Info on Merc's 525SC
 

Hello All,,
Has or Does Anyone run the Merc. 525SC ???
I would like to Know the Good, Bad or Ugly about the Engine!! Is it Dependable, Long-life, Maintance, Etc,,,,,,
Thanks in Advance!!!!!!!







2nd Place, is the 1st, LOSER!!!!

I've driven a 98 31 Sonic with 525SC's. I was very impressed by the motors. They idled happily for 20 minutes milling for the start of the poker run then were ready to rock as soon as the throttes were pushed. I would buy them in a heartbeat. BTW 89mph on speedo, so probably 83 or 84 legitimately.

Mitch,

Do I see upgrades in the future or could this be a whole new boat. Cmon man spill it.

I'm also interested in hearing about these motors as well. Are they taller than the stock 502 EFI and by how much? Where is the best place to look for one with low hours? Or would you be better off with a 500HP or 500EFI?

DallasHeat

I am running a pair of 525SC in my 1997 Black Thunder. I have 190 hours on the motors. I had my blowers gone through at 150 hours and I have had no problems at all with the motors. The only problem that I have is that I have to replace the spark plugs pretty often. By the way the Black Thunder is for sale! I get 79 MPH out of the boat!
Mike
704 622 9136

We have heard great things. I also saw some info in Powerboat Mag, check there.

I've got a 525sc in my Pantera and love the torque of the engine. It has 260hrs and I think I'm going to go through the top half in the off season.
Boost has been steadily creaping up (7-8 lbs). I think the valves may not be opening all the way to let fuel in or exhaust out. Runs fine still and doesn't seem to be down on power and uses maybe a quart of oil evry 20 hrs.
Long idles are no problem at all, except when it is REAL humid, then couple revs of the engine are needed every once in a while to clean off the plugs.

I have driven Griff's boat. And I can say that his motor is tough!! Just enough blower whine to let you know it's there, but not obnoxious like some I've heard. And it pushes his boat along pretty well too!!

Mama.......putting some new power in the Sunsation or looking at a different boat. Inquiring minds want to know.

Mike

I have also run Griff's boat. The 525sc seems to be a great engine. Relaible, good power and torque, good looks and just the right amount of blower noise. What more could you ask for?

Here is Griff's engine. This photo was taken roughly a year ago. Beautiful package!

I just put a 525SC in my boat w/a super chiller. I love it so far!! Awsome motor....And the whine those baby blowers make is KILLER!!:D :D :D Even with the super chiller I didn't need to cut the engine hatch. Motor starts no prob. idles no prob. not really any surge, I put GIL dry exhaust on it and it is loud as hell!!!....great motor! I did have it completely gone through prior to putting it in though.;)

Tank

Tank,

What did you have in there previously? And how much taller is the 525SC?

Where did you find the used motor? Where should I start looking for one?

Sorry for all the questions but I'm very interested in upgrading this winter.

Oh ya, what were your performance gains?

DallasHeat

Since you guys are on the subject of 525sc's I have a few questions.
A friend of mine is looking at a couple of disassembled 525's , he is looking to make a little more power than the stock 525's and i made a few suggestions, what do you guys think ?

Upgrade the rods and rod bolts, maybe Eagle or Manely
Upgrade the heads, Brodix with mild porting
JE pistons, Do the Merc 454's have metric rings like the 502's ? that's my reason for changing
A custom ground cam to take advantage of the supercharger
add an intercooler.
Do you think these upgrades would be worth it ? He would like to make a honest 550hp

Dallas Heat,

I had a stock 454L motor (not the mag). My boat was over propped with that motor so I could get like 62-63 out of it on a good day. Now that was on Speedo, not gps so prob. realistically 58-59.

The 525 itself is the exact same highth as the 454 block. The little baby weind (sp?) blower isn't really that much higher (see the pic from griffs boat) and the super chiller is what? 4-5 inches maybe. My Baja has alot of freeboard so it was not a big deal. Fits right under there.

The motor came out of my friends 38 Scarab. He threw a rod through the side of the other motor (thanks to a leaking stelling header) and parted out what he could from it. Then put Teague 800's in and after letting the good motor sit for just under 2 years he gave me the motor:D :D :D (it pays to have good friends!;) ) The only prob. was water had sat in two of the cylinders while the motor sat. So I had it completely stripped down new EVERYTHING and bored out the block, milled the heads, new pistons, rings, water pump, alternator, etc, etc, etc. The mechanic said it should be making right under 650 HP. with an estimated speed of somewhere in the range of 80-85.

I've had it out and run it pretty hard but it is over propped right now with a 28" 4 blade. So I want to get a 26" 4 blade and see what happens. I'm only getting 5K out of the 28 and I need about 5500. My speedo is not working right so I don't really know the max speed but I can feel it is dam fast!!!:eek: :D I'm going to get the gps out there soon and see what kind of numbers I get out of it.

I couldn't tell you where you could find a used 525SC. Look on the board here in the motor section and also in the back of Power boat mag. Thats where I'd start.

Tank

Tank,

Great friend:) Thanks for all the good info.

I'm a lookin:)


DallasHeat

Good luck bro...If I see one Ill let you know.

Tank

26Scarab, I don't think he would have to do that much to the engine to get an honest 550hp. Just add an intercooler and turn the boost up a # and it would be there.

blowers go out at 150 hours?!?..black thunder boat

I thought 525sc are strong as normally aspirated mercuries;
isnt it too early 150 hrs?
as I understand this engine is in
''always-take-care-of-me '' class

so why dont you buy a more hp generating engine with almost the same price?

just an idea...

Griff,
I know my friend won't have a problem with the intercooler but I know for a fact he doesn't want to increase the boost.
He is really concerned about reliablity issues, that is why he isn't building a bigger CI blower motor because then it would have more torque and will hurt drives.
My opinion would be to build some blown 540's and call it a day... he's got two engines , he can always get home !!:D

I was only saying to increase the boost from the stock 5# to 6#. I don't think this would create any problems. The only problem with spinning the 177 blower faster is that the heat created can overcome the gains from the boost. Thus the intercooler to keep the air charge temp down.

Adding just an intercooler without increasing boost will probably still get him to the 550hp. I'd check with Whipple and see what they say about HP gains with their intercooler. It is trick, but about twice the $$$$$ of a superchiller. Also, it only adds 1" to the overall height.

timucin, my engine has 260 hrs and as far as I know, nothing has been apart on it. It is definately are not in "always take care of me" class. Very turn key and reliable. The only thing I've done to mine is put in a set of spark plugs and a new coil. I would say that the 525sc is probably as low maintance as a blower engine can be.

Griff,

Thats what they did on my motor. They put a smaller pulley on to up the boost. The chiller helps keep the heat down. But like I said, I don't have any scoops so I need the extra cooling.

Thank god for that!!!!!:D :D :D :D :D

2 6 0 h o u r s

cool!

Thanks for the info Griff,
I will pass it along to my friend

Thanks Alot Gentlemen!!!!!

Griff,,,, Great Pic!!!! I'm sure your Pantera Kicks A$$!!!!
260hrs,,, That's *****in!!!!!

Tank,,,, Damn,,, now thats a Friend!!
:D :D :D

Matt & Fowl,,,,
:D :D :D




Second Place, is the First LOOSER!!!!!

Cmon man!!! Don't leave us hangin.

So how are ya man. Long time no see. Hows Boatinbill. I haven't seen him lurking for a while.