Can you guys use ZZ502's?
 

Just curious, I see a lot of talk about 502's here. I have a ZZ502 I am putting in my car, with stock aluminum heads, 9.5CR, and a fairly mild 224/234 cam. The info packet says to not use them for marine applications. Is that because of the aluminum heads? My MasterCraft has an aluminum headed LT-1 with sea water cooling, and they specifically say you can't take them in salt water cuz at elevated temperatures, the salt water will eat the heads. Does anyone actually use ZZ502's and figure that the heads won't disolve for a million years, so it doesn't matter anyway?

Yes, there are a few threads on how some ZZ502's have been turned into Marine 502's. Cam change, remove the 11lb oil relief valve on the bottom of the filter pad and plug or replace with a 30lb. A lot of people use aluminum heads, just flush good. I have a friend that used a base ZZ502 and made I think a 557 out of it. Same heads, diff cam.

If y'all don't mind me propagating this thread (cuz I think it's interesting).... What doesn't work on the original cam? It's pretty tame by muscle car standards. It seems like it wold pull pretty strongly off the bottom end while still having some revs for speed. Everyone in the car forum I frequent thinks I'm a sissy for not putting something more wild in the ZZ.

The LT-1 (1994) in my MasterCraft ski boat is box stock mechanically, no magic grind cams, milled heads, nothing. It does use a Cadillac Northstar ignition, which is kinda fun.

I run the ZZ502 heads and cam in my 454 and have had no issues with reversion or corrosion with the heads in salt. I flush for 10 mins everytime even if I run in fresh water.

Change the oil pan and replace the carb with an HP4150-950 w/mechanical secondaries. You can do more, but with these and the above basic changes, a solid 500 c.i. marine platform.

Also might want to put brass freeze plugs in the block unless it has them, make sure your running full dry pipes, so you do not get reversion.. As long as you flush the motor out good every time or in between you should be fine.. it doesn't know what its in. Only thing with a cam is one is made to have power to work with the weight of a boat in certain rpms, one with a car.. That cam prob wouldn't do all that bad depending on what boat it it went it.

John jr

One of the reasons that this crate motor (with a few changes) is a good marine package, is the fact that it does come with brass freeze plugs in the block.

One of the items that should be on your "to do" list is removing the stamped rocker arms and replacing them with some quality roller rocker arms.

Question: Instead of changing out the valve covers for the taller and angled marine style valve covers, could you use a valve cover height spacer? Or would the marine exhaust clearance be an issue? Depending upon which exhaust is used?

I do have (2) pairs of new Teague polished (and Zoop sealed ) valve covers with the tall polished breathers for sale. I went another direction with my valve covers needs.

there is a guy on this site put a gm 572 in his boat it had 300hours and is still running good

Eliminator build a project boat for a customer using a pair of GMPP ZZ572 (92 octane version) with sucess. I will put together a list of items w/part numbers on the changes those who have used in the ZZ502 for a marine application. Call it a checklist of things to do----in the order of importance. Besides the oil bypass valve, I feel the oil pan is the second most important item.

This is a Teague cat pan, but any good marine performance oil pan will do.

Replace the oil pressure relief valve as noted in post #2. Get a bigger oil pan (8-10 qts suggested), and bigger oil cooler. Use a complete marine approved ignition including alternator, marine starter (I used all the parts from my 7.4/330), and a 4150/850 marine carb, drop in boat, and haul azz.

Note ... The ZZ cam is similar to the old HP500 cam and I was told it can cause some reversion during long idle times. I used to "crack the throttle" a couple of times to clear it out before turning off the engine. The ZZ502/502 ran fine for me for 4 seasons without so much as a hick-up. Reasonable $$ for reliable 500 hp.

I ran the stock ZZ carb for the 1st season and the engine performed flawlessly. Season 2 I had it marinized by Nickerson ($$$) to be CG compliant.

the reason they say no marine apps is their warranty, they offer a warranty for most crate engines, the marine engines sold to marineizers are sold with NO warranty at all...Rob

A great powerplant :) I had a new in box GM ZZ572/620hp -06. We made some head job with inconell valves, new springs etc. made some modification to the oilsystem, new 14q pan + oilpump from Hardin Marine, change the 850cfm Demon to a Holley 1000cfm, 94Ah alernator, marin starter, CMI Sport tubes etc. Dynod to 631.4hp. I Use the 28" thermostat oilcooler from Hardin Marine
Had this engine in my 28 Pantera (80MPH) one season then pulled the engine and sold the boat.


Mange