motor builders advice
 

As you may or may not know of all the problems I have had with the new gm 454 HO
motors this year. I am now having the new motors rebuilt by a professional machine shop. I am looking for some professional advice on building these new motors. The boat is a 42' wellcraft excalibur eagle (go fast with a full cabin). the boat weighs approx. 11000 lbs. dry, so I figure about 15000 lbs. with gear, water, fuel and passangers. I am looking to build the motors with the most hp to get the most speed but with more emphasis on reliabilty. I am willing to sacrafice speed for more reliabilty, but I want it to go. with the 2 454 420hp I was getting approx. 55 mph gps. I am thinking about installing prochargers on the motors, is this a good idea or not or is there something better. I am looking for what type of pistons, valves, ect. to install. I would apreciate your help so i don't have to spend another whole summer dry docked

Re: motor builders advice
 

Not sure what your budget is but heres something to chew on. The bigger and heavier the boat, the more important torque is. You may end up spending lots of time and money on those 454's and never get the improvement you could see with a pair of 540's. Since you are clearly concerned with reliability, the bigger cubic inches would be less strained than the smaller ones developing the same hp. On to your question.

You need lots of torque, bottom end torque. Prochargers or any centrifugal blower really dont shine until they are spinning some. If you go the blower route, it would seem to me that a more positive displacement blower would be better for your application. Pistons? Forged. Valves? Dont skimp here, go inconel on the exhaust and severe duty on the intakes.

Re: motor builders advice
 

As many others will tell you here, it all depends on how much money you're willing to spend.
You could install mild camshafts and superchargers. With these changes you could reasonably expect 600 to 650 horsepower with a very nice idle.
If you still have the TRS drives you need to keep the horsepower at around 600.

Re: motor builders advice
 

Formula is right about centrifugal blowers. They belong on high RMP race application. BUT! You must take a look at the whipple chargers. You get off idle full boost. A very nice flat torque curve. Check out there web site. Cut and paste this link http://www.whipplesuperchargers.com/....asp?PageID=68
Hope this helps

Re: motor builders advice
 

From what I have been told the Whipple superchargers come on with off idle boost----which is much earlier than other superchargers designs. The Whipple will give those little 454cid engines the kick in the pants throttle response your boat needs.

Make sure it's a REPUTABLE machine shop that is acutely familiar with accurate machine work and knows what the hey they are doing when it comes to clearances and tollerances for a marine engine.

Also, althought it's not totally necessary, I would also add a set of aftermarket Stainless Marine exhaust manifolds. The aftermarket exhausts will help all the mods work together nicely by helping the engines breath much better thus giving even more performance once you add the Whipples. Just remember, torque is what moves the MASS---not horsepower! And torque is what you are going to need with a big HEAVY boat as you have.

Re: motor builders advice
 

If your are running Bravo 1's , the next thing to figure into the budget is a pair of good drives. Those B'1s will not last with Whipples and 15000lbs

Re: motor builders advice
 

Make sure your cooling system is up to snuff. Those engines will be under a huge load all the time. I remember when those boats were new. The guys that owned them were running 4000 rpms with the 420's all the time to get a decent cruise. The engines were lasting about 3 years between rebuilds.

Use the Eddie Marine 3 x 18 oil coolers with a thermostat. I run a plug in the oil filter bypass to make sure all the oil is cooled and filtered. Use a crossover in place of the circulating pump,(i know this will stir up some controversy but I've used them for years with no problems). Put in a 140 thermostat with 3-1/8 or 3/16 holes drilled in it. Make sure to use a crossover with a bypass hose to the thermostat housing. If you find you have too much block pressure, install a pressure relief valve. I've never had a milkshake oil problem. Good luck with the new engines.

Re: motor builders advice
 

A knock sensor would keep things together, it indicates harmful engine knock that is caused by lean fuel mixtures, bad fuel, too much spark advance or too much manifold pressure. 5 to 7 pound is all you need with a 8.5:1 pistons.
Don't get sucked into big boost. Only run the boost that your fuel and your timing can handle. This will all be determined by you engine designer. The more you retard the timing the hotter you get and then shorter the life of the motor. This is one of the biggest problems with the blower guys.

Re: motor builders advice
 

led...i have never heard of a knock sensor. where would i be able to get one?

Re: motor builders advice
 

Check out this link. http://www.eddiemarine.com/cart/deta...CategoryID=109

Re: motor builders advice
 

Knock sensor isn't necessary on a low boost application.
And the one shown is intended to be used on newer motors.

Blowers will definitely provide a lot of bang for the buck.
But in that boat, I feel there's a need for 540's.

He's already got the 454's though, so blowers is the only suitable option unless he plans to swap motors.

5 pounds of boost (roots or whipple), good head gaskets, and a mild blower cam. He'll probably need to upgrade his fuel lines and filter to handle the increased fuel flow. And then he'll be set.

Re: motor builders advice
 

The Eagles were equipped with 3/8 fuel pickups and lines, so he should be alright provided the engines stay aroung 600 horsepower. Still, the boat won't be a rocket ship and he can expect a top speed of 60 with reliability.

Re: motor builders advice
 

thanks for all the advice. The whipple I think will be a problem because of height. As far as exhaust I'm running stainless 4" headers. with holley 800 carbs. This may sound stupid but Is there a super charger that will mount to the front of the motor and not on top or something that is just as good that will mount to the front.
As far as speed I know the boat will never win any races, its way to heavy 60's would be great. the 540's sound good but I'd hate to waste that kind of money then tear it down to set it up for blowers. as far as drives I know the drives probally won't last they are TRS drives. I'll cross that bridge later.

Re: motor builders advice
 

Dont poopoo those trs's. They will handle "heavy" much better than Bravo's.

Re: motor builders advice
 

Why did Merc stop making the TRS's?

Re: motor builders advice
 

Most manufacturers, including the one I work for, want to market "new" stuff as aften as possible. Im sure that was one reason. I think the boat manufacturers had something to do with it too. I can imagine that they wanted rid of the transmissions so they could move the engines back for speed and room and cost. I think the Bravo profile may be faster than the trs profile too but maybe the weight moving back played more of a part there. There were "good" and "bad" Trs's and well as Bravos but overall I think the trs would take more torque and punishment from what Ive seen. Hopefully some of the merc guys will chime in their opinion

Re: motor builders advice
 

Every time I read a formula31 post my respect for his knowledge increases.

Sell those 454s and get some tall-decks. 540, 572 cu. in. with a single Dominator.

You have minimum down-time, good performance, decent economy and longevity.

The blowers will not only be expensive, but will shorten the life of any boat that heavy.

Keep the cubes big and the rest of the engine simple and you'll be far happier in the long run.

Re: motor builders advice
 

Oh yes, I just thought of something else!

If down the road you decide to upgrade the power, you have a much better base engine to work with.

Re: motor builders advice
 

Prochargers or Vortechs will mount off to the side and will not increase the height of your installation. But they are not the best option for a really heavy, marginally underpowered boat. They only make a pound or so of boost in the rpm range where you will be trying to get on plane. On this large heavy boat, I don't feel that will be suitable.

There are sidedraft carb options for roots blowers, but I can't recommend them for marine apps.

I believe Whipple makes a low profile carb adaptor that mounts the carb behind the blower. Might be an option.

Before you rule out a roots blower (cheapest and easiest), remove your flame arrestor from the carb and measure the actual amount of space you have for a taller intake system.

Re: motor builders advice
 

thank you all for your advice. still not sure what way to go. so lets throw this in the air. MOST OF YOU HAVE MORE EXPERIENCE THAN I DO WITH MOTORS. SO HERE IS THE QUESTION. YOU WANT TO SPEND NO MORE THAN 30000.00. YOU NEED 2 MOTORS, THE MOST IMPORTANT THING IS RELIABLE AND STRONG, DO NOT WANT TO DO THIS AGAIN FOR A FEW YEARS, YOU WANT TO GO AS FAST AS POSSIBLE, BUT DON'T WANT TO BE ON THE EDGE OF BLOWING UP. YOU HAVE 2 BRAND NEW 454'S HO'S WITH 420 HP THAT HAD OIL STARVING PROBLEMS WITH SLIGHT DAMAGE.WHERE ONLY RUN FOR 30 TO 40 MINUTUES. WHICH WAY DO YOU GO. REBUILD STRONGER OR BUY SOMETHING BIGGER AND NEW. I LIVE IN RI SO IF THERE IS SOMEONE NEAR BY WHO CAN HELP LET ME KNOW THANKS

Re: motor builders advice
 

Big cube normally aspirated. Talk to Total Marine & Performance about their 750 carb motor or Competition Marine Center in MO. Like others said keep it simple. When things go wrong with blower motors it gets expensive quickly.

Re: motor builders advice
 

All good options here. I noticed you are in RI. What machine shop is doing the work??
If I am reading your post correcly you have two 454,s that have only 30 hours on them.
that need to come apart.

The weight of that boat would easily justify 540,s.
$30,000 is a good chunk of change to get you where you want to be.
Blowers Roots or Whipple or even centrifugal will get you close to
600hp.

Blowers option you will need.

1) hatches scoops (Roots)
2) Iconnel valves( Heads)
3) Cometic or felpro head gaskets
4) Forged pistons 8.5 to 1
5) upgraded fuel system

540 option or even 572,s

1) sell the engines you have now
2) locate a couple of tall deck complete 540,s or build them.
3) upgrade fuel system

Two N/a 572 with single carb is the way I would go.
that way you have simplicity and reliability and the TRS will stay together.

If you go to rebuild the 454,s please be sure you take them to someone who
does marine work.
If you don't have anyone please call me I have a couple of excellent marine
builders local to us.
For $30,000 there are alot of engine builders who could help you right here
on OSO. They may even take the 454 in on trade.
A couple off the top of my head would be
Randy at Cobra engines
Laz Mesa at Mesa Balancing
Zul
TMP

Theres plenty more

Call me anytime I love to help people go fast.
Gerry
401-255-5242

Re: motor builders advice
 

This post confirms my earlier ones. Caveman understands too.