Lets talk Motors and Reliability not Performance
 

OK, I'm new to big blocks. I had a small block in my last boat. I bought it new, 5.0 mercruiser 225HP. I sold it after 10 years of ownership and had over 2,000 hours on it with not so much as a burp out of it. Still ran strong.

I have a 8.1 now 496h/p 375 HP. The motor is new, just broke in good. How long should it run before needing a refresh?

Now, here is the real question. If I decide to get a boat around 30' and want to run in the 70's what would be the best choice for reliability and a long lasting pair of motors and outdrives?

I'm thinking 525's with XR drives?

Is there a more bullet proof motor out there?

I'm looking for reliability and long lasting motors, not the most HP.

The thing is, if I cannot run in the 70's why bother with running twins.

I like fast and light boats, I don't see many big waves on Lake Cumberland.

A pair of 496's in a 30 ish will get you there and they will last for ever. I think you would be surprised how much more you would enjoy holiday weekends there with a pair of big blocks behind you.

NautiNuff

THANK YOU for starting this discussion

We have a 454 &.4 MPI with a Bravo II -- It currently has approximately 310 hours --- NO ISSUES AT ALL and all maintenance is up to date

I'm not the kind that is going to beat the snot of this motor and drive-- ski,tube and once a while WOT

it is pushing a Cobalt 226

But would like to know what should I expect for routine maintenance and motor longevity

thank you all in advance


3pointstar

I popped for a 525 because I wanted the reliability of a "racing" engine along with the performance. I could have pro-charged my 496 and made more power for less money.

I hit 70/71 mph on a good and flat day and mid 60's all day long with my 496 ho's and I am very happy. Of course I could go faster and we all like that but at the end of the day I am pretty much care free boating at a more than fair speed.

I enjoy the trouble free side of boating as of late.

stock 502 & B-1.

If you want to go faster later just put small procharger on it. My neighbor has 496 with 3000 hours in it. Now I might make some mad here but an engine doesn't know if its in a boat , car,truck,or go cart. As long as maintenance is done there won't be problems but parts fail and there is nothing that can be done about that. It always cracked me up when people say its got 130k miles but all highway. That's great but how does your engine know its highway miles it don't care .... Now as far as highway vs city miles I would think fine for suspension,brakes etc. But not engine. Some say high performance engines dont last but I had a 434 strikers with f2 on it with solid roller and raced and drive on weekends all the time I would say equal to 15000 qtr mile passes. Finally the trans went and it had a 5700 stall in it. Maintenance ,maintenance is all I can say. I change oil every 10 hrs and then use in shop truck. Some say overkill but I like doing maintenance.

My 34 will do 80 with twin MAG HOs. 300 hours, just turn the keys and go!

If you're looking for long term reliability on the drive side, XR's aren't it.

I live in Seattle where we have 4 decent months of boating so reliability is my #1 priority. I am definitely not fast (55 mph) but IMO the best part of boating is just being out on the water with friends and knowing that your boat will always fire right up and run for hours without missing a beat. Stock power is the way to go. My friend has a 496 mag ho in a 2002 Nordic Heat that has over 900 hours on it and it runs like a top--friends with blowers are always blowing up their motors and its just not worth the downtime. If you miss July and August around here your entire season is pretty much shot.

Agree 1,000%. And not hard on drives either (as long as you throttle it back while in the air...)

Shop for a fast hull first. Then you don't have to put big (unreliable) power in it to get the speed you want.

My hull is just shy of '32 LOA and runs 78 with a stock 525efi. Runs great in rough water too.

I'm no expert, but I know there's a HUGE difference in how an engine will wear depending on the usage scenario. A car is low load, varying RPM range, and usually lower RPMs. A high performance boat is pushing hard through the water, usually spending a lot of time in a narrow RPM band, either cruising or going fast - and that's usually a much higher RPM than a car which shifts to higher gears/lower RPM on the highway.

be religious and fanatical about oil changes, drives and engines especially if they are new. I did my 525's every fifteen or twenty hours (thats actually more boating then you think). 280 trouble free hours and they ran like new when it went on to its next owner. I would have done valve springs if i still had it.

I agree. I have a 496 HO in my Baja. Dam things are bullet proof. I have 350 hrs on mine and change the oil every season and outdrive every other never had a problem. Great enclosed cooling system. Same on the 525's.

I have stock 525s in the 42 closed cooling and change oil every 20-25 hrs with Merc semi syn 25W-40 and 330 hrs no problems. Start and run perfect every time. Merc rep told me 525s treated nicely will go a long time and knows a Formula cruiser with 800+ hrs no repairs only maintainance. My XR drives both needed lower gear sets at 250 hrs. Many 525s have had header issues with failed welds so be careful and professionally check out the headers if you get 525s. I have not had problems with mine but I don't use the boat in salt water or jump the props out of the water. Good Luck!

Yea, 20-25 on engine oil, 45-50 on drives and changed before winter no matter the hours.

OK, so the next level above XR's cost how much more? The HO's put out 375HP and a straight bravo is good for 400.

What do the 525's put out and what are the XR's good for? Bigger and stronger is good, but how much better for how many dollars ball park?

Besides being a bigger motor, what makes the 525 a "racing" engine? What does it have the 496 does not?

the best annology to describe what our marine engines live like is they are on a full time dyno. We prop our boats to run at their peak power/rpm with the maximum prop. which is essentially a full pull at WOT (and some of us do that a lot :D) I had to laugh when GM did their little marketing schpeal on the performance parts 572 where they said they put the motor on a pull turned the lights off and went home for the night. Big deal . . . . one of their truck motors off the assembly line can do that no prob. Heck some of the SV, SCL and SVL guys go a couple years at wide open throttle in a rough race environment and never have an issue. You also have to consider that your crank, while spinning, has a gyroscopic affect that makes it want to stay in one place meanwhile your engine block is moving radically through several planes. Yes . . . . . marines engines are impressively over built for a very dynamic environment.

A 30' Activator with a single 525 will probably get you 80 if not really close and it will eat any water you can throw at it. 525's have alot better parts in them than a 496.

First off if you're looking to do 70 in a 30' boat 525's are way overkill. Unless you're looking at a sport cruiser? Most of the 37-39 footers are running mid 80's with them(v's). 525's are gonna be your most reliable of mercs blue motors, but you're gonna get more hours out of their black motors. A real good reliable setup to get you where you want to be, would be 496's, or 502 mags with a pair of bravo x drives. The x drives have the added beef of the steel tower in the uppers but still have the spiral cut gears which last longer.

I think the helical cut gears are slightly faster as well. im really surprised the X drives haven't caught on more,

Maybe I'm an ignorant fool. Wouldn't be the first time.

But isn't how much HP (or really torque) any engine or drive can handle reliably relative to how many props are on the equivalent boat?

I'm no speed demon with a couple black motors in front of two Bravo 1 drives. They are built just like the old 425's with decent heads, Crane valvetrain etc and make pretty good torque and push the old girl along at around 75 ish with total reliability. The Bravo's have been bulletproof and I've put it down to each drive pushing around half the boat.

Seems to me if there was just one prop the drive would be working a lot harder, and I would need a lot more engine. So isn't reliability all relative to how much of the boat the engine and prop is pushing at the same speed?

Seems to me that torque breaks parts and hurts reliability, not horsepower. Whether engine created torque, or torque created by props re-entering the water etc. Does that make any sense?

Edit: Now watch my stuff blow up this summer after I just said it was reliable. Lol...

No. I think the 496 Mag puts out 375. The 496 HO puts out 425 hp.

But yet the blue motors have better stuff in them?

So based on what has been said, 525's with X drives is what I'm really wanting. If I run in the 80's that would be fine with me. So how many ponies do the 525's put out?

So all twins have hydraulic steering right?

This is why I'm not keen on adding power to my current boat. More power means upgrading outdrive. Then when I run higher speeds I need hydraulic steering. If I am going to spend this kind of money, I just as well should get another boat me thinks. My plan is to run my little Baja for a couple of seasons and unload before anything needs refreshed.

OK my bad, I currently have a 496 Mag with a Bravo I. Most likely I will be refreshing my outdrive at some time and should take it easy coming out of the water.

525 efis put out about 570 hp on a dyno. The main issue with the xr drives is the surfacing of the prop. Stay away from them. They are nicknamed explode and replace for a reason.


QUOTE=NautiNuff;4071670]So based on what has been said, 525's with X drives is what I'm really wanting. If I run in the 80's that would be fine with me. So how many ponies do the 525's put out?

So all twins have hydraulic steering right?

This is why I'm not keen on adding power to my current boat. More power means upgrading outdrive. Then when I run higher speeds I need hydraulic steering. If I am going to spend this kind of money, I just as well should get another boat me thinks. My plan is to run my little Baja for a couple of seasons and unload before anything needs refreshed.[/QUOTE]

Another option to consider is the new Mercury Racing 520. This motor comes with a 2 year warranty and will not have the header issues. DTS is also standard and this motor will save you around 8k over the 525.

Yea, sometimes going fast is a viscous cycle, the faster you go , the faster you want to go. I learned a couple of things for what its worth.
1. If you want to make your boat go faster, buy a faster boat. Over the long hall its usually cheeper.
2. Leaving your boat alone will drastically help your resale value. I've always left my boats alone. Believe me it was nothing for me to put a supercharger on my Baja in fact it was killing me not to. But its worth more when you leave it alone.
3. There is always someone bigger, faster, stronger, etc.
4. Once you go into the 80mph range its a game of inches and you might build a boat thats to fast for its own good.
I hope this helps. Not trying to take the wind out of your sails. Just sharing my experience.

Not at all, thanks for this reply. I'm going into this with my eyes open. I'm leaving my little Baja alone. I might get the prop labbed thats about it.

I found a website that priced a 525 with X drive brand new just shy of 30K. Then times two is 60K with sales tax.

I also found a 2007 Executioner with 496 HO's for about the same coin with 200 hours.

I love this forum, I'm learning and passing the time till boating season.