Oil pressure flutter at higher rpms.
08-22-2016 | 05:08 PM
#11
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From: chicago
Overfilling the pan is bad.
What size oil lines do you have to and from the filter? Icdedppl recently solved his oil psi issues at high rpm after fighting with it for a few years now. The culprit, -10 AN lines . He replaced with -12 lines, and oil psi no longer drops at higher rpm.
What size oil lines do you have to and from the filter? Icdedppl recently solved his oil psi issues at high rpm after fighting with it for a few years now. The culprit, -10 AN lines . He replaced with -12 lines, and oil psi no longer drops at higher rpm.
08-22-2016 | 05:17 PM
#12
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From: Olmsted Falls,Ohio Marblehead,Oh
The valley of the block, sometimes a screen can limit how fast oil comes back to the pan
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.
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.
08-22-2016 | 05:24 PM
#13
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From: SF Bay Area
Everything oil related are -12 lines and 3/4" npt. I've had trouble getting the new Hardin remote filter head to quit leaking and have been changing fittings, and I had to bend one hose (from filter head out to cooler) with a slight bend in it. Not a kink, but enough to slightly deform the shape of the hose a bit. It didn't look like much of a hinderence though. This is a new development though and that's the only change made since the last time out when it was fine.
Last edited by Baja Rooster; 08-22-2016 at 05:38 PM.
08-22-2016 | 05:54 PM
#14
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From: NW Michigan
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#
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#
08-22-2016 | 07:28 PM
#16
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From: SF Bay Area
Same carb. Changed the PVs to 4.5 and got 11.8 across the board. Dropping the primaries from 78 to 74.
I guess that I'll switch out that tight hose, check the sender wire, and go from there.
I guess that I'll switch out that tight hose, check the sender wire, and go from there.
08-22-2016 | 08:32 PM
#19
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From: Olmsted Falls,Ohio Marblehead,Oh
I doubt its the hose or fittings, my old engines 565CI and 600 hp, had the factory brass sharp 90's still and also 6qt pans, never had an issue, I held them at 5500 for miles at a time never sucked pan dry, I am sure I was close but at the time I had what I had.... blocks did not have screens limiting oil return either, so if you have screens that can hurt maybe, or look at other things.... start with a mech gauge and verify for sure then move on, until then it could be a stupid sender or gauge issue..
