Merc 575SC motors..
 

hey guys..

i did some searching on the forum but most of the finds were really old (2004 or older).. i'm looking at stepping up from my 23 baja 496mag to a 35 or 38 footer but i can't deside on the motors..

i know the 496 motors are turned key and with reg oil changes and services they could last a long time.

BUT i want some power and i love that Blower Sound :D.. so i want to know what type of maint i'm looking at with the older 575SC..

do they need the services like the 525 (valve jobs after 200hrs).. how is the service on the blower it self? What else should i have to worry about??

I guess i would have to run 91 gas and not 87 anymore, so thats a cost increase :( but will worth it...

thanks everyone..

mike

I have approx 330 hrs on a pair of 2002 575's
So far, they've been flawless.

Neither uses any oil between change intervals.

They have a flat tappet hyd. cam, instead
of a hyd roller like the HP500',EFI's,525 EFI's
so, the valve train doesn't take quite the beating
in does with the latter.

The newer B&M blowers have had some rear bearing
failures reported.

The only thing I've had to do different maintenance
wise, is to change supercharger oil in the front
and back reserviors.

I'm replacing the head gaskets this spring
as part of preventative maint.

Others will mention blower rebuilds at X hours.

I love mine, and would have no problem owning them again.

JaayTeee thanks for the post... thats the type of info i'm looking for.

ANYONE else out there have some input??

thanks,
mike

Yes they are awesome! Idle like a kitten (cmi headers, very loud)
No load up, very well mannered.
Blowers are weiands so they are fine, no they dont eat XR drives, they are perfectly mated with the xr's
the best is that they are injected not carbed so the computer is always compensating so that no loading will occur.

They do idle a little higher than a normal carb motor, around 800 850 or so but believe me they are just flat out impressive.

They will use about 5% more fuel.
The thing to look for is to make sure the front seals on the blower pulley's are not leaking oil. Early models had issues with bad seals. Check the repair history, it is likely that they have been replaced. Also have compression and leakdown test done. On leakdown, Merc says anything under 30% is ok by thier standards. I would be leary of anything over 15%.

So far they appear to be a rock solid turn key motor. Only extra maintenance is to change blower oil about every 50 - 100 hours.

Once you run these, you'll be hooked. I was VERY skeptical about blower motors, but since this is a very mild Merc engineered package; I am now comfortable.

Also, Scott Buteyn of Mercury Racing was here checking out Nauti-Props' boat and doing some field testing. I got to spend quite a few hours talking with Scott about the 575 (and others) and any issues that Merc may have experienced with it. Basically it is a VERY sound motor. Scott said that head gaskets should be replaced about every two years and "check" valve springs about 300 - 400 hours.
As far as rebuilding or refreshing them???
Any engine that has been run to death will have to be rebuilt NA or SC'd does not matter.

575 sci is good easy for however long you want it to last which depends how hard you are on it. You should see 400+ hrs on it if your really thrashing it, or 600-700 if you baby it and take care of it and oil changes constantly, keep an eye on everything all the time and dont run it WOT for 95% of its life.


Go for it, you'll be glad you did.


Also, pull off the thermostat housing and check the small hose passages. If they corrode easily.

From the research I have done, they are built like a brick s**t house. Should last a very long time as long as they are properly maintained.

WOW :) thanks BillR...

what are the years that these motors were built?

i'm looking to get into a 38 Lightning or X with these motors.. how is your insurance with your Cig compaired to a Cig with NON-blowen motors..

thanks,
mike

Good engine package and very easy to upgrade to 725-750 Horsepower!

(can't see the photos) thanks anyway..

Are these motors are Forged? crack, rods and piston?? are the only things weak are the head gaskets?

whats the MAX you can put out on a stock internal motor (700 or 800hp)

The factory engines have steel forged cranks, Manley H-Beam rods, and JE forged pistons. The rods are a press fit from Mercury and we bronze bush them in house for full floating pins. These components will handle 750 HP with out an issue.

Dean,
Will the stock fuel system support those kind of #'s ?

JaayTee,

Have your motors been worked or are they stock 575's? What kind of speed do you get out of your outlaw? Thanks

They're stock

Here's what it will do in the spring and fall

Sweet, I want some! DId you Baja come with them or were they a repower?

That's the way it came.

They're great engines, their neighbors that
live behind them ( the XR drives)
haven't been as maintenance free though:(
but, I think I have that issue worked out.

They've been better than the HP500's I had in my last
boat.

any mods to the swim pad or do they fit underneath it?

The X dimension is real high in this boat, and they just barely
fit underneath the standard hatch.

I have a pair in my 2002 35' Fountain. I love the motors; just make sure you follow everyone's guidelines above. I agree with the leak down test and head gasket replacement. I blew a head gasket at 281 hours and lunched the motor because I hadn't done a leak down test.

The blowers need to be rebuilt every 150-200 hours. I always had mine serviced religiously but at about 230 hours one went south, the rotors collided and I ruined. In case no one has told you, you can't get parts for them. I had to drop $3500 for a rebuilt one.

As far as squeezing HP out of them…stock they are absolutely perfect. They idle great and I had zero problems besides the lack of knowledge I had when it came to the head gaskets and blowers. However, I'm told you are limited to what the injection system will handle. I put intercoolers on my boat, which raised my HP to about 650 and I was told anything above that would necessitate modifying the fuel system and lower my reliability.

I would own another pair in a heartbeat. I feel the issues I had were due to my own ignorance.

Hope this helps.

What do you mean you cant get parts for them?

The engines are set up so rich from Mercury, that yes the factory fuel system worked just fine on the 725-750 HP range. That is real about the limit with the induction system. I put the emphasis on making more power through cylinder heads, camshaft design, and compression rather than trying to drive the supercharger harder. We also went to The Blower Shop 250 superchargers. We also focused on many upgrades to the oiling system : Canton power pans 10 qt., better oil lines, any small restrictions in oiling system such as at the oil filter remote inlet, and fitting size.

Any reason for not stepping up to 871 blowers?

Yes, on this job.....no hatch clearance.

where could I look to price some of these motors?

You'll occasionally see them here in the classifieds

I think 2004 was the last year they made them,
they were replaced by the 600SCi.

So after changing the head gaskets to better ones.. WHAT are the bolt ons everyone is using to get to 700 - 750HP..

when changing the gaskets, are people changing the compression to increase the boost?

how are the headers (stock), they are not CMI or performance style.

thanks guys for posting your input..

mike

The headers are CMI's

Mr Hp. covered the mod's a few posts ago.

I'd venture to guess that most of the gains come in
the camshaft area,( using a decent hyd roller)

Stock compression ratio is pretty tame too.
(7.5:1)

sorry. i read it to fast :(...

pulling that cam out, i HOPE you don't have to pull the motor (non-stagered).. i'm use to cars and pulling them while there are still in.

what type of gaskets everyone using?

Yes, we bumped the compression to 8.3:1, Brodix cnc ported heads, and custom Gellner/Crane Hyd. Roller camshaft.

Dean,
Have you done any with iron heads ( Darts ??) ?

All these pic's are making me re-thinking
my "2 more years" plan:D

I really don't want to take any more weight out of the
back of the boat. (c.g. issues)

damn i need to upgrade my account so i can see photos....

All the ones that I have done have been aluminum, but iron would be not much different.

This is great information as my 575's aren't going to last forever. When the time comes I'll either sell or rebuild.

Interesting information here. Just today, I was discussing rebuilding a pair of 575 SC's for a friend. I encouraged him to go for switching the cams to hydraulic rollers, rather than the flat tappets Merc used. With the exception of the type of cam, we want to rebuild stock, no upgrades at all. Does anyone know for sure exactly what cam Merc used in these?

i have been searching Youtube and Google for any videos of boats with 575SC motors.. i want to hear some :)

They do have a nice whine to them:D

do you have any video of your ride?

There's a couple of shot of it in this video,
but, you can't hear the engines, he set it to music.

http://www.youtube.com/watch?v=mD_FQvf-5CE

The engines in Mr Horsepower's pictures are mine. With the upgrades Dean did to them they have been flawless. I was able to put about 20 hours on them before the season ended. All I can say about them is WOW.

Mike, you're going to find that when you get in the range of 500hp per side and 38 feet, the insurance is probably going to hurt your feelings.:( Now, of course, the higher the hp numbers the worse the premium is going to be. Also, consider taking Tres Martins performance boating course. It will get you somewhat of a break on the ins and some extremely valuable info about operating a rig with that kind of power and speed.

Just my .02

nice video.. got a little close to that sailboat around the 2:30 minute mark :D...

thanks :).. where are those driving courses giving?

We have upgraded several of these engines also. we put Dart heads on and put are custom Hyd roller cam in and we also use Whipples intake with innercooler. I also up the compression a little so with the added breathing from the heads and cam I don't have to spin the blower any faster. The engine will make 725 HP real easy.