Big Block Billy

High oil temp, 588 BBC, Am reaching wits end, 12 An Hoses routed properly, another $500 oil cooler, motor runs cool, never over 140 but oil temp spikes after a hard run, and we have to back off the throttle. Oil is definitely hot, not a faulty sender. We need to swap where pickups get their H20 from. Other motor is a non issue. Could the problem be with the Gil oil pan , or the oil adapter on the block. This is really preparing me for the rubber room. We have tried oil t-stats etc. This is a Hardin marine cooler from CP Perf. What should I do next besides licking the windows of the tart cart.
Any input would surely be appreciated. BBB

t500hps

Fighting nearly the exact same problem.....one is OK, the other isn't. Good Luck, I REALLY know what it's like!!!!!

Biggus

iTrader: (1)

Billy,

Have you checked for a lean condition at WOT on that motor. Piston heat can transfer from the underside of piston and cook the oil.

Good luck bud!

Kurt

Big Block Billy

We will have to change carbs again. I like the way you think.
The motor in question ran fine on the dyno. Believe me I want this to be fixed so we can all move on. BBB

Turbojack

Could the oil bypass plug/valve be missing, wrong one, or gone bad? Installed in wrong location?

Oil might be going thru cooler at idle but when prussure goes up it starts bypassing.

For some reason the cooler not getting water or enough water? (you are addressing this one)

Too much oil in engine? Wrong Dip stick or tube?

Water going thru cooler before going thru engine?

Engine windage tray missing?

I would not compare a short dyno run to running in the boat.

Codered

I would check the transom assembly water outlet ,see other threads and posts about this very common problem often over looked . Engine temp normal oil temp up was the way mine acted.I chased it for 2 years

Kidnova

Everything Turbojack said.

Been battling high oil temps with my ZZ502/502. ZZ has been turned into a 557. Not in the water yet so don't know what to expect.

I have also been using a Hardin oil cooler, with a built in t-stat. CP site said good to 700 hp. Hhmmmm....

One thing that DID help..... I yanked the oil cooler T-stat, and plugged the by-pass on the oil cooler with a length of 1/2 inch SS rod (top t-stat by-pass tube between inlet and outlet). I also drilled 3 - 3/16 holes in the water t-stat. That combined lowered my oil temps about 15 - 20 degrees.

Oil temps lowered to +,- 260* while running WOT for +20 miles in local poker runs. Still too high for my liking. But the Mobile 1 V-Twin 20-50 kept the lower end in very good shape. No signs of heat/wear after a 140 hour tear down.

Best of luck.

Big Block Billy

Talked yesterday to Kurt (biggus) he truly is a brilliant man. I concur with your statement about the v- twin oil as he said so too. It doesnt start to break down until 550 Deg.
If it's good enough for an air cooled engine then it's more than adequate for a boat with 16 Qt capacity.
I need to get this thing perfect before I go Berzerk !
Found a fuel line that was defective and ballooning inside creating kind of a pocket valve, it had seperated in it's lamination, and was un-vulcanized.
Thought this may have been the problem, but went for another run, and still hot oil.
Could a through hull fitting be to blame.
We still have not swapped water pickups.
That's next. BBB

Mr Gadgets

BBB,
I did a quick reread on this thread, but one thing I did was install a piece or clear tubing in line with the cooler. That way you can see water flowing thru it. I also had a KE Oil thermostat and it would allow my oil to get to 300*, if I let it. When I removed it, oil temps dropped to normal.
Just some thoughts about what I ran into.. One thing that helps is to go back to basics and think simple. Water flow, oil flow, is it enough, then it should be cool. Is all the oil going thru the cooler? Is timing retarding causing heat?? Good luck with it.. but I know you will find it. Keep at it!

Another thought, did you check temps of water going thru cooler. One side should be warmer than the other if it is pulling any heat out of the oil..

D*ck

RedDog382

BBB,

Strange. Having the exact same problem with one of mine. Fresh O-hour complete rebuilds set up and dynoed by same individual. Merc remote filter blocks and t-stats. Coolers flushed and inspected. Oil temp rises quicker, and runs ~25* warmer than the other. This is the power steering engine, so running extra PS cooler. Going to change out the T-stat and also install water pressure guages next.