[y2k600f4]

I have a SBC with 7 qt oil pan and info from another post I pre-filled oil filter, added 7 qts and trimmed dipstick tube to read "full". I was just topping off the oil and I noticed a 1/2 quart difference if the line faces the engine or the fender. I have had other SBC before however I never noticed a difference in the fill depending on if the dipstick was inserted 180degrees. Now I am wondering if I trimmed it correctly. Is it the oilpan that is giving the difference in readings ? If so which way is correct ?

[Rob Keller]

The Stick should curl away from the motor & have you taken into consideration that after the motor is started .5 qt will be stuck to the inside of the motor?





R

[y2k600f4]

The Stick should curl away from the motor

In this case I think it is not curling correctly or maybe hitting the 7 qt pan, for some reason I get different oil levels on the front side and backside of the dipstick. I guess it is not that big of a deal but just curious what can be causing the difference and one reading must be wrong.

[MorrisonLC]

There's always a difference from front to back unless your dipstick goes straight down, but it's not all that much.

I'm curious though about trimming the tube--is that normal when installing a larger pan? I always thought the extra oil just would be added to the volume sitting in the bottom of the pan and the surface level would remain the same so the dipstick wouldn't need altering--maybe I'm wrong about that?

[y2k600f4]

I have noticed a very slight difference in other vehicles. Nothing to really grab my attention. This is like 1/4" w/o measuring it.

Trimming the oil fil tube is not standard practice....but I based it off of an article. I wanted to make sure I had exacty 7 qts + filter in the system....now I am thinking it was not the right thing to do.

[MorrisonLC]

1/4"--that's a lot. It must be intersecting the surface of the oil almost horizontally.

[y2k600f4]

I guess I need to toss the aftermarket junk one and get the proper OEM ones. I know this is a stupid question but is there a proper direction of the aftermarket dipstick (can go in 180 degrees). Still not sure why a difference in oil level depending on which way it is inserted ??

[y2k600f4]

While I am at it I was thinking of swapping my aftermarket summit 7qt oil pan with a stock SBC. Is there anyway that the pan can be interfering with the dipstick (hitting side etc) ?

[cobalt327]

Maybe I'm missing something here, but the idea in a 7 qt. deep-sump pan isn't to ride around w/7 qts. of oil sloshing around. It's to lower the level of oil down away from the ripro. asse'y. so as to prevent windage losses and frothy oil.

All that adding additional oil will do is take longer to reach stable operating temp. and might extend the change interval some.

That being said, I would simply add whatever amount of oil that you plan to run, to the engine and filter. Then insert the stick oriented in the way that it was when you trimmed the tube.

Don't turn it 180 degrees then worry because it doesn't read the same. You know how much oil is in it, right? Just read it the same way every time- no problem!

EDIT- The main reason for a stick to read differently is because most sticks have a tendency to curve one way or the other.

IF the tube that protrudes down into the sump (inside the pan, guides the stick past the crank/caps and points it downward) was badly bent or worse- missing/broken off- the stick's natural tendency to bend could cause the variation in readings.

[y2k600f4]

Maybe I'm missing something here, but the idea in a 7 qt. deep-sump pan isn't to ride around w/7 qts. of oil sloshing around. It's to lower the level of oil down away from the ripro. asse'y. so as to prevent windage losses and frothy oil.

Thanks Cobalt for the post. I was not sure if running 5qts (Standard oil pan) in a 7qts was ok since I thought you needed to maintain the oil level at the same distance below the crank. Right now I have the dipstick marked for 7qts + filter and I will just follow your advice and leave it as is. Thanks.

[cobalt327]

Let me quickly add that unless you have a pickup that extends to the bottom of your new pan, run all 7 qts.!

I also added an edit to my previous post.

Good luck.

EDIT- Check your PM's.

[Rob Keller]

On both my Chevy Trucks with factory external oil coolers , just that system holds a qt by its self.

Not sure if you have a external cooler.






R

[y2k600f4]

Cobalt327....thanks for your posts and PMs !

This got me thinking (I may be off so pls correct me if my thinking is flawed). Being that normally you want the oil level relative to the crank does the oil level change from going to a stock SBC 350 crank to a 400 crank as in a 383 stroker ? If so would it be advantagious to lower the oil level to prevent crankase windage from throwing excess oil on the cylinder walls, possibly over working the rings contributing to blowby and burning of the excess oil ?

Also being that I am using a deep sump 8 1/4" pan 7qt (+ fillter )with extended oil pickup I can easily run up to 3 qts lower (stock is 4 qts + filter). The oil pan is a summit G3502 and does NOT have a windage tray. Thanks.

[MorrisonLC]

I really am a total amatuer about this stuff, but if dry-sump oil systems work the way they do, then with a stock system as long as the pump pickup is covered at all times, why does it matter how many quarts are in the pan? You can't really measure what's sitting in the pan at 6000 rpm anyway, it's flying all over the place. Isn't the stock oil level just a calculated amount that is meant to keep the pickup immersed no matter what the rpm or the side force G's?

[cobalt327]

The counterweights on a 3.48" crank and a 3.75" crank are very close to the same diameter, so if there's a difference, I think it would be relatively small. I have never measured this though, so would be a good thing to check, I would think.

Of course if you run a couple quarts less than the full capacity of your deep-sump pan, it's a moot point- they'll be plenty of room between the crank/rods spinning around and the oil level in the pan.