PatriYacht

The plumbing looks correct. The line to the top of the therm. housing allows water to go to the exhaust when the therm. is closed. It doesn't interfere with the thermostat. If you drill 3 3/16 holes around the perimeter of the thermostat, the temperature fluctuations will be much smaller.

tomcat

You said you used a remote oil system. Did you change the block's internal bypass valve to the higher pressure marine spring and eliminate the other bypass valve that routes oil to GM's oil cooler holes? If you didn't the light bypass spring is opening and oil is neither filtered or cooled; gets really hot. this could be part of your oil pressure problems.

Ted's not expensive if he saves you from experiencing a problem. Shop rates get you knowledge too, not just labour. But hey, I learned just about everything the hard way so who am I to talk.

pullmytrigger

Firewalker - dont mean to hijack your thread but your PM box is full...... did you actually save any money having a heavy item like a motor sent up here from the states with shipping /brokerage fees/dollar etc etc...... as opposed to buying it from you local chevy dealer up here????......doug

Kidnova

Firewalker,

Bear with me here....I am no engine guru but I'll offer what I can from my experiences with my ZZ502/502.

My ZZ is on its 3rd season. Mine's in a Wellcraft 23 Nova. It runs like a bear. But I've gone through oil temp problems with mine as well. And the consequential lack of, or very low oil pressure after a hard romp.

I'd suggest that you get an oil temp gauage ASAP. After installing mine I would not be with out one, even on a stock set up.

I'd also suggest a bigger oil cooler. The stock 7.4 oil cooler is absolutely useless on the ZZ. And the 454 mag cooler isn't much better. I currently run a 3 x 22 Hardin Marine and includes cooling for the power steering and is "ok". But actually I could use one size bigger, considering that I am still using the restrictive stock Merc oil lines and fittings. The stock 1/2 inch fittings are not 1/2 inch....they are more like 3/8 inches. I'm sure thay do restrict oil flow.

Through trial and error I've discovered that water/engine temperature directly affects oil temperature. I was told that by a fellow site member but being hard headed, I had to find out for myself. And, I found out that he was right. That being said, I'd suggest a 140* thermostat. I bought a Merc stat after trying out a couple of cheapies from auto parts stores. The Merc {or Quicksilver...don't remember exactly} provides a much steadier temp...less flucuation.

Another suggestion, and this helped me, I would remove the bipass valve from the block that is in the center of the remote pad adapter location, where the oil filter would normally be located. Take it out and leave the hole empty. Also, yank the 11 lb. side bipass valve, and replace it with a 30 lb valve.

The combination of the bigger oil cooler, lower temp tstat, and bipass valve changes, lowered my oil temps from +300* to a now maximum of 255*. Yes, 255 is still too high. But a helluva lot better than being over 300. I've run almost WFO for 25 miles in poker runs and oil temp stays right around 250, and never gets higher than 255. After stoping afterwards, oil pressure is 35-40 lbs. I consider that a victory.

Oil....I run full synthetic as it handles heat better than the majority of dino oils. I use Mobile 1 V-Twin 20/50. Previous to that I ran Valvoline 20/50 synthetic.

BTW, I did not realize why my oil pressure dropped to 10-15 lbs at idle after spanking it, until I put the oil temp gauge in and started posting questions. I was real lucky that I did'nt cook the engine.

My ZZ was delivered carb to pan. We took the pan off my old 7.4 and put it on the ZZ. Also went with better/marine head gaskets. I sent the Holley 850 Vac carb that was bolted to the ZZ to Nickersons for marinization and tweaking. It came back jetted a tad on the fat side. I left it fat to protect from lean out at WOT. Also took the water circulator pump off the 7.4 and bolted that to the front of the ZZ.

All I've ever fed the ZZ is 93 octane. I think you can use 91 with the 9.6:1 compression, but what's another few bucks at fill up time.....cheap insurance IMO.

What prop are you running? How much does you boat weigh? I'm running a labbed 25 Mirage Plus and turning 5000 to 5100 rpms. Boat weighs a little over4000 lbs. I put a couple of nicks in the prop this summer so it gets shipped back to Throttle Up for repairs soon. Plus I plan on having them bend it a little to get the rpms in the 5300 to 5400 range. Red line is 5800, but no need to take it that high as far as I'm concerned.

I had a bud tell me the ZZ502 was a POS and would'nt last in a marine application. Few weeks after the ZZ was dropped in the boat, the Humble Little Nova did a whoopazz on his 502 efi mag powered 28 Velocity. Last summer after putting around 75 hrs. on the motor Mr. Velocity and I got into it again. My buds 502 mag overheated while we were running. Cost my bud around 4,600.00, and he still had not proven his point.

I've read a few things people have written about the short comings of the ZZ502 in marine application. Obviously they can't be compared to Merc's Blue motors. But I think if they are set up properly they are quite capable.

Hope this info helps. And I hope there's no serious damage to your mill.

Good Luck!!

Airpacker

Rob, call me at the shop.

Sean

Firewalker

I cleaned out my inbox.

Sean, send me your number.

Thanks for all your help. This is awsome!.

RT

mr_velocity

Hey I never got into it with you

Kidnova

Good thing too.....ya would'a crushed me

Firewalker

If anyone happens to have the part numbers for the 8 quart oil pan and the 30 psi bypass valve that would be a BIG help. The motor is a GEN 6


Thanks

RT

articfriends

iTrader: (1)

If your going to pull the motor and install a bigger pan buy one of the aftermarket ones. They have 10,12,14 qt pans that will work on your motor. Your oil cooler can never be too big nor your oil capacity.see the thread in post 6,it will clear up some of your oiling questions,Smitty