Oil pressure flutter at higher rpms.
 

So, I've never gotten this engine over 5k rpms due to crappy carb jetting but now the bugger can spin up to 5400 and occasionally 5600 and I'm seeing a bit of pressure flutter above 5k. It's not much but the needle is definitely twitching but is solid at rpms lower that 5k. Is a problem developing?

502 with less than 100 hours on it. ~500hp
Brad Penn 10-40. 70psi cold 60psi hot. It'll drop down to about 25psi at idle after a hard run but quickly recover to 35.
Stock GM 6qt pan
Oil level a little high because I've been fighting a small leak at the filter head. Possibly a quart high.
3x18" oil cooler with -12 lines. No thermostat currently.
Compression check shows 180-185 with the #1 a little weak at 175#

Two possibilities I'm seeing:

1) The over fill is causing the oil to get whipped up by the crank foaming it up.

2) The oil pan is on the verge of getting sucked dry with oil pooling up top on the motor and it cant drain back as quick as the pump sucks it out.

Make sure sender connection is tight. Similar issue happened to me.

There's a possibility there as I was fussing in that area sorting out the stupid leak.

im with trash on theory # 2.

Time to take a long drill bit through the heads and block into the pan? Need a bigger pan?



*J/k on the drill bit.

10w-40 ?

Is the block screened? Of so I woukd say the pan is running dry, if not it should be ok but very close to running dry, I was in a situation that I had 6qt pans and ran 5500 for a long time never had issues... But all boats and systems different

Yah. That's what it came back from the machine shop with so I just stuck with it. Seems thin for marine use, but I don't have a thermostat on the oil cooler yet, and rarely get near wot on our small lake, so I figured thinner is fine for now.


By "Is the block screened?" Do you mean in the pan or up in the heads? All of the orifices in the top end are open.

Another vote for sacking pan dry.

Try adding a quart of oil to see if pressure is steady. If so you need bigger pan.