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RUCAV
10-07-2004, 05:43 PM
This is for the more mechanically inclined than me. I was reading the article last month in Hot Boat about the Chevy 572 CI engine. It seems to be a sweet deal for a marine engine. Either 620 or 720 HP and its cheaper (14 to 16K each depending on HP) than a 525 HP engine. Whats the scoop. Is this the new deal or is there a reason its not the happening engine.
I appreciate your help.
:hammerhea

Havasu Hangin'
10-07-2004, 05:48 PM
I think this has been discussed in the gearheads section once or twice.
I think the concensus was that is you run a closed cooling system, the clearances will be OK...but a marine cam (with a 122 or 114 LSA) would be needed to prevent reversion (depending on the exhaust).

GlastronGuy
10-07-2004, 05:53 PM
Did your engine run up on a sandbar?

RUCAV
10-07-2004, 06:07 PM
Did your engine run up on a sandbar?
HUH?? I am researching engines for a future boat.

RUCAV
10-07-2004, 06:09 PM
I think this has been discussed in the gearheads section once or twice.
I think the concensus was that is you run a closed cooling system, the clearances will be OK...but a marine cam (with a 122 or 114 LSA) would be needed to prevent reversion (depending on the exhaust).
Is this something that will make this engine unreasonable pricewise?

Misogynist
10-07-2004, 06:26 PM
This is for the more mechanically inclined than me. I was reading the article last month in Hot Boat about the Chevy 572 CI engine. It seems to be a sweet deal for a marine engine. Either 620 or 720 HP and its cheaper (14 to 16K each depending on HP) than a 525 HP engine. Whats the scoop. Is this the new deal or is there a reason its not the happening engine.
I appreciate your help.
:hammerhea
572 cubic inch Chev based engines are "square" ... Nice all around performance ... Good rpm and Good torque... 4.5 inch bore 4.5 inch stroke... hence the expression "square"... Take a tall block and bore to 4.5... get an aftermarket crank 4.5.... you are in business.... :cool:

THOR
10-07-2004, 07:14 PM
Rucav,
You getting rid of the 247? What are you planning? Spill it dude.
The 247 would be a rocket with that motor. Mine does a solid 78 with stock power (496 HO), I couldnt imagine it with 300 more HP.

Havasu Hangin'
10-07-2004, 07:23 PM
Is this something that will make this engine unreasonable pricewise?
No...a cam switch is not really expensive, but it will lower the rated HP (less scavanging) long with wet exhaust manifolds.

RUCAV
10-07-2004, 07:26 PM
Rucav,
You getting rid of the 247? What are you planning? Spill it dude.
The 247 would be a rocket with that motor. Mine does a solid 78 with stock power (496 HO), I couldnt imagine it with 300 more HP.
Not getting rid of the Ultra. I spent 2 years looking at different boats when I bought this one. I know what boat I will buy next but I am not sold on the 500 and 525 engines. I dont love the mercury engine monopoly. But could you imagine that boat with a 620 HP motor. You couldnt keep it in the water.

PHOTOGLOU
10-07-2004, 08:12 PM
I was wrong today when I quoted 18k its 13 k for the 720hp my cost the 18k was for the ram jet with fuel injection

RUCAV
10-07-2004, 08:38 PM
I was wrong today when I quoted 18k its 13 k for the 720hp my cost the 18k was for the ram jet with fuel injection
I figured that after I talked with the local Chevy guy.

PHOTOGLOU
10-07-2004, 09:01 PM
I figured that after I talked with the local Chevy guy.
sorry I owe you a beer

RUCAV
10-07-2004, 09:03 PM
sorry I owe you a beer
No worries bro. Ill drink one anyway.

RUCAV
10-07-2004, 09:04 PM
J
Is that your boat in your picture. I thought yours was all white.
R

PHOTOGLOU
10-07-2004, 09:10 PM
J
Is that your boat in your picture. I thought yours was all white.
R
still have the white one trying to sell it got this one 3 months ago

jbtrailerjim
10-08-2004, 05:30 AM
I know my next boat will not have Merc power in it. The price they want for there HP525 is outrageous. I'll have a nice 500-600hp motor built before I buy the new one and save a lot of dough. I wish I would have done it with my present boat.

Krumbsnatcher
10-08-2004, 06:11 AM
I was wrong today when I quoted 18k its 13 k for the 720hp my cost the 18k was for the ram jet with fuel injection
Jay,
I am not positive however, I belive Teague mentioned in his tech section that automobile crate motors are NOT setup correctly for marine applications as far as the cam design (Reversion). Have you talked to him about them?
Havasu this weekend? Well be there. (JJ)
Article:
If the cam in your engine is the one provided in the GM automotive crate engine, water reversion might be your problem, since this cam profile is not suitable for marine engines with water in the exhaust.
BLOWER CARBS
Question: I read your recent column with much interest on carburetors with intermediate fuel circuits.
Here's my problem: I have recently replaced the engines in my 40' Fountain with marine-based Generation VI 502 Chevrolets with 256 Weiand blowers, and dual 750-cfm Holley carburetors. The engine is so rich at idle that it is covering my transom with soot. Above 3,000 rpm, it clears out and seems to run fine. The float levels are OK. The engine idles at about 9 inches of vacuum. The timing is set at 8 degrees initial with a total advance of 28 degrees. The camshaft is stock. The carburetors are 4779 double pumpers with two circuits. They are not marine carburetors and do not have J-tubes. They have been boost-referenced in the primaries only. I am really stumped on this one.
Ken Kleitz
Wethersfield, Conn.
Answer: If your engines are running rich at idle, it can only be two things related to the carburetors: Either the idle circuits are out of proper adjustment, or the carburetor is leaking internally. My experience with your setup has been that the idle mixture screws need to be set at about three-quarter turn on the primaries and about five-eighths turn on the secondaries for starters. The 4779 Holley only has power valves in the primary metering block. It is not necessary to boost-reference the power valve on your type of engine. The goal is to make sure the power valve opens soon enough to prevent a part-throttle lean condition.
This can be accomplished on your setup by using a 10.5 power valve instead of the stock 6.5. Remember, the manifold vacuum is not what the carburetor sees on top of the blower. Many times, when carburetors are modified for the boost-referencing, other internal leaks are created. You should be able to make the engine stall by turning the mixture screws in too far or all the way. If the engine idles with the mixture screws turned clockwise until they are closed, there is an internal fuel leak and the carburetor is bad.
You may be mistaken about the carburetors being the problem. If you have a type of exhaust system that reverts water, it will seem like the engine is idling rough and rich as water enters the cylinders and starts causing plugs to foul. If the cam in your engine is the one provided in the GM automotive crate engine, water reversion might be your problem, since this cam profile is not suitable for marine engines with water in the exhaust

PHOTOGLOU
10-08-2004, 08:13 AM
I really don't know much about this but I will call the boys at Pfaff and try to get an answer today and check into the marine applications from GM

RUCAV
10-08-2004, 08:33 AM
I really don't know much about this but I will call the boys at Pfaff and try to get an answer today and check into the marine applications from GM
You da man J