Picture attached.

Keith Eickert Big Block Chevy Mark IV,Dart,world product's 2 piece rear main 11 qt cast alunimum External Oil Pump Pan with internal oil cooler and External Oil Pump Windage Tray . Execellant condition $650.00

Rage - The ZZ502 is a 502ci GM crate engine that according to GM produces 502HP @ 5800 RPM. I had the ZZ propped at +,- 5500 at WOT. Never had/checked AFR or EGTs and no closed cooling. Like you I initially ran it with a stock Merc oil cooler. Mine was from the 7.4/330 we yanked out of my 23 Nova. That cooler was way too small. Long story short, after seeing oil pressure drop after WOT runs and suspecting excessive oil temps at/after WOT, I installed an oil temp gage (sender mounted on remote filter housing). I saw the +300* oil temps, and then hit the boat sites and asked tons of questions, as I knew abosolutely nothing about marine applications.

Between drilling the holes in the tstat (3 - 3/16 holes) and removing the tstat in the HM oil cooler and blocking off the bypass, oil temps dropped to a more acceptable range. I believe the rod I used was 1/2 in. It's been about 8 years so I can not swear the rod was in fact 1/2 in., but it was a relatively "proper" fit.

At present.... the ZZ has been bored/stroked to a 557ci. 315 AFR heads, 1050 Dom, mild solid roller, KE exhaust, 696 hp at 5900 RPM - which is just about what we were looking for prior to the build. Still running the same HM oil cooler. However, oil lines are now -12. After market remote filter head with NAPA 1060 Gold filter. Still using Mobile 1 V-Twin 20/50, changed at 25 to 30 hrs. Problem is, I can't run WOT for long because the hull does not handle speeds over 80 mph too well. However I have run WOT for a few minutes at a time, and oil temps will get into the 265 range even with the larger oil lines, which is more than I like to see. I believe the "problem" may be at the block in the area where the filter pad is located. It might help if the oil passages were enlarged at the filter pad. I will look into that next time the engine comes out.

edit;;;; btw - 10 qt. pan running 8.5-9 qt.s of oil

Rage:I don't believe that pan will even begin to fit the oil pan rail and diemnsions on a Gen 7 496-8.1L block like yours.
Why don't you try an easier test fix like putting a bigger oil cooler on the engine without a thermostat all together and see if that brings your WOT oil temperatures back in range? Lot less difficult and expensive thing to try.
JMO

Best Regards,
Ray @ Raylar

Thanks Ray. Yeah I know it will not fit. I just posted it to show that there is such a thing out there. The purpose of this thread.

A bigger oil cooler and removing the thermostat may help but I do not think it will be the final solution because on the cooling side of things I am convinced the oil flow through the bearings is too low above a certain engine HP output where the heat rate into the oil is greater than the oil flow's ability to carry it out resulting in the climbing oil temp. That is my belief.

I see work to be done on my coolant system side of things based on input form OSOer's and other sites which I will try next. Then I have some things I see as reasonably easy to install to add significant oil cooling capacity for cooling the crank case pan oil directly. TBC.

Man it is sooooooo spooky how similar your story is to my story.

Do you know what your bearing clearances are and what oil pump you are using? Did you remove the oil bypass valves at the filter adapter and plug the holes?

Thanks

I'd have to dig through a bunch of stuff to locate my build sheet in order to find out what the clearances are, and what oil pump. I've moved twice in the past 2 years (557 build was about 4 yrs ago) so no easy task finding much of anything. In fact move no. 2 was just two weeks ago. But yes, the bypass valves in the oil pad were changed. Well, 1 changed to 30 lb. and the other removed.

Yes our stories are eriely similar. Seems I've been fighting oil temps forever. Major PIA. You might have a point, clearences too close. Thing is though, the guy that built my 557 probably has +100 engines on our local lake, plus more state wide. And a few of his customers do the Alexandria Bay/1000 Island poker run. He has a superb rep, which is why I went with him. And I've not heard of anyone he built an engine for bitdching about oil temps. As mentioned my sender is in the remote filter head and after the oil comes out of the engine so it's bound to read on the high side. That said, I expect temps in the pan are less, but have not checked pan temps. He!! I've been so busy the past couple of years I've only had the boat out 5-6 times. Sux.....

It seems your priorities are all wrong sir.

Rage:

I understand your belief about oil volume and bearing clearances being your thoughts for your oil over heating issue.

Would you please answer my question about which oil pump you used to do your engine build?

The stock GM 8.1L pump, the 10778 Melling pump or something else?

Thank You,

Best Regards,
Ray @ Raylar

Here's the flow. I wonder if your builder changed the flow in or from the block and did not realize he caused an endless loop??? Maybe?? It could happen. See picture.

No Problem. Actually I answered your previous question on that earlier in post #15, 2-20-12 but it was a Melling high volume oil pump that I purchased from you along with many other parts back then. I do not have my files with me here so I can not provide the specific part number from your invoice.

Thanks,

Bill