Auto engine marinization

[hartley]

stonebreaker....Top marks for a informative and well researched post
particularly luuuuuuved the remarks about the "pink rods" and the ring gap
keep it up ....cheers

[stonebreaker]

Thanks, Hartley. Re your comment that technology shouldn't stop a DIY'er, I fully agree. In fact, new technology has made it easier to do it yourself, not harder. Fuel injection, for example, solves the problems of fuel control that require a marine carburator on older engines, and solid state, distributorless ignitions eliminate another area of marinization headache. Although more expensive than the older solutions, they more than make up for this with their safety and fuel economy. Older automotive engines had a breather cap on the valve cover; modern engines have a PCV valve, which cars use for emissions control but on a boat will increase safety by reducing engine room vapors.

Another thing I like about electronic fuel injection is the precision with which you can tune your engine. It takes longer, and you have to have a computer you can connect to your boat's engine computer, but you can double your fuel economy in the long run, as well as tune for better performance with both fuel trim and ignition timing. We will often fine-tune our cars at the drag strip between runs. I've even seen some of the turbo cars re-tuning for changes in the weather! Another benefit of the engine electronics is you can set a redline rpm and the computer will prevent the engine from ever exceeding that rpm - over-revving is a thing of the past.

[Poida]

Stonebreaker has read this thread with amusement.

I read it with confusion.

Hartley says Australia has a deregulated system.

In Western Australia laws are only passed if they can make money out of it.

There is not enough people maranising auto engines to either fine you for not complying or registering those that wish to do it. They have only started making people pay for skippers tickets because there is enough people out there to add money to the government coffers.

Safety in maranising auto engines? I have a petrol (gas to USA friends) that looks like it has a standard starter motor, carby and alternator. The chances of it blowing up?

I would say less than the chances of me getting killed by some knob head 1/2 asleep at the traffic lights, going through a red light and wiping me out.

Except that statistics show that both of those ways of dieing pale to the chances of dieing from a heart attack. My wife has told me that dieing should be spelt dying, sorry.

So it makes me wonder why a country would bother worrying about making laws about auto maranising when it's almost impossible to die doing it.

There seems to acceptable ways to die and non acceptible ways to die. If you die an acceptable way you're a hero, if you die a non acceptable way you are an idiot.

So if you are a formula 1 driver, get into an skid, hit the barrier and die you will die a hero.

If you marinise an auto engine and it blows up, your an idiot and the country will legislate against it.

I'm an idiot and I'm not even dead yet.

[stonebreaker]

It all has to do with risk management. F1 is a risky undertaking, to be sure, but don't think they aren't regulated. Those cars have to meet all kinds of safety criteria to be sanctioned - crash worthiness, fluid lines, driver restraints, steering wheel quick release, fuel cell, driver's helmet, even the driver's clothes must meet minimum safety standards, and that's just the stuff I can think of off the top of my head. So yes, racing's inherently dangerous, but they don't take needless risks.

Running an automotive carb on a boat is a needless risk, because there's a better solution available.

[tom kane]

It sounds like you have fun stonebreaker,do you use air-assisted EFI technology?

[stonebreaker]

What do you mean by "air-assisted"? I'm not familiar with the term.

[tom kane]

To improve injector performance,by injecting high pressure air along with the fuel spray,greater atomization of the fuel droplets can occur which is especially helpful in improving engine performance and reducing emissions at low engine speeds.Studies have shown that the short burst of additional fuel needed for responsive transient manouvers can be reduced significantly with air-assist fuel injection due to a decrease in wall wetting in the intake manifold and on a 3.8 litre engine with sequential fuel injection air-assist reduces HC emissions by 27 percent during cold-start operating conditions.Wide open throttle with air-assist and a air-fuel ration of 17 the HC reduction is 43 percent when compared with a standard injector.more..for performance enhancement mixtures...economy..Google search air-assist EFI.

[stonebreaker]

Sounds interesting. The nice thing about technologies designed to increase fuel efficiency is that they can also usually be used to increase performance - EFI being a prime example.

Thanks for the tip!

[Frosty]

I googled air assisted EFI and got some stuff that sounded a bit like yours but not right on. There was a couple of sites on Aprilla scooters but Im sure you didnt mean that one. I did see a couple on Air assisted direct fuel injection though. Now this raises a few points that I cant get to grips with. If it is direct why is the inlet manifold wet? High pressure air injected along with the fuel helps atomization of fuel droplets?. I thought droplets of fuel was a no no. Infact the old Lucas injection systems that I understand the cylinder would be dead if the injector was not atomizing its fuel perfectly. Air fuel ration of 17,--- now im not picking spelling here but I assume thats ratio? and the 17 bit? I thought that an engine would have difficult in running at such lean mixtures.?
And finally is the injection of high pressure air at the same time as the fuel is injected or after. Raising questions that the air injected will increase compression ratio just before injection wich would of course increase efficiency with out the extra load from the engine to compress it. Or is it as the burning process is alight meaning extra oxygen to the process?
All very interesting stuff.

[stonebreaker]

Read a paper on air-assist EFI at http://www.hait.ac.il/jse/B/vol0201B/l040714.pdf . Seems pretty interesting, but kind of complex. GM currently solves the fuel vaporization problem by spraying the fuel directly onto the back of the intake valve, which both cools the intake valve and evaporates the fuel. I understand the next evolution in injector placement is direct injection - putting the injector orifice directly into the combustion chamber. I don't know if air-assist would help with that or not.

[tom kane]

Air-assist fuel injection nozzle-Patent 4693420 www.freepatentsonline.com/4693420.html-37k
Oxygen enrichment for air-assist type fuel injectors-Patent 6397825
www.freepatentsonline.com/6397825.html-22k
There seems to be many people trying things like this all over.Air plus fuel injection.Cam less motors that dual rotate in two or four stroke mode and run on two or multi cylinders.
You should find Uninterupted torque for motorsport or marine interesting at www.zeroshift.com

[Frosty]

Ahh camless motors now theres a thing. I think I am right in saying Bosch are leeping ahead with this throw off from common rail injection technique. The ultimate control of an injectors timing and duration has now been carried on to valve control. No cam,no chain, no rockers, less friction, less noise, and no need for oil up top I suppose. Coupled with the ultamate variable control of valve timing ,lift and duration>. And yes Tom I guess you could run 4 stroke or 2 stroke (if it was a blown engine with common rail injection) along with safely disabling a cylinder or two for economy. Hey --fit another starter and with a flick of a switch it would be reversable-----Fantastic
Eerr with all this exitment we got off the thread,-- but I guess you could put it into a marine engine. I personally would like some guarantees on reliability. I assume that it would be a "safe engine' in so much as should an electronic failure occur the engine would not destroy itself amongs half open valves.

[stonebreaker]

Tom,

I don't know about the oxygen enrichment. Racers use nitrous oxide instead of pure oxygen injection because injecting even a small amount of pure O2 will melt pistons - it burns too hot. the nitrous burns slower than pure O2.

Jack,

Check out http://www.coatesengine.com/look_mom_no_camshaft.html

[fasteddy]

Nitrous is just a way of getting more oxygen into the system, so you can burn more fuel. It's just a way of getting around the air flow limitations of the intake, and it's VERY cold, which chills (makes more dense) the rest of the intake charge. You have to inject fuel with the nitrous to maintain your air-fuel ratio (afr), or you'll pooch the motor quickly.

I'm about to build a 400ci small block 4 bolt main chevy (4 bolt main 400's are rara avis) to bolt in place of a 305 in an old Cobalt Mercruiser 888. I plan to use Manley stainless valves, a 5.7 marine cam, copper head gaskets, Mahle forged pistons fitted a tad loose with tops heat shield coated and skirts low friction coated, Clevite premium bearings, remote oil cooler and filter, and marine exhaust. Fuel management will be by a Megasquirt tunable FI system on an MPI manifold (probably GM with flow improvements) or a big block TBI. I'll probably run 8.5:1 compression. I'll use either GM pink rods or aftermarket performance rods.

I'm a little up in the air over getting a forged crank. Cast cranks take shock loads better than forged. Forged has higher rpm strength than cast, and higher ultimate strength (same thing, I guess). I've successfully used cast cranks up to 550hp in a 350ci, but only for hot street use, not marine or race.

In any case, I'll tuftride/nitride/jetspray the crank journals.

I'll use a true double roller timing chain or a gear drive, too, and hydraulic roller lifters with just enough valve spring to keep the valves from floating at 6krpms.

There are SBC blocks of many different casting strengths. Mine is a thick walled old truck motor, with 10% tin and 10% nickel in the cast iron for strength and corrosion resistance. Many GM blocks stink even for light car motors.

Show me a Volvo Penta 5.7 built that tough...

[marshmat]

Re: EFI
Ok, let me get this straight: I hate carbs. I hate having to adjust the jets every time I change altitude, or between 15 C April weather and 35 C July. So you can see how I'd be a fan of EFI. Especially as a computer-savvy modern techie. Still prefer diesel though....
I've seen the air-assist idea a few times, it looks interesting. Some of the big carmakers (I think Mercedes was the last one I saw) have been making big progress with direct-injected engines; one of the Mercedes (I think) ones they were boasting about had a "stratified charge" mode that could run at air/fuel ratios as low as 40:1. It ran great in Europe but apparently blows up in minutes when fed on Canadian gasoline.
A big barrier right now to these advanced technologies, at least to a North American, is our sulphur-laden, cruddy fuels. Canada's starting to mandate cleaner fuel and the US is making progress, but there's still a lot of neat stuff that just can't be made to run reliably on poor quality fuel. And in Canada at least, most of us balk at the thought of paying even a few cents extra for premium grades.