reliability GM ZZ502-502 HP GM CRATE ENGINE
07-10-2006, 02:10 PM
#1
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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?
If so, had any problem? Did you change something in it or it is stock?
07-10-2006, 02:57 PM
#2
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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.
I think you can PM him on the "Lake Champlain" Thread.
07-10-2006, 03:07 PM
#3
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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.
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07-10-2006, 03:12 PM
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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
07-10-2006, 04:29 PM
#5
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Re: reliability GM ZZ502-502 HP GM CRATE ENGINE
Originally Posted by Audiofn
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.
07-10-2006, 05:46 PM
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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!
07-10-2006, 07:00 PM
#7
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Re: reliability GM ZZ502-502 HP GM CRATE ENGINE
Originally Posted by GLH
He had ZZ572's speakerboy so get your facts straight !
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07-11-2006, 07:10 AM
#8
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Re: reliability GM ZZ502-502 HP GM CRATE ENGINE
Originally Posted by Audiofn
I do my best not to. It is more fun to cloud issues with missinformation!!!
It's don't cloud the issue with facts...
07-11-2006, 08:21 AM
#9
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
Sorry to be so long winded, but hope this helps.
Bill
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
Sorry to be so long winded, but hope this helps.
Bill
07-11-2006, 08:23 AM
#10
Re: reliability GM ZZ502-502 HP GM CRATE ENGINE
Originally Posted by GLH
You Edward Kennedy voter dudes always get it wrong...
It's don't cloud the issue with facts...
It's don't cloud the issue with facts...
Last edited by Kidnova; 07-11-2006 at 08:25 AM.
