502 broke- starting over - need assist
 

Hello - I'm new to the board and have the following situation and could use any help you experts can provide:

I repowered a project boat with the wrong motors from the wrong engine builder. For 18 months he has only been able to keep both motors running at the same time (too many issues to list) for about 20 hours. Last week the port 502 430 HP Counter-rotating 502 roller threw a rod at 3300 rpm and chewed everything up. He says too costly to fix and warranty wont cover it since it has been 18 months. Tells me he'll fix it for $6k (like I'd let him at this point). I'm done with this guy.

Boat: 43 foot by 10'6" , 18,000 pound deep vee : 1988 Harley Superstar with arneson ASD8 drives and in-line Borg warner transmissions with reductions.

Motors: 430 HP not enough for this beast so need a bigger hammer. Would like to start with fresh long blocks and 550-650 HP but have room to build up if needed. Goal is a strong reliable cruiser with good top speed when in the mood. Current 502s have Gill exhausts, Holley 850 CFM carbs.

Questions:
1) Where can I source NEW well built/reputable long blocks
2) Will my carb/intake work if I get 540 ci rated for 550-600?
3) Will my carb/intake work if I cough $$$ for 630 ci motors?
4) What if anything will not move over to new blocks and what will I need to buy?
5) Since the guys engines are junk - should I bother? Should I start over with new everything?

I'm a working shmo with 2 kids in college (hence project boat) - help

MANY THANKS!

Re: 502 broke- starting over - need assist
 

1. Go with somebody nearby. That way if there's a problem, you can get it looked at easily. Where are you located.

2. Yes. You're looking to build torque motors not going for the last hp.

3. Yes again.

4. You will have a few changes if yuo go to tall deck blocks. Intake manifolds can be made to work with spacers. Exhaust locations will change and may require reworking your transom. New distributers will be required. Larger oil coolers also.

5. In reality, not a lot will transfer if you go to tall decks. If you stick to 540's, at least you could reuse the blocks. You may be farther ahead selling the engines as is and starting fresh. Keep your exhaust manifolds, intakes( if they're good ones,Merlin, Dart,Victor etc) and carbs and get rid of the long blocks.

Re: 502 broke- starting over - need assist
 

WHere are you located?
GO to the marine links section up top and you will find anything your looking for.

Re: 502 broke- starting over - need assist
 

switch to diesel!!!!!

Re: 502 broke- starting over - need assist
 

Read this thread

http://www.offshoreonly.com/forums/s...d.php?t=106170

Re: 502 broke- starting over - need assist
 

I'm in South East Florida. A buddy builds corvette engines from the ground up and can assist with assembly but not checking tolerances and any fancy mods. Diesel is $50k for used - wont happen while my kids are in college....I wish.

Merlin III 555ci are not tall deck blocks are they?

Keep ideas coming guys and thanks for the responsiveness!

Re: 502 broke- starting over - need assist
 

there was 540 bulldogs new in the clasifeieds not to long ago turnkey fairly reasonable.

Re: 502 broke- starting over - need assist
 

Talk to Flagship Marine, Innovation Marine, Chief Engines, and Mesa Balancing. Do your comparison and make your choice. I think Innovation may still have some 600 HP Volvo normally aspirated closed water cooled EFI motors for a reasonable price. Remember cubic inches = torque.

Re: 502 broke- starting over - need assist
 

f311fr1 has given you four excellent sources. Just remember that good motors cost more but there are no good cheap motors! Especially for boats. Remeber there's no replacement for displacement!, but talk to these people and remember to LISTEN & Trust! Their businesses and reputations have depended on them giving out the right expierenced advice!

Ray @ Raylar

Re: 502 broke- starting over - need assist
 

If you're going to spend the money for Merlin blocks, get tall decks. Build something around 600 ci. The difference in height is only .400 in. You could have larger flanges welded on your exhaust tips to cover the old holes. Mild cams and carbs would still make 650hp and probably 700+ lbs. of torque.

Re: 502 broke- starting over - need assist
 

Guys - the "newby" thanks you all for your assistance. I think I have a good plan of attack for my situation. Talked to many of the guys listed above - great information and solid people. The boat is underpowered (wish I'd known this 18 months ago but live and learn) but I am in no position to repower the way it should be powered right now so I am going to take this is steps:

1) get blown motor machined, re-assembled, running, and re-installed.
2) picking up two transmissions next week with more reduction which should raise RPMs at WOT to 5200 and reduce load in the rpms I will run it 3300-4500. This will also allow me to be able to turn more modern 4 or 5 blade cleavered props and gain the benefits associated with arnesons. I'll lose some top speed but gain better cruise and quicker plane and keep motors alive.
3) Get legal on builder and see if I can get some of my lost $$$ back (long and very sad story nightmares are made of...).
4) Work with above to build some bigger, stronger, better motors and sell the running take outs when I am ready to swap.

wish me luck

Re: 502 broke- starting over - need assist
 

Patriyacht - my motoers are mounted 5 feet forward of the transom with Gill exhausts and 4-inch dimeter rubber hose that drops down to the exhaust throughulls.... .400 inches wont matter. Will my Gills still work with Merlin Tall Decks?

Re: 502 broke- starting over - need assist
 

Yes, you could use your existing cylinder heads also but you might want to have a little chamber work done if you go big bore just to match.

Re: 502 broke- starting over - need assist
 

Spacers:

Using them on a tall deck for using a standard intake is a pain in the ass. To do them properly, the block, heads, and intake should be drilled for set pins to hold the spacers in place, and then you would have to buy new distributors meant for a tall deck block. They're not cheap. You'll spend $300-400 just to save your old intake.

Add it all up with the intake spacer kits being almost $100 each, and tall deck dist., two intake gasket sets, etc. So why not just buy a new tall deck intake for @ $300 which is already set up for your standard deck distributor - much simpler for same money.Just my .00002