Auto engine marinization

[Frosty]

I agree with you Hartley, and if what you said wasnt enough, the well known and well respected Yanmar 6LP is a Toyota engine 1hd, from the land Cruiser. The cooling system is of course Yanmar. Mine came with Toyota filters on them and if you dont beleive me,- reach round with a flash light you will read Toyota at the back of the block by the raw water pump.
This at first might seem a rip off but hey wait a minute I buy everthing from Toyota--- filters, timing betls. timing belt tensioners, head gaskets.

[hartley]

Thanks to Tom Kane for his comments,I believe N,Zers also have a long tradition of marinizing auto engines ,but as you say Tom techonogy has moved on ,but that should not stop anybody from marinizing an auto engine if he so wishes ,after all we both live in free countries (I only hope it lasts).
As regards your query on regulations over here ,we are for better or worse a de-regulated society,Boat building over here is in the hands of a relatively few builders of high repute , the shonks have long disappeared,therefore the industry is mainly self regulated.there are of course A.D.Rs (australian design rules) but these were formulated some years ago ,and as far as I know there is no Government agency overseeing these ,Of course small alloy boats (tinnies) have to have the required buoyancy and max weight ,but there again it is industry regulated .this of course applies to recreational boats ,commercial boats are a different kettle of fish.
Safety issues are once again a different issue ,and these are very detailed and strictly policed ,covering from the smallest craft to larger offshore.
I wiil post these if anyone is interested.
Thanks to Jack Frost for his comments ,I would be interested to know what happens in Thailand re boating in general.As regards powerplants for boats in Australia these of course are all imported ,mainly from the U.S.A and Japan and the industry here accepts that these engines comply with international emmision and safety standards .......Cheers .

[brian eiland]

..an announcement I received recently....

December 2005
YANMAR AND BMW ENGINE SUPPLY AGREEMENT
YANMAR CO LTD and BMW AG, German manufacturer of luxury vehicles, have agreed
that BMW will supply four and six cylinder Diesel engines designed for high
performance use to YANMAR MARINE INTERNATIONAL BV as the base engine for the
new YANMAR MARINE product line.

This agreement enables YANMAR to have the most advanced marine engines for its
product range. Customers will be in the position to benefit from the joint
efforts of two of the most reputable companies in their respective fields of
operation with a product that will set new standards in the Marine industry.

YANMAR is aiming to introduce this new fully electronic range of Premium
Marine Diesel Engines in the market around mid-2006.

The engine will be 'Marinized' and marketed under the Yanmar label. We have
had our eye on the BMW diesel six for 2-3 years now.Rumour had it, two
Austrians, in the vicinity of the BMW Steyr plant where they are made, have
been running the 'Hot Rod Six' in their boats. BMW's 3.0 litre diesel six
cylinder engine has received world wide acclaim from the Automotive press and
the Automotive engineering communities. BMW is recognized as the leader in
Diesel engine design in the world. Europeans can option the 'Hot Rod Six in
the 530d sedan and the X5. This engine is not available in North America BMW
vehicles. Soon, we hear.

I've always thought that the in-line six-cylinder engine was the most
inheriently balanced engine configuration for a 4 cycle engine.

Here are a few comments on same subject:


The benchmark in diesel motoring: BMW's three-litre straight-six.

BMW's straight-six features the most advanced technologies, such as common
rail direct fuel injection, a turbocharger with variable geometry and
four-valve technology. The combination of common rail fuel injection and the
classic straight-six engine configuration provides ideal conditions for a
genuine high-comfort diesel, the rapid charge cycle ensured by the high-tech
turbocharger as well as four-valve technology offering the additional
advantage of an excellent engine response: While conventional diesel engines
are usually a bit sluggish in their response to the accelerator pedal, as
opposed to a petrol engine, BMW's straight-six diesel builds up torque
spon-taneously with virtually no delay. So it is no surprise that this
six-cylinder is already featured in all three of BMW's saloon series - the 3,
5 and 7 Series - and is acknowledged in each case as the absolute benchmark in
the market.

http://www.germancarfans.com/print.cfm/ID/2040718.001/lang/eng

[stonebreaker]

I've read this whole thread with some amusement. I've seen a couple of folks who seem to believe marine motors are magical and an automotive motor can never be marinized without the requisite magic wand.

It's like the guys I see at the car shows who think factory police motors are somehow magically unbeatable. When you try to tell them that the car came stock with the same engine as the police version, they try to claim the factories don't sell "interceptor" motors to the public; and nevermind that you've built a 383 stroker with forged internals that will put your car through the traps in 11 flat at 120 mph; you can never outrun a police car.

I've also seen one or two guys who have claimed their territory and are sticking to it no matter what - like quoting stats out of context to support their position, even though the stats have become meaningless in their posts. Most of the arguments I've seen from these guys are, at best, 15 years out of date.

I don't know about the corrosion side of things, but I do know performance engines and I do know about cooling race motors.

As far as which engine is cheaper, I have to say a performance automotive engine is going to be far cheaper - about 2/3 the price. I went to two websites: http://www.sterndrives.com/supplies/mainsupplies.html and http://www.bayshorepowermarine.com/engines.html, and priced a mercruiser 350 Magnum 300 hp fuel injected engine. Discounted price was $7195 at Bayshore Power, and $8743 at Sterndrives.com. This is engine only price.

Now, I can go to a performance automotive website and price an equivalent motor. GM builds several smallblock packages off of the ZZ4 shortblock. This motor will have a nodular iron crank with nitride hardening, fuel injection, powdered metal connecting rods (these replaced the forged pink rods about 15 years ago), hypereutectic pistons (the same high silicon alloy cast pistons favored in some of the previous posts), and on and on.

Ramjet 350 crate engine

Anyway, the price of a Ramjet 350, 350 hp rated motor with included fuel injection computer is $4895.

Here's the same engine set up for circle track racing. The only differences are aluminum heads for better cooling, a racing wet sump oil pan, and a carbed induction system to meet sanctioning rules. Yet, the engine is designed for circle track racing right out of the box. That hardly sounds like an engine designed for 80% throttle 20% of the time.

What does the extra $2300 for the marine motor get me?

Interesting factoids:

Compression ratio in Ramjet 350 automotive crate motor: 9.4:1
Compression ratio on the Mercruiser 350 ci 300 hp: 9.4:1

Hmm, they use the same chamber volume. Both use iron heads.
Horsepower on the mercruiser is listed as 300 hp between 4600 and 5000 rpm.
Max horsepower rpm on the Ramjet is 350 hp at 5200 rpm. However, the Ramjet makes 325 hp between 4500 and 5000 rpm. Hmm, same heads, same horsepower curve...sounds to me like they probably use similar cams, if not the same cam. Whatever, the power curves are so close as to be nearly identical.

I could go on and on, but the fact is the mercruiser and the Ramjet are the same exact motor internally, with minor differences like the oil pan to accomodate the different intended uses. They even share the same fuel injection computer - it says right on GM Performance Parts' website that the Ramjet computer was initially developed for marine applications.

So what does the extra $2300 for the mercruiser get me? Not much. Mercruiser makes a point of talking about their 4340 forged crank on the 6.2 liter model, as well as the fact that it has a custom cam - but no mention is made of stainless valves or aluminum roller rockers. I seriously doubt they're needed. GM has used sodium-filled exhaust valves on their production motors for more than a decade, eliminating the need for stainless, so the valves are the same on both applications.

So yeah, the mercruiser motors are extremely overpriced. The cheapest I saw for a rebuilt motor was $2600, which is again ridiculous - I can take a worn out block and have it machined and blueprinted, and drop a fully forged rotating assembly in it, for that price, and stroke it to 383 ci while I'm at it.

Even the ring gap argument I saw one guy make is bogus - running a .080" ring gap is just a cost-cutting measure. If they really do run that much gap, that probably accounts for the lower horsepower rating of the marine motor - that extra gap could easily cost 25-30 hp. Instead, why not run Total Seal gapless rings? The vettes racing in SCCA GT1 and GT2 classes use them, including the 24 hrs of Daytona, and have taken the class championship for the umpteenth time in a row; so their reliability has been proven publicly. The only problem is gapless rings are about $200 a set, regular cast iron rings are only about $35.

So what does the extra $2300 get me? Well, the marine engine comes with a 3 year warranty. The GMPP crate motor does not. So, what it boils down to, is I'm getting a 3 year warranty for 2300 bucks with the marine engine.

[gonzo]

The marine version of the engine has an electric system that is explosion proof. The fuel injection is self contained and legal for marine use. The cylinder temperatures of an engine in marine use are much higher than in a car, even a race car. It is the equivalent of running a vehicle with a full load at WOT uphill for hours on end. Boats don't reach cruising speed and then require less power to maintain it. A larger gap is necessary for extra thermal expansion. It is not bogus. Also, Mercruiser engines have Vortec cast iron heads. Aluminum heads wouldn't last long in salt water. I sell new 5.7 engines for $5495.00 complete. The link to the engines you sell is advertising a base engine. The comparison is really bogus.

[stonebreaker]

Originally Posted by gonzo

The marine version of the engine has an electric system that is explosion proof. The fuel injection is self contained and legal for marine use. The cylinder temperatures of an engine in marine use are much higher than in a car, even a race car. It is the equivalent of running a vehicle with a full load at WOT uphill for hours on end. Boats don't reach cruising speed and then require less power to maintain it. A larger gap is necessary for extra thermal expansion. It is not bogus. Also, Mercruiser engines have Vortec cast iron heads. Aluminum heads wouldn't last long in salt water. I sell new 5.7 engines for $5495.00 complete. The link to the engines you sell is advertising a base engine. The comparison is really bogus.

Bogus? Is that a scientific term?

First point: I do not sell anything. I don't sell engines, I don't sell cars, and I don't sell boats. I'm a computer programmer. So, unlike you, I have nothing financial to gain by pushing any particular engine or engineering solution, other than the satisfaction of helping fellow enthusiasts get better bang for their buck.

Secondly, the Ramjet engine is hardly a base engine. It even comes with its own fuel injection computer - it only requires a fuel supply and 12 volts and it's good to go. And it comes with the same iron vortec heads you get on mercruiser engines.

Thirdly, I've seen your "uphill at WOT" analogy posted several times. I've got news for you. Running uphill at WOT is not the most stressful thing you can do to an engine. If it were, mercruiser engines would have to run forged pistons, not the same cast pistons that GM puts into every car going out the door. Running flat out at WOT, like a race car, is far more stressful. Why? Because the higher rpm put added stress everywhere in the engine - on the valve train, on the rotating assembly, and on the cooling system.

And your statement about cylinder temps in boat engines being higher than a race car's engine, and thus requiring wider ring gaps, is not just wrong, it's DEAD WRONG! A) A race car's engine turns at higher rpm than a mercruiser engine. Thus, with more cylinder firings per unit time, the cylinder temps in the race car are going to be hotter, if for no other reason than there is less time for the cylinder walls and piston head to cool off between firings. B) Boats have raw water cooling, or at worst, liquid to liquid heat exchangers. Cars, even race cars, are stuck with liquid to air radiators. Even if it were possible to move enough air mass through a radiator to equal the same mass of water moving through a heat exchanger, the radiator would still be behind simply because water has a specific heat capacity 4 times greater than air, pound for pound. And lastly, the fact that cast, hypereutectic pistons funtion just fine in boat motors is the final proof that boat motors are not some sort of elite athlete compared to car motors. I burned holes in my stock hypereutectic pistons long ago, and moved up to forged.

If cylinder temps were all that high in boat motors, they would have to run forged pistons, just like every factory turbo- or supercharged car sold today has to run. But they don't. And your ring gap of .080 is ridiculous. This link will take you to JE/SRP pistons' high silicon alloy piston installation guide. Scroll down to the ring gap guideline. For the MOST SEVERE race-only situation, a nitrous-injected full race motor (ya want to talk high cylinder temps?), the top ring gap is recommended to be .028" in a 4 inch bore, which is the bore of the mercruiser 300. .080" is nearly 3 times the recommended gap for a full race motor, and as such does nothing for the engine but increase blowby, which raises the crankcase pressure and costs you horsepower.

[Frosty]

WOT for hours on end? --Mmmm your not supposed to do that. There are different HP rating for an engine, there is Max HP and there is constant rated HP wich is the HP it can give for "hours on end" , WOT --yes. Hours on end--yes,--but not both together. 80 thou??? as an engine builder --well 25 years ago, I would be reboring that one. There is a lot of hot gases and acid going down the piston skirt there. You would be relying on your oil control ring really. Are we sure the book has been read correctly, like discard at 80 thou,even that is enormous. Its not 0.8mm is it? wich is 28thou ish!!

[Frosty]

Gonzo--Aluminium heads wont last long in salt water?? there is no salt water running through the head of a sealed cooling system. So why wont they last long then?

[gonzo]

We are discussing raw water cooled engines. WOT for hours on end is how boat owners usually operater their boats.
stonebreaker: "bogus" was the scientific term used by you, so I thought I'd use it too

[brian eiland]

A good friend of mine recently purchased a 44 Dutch motoryacht with a DAF 6 cyl diesel engine. He would like to find more info on these but it seems rather limited.

Can anybody supply more info??

[tom kane]

Running an engine in a boat is like running an engine on a Dyno with out all of the over run stress of road work,you can run the motor to destruction if you want to,or you can run it and test it sensibly to get the best from that design.A well set up motor in a boat shoud have a good life.

[gonzo]

A dyno would give a really good aproximation of the way a marine engine works.

[yipster]

Originally Posted by brian eiland

A good friend of mine recently purchased a 44 Dutch motoryacht with a DAF 6 cyl diesel engine. He would like to find more info on these but it seems rather limited.

Can anybody supply more info??

piet bos may have a manual or surely can help

[Frosty]

I was hoping that "Stonebreaker" would have come back by now. I didnt mean to take the floor away from him. He made some very good comments and backed them up. If this had been in court he would have won the case.
Personally I am not yet ready to accept ring gaps of 80 thou. The best I can find on the internet is a ring supplier that said up to 8 thou per inch of dia is acceptable. Where can I read this information of 80 thou? I read on one site that the ring gap for marine applications should be increased but by 4 thou !! I could be wrong but im not accepting it yet
I am not prepaired to accept that boat owners usually operate thier boats at Wide Open Throttle for hours on end. But if they do then its not surprising that engines can be bought so easily. It would seem that in the US you can you simply re-place the motor at any good marina. If I sold and repaired engines I too would make comments that would suggest that it was normal practise. But with my tounge in my cheek
I have never given my boat WOT, her 14 tons comes up on the semi displacement plane at approx 3/4 and then I back off. They then run at 3400 RPM,--Diesels of course.
If you put an engine on a dyno that produced Max Hp at 4800 and you kept it cool and lots of air and all perfect conditions but you ran WOT and held it at 4800RPM .How long will it live?

[stonebreaker]

Originally Posted by jack frost

I was hoping that "Stonebreaker" would have come back by now.

What did you want me to say? Gonzo hasn't replied to the ring gap statement yet, and you were exactly correct about the closed cooling system and aluminum heads.

Originally Posted by jack frost

If you put an engine on a dyno that produced Max Hp at 4800 and you kept it cool and lots of air and all perfect conditions but you ran WOT and held it at 4800RPM .How long will it live?

That depends on how well the engine is built. For anything OEM-built since about '93, I'd say the bottom end is capable of handling 4800 rpm, no problem, even the stock automotive engines. We've torn down 100,000 mile engines that still had crosshatch marks on the cylinder walls from the factory cylinder hone. The bearings are going to wear out faster at 4800 rpm than they would at 3000 rpm, of course, but that's going to happen with any engine, not just GM engines.

About the only thing that I would consider absolutely necessary to upgrading on a roller cam'd engine I was going to drop into a boat would be the valvetrain. GM uses very light valve springs to improve gas mileage. The problem with this is that the engine's peak performance will start to decline almost immediately. You'd never notice it if this was your family car or commuter car, but it becomes very apparent at the drag strip. By putting stronger valve springs in the motor, you improve its reliability at high rpm because the stronger springs provide more positive control of the valves at higher rpm.