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572 marinized?

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marinized
11K views 27 replies 12 participants last post by  HammerDown 
#1 ·
I've got a ZZ502/502, ahead of a Berk, 12jg, SS "A", droop,Place and open loader, in my 22' Schiada Daycruiser. I want to put in a ZZ572/620 (p/n 12498793) in the same boat. The GM performance catalog states this engine is not for marine use. Any input? Anybody?Reality
 

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#3 ·
and you will hear that lots of people have done this without a hiccup! There are a ton of boats out there than don't pay the $$$ for a "marine" engine. Often just getting at the roots what makes a marine engine is questionable (besides J tubes, sealed started, etc.). ZZ502, isn't that already a non-marine engine????
 
#4 ·
Marine engines experience a wide range of temperature during operation as opposed to an engine in a car that has a thermostat keeping the engine at a defined operating temp at all times. Loose tolerances to allow the metal (block/pistons) to expand and contract in conjunction with sometimes rapidly fluctuating temperatures.
 
#9 ·
I have had 2 different customers put these in marine applications and both dropped valves. Knowing where GM is getting their valves and what they are paying for them I would pull the heads and put good valves in them.
 
#10 ·
572

Chris, It's not the valve that is the problem the problem is the guide clearance.All of the heads are set up with an automotive spec on a closed cooling system.The guide clearance has to be opened up to atleast 1.5 thousandth's.This also applies to the Edlebrock cylinder head because they are the people that cast up the Chevy head. A severe duty valve is a good choice for a normally asperated engine and an inconel for a blown or nos engine.I know this first hand because the same thing has happened to me ,cooler cylinder head tight guide clearance means valve get stuck in the guide makes contact with the piston and then all hell breaks loose.
 
#12 ·
Chris, It's not the valve that is the problem the problem is the guide clearance.All of the heads are set up with an automotive spec on a closed cooling system.The guide clearance has to be opened up to atleast 1.5 thousandth's.This also applies to the Edlebrock cylinder head because they are the people that cast up the Chevy head. A severe duty valve is a good choice for a normally asperated engine and an inconel for a blown or nos engine.I know this first hand because the same thing has happened to me ,cooler cylinder head tight guide clearance means valve get stuck in the guide makes contact with the piston and then all hell breaks loose.
Agreed. I don't feel these are bad engines to start with but they need to come down and have some marine parts and clearances put in them. Once this is done go play.
 
#14 ·
PM'd Greg

I'll wait to see what Greg can do for me.
Thanks for the input.
Greg,
I'm currently turning 5200 rpm, 65 mph on the SS "A", 12 jg. Pump recently rebuilt by Dave @ GT Boats in Cordelia. Every thing is tight, I just want to go faster. 5 mile an hour itch...
 
#16 ·
Thanks for the feedback... the information regarding the head/valves was of particular interest.

You have already experienced what happens when you put a car engine in a boat (ZZ502). A crate 572 is what, ~13k? A marine 572, ~30-40k? Clean up the gm 572, blow it up once, twice, three times? You may still be ahead of the game... I met in Steamboat running a 572 (low comp) in his Warlock... very clean and fast. He said he has >100 hours of hard run time without a hitch. Go w/closed cooling and you may be better yet (and keep all the crap out of the block!).

Good luck.
 
#17 · (Edited)
Any crate engine, IMO, needs to be torn down and at least inspected. The only way they can make any $ on these at the prices they sell them, is to do mass production, and buy parts in bulk. Bulk parts vary in quality from very good to just passing, and sometimes unusable. Mass production is just that, and leaves many opportunities for mistakes. I know there are plenty of successful installations of these engines, but there are enough horror stories that IMO, it's not worth taking the chance. Clearances need checking, machine finishes, cranks, rods, balance, heads, guides, etc. all need to be at least verified for correct. If anyone knows about these engines and the parts that go into them it's Chris, and he's right. Even if the guide clearances are set correctly, the valves are el cheapo. Likewise with the springs. Bore to piston clearances are most likely too tight for marine use (hot piston cold block syndrome) and I've heard the bearing clearances are tight, as well. The biggest complaint I've heard with these engines are oil pressure complaints. An oil pan upgrade should be in order as well. Re-assembled corectly, these should be good engines and give plenty of reliable service.
JMO
One more thing to add: If you're targeting a specific power requirement, it might be beneficial to flow the heads and get a specific cam ground. especially in a jet boat. NO doubt you'll be leaving power on the table if you don't. You're also compromising a lot of the potential of any engine you run with that ex system (that I see in your pics) Might consider an ex upgrade to compliment your engine upgrade.
 
#22 ·
I've had good luck with the crate engines. I just put another new one in a boat today. Yes, it is nice to tear them down and build a professional engine and probably the better way to go if you have the money. The trick of making these engines work and last is mostly in the break in. We always break them in for the customer, (I spent almost two hours on the water with it today), and when the customer picks it up tomorrow, the rev limiter will be set on about 4300 rpm for the first 50 hours. Then you can run 'em.

I have 2, 502/502 crate engines that we put Isky roller cams in and were tweaked on the dyno. We put them in a boat that was ran less than 10 hours. The customer decided he wanted a little more punch so we took them out and put the 720hp/572's in their place. Make me some offers Guys!
 
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