Oil pressure question

[Ed Wright]

Originally Posted by HP HUNTER

Type of cam bearings? BBC - you have to pay very close attention to cam to cam bearing clearance, at least that's what I've found. When you drop pressure on a run its usually a windage issue, type of pan and amount of oil?

I was thinking amount of oil. Or, drain back issue. Returns blocked off? Personally, I would try adding a quart.

[CMcAllister]

I like -3 for pressure gauges. It's more responsive than -4 due to the reduced volume in the line. If using a Racepak, why not go total electric and use a transducer?

[Nmbr1GMfan]

Originally Posted by Ron Gusack

The pressure is about 50 at 2500 against the converter, goes up to 55ish on launch, then drops to low 40's for the rest of the run. After the stripe it climbs up a little.

I had an issue like this once and it was the distributor body not sealing.

[Ron Gusack]

Originally Posted by HP HUNTER

Type of cam bearings? BBC - you have to pay very close attention to cam to cam bearing clearance, at least that's what I've found. When you drop pressure on a run its usually a windage issue, type of pan and amount of oil?

Cam bearings are King's but I don't know part number. The pan is a 7 quart Moroso which is basically a stock pan with a deeper sump, nothing special. I run 6 quarts of Penn 10-30. It's possible that I have the pickup to close to the pan. I recently read a post that said it should be about 1/2" and I've always put mine at 1/4 to 3/8.

[Ron Gusack]

[QUOTE=Ed Wright;569241]I was thinking amount of oil. Or, drain back issue. Returns blocked off? Personally, I would try adding a quart.[/QUOTE
My last oil analysis was the last 26 runs from 2017 and that oil sat in the car over the 2017 winter. I forgot to send it in until a few weeks ago and when I got it back it showed 5% fuel dilution. My only explanation for that is a couple start ups in pretty cold weather over the winter with no choke and a very lean idle circuit. I just sent in a sample for the first 31 runs this year and if the dilution numbers are still bad I'm thinking that could be the issue.

The oil is fresh now and if pressure doesn't improve, I'll add a quart and see what happens.

[Coleydog]

Originally Posted by Ron Gusack

I think that was the pressure when it was new, or at least it was very close to that. I have a Racepak but I don't log oil pressure yet.
I'm not sure the gauge is correct because I have a small copper line going to it. It's a SW mechanical gauge that is very old.
The lifter galleys aren't restricted but my pushrods are restricted to .028.
Lifters are Crower Hippo severe duty.
I learned that 10 lbs per 1k rpm was old school and over kill. I know that volume and pressure are different too. That's why I went with a standard volume pump but 40 at 6300 has me a little nervous. It might not be much higher at 7k when I run 1/4 mile. I need to start logging it or at the very least put a larger ID line to it.

Did you bleed the oil guage? I've had air trapped in the line and gave weird readings, looked at everything untill it was found.

[HP HUNTER]

Originally Posted by Ron Gusack

Cam bearings are King's but I don't know part number. The pan is a 7 quart Moroso which is basically a stock pan with a deeper sump, nothing special. I run 6 quarts of Penn 10-30. It's possible that I have the pickup to close to the pan. I recently read a post that said it should be about 1/2" and I've always put mine at 1/4 to 3/8.

I run the pick up .310 off the bottom of the pan. I use coated Durabond cam bearings. The Durabond CH12 bearings go oval, never use these, especially if clearance isn't maintained. 6 quarts is fine if there's no excessive leaks. What is inside your pan?

[Ron Gusack]

Originally Posted by HP HUNTER

I run the pick up .310 off the bottom of the pan. I use coated Durabond cam bearings. The Durabond CH12 bearings go oval, never use these, especially if clearance isn't maintained. 6 quarts is fine if there's no excessive leaks. What is inside your pan?

I used to run a windage tray but after hearing many many opinions on the disadvantage/advantage of using this type, that type or none, I decided to not run one. The pan has the 2 layer sheet metal tray spot welded in just like the factory pans did. So that's all I have in it. Pressure stays up after the stripe but I don't run big numbers and ease off the throttle so there's not a lot of negative G's.

[nhramnl]

OK, I'm going to step right into the line of fire here, and ask what's so bad about the oil pressure figures you're seeing? If you've got enough pressure, and more important, volume to keep everything lubricated (i.e. you're not burning cam bearings, pushrod tips or rocker arms), why are you worried? Ask the majority of Stock and Super Stock guys what kind of pressures they see from the starting line to the traps and I think you'll relax. I haven't seen 50 psi for decades, at any time.

[Ed Wright]

Originally Posted by nhramnl

OK, I'm going to step right into the line of fire here, and ask what's so bad about the oil pressure figures you're seeing? If you've got enough pressure, and more important, volume to keep everything lubricated (i.e. you're not burning cam bearings, pushrod tips or rocker arms), why are you worried? Ask the majority of Stock and Super Stock guys what kind of pressures they see from the starting line to the traps and I think you'll relax. I haven't seen 50 psi for decades, at any time.

I don't think he has low oil pressure, but changing like that going down the track? I doubt anybody would think that is normal.