Engine building ?
 

Has anyone here rebuilt their engine or build a shortblock from scratch? How difficult is it to do? I have swapped out the top half of car engines before but have never tried to build/rebuild a shortblock. If I purchase the correct rotating components components already balanced (I would check them of course) and purchased a merlin III block (race prepped)(4.500'' Bore 9.800'' Deck Height) 9.0:1 compression, complete merlin Heads and intake, how difficult would it be?

I would think that it would be better than an assembly line motor, much more care being taken when building. I do have the book Big-Block Chevy Marine Performance by Dennis Moore and have read it several times.

I am looking for very high grade components but not looking to put out a huge amount of Horsepower. I would like to build a BBC putting out around 500 HP turning in the neighborhood of 5,500 RPM's.

What additional machine work would be needed before assembly? Any recommendations on additional reading?

Re: Engine building ?
 

Basically what I do is take everything to my machinist for his prep and balancing ect. I will conference with him on assembly for any new tech I'm not up on. Be sure to call the manufacturer tech lines for input too. Just be sure of everything and double check if you don't remember if you torqued something.
I built almost every engine I've had in the last twenty years but the engine in my Superboat. I probably could have but to get 800hp on natually asperated engine I figured best if i had someone with experience and a one year warranty as well. More later.

Re: Engine building ?
 

Hey Razor,
What engine do you have in your boat now?
If it's a 454Mag, that can be rebuilt to make 500HP @ 5600rpm no problem.
There is no need to buy an expensive aftermarket block or heads unless you want to make 600HP+.

Re: Engine building ?
 

I agree. My American Offshore cat was a 454Mag with a good cam and heads. Bolted on a Procharger and I was over 700hp and doin 100+.

Re: Engine building ?
 

Would the great ci give more torque? so you could break more bravos?
Pat, could one of the volvos you get be built up to 500hp easily?
... actually a raylar kit on one of those would be nice.
... buy the volvo and just do the upgrade w/ the raylar. :cool:

Re: Engine building ?
 

Yes, Torque is easier to build with more cubes.
Yes, the Volvo 375HP or 420HP 496 cube can be built up with a Raylar kit. But now the $$ are going to flow from your wallet... :eek:

If 500HP is the goal, a 454mag is a good base for modification... :cool:

Hey Storm,
What did that modified 454mag JC Perf. built for you dyno at?
Over 560HP @ 5800 if I remember correctly... :D

Re: Engine building ?
 

Yup... 552 @ 5800, 558 @ 6000 and torque at 552 @ 4800.
If all you want is 500hp, no need to go more than 454.
I guess its all about your budget.
I just thought since Razor has experience w/ the top end, he could do the Raylar package w/ confidence.

Re: Engine building ?
 

Pat, btw... spoke to the new owner of my boat today.
He loves it. and is thinking of putting a 1-2" shortie on it.
I'm glad its in caring hands. :D

Re: Engine building ?
 

The engine is 10 years old and I would like to race (P6 if it lasts for the 2007 season and P5 if it doesn't). I was calculating the costs of a Merlin III short block race prepped, World balanced rotating assembly, all the odds and ends, plus the merlin single plane manifold. I was talking to World performance, the block needs no additional machining after it is race prepped. Parts for what I am looking to do is not much more than a replacement "rebuilt" short block in the 502 Mag variety.

I would like similar internal specs to the Merc 500 Bulldog without the price tag. I would like to build as close to a bullit proof race engine as possible. Looking for the ability to run 70mph all day long (almost as if it was cruising speed) without breaking engine parts.

Is this a lost cause? My current engine is a Gev V Carb (350 at prop)
Full Hydraulic steering will be hooked up within the next couple of weeks.
New 3 button Livorsi Throttles will be hooked up this week. My Trim indicators will be added somewhere in the mix. Have not made the measurements for the indicators yet.

I do not really care about top speed but being able to hold the throttle between 60 and 70 mph with reliability is.

Thanks,

Re: Engine building ?
 

I am still looking to do the build, (cubes vs rpm debate). I would love to see the spec's on Stormriders motor. What his top speed at RPM and what his cruise speed is/was?

Would a motor like that be able to carry my 24' Superboat at 70 for extended period of time with reliability?

Re: Engine building ?
 

Deal of the Century,
don't hold me to this, but I thinking of letting my VORTECH engine go, less header, soon, very cheep maybe on Ebay, you heard and saw it run this past weekend at the Races, for those that don't follow Racing, Mark Henderson and I got 3rd in Michigan, we ran extremely well but the big bastard couldn't get out of the turns fast enough. So I'm thinking of building my HP500efi, the Joker was burning Race Fuel (smell) and pushing 600+ hp, the Ocean will be an equalizer but many of the Races are in Rivers with tight turns, nothing turns like a Superboat but it takes power to get her going again. I thinking $5k range for 520+ power, you cant beat that price. will make that decision soon, very soon.

Eddie

Re: Engine building ?
 

It is true. I am still surprised at the fact that my motor started out at a 454 mag. The mid range acceleration is really the part that blows me away. She sounds pretty good too (might take a little bit to load) http://media.putfile.com/superboat-idle

Re: Engine building ?
 

There is nothing wrong with rebuilding a 10 year old engine so long as it has not been rotting in salt water.

I did a total rebuild on my 1996 502MagMPI last year for about $2500. The engine was vary tired at 480hours as it had a tough life pushing my buddy's 29' Fountain before I bought it from him.

The short-block is a piece of cake to overhaul.
Bring the block to a machine shop and have them hone the cylinders, clean the oil passages, and install new cam bearings.
The rods should be magnifluxed, shot-peened, and re-sized with new APR bolts.
The crank should need nothing more than polishing with crocus cloth.
Ring, bearings, an oil pump, and gaskets are not a lot of $$ and you should be able to reuse your existing pistons as they are forged.
If you don't have the confidence to complete the work yourself, I would bet a shop local to you would do what I've described for around $1500.
Now you have a short-block that will hold up for many more hours of abuse.
Now your valve train selection and head modification/replacement will decide how much power the engine will make.

A 24' Superboat will run over 80mph with 500HP if set-up properly. 60-70mph cruise, no problem... :drink:

Re: Engine building ?
 

I was running 5700rpm, 23mir+, 74-75mph gps salt water.
Valve train was changed over to hydraulic roller. Bored out to 461ci, compression 9.35:1.
Dart iron eagle heads, intake by Zul racing Demon carb... 800cfm, i think.
JC perf built the engine, and he knows what was in it. He is one who will help a board member, not sure if he gives secrets away or not.
Razor, where are you located?
Jeff can rebuild your motor reasonably, probably to whatever level you want, and you can dress it yourself.
Give him a call 516.216.0778.

Re: Engine building ?
 

fasteddy -
I was wondering what name you go by on the board, Great Race. You have seen my boat, I think 500HP would be the ticket for my 24 in the P6 Class. And I do agree with the others that it would be cheaper to rebuild my 454. I would just rather go prepared and not blow an engine. I was talking with Tyler Crokett about some posibilities, and I think his price will be a little too high for me.

Also, I would not mind having 2 engines, One in the boat and on ready to go in the boat. If I loose one I will have something to fall back on.

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Stormrider, I live in Michigan, Metro Detroit Area. One of the Guys from the Cat Can Do crew (Won the the P2 Class in Algonac) works at my marina.
I am thinking a 509 or 540?
How much power will my Stock (Square) Heads support? (I will have them redone.) I would think they would be fine at the 500 HP level.

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Also, My boat was from Massachusetts. It was always trailered but was used on the rivers primarily (brackish) and used in the ocean? There is really no way for me to tell just how bad the corrosion may be.

I think I will just go new components.

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Your stock rectangular port heads can be modified to support 600HP, but unless you do at least some of the work yourself, it will cost nearly as much as a new set of aftermarket heads.
I had the heads off my 502 bowl ported, milled 0.020", and the valve job done for $650 including new springs. They would likely support 550HP with the port work that was done.

1-800-runsnew sells a 500HP/509 base engine (long block with tin) that dyno's at around 515HP for $5800. It is basically a HP500 with a better cam and comes with a one year warranty. I have bought engines from JK and they do stand by their product.

Have Fun and Happy Boating... :drink:

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Thanks Pat,
I know you went through the same growing pains that I am just beginning. I think I will build my own, I just now need to figure out the best combination for my purpose. I will build new with World (Merlin III) products. Horsepower of torque, torque or horsepower. 24' Superboats are light, I think I would do better spinning a smaller 23" prop around 5500 RPM (should be around 70) and have the ability to run it to 6000 RPM. The question is, do I try to do it with a 454, 509 or 540? I would probably have the best luck with the 454, less stroke should wind up quicker for me and give me better acceleration between 40 and 70mph.

Any experts out there I would love to here what you think?

Re: Engine building ?
 

Razor,

From what I am reading it sounds like you want something along the same lines as the motor in my boat. Started off as a 454 Mag then the top of the motor was reworked including new carb, intake, rockers, etc she dyno'd at just under 500 hp at 5700 rpms with 502 lb/ft torque at around 4700-4800. Pat talked to the previous owner of my boat and may be able to shed some more light as I am going off of the paper work that I have. The thing about this motor is the mid range punch and the run from 45-75 will throw you almost in the backseat. Also I am back and forth right now between 25p 3 blade and 26 bravo 4 blade. I still have the 3 blade on now so that I can see what handful this boat really is and what I need to look for. Supposedly the 4 blade will tame the ride and chine walk a little bit. BUT the top end prop for this boat is a worked 25 Non plus mirage. Hope this helps a little bit

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If you happen to come up with the specs, I would love to see them.
Thanks,

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I will see what I can dig up...I can post the dyno numbers before and after no problem, the parts list was all handwritten so I will see what I can make of it tonight.

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From what I remember about the upgrades Gary did to that engine are the following:

The heads were milled to increase the compression and race ported for better flow.
An Inski roller cam with all the mating valve-train components installed.
The intake was replaced with an Edelbrock Vector single plane and on top is a 850 Demon carb.
Imco Power flow exhaust replaced the cast iron crap.
Last, I believe is an MSD ignition so she will rev higher than the stock Merc 5150rpm.
I would guess, between 5 & 6K worth of upgrades... :drink:

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See Razor what did I tell you :D But I think it may have a Demon 825 carb....will double check though. The rest is right on. The motor is a nice piece, and really came alive with the work Gary had done. Revs a LOT higher than a stock 454 that is for sure. As if this motor wasn't enough in its N/A form, there were plans for a blower (177 i think) but hatch clearence became an issue. Shop up outside of Albany did the work.

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Razor, Jeff's been on this thread and would be happy to talk to you. For less than 5-6 you can get your engine rebuilt w/o having to touch it... +exhaust.

New better heads will make a big difference in power too.
I paid around $1000 for dart iron eagles.

Best of luck to you, and keep us updated.

Re: Engine building ?
 

Always,
After a lot of personal debate, I ordered my steering (Zeiger Single Ram, Full Hydraulic) and indicators (Livorsi) from Trick Marine today. Hopefully they will not take to long to come in.

I am currently pushing a 24" Bravo1 prop to 4900 RPM for 66mph (GPS) in a light chop (1 to 2 ft), 3/4 tank of gas and 2 - 200lb adults. Do these numbers seem par for the course? I have to trim the Bravo1 pretty far out as the speed increases, but the ride is outstanding. The whole boat feels like it is lifting higher out of the water. Cruising back in late Sunday, she road like a champ in 3 to 5 foot rollers at around 50mph. Zero tendency to drop her nose, and running real strong.

I will probably have Mark from Litre Marine (local) do the engine after this boating season. He thinks I should go with displacement, but I am still on the fence. If I can squeeze out 500HP and good torque numbers out of my current block and crank, I will probably keep my 454 Mag (cheaper). I know I will have to drop some $$$ into the drive so she can handle the extra power with reliability, so I may run into a money issue later down the line.

Do you think 500hp will be enough power to turn a 26" Bravo 1 to 5500 to 5700 RPM? With the same slip #'s that should put me between 80 and 84mph.

What would by cruising RPM be with a setup like this? Cruise speed between 65 and 70mph would be ideal.

What about for P6 (OPA) Race Class combo?
22" at 5600, 24" at 5250 or 26" at 4800

Is their anything else I should be thinking about?
I really love hearing all of your thoughts.

Re: Engine building ?
 

Bravo 1 props do give great overall performance on these hulls. If you have a B1 altered to give more bow lift then you will not have to trim out/up as far and top speed will increase.

Your speed does seem to be a click or three slow. The guys I have talk with have run 25p Mirage or 26p Bravos on 24 Supers or Panteras powered by 454Mags. Running light your boat should run in the low 70s.

When I first bought my boat, I installed a 310HP/7.4MPI. With two people and 1/2 tank the boat would run 65mph with a 25p Mirage+ and 63mph with a 24p or 26p Bravo 1. I had my 26p B1 labbed a couple of times (long story) and got to the same top speed as the 3 blade. The fastest I got the boat to go with the 7.4 was about 68mph running real light.
Last year I installed a 415HP/502MagMPI and with a 28p Bravo 1 she ran 74-75mph consistently. This year with a modified B1 she is a bit faster.

With a 500HP engine a 24' Superboat should run over 80mph.

As for propping a boat for racing, that will depend upon your engines torque curve. If you build a 500HP/454cube then prop for 5500-5600, if a 500HP/502 then 5200-5300. My bet is that a lager displacement engine that creates its max torque at lower rpm can spin a bigger prop and will accelerate the boat faster in turns and be better for racing.

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Did my slip number look correct?
I am currently pushing a 24" Bravo1 prop to 4900 RPM for 66mph (GPS) in a light chop (1 to 2 ft), 3/4 tank of gas and 2 - 200lb adults.

What RPM Should I be able to turn a 26" Bravo1. My engine was rated at 350hp at the prop and I have a Stainless Marine Exhaust on that. So lets say 365 at the prop (this may even be generous).

Re: Engine building ?
 

The slip % looks about right.
I would think you should be able to spin a 26p B1 at 4800+rpm.