Gas Engines on Trojans...Past, Present, and Future

[todd brinkerhoff]

I saw the post on "What is your top speed", and I thought a conversation about gas engine options from yesteryear and today would be interesting.

I've been researching repowering recently, and have expanded my search from Diesel to Gas options. I have also been talking to John Leed because I wanted to write up an article about the history of the International Series and the 10.8 Meter Express. If you didn't know, John was an engineer at Trojan until it closed, and now is a great point of contact for information and history. Part of John's job with Trojan was to test engines in the particular models. Because I was questioning him about the International Series, that is where most of our conversation focused.

Most of the Trojan Internationals sold were gas. Gas prices back in the 80's were pretty low, and the cost of the upgrade to Diesels was pretty significant. Most Trojans in the 10 and 11 Meters were powered with the Crusader 454s. John told me they had a river that they would run the boats on with someone on a bridge running a radar gun. He would do multiple configurations to determine the best speed for any particular boat. John told me that he had engines lined up on the dock, and figured out a way to change them out while the boats stayed in the water. He had jerry-rigged a platform for him to stand on.

So inevitably our conversation turned to power options of yesteryear and today. John said that, although the 454 was a great reliable engine, it could never push the Internationals to the speed they were intended to make. Of course he made some references to Harry Schoell and Harry's guarantees of the Delta Conic's speed with low HP motors, and that his theory was turned upside down in the first test runs. From John, "That Delta Conic hull had a huge wet surface, which requires a lot of horsepower to run it. Harry told us that the boat would do in the mid 20's with 85 horsepower diesels. Needless to say there was a difference of opinions between Harry and Trojan Engineering." Even with the 454's, that boat was never ran at a speed where it should be for cruising.

When the GM 502 was introduced, their was much optimism and hopes that this engine would push the internationals where they needed to be. John said that they hired an independent company to test both the 454 and new 502 in the largest gasoline platform they had, which was the 12 Meter. When they got the results back, the 502 was impressive. John said, "the results we got back was that this engine ran like a raped ape. We were pretty enthusiastic."

But then John went to work and started testing the 502 in various platforms. "That was the most inconistent motor I have ever tested. The problem was that if you got a motor built on a Monday or Wednesday, you might be ok, but if you got a engine made on a Tuesday, Thursday or Friday, you were screwed (sarcasm of course). We were out testing the 502 in a couple of boats and were having major issues. We called Mercruiser and they sent their "Men in Black" crew, who really just came down for intimidation purposes. Initially they blamed us and not the motors. I tried to tell them that these motors are not burning fuel correctly. I had to go to the bathroom, and their was a payphone around the corner. I overheard one the Mercury guys that was talking to their HQ saying - 'Pull all those 502's and lock them up until we figure out what is happening'. That 502 never worked out for us."

As a side note, John stated that their best cruising boat was the 11 Meter with Detroit 6-71 TI's at 450 hp. "That engine and boat configuration was fantastic. That boat would run at about 39 mph WOT and cruise at 30 or 32. That is where that hull was designed to be.

So our conversations led to more modern motors. John had heard good things about the GM 8.1 Liter motor. The 8.1 Liter was introduced in 2001. What was interesting about that motor is it was the first Big Block Chevy that was underbored, in that it had a larger stroke than bore, which is more typical in diesel configurations. The motor used the same 454 bore of 4.25, but had a healthy stroke of 4.37 (454 has a bore of 4.0). This characteristic made this engine an outstanding torque motor, with a very flat torque curve, which was highly desireable in the Marine world. That engine was discontinued in 2009. Most machine shops don't like this motor because there is NO interchangable parts with other BBC's, and parts are very expensive. So, if you have an 8.1 Liter, treat it like gold. Even tired engines bring top dollar, if you can even find them.

So, now the big marine engine companied are limited on choices. Mercury has decided to make their own 502 from their Mercury Racing Side. Crusader and Volvo Penta has decided to use the 6.0 liter. This is the only motor being produced in GM's truck side. Crusader has only 1 option with that motor, which is 370 hp at 5400 RPM's and 400 ft. lbs at 4400 RPMS. Volvo penta has the 6.0 Liter in 2 configurations, the 380 hp model and the 430 hp model. They have no RPM to power numbers. With all this, I think Mercruiser will be ok, as they are the biggest supplier of inboard motors, and have their racing side. Volvo Penta will be ok, because a majority of their sales are diesels and their new IPS system. Crusader on the other hand is a big question mark. They used to be the Main supplier for Tiara boats, but now Tiara has put the Mercruiser 502 as their base option in their 3600 open. The Crusader 6.0l is the base option in the Tiara 3100.

As another side note, Indmar, who is a large manufacturer of marine engines for ski boats, has made a deal to produce Ford Marine engines from Ford's Raptor series (Ford's off-road sport pick-up truck), which is Ford's 6.2 liter engine. They produce 3 configurations of that motor in 400 hp, 440 hp, and a supercharged 560. What is even more interesting is that Ford is discontinuing the Raptor 6.2. When someone asked a spokeman from Ford if they are in fact discontinuing the Raptor, he said, "I didn't say that, we are discontinuing the Raptor 6.2." People are speculating that the New for 2016 or 2017 Raptor will have the Ecoboost, which is a lot easier to modify HP and torque. I think most people who know the ecoboost hope it winds up into a marine engine. It has one of the flattest torque curves of any gas engine.

What I think needs to be added to the equation is that GM has announced that they will not be building a gas engine to compete with the ecoboost. Instead, they plan on building the first diesel 1/2 ton pick-up option. So once again, where does this put Crusader for engine options?

What your thoughts? What is the future for gas repowers if you want to improve performance?

[jddens]

Just a non-marine comment on the ecoboost......I am and always have been somewhat of a motorhead. I have a 2012 F150 4WD Supercab with the 3.5 ecoboost. This truck is bone stock. It is easily the most impressive motor I've experienced. I can climb hills at 65mph pulling my small travel trailer in 6th gear at 1600rpm. Amazing torque! Put the pedal down and it just growls and goes like hell. I can get 21mpg(not towing) on the road if I can keep my foot out of it. I also have a 1972 Chevy 1/2 ton shortbed fleetside with a 388 stroker making about 450hp and the ecoboost still impresses me.

And I keep hearing rumors about a 5 liter ecoboost.........one can only hope..........John

[todd brinkerhoff]

I too have the F150 with the ecoboost. I've had the truck for 3 years. The only issue I've had is with the Transmission, which Ford fixed. The motor is a monster. What is amazing is that although the 3.5 Liter Twin Turbo Ecoboost produces its peak horsepower of 365 at 5000 rpm's, it makes 420 ft. lbs. of torque at a low 2500 RPM's and it's torque curve stays flat through 5000 RPMs. I have been researching the Tuners from SCT. The reviews have been good. Again, another amazing thing with this motor, is that you can plug in a tuner that looks like an ipad, put in the fuel octane you are using and what type of driving you want to do, and it reprograms the engine. By simply plugging the tuner in, it reaches 425 HP at 5000, and a whopping 520 ft. lbs of torque at 2500. And that is still on 87 octane. It will go up to 93 octane, at some whopping 600 hp.

I think the biggest challenges for Ford is ensuring longevity of this motor, and ensuring that it can stay properly cooled at these bigger numbers. I've heard the intercooler is too small for this motor. At any rate, I think Ford has hit at least a triple, if not a home run with the ecoboost. I've heard of the 5.0 ecoboost in the Mustang. I'm not sure if it will come with an iron block.

Now back to marine engines. What are peoples thoughts of Crusader and Volvo Penta advertising the 6.0 Liter as a competitor against the Mercruiser 502 and a direct replacement for the obsolete 8.1? They advertise that these motors are suitable in boats of up to 40 feet. Do you see these motors as viable replacements for the bigger torque Big Blocks?

I personally think the Motor companies are in a weird place, in that they have ongoing regulations that Obama has put into place in regards to fuel mileage and emissions, but at the same time trying to stay competative and creating motors that a Horsepower hungry society wants. The light trucking world will be the biggest unknown. I'm sure that if the motor companies had their way, all trucks would be diesel, but that would put truck prices out of the hands of average folks.

[RWS]

First off, THANK YOU, TODD, for all your efforts on these issues.

We all enjoy learning more on these topics and are looking forward toward seeing your work.

Meanwhile, a few comments, all based on my own opinions with a little fact splashed in.

Regarding the differences between Schoell’s anticipated performance figures and the actual numbers, I believe there are two main reasons for the difference.

Weight and Puffery.

I’ll address the weight issue:

The hollow stringer design and the use of vacuum liners, compound curves built into structural members like bulkheads, the completely lined head compartment, HVAC ductwork built into salon ceiling/fwd deck, and Schoell’s modular concepts, SHOULD have resulted in a far lighter boat.

I believe the realities of production and perhaps caution resulted in a heavier boat than he originally envisioned. In my opinion, the 10 meter is a bit overbuilt. When I cut through the aft deck to install an inspection plate for the fuel tank sending unit, or cut an opening in the helm for a battery monitor, I am shocked to see just how thick the fiberglass is that encapsulates the balsa core in those areas, and that’s just one example. Simply put, SHE IS A TANK. I have seen published dry weights on these boats (express) of 11,500 and 12,000 lbs. Really? After we did the refit we weighed my boat on the travellift. Now this is an unscientific measurement, and the boat was fully loaded so we could do a proper seatrial. Full fuel, 242 gallons, full water, 40 gallons, tools, spares, etc. I even filled the waste tank, 40 gallons full of water. Do the math yourself. Now, consider that the Yanmar 6 cylinder aluminum block engines weigh less than the 454 Crusaders.

Imagine our surprise, when she weighed in at over 18,000 lbs !

We knew before her splash for the seatrial, that she would be a bit overpropped, an issue we had to subsequently resolve.
That said, I believe the boats coming off the production line were in reality far heavier than Schoell envisioned.

The weight issue may also be one of the MANY FACTORS, most of which were cost savings, that played into the decision to build the MID CABIN based models with conventional stringers, and eliminate the compound curves, built in bulkheads, gel coated integral water & waste tanks and gel coated liners on those models. I would be willing to bet that the hull itself is no thicker on a midcabin model than on the original hollow stringer/vacuum liner design.

Based on everything I have read, once you get into the 12,000-14,000 lb weight category for planning vessels, diesel engines make more sense because of one single item that separated the diesels from the gas engines of similar horsepower.

TORQUE.

More than thirty years ago, when these boats were designed in the early 1980’s diesel engines were heavier, noisier and smellier than today. In addition, they were far costlier, and a combination of the additional cost PLUS the additional weight made a good case to run the 454 Crusaders into 11 meter territory.
Fast forward to today.

Lightweight high RPM/low displacement turbocharged, multiple valve diesel engines are available which also have the technology to be less noisy and smelly. So, other than cost, we have reduced the issues related to weight, noise and smoke/fumes.

Now add into the equation the relative cost of fuel today vs. the early 1980’s.

GAME CHANGER !

Fact is that if these technologies were available back then, the Internationals and larger F series vessels would have been built with very different propulsion systems.

So let’s address Todd’s gas engine issue.
The 8.1 is in fact a superior engine to the 454 in the fact that it eliminates the carburetor, has more precise fuel and ignition systems, and far more torque and horse than the 454. Additionally it is more fuel efficient as well.

In 2003, my factory Onan gas genny died. Attempts to repair were met with rusted bolts that simply broke off when removal was attempted. In the interest of reliability and safety a diesel genny was selected as a replacement that was actually certified to run in a gas environment. A 17 gallon separate diesel fuel tank was added, which allowed it to run 2.5 days continuous, even with the HVAC running.

In 2005 my well worn, 2,600 hour (yes, that’s NOT a typo) 454’s were understandably tired. The lack of a decent PM schedule for the cooling system and zero zinc changes in 18 years by the PO had deteriorated the condition of the closed cooling system where coolant was seeping out to the seawater side. The port engine intake manifold was cracked at the choke warm up area. All 8 engine mounts were rusted and the plastic adjustment caps were damaged. Engine alignment was impossible. Two of the wooden (oak?) motor mount blocks were cracked, and the previous owner had laid fiberglass mat over the worst one to try to save it.

In consideration of the age, condition, lack of care and the additional items required to rebuild the 454’s into a reliable system, the BRAND NEW replacement Crusader 8.1 “Captains Choice” engine was the logical and more cost efficient approach to resolve the problem.

After reviewing the specs with the local Crusader dealer, it was determined that the very long 1.25” shafts were borderline for the additional horsepower/torque. Even though they were supported by TWO struts each, we were slightly beyond the margin of safety to break a shaft.

Additionally it was determined that the existing raw water system, seacocks, strainers, etc. were marginally smaller than what the 8.1’s engineering required.
Well now, if I have to replace the shafts, maybe even the props and now the raw water system, why not take a look at just doing a diesel refit?

So in this case, the genny was already done, given the condition/cost of rebuilding the existing 454’s and all their systems correctly was higher than the new Crusader 8.1’s, the baseline for this project was the new Crusaders. Once you factor in the real costs of the driveline and raw water system, the DIFFERENCE between the Crusaders and the Diesels began to make some sense.
I believe in the K.I.S.S. principle, keep it simple, stupid. I did not much like the idea of all the sensors, electronics and microchips on the 8.1 and on common rail diesels. Fine for cars, heavy equipment and over the road trucks, but the idea of all these electronics AND ALL THESE CONECTIONS in a saltwater environment translated into less reliability and more ongoing repairs/maintenance in my mind.

The six cylinder diesels under consideration were all taller, longer and narrower than the 454’s. In measuring, even with a downangle gear, the Cummins was too tall, leaving the choice at that time between the Volvo and the Yanmar. The Volvo is electronic and the Yanmar purely mechanical. Although early versions of this motor had seen valve seal issues, that problem had been resolved years earlier, and the Yanmar was chosen.

Economy and range has more than doubled. Our most economical sweet spot cruise went from 14-15 kts to 19-22 kts. The only time fumes are noticeable is when the side exhausts are dumping out directly under a seawall trapped dock, or for just an instant just as we get on plane. Interestingly, there is no, I mean ZERO station wagon effect, as we had with the 454’s. I have no explanation for this other than the improved running attitude allows those side exhausts to function to 100% of the intended design.

Her 20” props and the torque, coupled with her wide beam which leaves the shafts farther apart than on a similar vessel, making docking a breeze for even a novice.

Her running angle is now different, and surprisingly, where we used to adjust the trim tabs all the time to obtain the best economy/speed on the 454’s via GPS/Floscan, the tabs now make virtually zero difference on speed/fuel burn. Her a$$ seems to be more out of the water, even with a crowd of people, luggage and supplies onboard. Although I can’t confirm this, I imagine there is less wetted surface at planning speeds. She feels far more agile and responsive than with the 454’s, not squirrely, and of course she is no speedboat, but when those diesels are singing out of those side exhausts, and she’s up and out of the water she just plain feels like an entirely different boat. I believe that given her weight and unique hull design, this combination is delivering the goods originally envisioned for this boat, had she weighed less originally.

Again, in addition to safety and reliability, the advantage here is increased range and a better, far more efficient cruise speed. This allows us to do more and see more in a weekend than we would be able to do with the 454’s . A trip to the keys with the 454’s would result in a required fuel stop in both directions. Add in the time required for that stop AND the lower cruise speed, now we are taking two travel days in each direction. With the Yanmars, we can leave at 6 AM and pull into Galleon Marina at 2PM, avoiding the PM summer thunderstorms. Funny, we can just about do an entire round trip on one tank of fuel. If you split the fuel cost/dock fees with another couple, all the better.

So, given the weight, wetted hull surface and other issues listed above, the diesels make the most sense. The DIFFERENCE in cost is recaptured in the benefits listed above, plus USING THE BOAT MORE and the ability to sell her FASTER and for MORE MONEY than a comparable gas powered version.

Yesterday, big block, twin engine 30’-38’ cruisers were popular new purchases.

Todays trend is more toward the 24’-28’ outboard style.

There is now far less demand for used, 30 year old big block gasoline powered boats.

I am the second owner of my boat. She was bought off the floor of the Miami International Boat Show in 1983, and her original owner had her for 18 years, making numerous runs to the Bahamas with her.

THAT says something.

I have owned her for 13 years.

THAT also says something.

I hope all this information is a benefit to the Forum.

RWS

[rossjo]

Great post Todd - thanks!

[Seafun]

RWS
Very eloquent and convincing explanation of Diesel Vs Gas, I could not agree with you more.
In fact, I have been reading you on this forum for a while, and I just decided to join and benefit from the experience and knowledge everybody shares in this forum, but especially your thoughtful insights and expertise with the Trojan.
I acquired a 1983 Trojan 10 meter Express Cruiser a year ago in Miami. The boat was repowered in 2004 with Yanmar 315 and currently have 860 hours...and also equipped with a 8KW Westerbeke diesel Genne....
Needless to say I love the Yanmar engine's performance, efficiency and simplicity ( Its my first experience with Yanmar and my second Trojan boat).
Of course, I am still in the process of getting to know the machine, however so far I am very satisfy with the handling characteristics of the Trojan and the fuel efficiency of the Yanmar engines.
Thank you for your insights, I will keep on reading you!

Cheers!
Captain Morgan
1983 Trojan 10 meter International Express Cruiser.

[todd brinkerhoff]

Yeah, Yeah, Yeah...RWS is great!!! He's the guru of Internationals...blah blah blah. He has an awesome boat...Yadda Yadda Yadda...Diesel Diesel Diesel...Whatever!!!! (I swear I'm not jealous)

One of the most surprising things for me as I researched the Trojan Internationals, and more specifically, the 10.8 Express, is the turbulent relationship between Schoell and Trojan Engineering. I thought it was a perfect relationship, but soon found that there was major corporate drama. All you have to do is ask, "Why did Trojan move away from Harry Schoell for the new International?" and be prepared for stories... The only pure Schoell designed Trojan was the early Trojan 10 Meter Express. Major changes were made shortly after that first design went out.

So as the diesel marine engines have become more advanced, lighter, and economical, will we see the gasoline inboard marine engines go the same route? In the automotive truck world, companies are moving from BBC based motors, to high tech, small and lighter engines. The lighter diesels of today do not have the torque of their Detroit or John Deer brethren, but turn much higher RPMs. With that, the use of higher reduction gears are becoming common. Volvo Penta reported that they run a 2:1 gear for their 6.0 Liter compared to a 1:5 for their previous 8.1. As I said earlier, we will see if there will be even lighter turbo charged engines in the future of marine gasoline engines.

In my opinion, gasoline inboard motors failed to keep up with the advances of diesel, or for that matter, outboards. The technology of outboard motors is incredible, in the fact that they somehow shoehorned a GM LSX V-8 motor into a 555 hp outboard, incredible. Again, in my opinion, part of that is the reliance of General Motors Truck division for technology, and GM's new mandates based on their government bailout. I think Ford trumped GM with its Ecoboost. Whether you see that in a marine format will yet to be seen.

So lets look at the 10.8 Meter Express (with V-drives) and the outline of different repower options. I will list things that need to be replaced or rebuilt. I have no cost numbers, so feel free to add those:

Option #1 - Diesel
- 2 New or Refurbished Marine Engines
- 2 New Transmissions
- 2 New V-drives
- New wiring and guages
- New shafts and prop
- New Strut
- Modify Exhaust System
- New Fuel Lines
- Remove and Flush Fuel Tanks
- New Diesel Generator
Performance - Vastly Improved / Fuel Economy - Vastly Improved

Option #2 - Crusader or Volvo-Penta 6.0
- 2 New Gasoline smallblock engines
- 2 New Transmissions
(I am assuming the rest of the driveline can stay unchanged)
- New Props
- Modify Exhaust System
- New Wiring Harness and gauges
Performance - Probably Unchanged / Fuel Economy - Improved

Option #3 - Mercruiser 8.1 Horizon
- 2 New Refurbished 8.1 Liter Motors
- 2 New Transmissions
(I am assuming that the rest fo the driveline can stay unchanged)
- New Props
- New wiring harness an gauges
- Modify Exhaust system
-Performance - Improved / Fuel Economy - Probably Improved

Option #4 - Rebuild Current Motors and Modify with Adding Stroke and Appropriate Cam
- Rebuild Engines
- New Props
- Potentially modify exhaust for better performance
Performance - Improved / Fuel Economy - Unknown

Option #5 - Rebuild Current Motor as Stock
- Rebuild 2 new motors
- New Props
Performance - Same / Fuel Economy - Same

These are my competely made up guestimates:

Option #1 Diesel - 100K plus
Option #2 - Smallbock 6.0 - 30-40K
Option #3 - Refurbished Mercruiser 8.1 - 50 to 60K (I think those motors are 20k/engine)
Option #4 - Modify current - 15-20K
Option #5 - Rebuild to stock - 10-12k

[RWS]

Todd,

One of the items that does not show up in ANY of these numbers is usage.

Here in Florida, we use our boats year round, including going out for New Years fireworks and the lighted Christmas Boat Parade.

The lifestyle/usage is not comparable to areas with ice and winterization/haulout requirements.

Here are my comments on your options.

Option #1 Diesel - 100K plus
Had these boats been built today, the diesel option would be popular

Option #2 - Smallbock 6.0 - 30-40K

Does this choice have the TORQUE necessary to do the job?

Option #3 - Refurbished Mercruiser 8.1 - 50 to 60K (I think those motors are 20k/engine)

In my opinion, this option makes the most amount of sense on the gasoline side

Option #4 - Modify current - 15-20K

This item requires research - IMHO, with the exception of the exhaust, you will decrease the life of the engines with this modification

Option #5 - Rebuild to stock - 10-12k

Unless they are WORN OUT.... why even consider this option?

If you could use your boat all year long, with lots of options for adventures and places to go, things to do, you might find more value in the diesels.

They are, with no doubt the obvious and best choice for your hull.

Now for the reality...

Financial constraints,

Costs,

Resale Values,

and other considerations all play a part.


RWS

[todd brinkerhoff]

RWS,

Excellent insight as usual...

Just a couple of comments, and I would love to hear from other International folks who are looking into the repower options. Let me premise any future comments based on the fact that I am looking to increase the performance of this boat without increasing the fuel usage. I would preferably like to use LESS fuel. There are certain things that I could do to increase my performance now, to include moving to a 4 blade prop, etc., but OVERALL I think the only way to increase performance (and hence usability) would be to truly look at the powertrain.

Here in Florida, we use our boats year round, including going out for New Years fireworks and the lighted Christmas Boat Parade.

The lifestyle/usage is not comparable to areas with ice and winterization/haulout requirements.

This is probably the BIGGEST factor in determining cost relative to a repower. You are absolutely right that usage and lifestyle need to become a major factor in total cost output. With that, the Northeast boats sit in dry dock for 6 months. My life changes from Boating to Skiing. With that, my cost-over-time factor has to calculated based on a 6 month year and not a 12 month year.

Option #1 Diesel - 100K plus
Had these boats been built today, the diesel option would be popular

You are absolutely right. The subsequent "Carver-Trojan" 370/390/400 came with the Cummins 6BTA option. This probably would be the ideal set-up. Again, we are talking about a Remote V-drive Set-up, so engine weight is a major factor.

You'll see very few diesels in my area, even in Charter applications. In talking to Marine Mechanics, they felt that the diesels had more issues when they don't get continual use and sit over the winter storage time. Yet another factor to consider.

Option #2 - Smallbock 6.0 - 30-40K

Does this choice have the TORQUE necessary to do the job?

These engines certainly don't have the torque of their big brothers. But if you look at the transition of heavy, HUGE stoked diesel engines to more modern, lightweight, high turning diesels, can you make the same comparison to the gas side? The Torque of a 8V-92 compared to a Yanmar 8LV-370 is significant. But the power to weight ratio certainly favors the Yanmar. There was much concern that the new "high tech" lightweight diesels would never last, but I don't think we are seeing that opinion come to fruition. SOOO...Can we make the same comparison to a "high-tech" lightweight, high RPM smallblock compared to a big heavy Big Block?

Option #3 - Refurbished Mercruiser 8.1 - 50 to 60K (I think those motors are 20k/engine)

In my opinion, this option makes the most amount of sense on the gasoline side

Normally I would agree with you. I think most people who repowered with this motor have been very happy with the increase in performance and fuel economy. But because this engine is no longer produced by GM, the motor listed above is a Remanufactured engine made by Mercruiser. Crusader does not produce a Remanufactured 8.1.

The issues I am finding is that there is no support for this engine. Although it was out for 8 years, in the whole scheme of engine supplies and support, that is not very long. I've been steered away from this engine by a few people "in the know" because of the expense of parts and support. I have spoken to several marine engine shops (which will come up again in a second) and they all shy away from the Vortec 8100 series. Parts are expensive, and becoming harder to find. And for the same reason you went with a non-electronic Diesel, I too am concerned about the electronics on an engine that is not produced any longer.

Option #4 - Modify current - 15-20K

This item requires research - IMHO, with the exception of the exhaust, you will decrease the life of the engines with this modification

Originally, I was not even considering this option. For the weight and design of my boat, putting up a modified 454 was not attractive at all. I had no interest in some high Horsepower engine that consumed 80 gallons an hour. But, because I am a nut when it comes to research, I could not leave this option off the table. I am fortunate that we have some highly reputable marine engine builders, as well as a very well known custom camshaft guy at Marine Kinetics here in Rochester. The best advice I've received is to completely study my current set-up and truly understanding the needs of this boat and where the deficiencies are. They have said that people fail to understand the needs of their current set-up, and blindly have engines made with their attraction toward horsepower. The results are usually less than good.

So the advise has been to purchase a good fuel flow meter, and to ensure my current engine and driveline are running smoothly, to include reaching the recommended RPMs at WOT. I need to understand where my current hull feels most efficient, and compare that to speed, RPM and fuel flow. Not until you truly know your current set-up, its' TRUE deficiencies, will you be able to understand your needs. So, needless to say, I have some work.

These marine engine guys have been great. Their advise is to not get caught up into the "Big" part of engine building (Cams, Heads, etc). All have advised that they would absolutely recommend stroking the engine to make it more "square", with minimal boring (if at all). They all recommend "Minor" work to the heads to increase "Efficiency" and not necessarily "Flow". Roller Rockers, which apparently "frees" up torque. A custom camshaft based on my NEEDS (power to RPM), new intake manifold and stick with the Q-jet. One of the guys showed me some results of a VERY Mild engine build with a stroke kit, and had limited RPM to 4900 where it made 460 horsepower and 600 lbs of torque at 3200. It made over 500 ft. lbs of torque from 1800 to 4500. Compression was 9 to 1. Idle was set at 600.

So my next question was fuel usage. This is what they have said their experiences have been... The engine set-up should not use much more (if anymore) fuel than the current set-up. BUT you will be able to go the same speed at a lower RPM, or go FASTER at the same RPM, thus increasing MPG.

More research to be done.

[RWS]

to quote Tony Athens,

" I think the most misunderstood concept related to vessel propulsion is that the propeller moves the boat and not the engine. The engine just rotates it and it does not really matter what type of power you have doing it (maybe a hand crank mechanism with a bunch of trained gorillas turning it while being fed banana soup?). In other words (this is Gospel #1), PROPELLERS MOVE BOATS, ENGINES ONLY TURN THEM. Pretty simple concept, yet so few seem to understand that...

With that said, understand this second concept about a propeller - (this is Gospel #2). It takes a certain amount of HORSEPOWER to turn any given propeller under any given set of circumstances... Think about that a tad. Under any given set of circumstances. This means two distinct things:
1. The exact same propeller with one set of circumstances can require more or less power to rotate the same propeller RPM than when operating under a different set of circumstances.
2. The particular set of circumstances is controlled by all of the following variables such as boat size, weight and shape, vessel trim, bottom condition, running gear design and underwater drag, along with other external forces such as weather (wind, waves & current)."


HERE'S THE LINK FOR ALL THE GORY DETAILS:

http://www.sbmar.com/articles/propeller ... turn_them/

rws