reliability GM ZZ502-502 HP GM CRATE ENGINE
 

Anybody runs ZZ502-502 HP GM crate engine in a twin engine set up boat?

If so, had any problem? Did you change something in it or it is stock?

Re: reliability GM ZZ502-502 HP GM CRATE ENGINE
 

Ask Velocity4me he ran one in his previous Velocity...

I think you can PM him on the "Lake Champlain" Thread.

Re: reliability GM ZZ502-502 HP GM CRATE ENGINE
 

I know a Jeff that started this board had them in his Gladiator. If memory serves he had to rebuild them both for Marine spec but other then that I seem to recall him liking them.

Re: reliability GM ZZ502-502 HP GM CRATE ENGINE
 

PM "kidnova" he runs one, there are some small changes that have to be made relating to the oil bypass valve. I believe he is happy with the results

Re: reliability GM ZZ502-502 HP GM CRATE ENGINE
 

He had ZZ572's speakerboy so get your facts straight ! :D

Re: reliability GM ZZ502-502 HP GM CRATE ENGINE
 

I pm'd velocity4me and kidnova. I'll see their comments and I'll let you know their comment, unless they answer in that tread. Thanks GLh, Audiofin and Wobble!

Re: reliability GM ZZ502-502 HP GM CRATE ENGINE
 

I do my best not to. It is more fun to cloud issues with missinformation!!! :drink:

Re: reliability GM ZZ502-502 HP GM CRATE ENGINE
 

You Edward Kennedy voter dudes always get it wrong...

It's don't cloud the issue with facts... :drink:

Re: reliability GM ZZ502-502 HP GM CRATE ENGINE
 

Hey Jeff32 -

Thought I'd post this here instead of PM'ing you. That way, if anyone has anything else to throw into the mix the option/opportunity is available.

My ZZ502/502 came complete carb to pan, with automotive (non marine) ignition and starter, etc. We yanked a 1995 7.4/330 carb motor and replaced it with the ZZ. The alternator, power steering pump, sea pump/fuel pump, and related brackets were removed from the 7.4 and bolted on to the ZZ. A new marine water pump was bolted on to the ZZ (old one off the 7.4 would have worked fine but for the $$ I decided to get a new one). The starter, distributor, coil, etc. from the 7.4 were moved over to the ZZ. I also used the stock Merc exhaust for the 1st season. Everything bolted up without a problem. My engine guy replaced the head gaskets with those better suited for marine use. Sorry, I don't remember what head gaskets were used, but you should not have a problem finding out which ones to throw on. Brass freeze plugs were popped in. The Holly 850 that came with the ZZ was shipped to Nickerson's to get marinized and tweaked for marine use. Because of the 4800 RPM (+,-) rev limiter, the T-bolt V ignition module was replaced with a T-bolt IV module.

The only issue I had was oil temps. I found that (my) ZZ502 likes a BIG oil cooler. I ended up using a Hardin Marine 3 x 22 engine oil / power steering cooler with a built in thermostat. After some running time and 3 oil coolers later, I finally figured out that the center bypass valve in the engine oil pad needs to be removed. And the bypass valve on the side of the pad needs to be changed from a +,- 30 lb. to a +,- 11 lb. (The "lb" reference may not be correct but if you need more on this let me know and I'll see if I can dig out the info).

Suggestions....depending on how hard you run an engine, two things that you might want to consider changing that I did not....the valves are stainless steel. Changing to Inconell exhaust valves might be a good idea. I think the ZZ comes with a 6 qt. oil pan. I think an 8 or 10 qt. pan would be a better choice. Also, if I were to do it again I would get rid of the stock Merc oil lines and go with -10 AN's or larger.

There is an EXCELLENT thread here on OSO referring to Merc oil lines/fittings in comparison with AN lines/fittings. AN will provide much better flow which should result in much more/better control over oil temps. I don't recall who started the thread. But IMOH doing a search for the thread would be well worth the effort. If/when I pull the ZZ out of my boat for what ever reason, I will be looking up that thread and will be changing over to AN.

I'm starting my 4th season with the ZZ502/502. Other than oil temp issues covered in the above paragraph/s, to date the engine has run flawlessly and has always been dependable. My ZZ is in a 23 Nova. I've been in a few poker runs with it and we are generally the smallest boat in the pack. To keep up with the big dogs, I've gone just about WOT. Sometimes for 25 miles at a time. The ZZ has never complained, and has suprised a few un-suspecting name brand victims in dishing out a healthy portion of whoop-azz :evilb:

Sorry to be so long winded, but hope this helps.

Bill

Re: reliability GM ZZ502-502 HP GM CRATE ENGINE
 

Skumbag Ed used the wrong size prop on his car, and forgot the life preservres :mad:

Re: reliability GM ZZ502-502 HP GM CRATE ENGINE
 

I had a pair of the zz502's in my old boat (Cigarette Bullet)and it ran great for the two seasons that i had it (115 hours). The new owner has put another 100+ hours on them and they are still running great. I believe that they had 35 hours on them when I got the boat. They had been marinized (valves changed to inconel, cam and lifters, head gaskets, brodex single plane intakes and 1050 Dominator carbs).

Re: reliability GM ZZ502-502 HP GM CRATE ENGINE
 

Kid I know you meant to say that you replaced the 11pound bypass valve to the 30lb one spec-ed for external filter/cooler :D

Re: reliability GM ZZ502-502 HP GM CRATE ENGINE
 

This thread should be required reading for anyone upgrading power or experiencing oil pressure/temp issues :drink:

http://www.offshoreonly.com/forums/s...d.php?t=106633

Re: reliability GM ZZ502-502 HP GM CRATE ENGINE
 

I know you knew that...I know you knew I knew....you know....ah fuggit :o

Wobble - Thanks for the correction. Hence my little disclaimer in (***) after refering to the bypass valve....senior moment perhaps? :drink:

Re: reliability GM ZZ502-502 HP GM CRATE ENGINE
 

That is THE oil temp/pressure thread for sure!!

Re: reliability GM ZZ502-502 HP GM CRATE ENGINE
 

:D :drink:

Thanks for the post. Still relevant ten years later.

I'm pretty sure they had issues. I don't remember that ending well. I think there is a thread in the Scarab section with someone having good luck with the GM crate motors. I forgot which though, might be the 572s.

I had been thinking of putting that exact motor in my 22 SCARAB, because GM stated in their performance catalogue that this engine was suppose to be good for marine use. I called an excellent engine builder in our area, to get his thoughts and opinion, and his answer was, if you want to see what happens when you put that engine in a boat, come out here and have a look at the 2 I have sitting here. He said some guy tried to re-power a 34' BAJA with 2 of those, and they both broke within 20 hours.
That made my decision very easy, and I left the stock 350 in my SCARAB.

It is clearly written black on white in that performance catalogue NOT INTENDED FOR MARINE USE !

No where is written they are ok... Wondering where you saw that i have one of each year for the past like 15 years!

^^^^ that is correct and always remember about that bypass valve. I have one in now ---- engine with 38 hours only and it has piston / cylinder noise back port area. My guess wrong by pass valve, maybe wrong cam that created water reversion - just guessing --- winter project so far have not looked at a thing other than start it up / idle warm up - located noise and parked it. Owner states its a new crate longblock . Jeez

a 572 you have your eyes on right now?

The guy in the Scarab section has the 572. Says all the clearances and cam were fine. I think all he had to change were valves and springs. Pretty sure he changed intake and carb, but by choice, not because it needed it. I would however bet a drink that the 572s in the OSO boat met a nasty end shortly after being installed.

My scarab boat was a 1994 model, and the GM Performance catalogue I had from that time frame definitely did state that the 502 ZZ motor was for auto and marine use.
After so many failures during the following years, maybe GM removed the marine portion.
Going back 15 years would take us back to 2001. Time does fly by.

"My scarab boat was a 1994 model, and the GM Performance catalogue I had from that time frame definitely did state that the 502 ZZ motor was for auto and marine use. "
IF you had a 19' Hondo/Sanger/etc. flatbottom V-drive I think the 502 ZZ could be considered a good choice for "marine application" Just saying.

I used a 502/502 short block assembly for my 208 Baja build. It comes with brass freeze plugs, so with the oil bypass change there is nothing else needed for it to be " marinized" other than the 502/502 cam lobe centers are not ideal for a boat (reversion prone). I used an UltraDyne roller cam, Edelbrock O port heads, Eddie Marine exhaust manifolds and could turn 5900 rpm on a 24 bravo prop. 12 years later it was still running perfectly when I sold it. I think the 502 short block is an ideal starting point, at least in my experience.

Last one i had outlived the boat. Aluminum large ovals i believe. ,and the street grind yet lumpy cam..i got it with the 6 qt pan but a huge aftermarket cooler and correct oil cooler bypass provision. and closed cooling.
Mine was a gen 6 block . When the transom went out it became a organ doner. Had buyers lined up for that trailer.lived a long horrible glorious life and is now in a 69 chevelle going strong . Still running the orig gmpp performer style intake i believe.

Aluminum water pump too . Btw.

I have the exact same setup and hopefully will have the same luck. I have CMI headers dry to the tip, and when I pulled the heads we didn't see much if any evidence of reversion even with the 110lsa. I may still swap that cam for a piece of mind though.

How long have you been running your 502 and with 110 LSA cam and of course running totally dry to the tip surely helps to

What heads and valve train set up ? Just asking

Edelbrock RPM Performer, stock intake, ferrea exhaust, comp cams steel roller rockers and pushrods.