GM 572 crate eng.
 

Can I- And how hard is it to change a GM 572 crate eng for marine app.?
I have one sitting here in the crate..........
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ddg814,
I'll send this answer, and likely someone with more info will pipe in.
It is my understanding that the following should be performed.
1) Heads - You will need to change valves and likely valve springs.
Marine applications employ a higher nickel content exhaust valve to survive the heat, and moisture of a marine application.
Severe duty intake ss valves are required.
2) Cam - If you are running dry exhaust, you may get away with without changing the cam, for a marine application it is best to obtain a cam suited for Marine loads, and generally an LSA ( lobe separation angel that does not exceed 112, 110 is better for fighting reversion. ( Sucking back water from the exhaust cooling if using a wet exhaust)
3) Frost plugs - Marine engines use brass rather than steel, which generally are supplied on crate engines.
So that is about it, Cam, Valves, Springs, and frost plugs.
I am sure that now this answer is posted, someone will pipe in to elucidate this more completely. If you perform a search, in this section, you find a great deal of information already posted.

This is incorrect. You want a bigger lobe seperation on marine engines. The wider the angle, the lesser the chance of reversion. The angle will depend on what exhaust you will be running.

The engine will work fine I am going on 309 hours :drink:

You need to make sure that use a marine carb and ignition. You may need to change the cam to one that is more suited for marine use.

change the freeze plugs too...has steel init now...put in bras or bronze or stainless.

I am running marine msd and the engine came with brass freeze plugs and the 632/632 254/264 @.050 cam works just fine with 650 fp of torque. Like I said going I have 309 trouble free hours on the engine. And if it blows all apart tommorow I will buy another and stick it back in their.

I feel for the money you can not beat this engine 12,500 and no dry exhaust needed

ZZ572 are built around an all-new generation VI one piece main seal tall deck 572 cid with approximately 9.6:1 compression, 620 hp at 5,500 rpm, and 650 ft./lbs. of torque at 4,500 rpm with a recommended max rpm of 6,000. These all-new race blocks have a 4.560 in. bore and are filled with forged 4340 steel cranks with 4.375 in. stroke, shot peened forged 4340 H-beam rods, and forged aluminum pistons with full floating wrist pins. Redesigned rectangular port aluminum cylinder heads with 118cc combustion chambers, Stainless steel valves at, 2.25 in. intake side and 1.88 in. exhaust side. Hydraulic roller camshafts are used with valve lift being .632 in. intake, and .632 in. exhaust side, duration at .050 in. for intake is 254 degrees and 264 degrees exhaust side. Hardened chromemoly retainers are used with dual valve springs 1.50 in. coil diameter, 1.800 in. installed height with 197 lbs seat pressure. Aluminum roller rockers with 1.7:1 ratios, high performance one-piece push rods are installed. New GM Performance Parts tall deck single plane intake manifold and 850 cfm Demon carburetors deliver the air. A GM distributor handles ignition, spark plugs and wire are included. New screened and louvered windage trays, High-rpm torsional dampers are used. Pump gas friendly, massive torque and horsepower, all from GM Performance Parts.

Ditto...
Simple Math.

There's your answer.

This old thread may give you a little more insight.
http://www.offshoreonly.com/forums/g...ing-today.html

[QUOTE=CROWD CONTROL;2776669]I am running marine msd and the engine came with brass freeze plugs and the 632/632 254/264 @.050 cam works just fine with 650 fp of torque. Like I said going I have 309 trouble free hours on the engine. And if it blows all apart tommorow I will buy another and stick it back in their.

What motor did you replace? Would it drop into where a 496 was?

Thanks

I read the thread and that is good info. But what the guy did by thrashing the engines right from the start I blame on the lock down. If you do not build a engine loose break in time is required. My engine had around 2500 auto miles on it before I put it in my boat. The reason the car I stuck it in got totaled. Maybe this is what saved me or not, I am not a big fan of running the crap out of a new engine. And the way I feel most about this is if a man does not put his own engine in he does not no any better. He thinks in his mind is, my mechanic said take it easy for a bit. But one quick blast up won't hurt anything then I will take it easy the rest of the day.


I really like the engine and have had good service but I would really like to here what a well known engine builder has to say about how much clearance is needed in the valve guides. You cant build a engine but so loose and get it to last,

[QUOTE=twanger;2776889]My boat had a 454 originally and yes the engine mounts are the same. The 572 is a tall deck, it is a bit wider at the top from head to head. I had no problems

Hello are you running the Blue Gm roller rockers that came with the engine? I was just wondering how they are doing I have a set on my brand new 502 but I have no run time on them do they hold up?

The Blue Rockers Work Just Fine

Yes I am the part # is 12361323 it is a GM rocker with the bowtie on them. 309 hours and going strong

I need some concrete evidence on this GM 572 info. A few are saying that the engine needs more clearance in the guides and maybe other places. Well I have searched all over and I can not find the builds specs on the clearances. If somebody can find these and post a link I would like to read them and compare them to factory merc. engines.

Like I said I am still running strong after 309 hours on mine. But is this due to the fact mine was in a auto for the first 2500 miles allowing the engine to loosen up. Or did I get lucky.

All I have to go on is hear say with no proof somebody show me the clearance specs

how fast is your boat going now compare to the 454??? wt headers are you useing

Personally, I think someone is trying to jerk your chain on the more clearances thing...meaning I think it is a crock of stuff. I know several people out here running the crate motor that you are probably talkingabout and they got it from Jegs. They are running dry exhaust, but they are NOT having any issues at all and the motors are working perfectly...just as yours is.

I am running imco exhaust and my water dumps in at the end of the riser. I never had any reversion problems with the cam. best run is 85.4 in a 28 footer I feel maybe if I played with a lot of props I might get better speeds I am running a stock 28p bravo on a 1.5 xr drive. Its between night and day over the 454.

Well we could find out if somebody will post the specs and we can compare apples to apples.

I'd like to hear some more people who runs those engines in their stock version, not marinezed... Any one else having success ?

Old topic but still interesting.
We are always looking for reasonably priced HP.

I thought this was an interesting read - talks about Marine crate engines.
http://www.truckinweb.com/newproduct...crate_engines/

I also found a link to this site on another website - a marinized 572.
http://www.flagshipengine.com/

Anyone else still having great success with a stock 572-620?

5050 used to run them

Flagship has very high prices.

Crate sounds good in a smaller fresh water boat like a Donzi 22 where it does not have to work too hard..

Thats what i think also...

i tore into mine mainly cause I bought them used. but really main changes valve spring need changed to much pressure for hyd roller spinning 5400 for very long at all, can’t remember open pressure but mine stock had #195 on the seat, I’d run a better ignition system, and I’d run quickfuel 1050 and I would put a nice marine oil pan and run water and oil thermostats. I am always looking for them used sometimes pick them up for around $7500 used tear it down hone it rings n bearings.

Ask FULL FORCE here on the boards about clearances.He made the mistake of not checking clearances before putting 2 really expensive engines in his boat....MANY folks have had clearance problems when they dont set an engine up for marine use. Clearances are important in a marine engine. Not saying you wont have success with just throwing any old engine in a boat. But when running an engine hard for longer periods of time and the engine starts building heat, things like pistons and valves expand. If there isnt enough clearance for these things to expand, things can begin to seize. Without checking for these clearances BEFORE you put an engine in a boat, you are running the risk of a failure in an engine that lots of boaters like to refer to as CATASTROPHIC FAILURE !!!!!! Happens all the time... Again, not sayin you wont get lucky, but it is way safer to do it right the first time.

It makes sense, hotter pistons/rings and colder cylinder walls than an automotive engine but Merc does not adjust clearances in their stock motors.

Old thread, but here is an even older one on GM Crate 572s in a go-fast boat:
https://www.offshoreonly.com/forums/...gladiator.html

I personally thought it was one of the coolest things ever.
I also had a jet boat with a ZZ502 in it.

https://www.offshoreonly.com/forums/...ator-small.jpg

Basically as Kreed mentioned however I read an article how they are basically assembly lined assembled engine without the care and precautions of marine engine. Basically like an early 454/330 truck engine with much more power that could potentially lead to more concerns. On the flip side sounds like some have had great luck. No need to list what's already mentioned earlier. I'd question running a near full throttle run for 30 minutes or so. But at the same time I ran across Lake Michigan to Wisconsin full throttle twin engine 78 boat 454/330's 4,700 rpm. Was about 68 miles. Not sure if merc did anything in that era to boat engines or not. No oil coolers and oil filter on the block.

If the engine has the clearance, your good!.... If it doesnt,,,. your fu*ked....but with an expensive build, why not check.