excalibur27

Can anyone let me know what the typical WOT rpm range for a 572 Merlin engine is ?

Thanks

Back4More

Block: World Merlin III cast iron, Merlin X aluminum
Crankshaft: Eagle 4340 forged crankshaft
Balancer: ProStreet internal
Connecting Rods: Eagle H-beam 4340 L-19 bolts
Pistons: Mahle coated/Manley
Piston Rings: Total Seal
Compression: 10 :1
Bore/Stroke: 540 c.i.d. = 4.500" x 4.250", 572 c.i.d. = 4.500" x 4.500"
Bearings: Clevite H-bearings
Camshaft: Hardcore solid lifter
Timing Chain: Hardcore double roller
Cylinder Heads: World Merlin (cast iron or aluminum)
Valves: Manley Stainless (2.300" intake, 1.880" exhaust)
Valve Springs: Hardcore
Retainers: Manley
Valve Locks: Manley
Valve Seals: Hardcore
Rocker Arm Studs: Hardcore
Pushrods: Hardcore 1pc., .080" wall
Pushrod Guide Plates: Hardcore
Rocker Arms: Scorpion aluminum rollers
Oil Pan: Moroso
Oil Pump: Melling
Assembly Components: Stainless hardware
Intake Manifold: Merlin-X single plane
Carburetor: Hardcore 1050 cfm (4500 type)
Distributor: MSD
Fuel: Pump gas
http://www.worldcastings.com/prods_pages/108052.htm
Max Rpm on the (#108055)572/675hp model is 6200rpm.

Griff

It depends on how it was built to run. It could be anywhere from 5200-6000 depending on several things.

Chris Sunkin

I wouldn't want to be spinning Eagle cranks & rods at 6200 in a steady-state application. A few second burst running a car out on a 1/4 mile might be OK. I'd want to stay around 5600 with beer budget components. 62-6300 with premium components in a billet-cap block is reasonable.

The spec posted above is probably the Merlin crate motor, made for an automotive application.

Hang Time 27

I'm no expert, but it depends on the heads, cam and springs, which would help tell you where the power is - no use going any higher than needed - and that may only really be determined by actually running the motor in the boat at speed, trying different props etc..

offshoredrillin

Hey tommy,
the guy that built those engines for dave built everything safe. you should be fine for 52-5400. they were propped big for longevity with the trs setup. now with the Konrad's you have the durability. If i remember right Jeff told me that those engines are sweet, all the good stuff.