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525SC Rebuild Recomendations

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525SC Rebuild Recomendations

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Old 03-06-2018, 01:29 PM
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Default 525SC Rebuild Recomendations

Rebuilding the power plant in my project and need some OSO advice from those who've been down this road.

Goal: 500-575HP, where I can run my Bravo 1 and keep it together for more than 2-3 seasons at a time, I'd like to make this thing as bullet proof as possible and get 300-500 hours out of the rebuild. Not super concerned with how fast I can push the boat, it's a 75mph boat with the Orig 525SC set up and that is plenty fast enough for me as it'll be used mostly on the river with occasional western US lake trips, some skiing & wakeboarding.

Current Set up: 94 -27' Warlock world class, Weiand 177 with super chiller over driven at 2.15:1, stock 88 rectangle heads, Brand New Set of Hardin Marine Orig replacement manifolds (420-901180-MER) with orig Gill E-top, through transom, original manifold water ports seem to be ok (if not I can weld it up and machine it), 12" K planes, external power steering, Bravo 1 outdrive, 26P 4 blade Bravo prop. (let me know if I missed something).


I have the block stripped and it's time to send it out for machine work but I need/want a plan before I start having work done and I could use your help Griff & Mild Thunder


I've done a lot of reading and have gathered a few recommendations so far, here's what I think I have, take me to school please:
-I have water damage in 2&8 and will most likely need to go 30 over, so that means new pistons & rings, if a power hone (CK10) can't clean it up or it'd be out of spec.
-If it needs a bore, probably just do the speedpro OEM +30 on the pistons
-Not sure on the rings someone said Total Seal AP top & Napier 2nd?
-The motor came un-ran with a mystery cam, so I'll need to buy a new cam, I can go Orig, Crane 132561 ($260), OR is there a better one for my application (I think roller might be out at over 1K for the switch as I'm not sure if that money is better invested in heads or roller)?
-Heads have been redone but I'm not sure what's been done or how good of a job they did, so most likely Redo the heads or get new ones depending on price (Young Performance quoted $1,800 for the full boat and all the new parts on the OEMs)

-If I stay 88, replace valve springs with ISKY 8005-A, and new 10*retainers & Locks
-If I stay 88, replace head bolts with ARP bolts, which ones/part numbers?
-Replace head gaskets with Cometic MLS 40 Head Gaskets
-Replace the rod bolts with ARP, which bolts fit the original rods or is there a better option to keep them together?
-Has Orig Merc TB IV, with a MSD blaster coil & a 6L box (not sure if I should run the 6L box?)
-Has original Distributor & cap, should I get a new one, if so which one?


Other Misc things I need to address:
-Like to get a stainless manifold riser set up as the cast one is in pretty bad condition
-Need to replace raw water pump, maybe with a stainless one, hardin, CP, do they make just a stainless intake and use the OEM plastic housing?
-Mechanical fuel pump needs to be rebuilt, who has the best parts?
-Need a fuel/water pump pulley, is this the same as the power steering pulley? Can I just get a black one and paint it Merc Racing Blue?
-Need a sea strainer or sand strainer for the Super chiller as it has no filter on it now
-Need a new harmonic balancer, dyco was mentioned?
-Need new oil pan, go with billet or just stamped steel so things can escape if needed ?
-Need new Windage tray, solid or screened?
-Should I get a new oil pump & pick up, or is stock sufficient?
-Does this motor need a billet timing cover to help it from flexing or does stamped steel do the job?
-Need new timing gear & chain, what is a good set?


Let me know if you need more info.

Thanks
MoHav

Last edited by Mohavvalley; 03-06-2018 at 01:53 PM.
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Old 03-06-2018, 05:42 PM
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Do a cam or aftermarket heads, doing both will put you up there...

For reference I am just finishing a build... 454 motor with a 731 cam and AK heads, .030 over and went to 8.5:1... 525sc blower should be a little over 600 hp,
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Old 03-06-2018, 11:09 PM
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Old 03-06-2018, 11:10 PM
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If I did Dart iron eagle heads which ones should I look at, 345?
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Old 03-07-2018, 01:27 AM
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Making 575hp will be pretty easy.

For your power goal and budget, I'd just keep the 088 heads.
Bump the compression ratio up to about 8.25:1
Go with a roller cam. An off the shelf Crane 168731 will work well. That's what I put in mine.
I would send the blower off to be inspected and rebuilt. I've heard very good things about DMPE Inc. / Home page
As long as the TB IV distributor is working well, I'd keep using it.
I assume you are still running the Merc timing advance module and using the rev limiter on the 6al. I'd keep using them also.
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Old 03-07-2018, 07:52 AM
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If I keep the 88 heads like you've suggested and upgrade the cam instead what do I need to do to the heads and what parts do I need to put in them? Valves, springs, locks & retainers, head bolts, machine work etc? If that's the case I'm still dropping $1k to 1.8k to try to make them right in addition to the cam upgrades.

If I do one or the other, is it better to run the less expensive flat tappet set up and dump the money in to better heads like some iron eagles or brodix bb2s or put the money in to the cam and run the stock heads with spring, retainer, lock, arp bolts upgrades only?

From what I think I've read, doing a cam upgrade without going through the heads is only asking for trouble, as these heads have notoriously weak springs and possibly other issues?

Thanks


I'll check on the advance module, everything else yes

Last edited by Mohavvalley; 03-07-2018 at 08:03 AM.
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Old 03-07-2018, 02:31 PM
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You'll need new head bolts, springs, retainers and locks and seals the same as you'd you'd need with a flat tappet cam.
No way to determine what else the heads might need until they are inspected at machine shop.
The biggest cost factor will be if they need new valves. All new valves will add about $800.

You can't just buy a set of aftermarket heads complete and expect to bolt them on. The machining tolerances are not good enough and they would need to be torn down and checked. Several people have found that out the hard way.

Stock 525SC valve springs are not notoriously weak. They do loose pressure over time and hours, but the stock cam is not very big and does not overly stress them.
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Old 03-09-2018, 02:32 PM
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I made [email protected] with the following setup.

Stock crank and rods
TRW 2399 pistons
Crane 134561 cam with recommended springs
stock 088 heads
525sc blower setup
I have over 100 trouble free hours on it. Im very happy.
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Old 03-12-2018, 11:29 AM
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79formula's recipe is exactly what you need to do what you said you wanted.

ARP rod bolts are great, and I would use them if you plan to run 5600, but you WILL need to have the big ends resized if you change rod bolts.
Stock crank is fine. If it looks great, then use it. Set your bearing clearances for 40wt oil.
Stock oil pump size is fine - if you plan to run WOT for longer distances, upgrade the oil cooler (one with a t stat on it).
Stamped pan is also fine, your choice - but you did mention a budget..
Louvered tray is adequate.
Crane 731 is a h-roller. You already said you didn't want that expense and if you are honoring a budget you don't have to go roller.
The 134561 cam is a great cam, but may result in water reversion around the docks - check with others running this cam...
Also, the springs recommended for that cam are on the high side of what you want to run on a flat tappet with 1.7:1 rockers... You will have to probably run a lighter set of springs during break in (a flat tappet cam HAS to be run-in, preferably on a test stand, with proper break in oil before you can expect it to last at all). Those springs are 354# over the nose, and I'm leery about breaking in ANY flat tappet cam with more than 325 and I PREFER staying under 305 ish.. You could always break it in with the outer springs, and then add the inner springs and run a second cycle on the stand.
OR you could drop to a 134241 cam and use the recommended springs - that combo would go a long way towards reducing reversion AND those springs would give good service at a 5600 rpm limit. It's your choice, but somebody needs to give you things to consider.
DEGREE your cam, don't trust the markings -
If the heads arent rotted out in the water jackets, then just check for cracks and measure the seat width. If the seats sealing width is overly wide, then the seats will need recut. Exhaust seat width is okay to be a little fat for a blower motor. Check stem clearance. If that's all good then add springs matched to the cam. Check locks for wear on the stems, and if the lock area is questionable on the stems, replace those valves. New retainers and locks for sure. Mid-grade is fine. Comp mid-grade works great in sub 6k rpm. Be sure to set up the installed height to spec.

MC
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Old 03-13-2018, 06:42 PM
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Thank you 79 & MC, some good info.
I have been looking at comp cams as their rollers are bigger, .82" ( I think that's better? & Not sure if they use needles or solid bushings) And their 1/2 to 2/3 the cost of crane for all of the parts, so a retrofit roller might be an option if I can find a good set up for $1,200 all in BUT so far I can't find a comp retrofit roller grind comparable to the 731 or 741, any suggestions?

Also, 79 do you mean you where running a 134551 (553/571 and 110*lsa)? I can't find a 134561 and the 134571 rpm seems to high. Also your L2399 Pistons where domes?

Which brings up another question, what is the best way to raise the compression to 8.25:1 to 8.5:1 in this motor? Go from dished Pistons to flat tops, or domes, deck the head, run thinner gaskets??? I'm sure some of these have their down sides, so what's the best way to bump it up on the 525sc running the 177 at 115% over driven?

Do they make a dished piston with a lowered wrist pin to raise the compression?

Thanks for the help

Last edited by Mohavvalley; 03-13-2018 at 06:47 PM.
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