572 crate engine problems

[rmbuilder]

Essentially there are two factors involved in the equation. The given, which is the camshaft, has more than enough overlap that it will revert water if in fact the water is introduced within a certain proximity of the exhaust port. The variable is the exhaust manifold used. The point at which the water is introduced will determine whether or not the engine will fail. Inconel exhaust valves, while necessary to sustain the prolonged temp increase associated with marine applications, do nothing to deter the effects of reversion.

[Party Cat]

if you are gonna run a cam like the '741 crane or bigger...you will need a good exhaust manifold....I put a 509 in my boat last year....initially with the Dana Marine cast manifold with their cast risers....per Dana...I should have had no problems with reversion....well $3k later on a brand new motor, and a set of their Stainless risers (water is introduced further down the pipe) the boat runs great....I sucked water enough water into the motor on initial start up and tuning in a test tank with not a good enough exhaust to screw things up....the reversion may not have caused the problem....but is definatly an issue with a cam like a '741 or bigger....
PC

[Infomaniac]

I am able to sell the Deluxe ZZ-572 for the same price as Scoggins Dickey 12,900.00 or long block only for 12,000.00
Disassemble and increase all of the necessary clearances, add inconel exhaust valves, severe duty intake valves, Isky's latest greatest hydraulic roller lifters. Isky premium Cryo treated valve springs set up at 150# on the seat. Crane 741 cam (or cam of choice). Marine head gaskets. Oil pump prep. Moly ring set, $1,900.00 plus shipping once (me to you) and exchange of removed parts.

[cstraub]

I'll chime in on Bobs comment about inconel. An exhaust valve that is running at 1300 degrees and has 160 degree water come in on it. . . doesn't matter what material it is. . .it will break.
I have worked for 3 valvetrain companies over the years while in this industry. I have learned a great deal about materials and marketing BS. A 21-2N or a 21-4N stainless valve can be solution treated with chemicals to increase yield and tensile to match better materials. Nothing will survive a dose of cold water.
Crate engines are great, just do as Info says and have them "marineized" by a Marine guy.
Chris

[Dave C]

BINGO.... hence the use of CMI's that dump the water at the end after the down turn . I forgot about that, I gotta remember that!
Thanks.
Originally posted by flat broke
The difference would be that as you came off the gas with the injected headers the water flow was cut off ,whereas with the Kodiaks the water would keep on pumping and with overlap at idle, and an increase of H2O volume in the system from being on the gas, you'd have a lot of water dumping into the exhaust while the motor is coming back into a state where overlap is causing reversion. This was the main reason I initialy asked what exhaust was in use in the failed motors.
Could probably get away with the cam if he switched to a system that introduced the water into the exhaust stream much further down the pipe. He can get some custom lightnings with long collectors done up, or custom lightnings with long collectors and reduced water option, or go to a different setup like some CMIs or Stainless Marines with the long riser/pip option that drops the water back into the exhuast a long way from the motor.
When we're putting these things together, we have to remember to look at the whole enchilada and not just a bad ass engine.
Chris

[Dave C]

Thats pretty good right there.!
Re increase necessary clearances.... care to be more specific? I'm thinking valve lash, ring clearance.
Originally posted by Infomaniac
I am able to sell the Deluxe ZZ-572 for the same price as Scoggins Dickey 12,900.00 or long block only for 12,000.00
Disassemble and increase all of the necessary clearances, add inconel exhaust valves, severe duty intake valves, Isky's latest greatest hydraulic roller lifters. Isky premium Cryo treated valve springs set up at 150# on the seat. Crane 741 cam (or cam of choice). Marine head gaskets. Oil pump prep. Moly ring set, $1,900.00 plus shipping once (me to you) and exchange of removed parts.

[Infomaniac]

More complex than that.
An extra .0015 - .002 piston to cyl wall clearance with torque plate
ring end gap per ring mfg marine specs.
.003 main and .0025 rod bearing clearance
lifter bore and valve guides honed on condition.
rotating assembly checked for proper balance.
block off the Gen VI filter bypass located in the block.
brass freeze plugs

[Dave C]

I was always wondering about this. Do you have to order the pistons with additional clearance? or are they machined.
inquiring laymen's minds are dying to know!
Thanks for the "info" as usual.
Originally posted by Infomaniac
An extra .0015 - .002 piston to cyl wall clearance with torque plate
ring end gap per ring mfg marine specs.
.

[Infomaniac]

That extra clearance is standard for a marine hot piston - cold block application.
You just have the cylinder honed to .0XX" larger than the piston diameter. Depending on what brand and material the piston is made from.

[Dave C]

that makes perfect sense.... I think I need some more coffee