Thread: max oil temp and min oil pressure

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Hi guys I am new here but figured I would ask a question. I have looked around and seen alot of great advice. I am not a car guy but I do have a hot rod boat . ok so here is my question I have a new 496 that I put togeter that makes 710 HP on 91 octane pump gas. I was out over the weekend and the oil temp was around 245 now I have been told that is to high. I have been told to keep it down under 230 as thats when oil starts to breakdown and varnish. I am running a big oil cooler that is fed directly from the lake or river I run in and the water temps are anywere from 60 to 85 degrees F after adding the cooler it only droped abput 10 degrees. so were should I run it??

I also run a multi weight oil 15/40 kendall and I notice that when the oil temp is around 245 when I drop to an idle the oil pressure drops to around 20 after running around 70 to 80 psi while in it. should I go to a straight 40 or 50 and loose the multie weight?

thanks
Shawn


Engine:
BBC 2 bolt block studded
eagle 4.25 4150 lightened crank
eagle 6.385 H-beam rods with Arp L-19 blots
JE forged pistons 4.310 bore 10.2 /1
AFR 325 heads with 2.30 intake and 1.88 exaust
custom solid roller .700 lift 109 lobe sep cam
morell soid roler lifters
Crower pushrods
Crane Gold Rockers 1.8 on intake and 1.7 on exaust
10 quart milidon Pan
Edel victor TR2 tunnel ram
2 600cfm blower carbs
made 710 HP @ 6100 and 689 TQ @ 5400 on 91 octain pump gas

everyone likes pics as well

20lb at idle isn't bad as long as it stays up at revs. 245 degrees isn't terribly hot for oil, either. Keep in mind that oil must run hot enough to evaporate any water contamination from condensation. Still, I don't see any reason to use multi-vis oils in a boat engine. It ain't gonna get used in winter!

I concur with R Pope. I've got a 351 GT-40 in a ski boat and the owners manual says run straight 40W.

I'm surprised the oil cooler is not more effective than that. Where are measuring the oil temps?

Those temps are not too bad, particularly for synthetic oil. I would consider getting some hours on it (50-75?) and then switch over to a 20W-50 synthetic such as Redline or Royal Purple.

Nice engine and pics. That must be a scary blast on the water! I'll bet it will fly around most everything (except the gas station).

Kitz

Originally Posted by R Pope

20lb at idle isn't bad as long as it stays up at revs. 245 degrees isn't terribly hot for oil, either. Keep in mind that oil must run hot enough to evaporate any water contamination from condensation. Still, I don't see any reason to use multi-vis oils in a boat engine. It ain't gonna get used in winter!

in my neck of the woods we use our boats all year long. winter here is not that cold

Originally Posted by kitz

I concur with R Pope. I've got a 351 GT-40 in a ski boat and the owners manual says run straight 40W.

I'm surprised the oil cooler is not more effective than that. Where are measuring the oil temps?

Those temps are not too bad, particularly for synthetic oil. I would consider getting some hours on it (50-75?) and then switch over to a 20W-50 synthetic such as Redline or Royal Purple.

Nice engine and pics. That must be a scary blast on the water! I'll bet it will fly around most everything (except the gas station).

Kitz

i was surprised that the cooler didnt do better than that as well. the oil I am running now is not a syn. and I am not a fan of running syn in a new engine after a while it may get changed out. the oil temp is getting picked up in the pan about 1/2" from the bottom in the rear trap. so what I gather is I am fine to run the oil temp that high. so the next question is how hot is to hot?
thanks for the complaments Kitz it definatly shits and gets and gets great milage for a boat with that HP about a mile to the gallon

Oil temps should be no cooler than 190 when using the application under severe load. Whether it boating or drag racing or circle track. Temps do not like anything above 230. @215, it breaks the moisture and lets the add packs do their job. Eagle rods run very tight side to side rod clearances and need to be relieved. I know it's a boat motor and requires major surgery to pull, but the side clearnaces need to be double checked and releived. Temps and oil control will fall back into place if you re-clearnace the rods and start from scratch at that point.

Originally Posted by nitrowarrior

Oil temps should be no cooler than 190 when using the application under severe load. Whether it boating or drag racing or circle track. Temps do not like anything above 230. @215, it breaks the moisture and lets the add packs do their job. Eagle rods run very tight side to side rod clearances and need to be relieved. I know it's a boat motor and requires major surgery to pull, but the side clearnaces need to be double checked and releived. Temps and oil control will fall back into place if you re-clearnace the rods and start from scratch at that point.

so you are saying that its the rod side clearance???? I had this checked and fixed when I hade everything machined and if i rember right it was @ .005 or so but I cant recall for sure. I spoke to friend ( pro engine builder) and he told me that I am reading the temp in the hottest place I can and that it is on;y around 215 or so going back into the block and I was ok. He also told me that in their trophy truck dry sump engine that it runs 300 degrees in the sump but only 230 feeding the block. so whats your take an all this???

ohh and getting the engine out is only 4 bolts and a few wires 5 min and its out .

I think it's a bit of a stretch to say it's rod side clearance with any certainty. You could be solving a problem that doesn't exist. Get hold of an infrared thermometer and test the oil temp with the engine hot and running, the filter temp should give an accurate reading. "If it works, don't fix it!"

If .005 is accurate for rod clearance, Yep it's too tight. .020 t0 .025 is much better. I'm sorry the trophy truck has that much at run temp. WOW! Huge breakdown issues in the oil department. Now a bit of old school advice, Put a mechanical gauge in the pan. It's better to be sure of what you have than run around on the lake and wonder. Paddeling back to shore really bites

Originally Posted by Fourq

Hi guys I am new here but figured I would ask a question. I have looked around and seen alot of great advice. I am not a car guy but I do have a hot rod boat . ok so here is my question I have a new 496 that I put togeter that makes 710 HP on 91 octane pump gas. I was out over the weekend and the oil temp was around 245 now I have been told that is to high. I have been told to keep it down under 230 as thats when oil starts to breakdown and varnish. I am running a big oil cooler that is fed directly from the lake or river I run in and the water temps are anywere from 60 to 85 degrees F after adding the cooler it only droped abput 10 degrees. so were should I run it??

I also run a multi weight oil 15/40 kendall and I notice that when the oil temp is around 245 when I drop to an idle the oil pressure drops to around 20 after running around 70 to 80 psi while in it. should I go to a straight 40 or 50 and loose the multie weight?

thanks
Shawn


Engine:
BBC 2 bolt block studded
eagle 4.25 4150 lightened crank
eagle 6.385 H-beam rods with Arp L-19 blots
JE forged pistons 4.310 bore 10.2 /1
AFR 325 heads with 2.30 intake and 1.88 exaust
custom solid roller .700 lift 109 lobe sep cam
morell soid roler lifters
Crower pushrods
Crane Gold Rockers 1.8 on intake and 1.7 on exaust
10 quart milidon Pan
Edel victor TR2 tunnel ram
2 600cfm blower carbs
made 710 HP @ 6100 and 689 TQ @ 5400 on 91 octain pump gas

What most people forget is 100 mph in boat is like 200 mph in a car and boats don't have brakes either.

talked to my machinest today and was told the rod clearance was setup at
.028. so I dont think thats the issue. I was instructed to put a good 50 wt in it and run it and it will be better so I will try it and see. If I cant get the oil temp down to 215-225 then I will have to re plumb the oil cooler to its own open water source. I think my problem may be the pressure regulator I had to install to keep the block pressure down to 18 psi. when I ran it without it was way to high and I started blowing freeze plugs out.


100 on the water is fast and no you dont have brakes you have to pick your water wisely. I have been in boats my whole life, seen many pepole die from it. saftey is my main concern so no full passes with passengers or lots of pepole on the water. when making passes I wear a life jacket that is racing approved. no second chances in life when playing with big MPH on the water...

I don't understand running the block at 18 psi. Why would it not be evacuated as good as possible? Positve pressures will advance the likelyhood of seal problems and actually reduce oil flow through the bearings. The ambient pressure is a boundary condition for determining flows through the bearings.

Kitz

Where is the cooler in relation to the regulator? It could well be the problem if it's restricting the flow .

i also agree your cooler should do a better job than it is doing, i know even in my boat (a little 4cyl 180) the oil gets hotter than a firecracker even to the pount that if i had my choice i would run a hi capacity pan to give the engine some thermal room.
a car has a lot of loss of heat just to the air moving by the pan as opposed to the basicly still air in a boat compt.