shame, Mercruiser :rolleyes:

    Jimbo
     
  11. CDK
    Joined: Aug 2007
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    CDK retired engineer

    The Vortek 3000, last seen in the 2006 GM catalog, was used in the cheapest 1962 Chevrolet Nova, but quickly discarded. It has been Merc's core business for many decades and is still on the market as the (Mexican) 3.0LX with a dual barrel carb. Same goes for the small block V-8: EFI is an expensive option.
    Pushing a rod up to move a valve down is a bit awkward, but in the 1950's we didn't know any better, although Floyd Climer's 1948 book "British Sports Cars" lists many engines with SOHC or even DOHC. My only car with pushrods was a 1960 Renault Dauphine.
    MotoGuzzi uses desmodronic valve lifting without springs because it allows still higher rpm and is more efficient than pushing a valve open against a heavy spring.
    But I feel we are drifting too far off the subject here.

    An afterthought: Merc was once Kiekhaefer, now Brunswick, from the jukeboxes and bowling alleys. Good marketing, lots of money, little innovation.
     
  12. Jimbo1490
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    Jimbo1490 Senior Member

    Ah, I see. You call all small block Chevrolet V8 engines 'Vortek" :D

    This is as inappropriate as calling the modern Land Rover alloy V8's 'Buick 215' (1960) since that is their origin.

    There are few (if any) parts interhangeable from these earlier engines. The Vortek trademark refers to a specific cylinder head and intake manifold major re-design that incorporated fast burn, high swirl combustion chambers, even port spacing (which alone makes these parts wholly unmountable on an older engine without major modification) and other details.

    All small block Chevrolet engines ARE NOT Vortek engines.

    Jimbo
     

  13. CDK
    Joined: Aug 2007
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    Location: Adriatic sea

    CDK retired engineer

    I'm sorry Jimbo1490. Foreign language...., wrong character.
    What I meant is: industrial-irrigation.com/Vortec%20PDF%20Brochures/2007_industrial_engines.pdf -
    And of course everything GM writes about it.
     
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