525 EFI clone
 

ok this thread is just one for future curiosity. I always see Merc 500 and 525 set ups for sale in the swap and wondered what it would take to replicate the EFI's long block. I am assuming the intakes are relatively similar with the aluminum heads being the diff between the two. What would be the punch list for the long block to be as close to Merc specs or what needs improvement from OEM

heads
valves
springs
block
crank
cam
rods
pistons
???

Dave, the money isn't in the long block on the 525's, the most expensive part of duplicating that engine would be all of the accessories: distributorless EFI system, smartcraft, closed cooling, pulleys, brackets, etc.....

I understand that, I would think it could be done as a stand alone system and much of those parts arent hard to find if ya dig enough. Dont need smartcraft or closed cooling. I would think earlier systems could be done as a stand alone, maybe even use a newer aftermarket ecm. I see complete manifold/harness/fuel pump/etc in the fifteen hundred range every so often.

I just did two of them, bought 2 take offs. Got the compleat systems with computers for 2300 @.
You can build anything you want, then use the 525 efi sensors, ignition, intake and throttle body.
Just need to send a build sheet along with the computers to Dustin, and he will program them.
One word of caution from him is to keep the c/r 9.3 or under. I used all my brackets and acc. off my HP500's
Just needed to make spacers so all pulleys would line up and clear the crank trigger.

Raw blocks are CNC machined by Mercury.

I'm curious what it would take to turn one of those Volvo penta intake assy from their5e asm hp efi set up sure looks similar and go doesn't use the cheap stuff Volvo penta doesn't use the cheap stuff phone making this hard on me .

Much easier and less expensive to build a hopped up 500EFI clone.

502 GM Block
GM Rect port heads with some port work and Manley valves
Use a 500EFI intake and MEFI 4
GM forged crank
Manley rods
JE Pistons
Cam similar to a 525EFI cam(Crane 741 on a 114 lob sep) and matching springs
I would work with Bob M and duplicate something he has already spec'd and something that somebody already has an ECM tune for.

I would not use 525EFI heads as it limits the exhaust you can use and increases the price.
You could go to Dart Pro 1 heads or AFR's to boost the HP some more.
The 500efi intake is only good to about 600hp before it becomes a limiting factor.

The most we could get out of the 525 intake was 670hp, it just wouldn't flow past 5800 rpm. We ended up having Wilson build us one.

I agree with Griff, I to would stay away from the merc 525EFI heads/exhaust...more of a pain than anything else when you need to replace either...

I agree, in our build the only things we used was the computer, all the sensors, wiring harness, ignition, and their throttle body.
A 565 cu in, 750hp efi with smart craft and the protection of guardian mode![ATTACH=CONFIG]520992[/ATTACH]

Thats pretty much what i would be after. Not really concerned with wringing every last hp out of it as i know the intake sets the limit there. I really just like the looks and the reliability of the system and with the intakes that pop up regularly think i could build a good pair for the Scarab at some point in the future. OffshoreDrillin Rob had (i think) MGD Performance in MD do his 500 EFI w/AFR's and some other stuff. I think they were in the low to mid six hundred HP range. I guess i should have worded this thread differently as a "500EFI clone with added HP" as i kinda knew the 525 was a different animal. :cool:

Griff you are a warehouse of knowledge :D which AFR's btw?

Tell ya something else i like about the EFI's . . . .you can throw a towel across the tops of the intakes and lay on 'em to work on the boat :D

315-335cc depending on the cam and overall package and the desired goals.
Might want to use the 315's for more torque down low and at cruise rpms or use the 335's for more hp up top

I think that the intake manifold and throttle body are a key part of the 525. I'm also liking the intake system on the new 565 a lot. Full length headers are a must for scavenging. Dual mechanical & electric fuel pumps and fuel cooler are another interesting part of the package. Must be able to run on 87 octane. I have to disagree on using ported GM heads. When you can buy a very low hour 525 take-out for $20,000 I think that it would be hard to duplicate this engine for that amount. As pointed out earlier there are all of the bolt on pieces like pulleys, high output alternator, high output steering pump, raw water system, fuel cooler, p/s cooler, oil cooler, headers alone are 4-5G.

Do not forget about the Brodix heads. There flow numbers do not show as well but in actual application they work Very well. Best horse power is in the heads and easiest on the engine.

Hey KWright any info on the wilson manifold you used(part number /cost). looking to go the same route on a 525 efi i am rebuilding.

Sorry been gone. My phone wouldn't let me post. There are all kinds of options best thing to do is to give Tim Hogan a call. Great people to work with.

Hi KWright ,
i want send you a PM but your box is full.
Please clear your box....
Have left you a visitor massage.
Thanks

Cleared. Sent you a email let me know if you need anything else.