What's new
CK5
Register an account today to become a member! Once signed in, you'll be able to participate on this site by adding your own topics and posts, as well as connect with other members.

Deeper oil pan a good idea for off road?

bp71k5 said:
What’s the rule of thumb for a GM small block oil pressure requirements, was it 1psi for every 100rpm? If the oil pressure doesn’t meet that minimum level anymore, I could see how bumping it up might help, but that would also point to a much bigger problem wouldn’t it?

A couple possible downsides are more oil up to the valve covers which gets pushed into the cylinders and blown through the PCV into the intake, and also any leaks that exist will likely get worse. A higher pressure pump may not be a problem but if it does, tearing things down again to fix it wouldn’t be fun.
Click to expand...
If GM wants 1 psi for every 100 rpm, then your engine doesn't make the grade when hot and your wheeling since you only have 2-3 psi at 600 rpm. Seems a bit low and while you may not have metal in the pan, you might in your filter. Wouldn't hurt to cut one open and it costs you nothing.

Which kinda brings up another point. You or anyone else for that matter, could have your oil analyzed by Blackstone or some other company. Might give you an idea of bearing condition and head gaskets.

The only way you are going to get oil into the cylinders is if either the rings are toast or the valve seals are and if either of those are toast, you already know the engine is weak and its time for a rebuild or at least a freshen up. And in order for oil to get into the intake it has to get through the PCV valve, through the PCV filter in the air cleaner, then through the air filter itself. High volume does not necessarily mean high pressure. If you aren't burning or leaking oil already, I don't see how its going to create problems.
 
Joel Wilson said:
If GM wants 1 psi for every 100 rpm, then your engine doesn't make the grade when hot and your wheeling since you only have 2-3 psi at 600 rpm. Seems a bit low and while you may not have metal in the pan, you might in your filter.
Click to expand...
You mean 6psi for 600rpm right? And that’s not necessarily what GM wants, it’s a rule of thumb for minimum oil pressure. I read a spec that GM wants 25psi at 1500rpm.
 
Thanks for all the great replys been busy and will replay more later but looking at work today on alldata here are the specs for my 1990 suburban 350tbi note these are listed as minimum. 20210623_080340.jpg
 
GM has also said burning a quart of oil in 1000 miles is acceptable. :haha:

I find those numbers quoted for LS series, I'd find it a bit unusual for two completely different engine designs (and oiling systems) to have the same specs. Can't find GM book specs for the SBC.
 
dyeager535 said:
GM has also said burning a quart of oil in 1000 miles is acceptable. :haha:

I find those numbers quoted for LS series, I'd find it a bit unusual for two completely different engine designs (and oiling systems) to have the same specs. Can't find GM book specs for the SBC.
Click to expand...
LS series I’d expect to be way different. My 5.3L with 270k miles idles about 40psi, but my 7.4L from ~1986 idles warm about 20-25psi.
 
dyeager535 said:

Oil pressure specs for those who want to know. - LS1TECH - Camaro and Firebird Forum Discussion

Generation III Internal Engine - Oil pressure specs for those who want to know. - Lots of people are worried when their oil pressure goes down or is in the 20's. I looked up the specs on what it is supposed to be on Mitchell. Specs are as follows. With engine at normal operation tempeture, oil...
ls1tech.com
Click to expand...
If my 5.3L was idling down at 6psi I’d for sure know something bad was going to happen in the near future.

i guess I could agree that if @mrgoodwrench has a stock 5.7L TBI motor with tons of miles on it, notices that the oil pressure drops a little on steep inclines while wheeling, maybe a HV/HP pump could help in that specific situation. But he didn’t say what the low pressure was. If it’s 3psi, then yea the better pump might help, but that would also tell me the motor needs a rebuild as well so why throw money at an oil pump? But if it’s just going from 25psi to 20psi, that’s still well above the minimum pressure.
 
I don't disagree. There is no guarantee any engine will last, especially as mileage increases. Things happen. I'm not one to normally use the "cheap insurance" rationale, so if it's bearings, more volume and pressure MAY be able to maintain the cushion of oil required to keep bearing wear to a minimum. If it's the pump that is shot, then replacing it (whether with stock replacement or other) is going to help. You just won't know until you try a new pump. Good thing with a pump (specifically "better" one) and bigger pan is, as long as the engine doesn't come apart while running, they can be swapped to a replacement.

But low oil pressure under significant load, at low RPM, is going to be a given regardless of engine condition. As you said, that bit of information (what psi at what RPM) hasn't been given.

FWIW, I couldn't find a specific statement one way or the other, but a "stock" style five quart pan doesn't seem to be any issue for clearance. The stock design 5qts (vs ones with kickouts, etc) aren't any deeper than the 4qt pans, the depth of the sump area is just extended further forward a bit. I thought I measured all that, but I can't find it.
 
Last edited:
dyeager535 said:
FWIW, I couldn't find a specific statement one way or the other, but a "stock" style five quart pan doesn't seem to be any issue for clearance. The stock design 5qts (vs ones with kickouts, etc) aren't any deeper than the 4qt pans, the depth of the sump area is just extended further forward a bit. I thought I measured all that, but I can't find it.
Click to expand...
Oil pans with kickouts are not necessarily any deeper than stock pans. They kick out to the right or left or both so that they do not affect ground clearance. Ground clearance being measured from the ground to the lowest point of the oil pan. I have a 7 qt Moroso pan with kickouts, trap doors, and scrapers and I am only 3/4" of an inch lower than stock. My oil pan is probably 1.5 inches above my transmission pan and another 1.5 inches above the crossmember. Looking at the front of the engine, the bottom of the engine oil pan is right about the same height as the top bolt of the front differential cover. Maybe the 2nd bolt down. If you are worried about the ground clearance of the oil pan, that should be the least of your worries as there is a whole lot of other things that are way lower than that.
 
I think someone mentioned earlier that the front diff pinion is where clearance issues can arise, if you manage to puncture any oil pan from an obstacle, you were giving it your best shot. Lol.
 
I was on a trail in Moab with @kgblazerfive when he punctured his oil filter with the suspension, which is at the back of the motor. Was just saying it’s something to watch out for.
 
dyeager535 said:
I think someone mentioned earlier that the front diff pinion is where clearance issues can arise, if you manage to puncture any oil pan from an obstacle, you were giving it your best shot. Lol.
Click to expand...
Now that, I might buy. I can take a pic of mine so that others can at least have a general idea. As soon as I get adequate daylight.
 
If I am going to go through the trouble of dropping the pan, I always roll in a set of main and rod bearings. relatively cheap, simple to do and just a little extra insurance. but that's just me.

Replace the pump with a good mellings high volume pump with the pickup tack welded on,
5 or 6 quart pan from Canton,
one piece pan gasket,
large AC Delco filter,
overfill it by a half quart with your favorite oil, prime it and call it done.

I'll take volume over pressure every time...
 
wasted wages said:
If I am going to go through the trouble of dropping the pan, I always roll in a set of main and rod bearings. relatively cheap, simple to do and just a little extra insurance. but that's just me.

Replace the pump with a good mellings high volume pump with the pickup tack welded on,
5 or 6 quart pan from Canton,
one piece pan gasket,
large AC Delco filter,
overfill it by a half quart with your favorite oil, prime it and call it done.

I'll take volume over pressure every time...
Click to expand...
One main and the corresponding rods at a time? You check clearances while in there or just put some new ones in? I’ve contemplated doing that to my current engine since it’s got such low pressure. Pan is leaking and I need to replace the gasket anyways.
 
dyeager535 said:
GM has also said burning a quart of oil in 1000 miles is acceptable. :haha:

I find those numbers quoted for LS series, I'd find it a bit unusual for two completely different engine designs (and oiling systems) to have the same specs. Can't find GM book specs for the SBC.
Click to expand...
I checked and your right good old all data shows that oil pressure for newer ls engines aswell so we know its wrong. Newer ls engines will set a warning light if it drops much below 20psi at idle. Thanks for all of the good input. Unfortunately i dont have any actual pressure numbers i never checked and now i have the trans out and am manual swapping. With all that out of the way it seemed like a good time to do oil pan gasket and rear main seal. With pan off and remembering seeing oil pressure look lower on the gauge than i would like when on the trail i was thinking should i go deeper pan or upgrade pump. Thats all thanks guys for the input. Melling when emailed responded quickly that they reccamend the hv hp pump for my application and millage. Im still on the fence. Also they state hv pump is only aprox 20%more and hp is only 10 psi more than stock so thats not huge.
 
I crack all the main bolts loose and back them out a turn or so. then pull one cap at a time.
You can usually pop the upper ones in the block loose with a skinny screwdriver, and they roll right out. Wash the crank and main saddle with a shot of brake cleaner and install the upper bearing. ( the one with the hole ) line up the tang on the bearing and push it into place. squirt some assembly lube onto the crank. clean and change the lower bearing shell in the cap, lube it up and install it back into the block. make sure the arrow faces to the front. install the bolts finger tight for now

do the same for all the other mains.

I don't think the #5 cap can be done on blocks with the full circle rear oil seal. but the older engines can be done as well as a new two piece seal installed . Some people just skip the rear cap unless there is high wear on the other bearings or a rear seal leak. If you do decide to change the rear cap bearing, be sure to lube the thrust surfaces with grease, and pry the crank end to end before you torque the cap to square up the bearing thrust. you must have end play.

after all the mains are done , I start in the center and work my way out torquing the mains.
Go over them two or three times, just to be sure.

Then just roll the rod journal down, change one rod at a time, be sure to line up the bearing notch as it came apart, lube it back up and torque as you go. You may need to rotate the crank a tiny bit to get clearance to the top rod bearing just don't turn it a bunch. After you torque it down, make sure the rod still slides sideways on the journal. It has to have side to side clearance....

Once all 8 rods are done go over everything with the torque wrench one or two more times.
It's not a hard job to do,, just be very careful and if something doesn't feel right...find out why.

As far as clearance,, if I know the motor and the sizes, I just order parts and have them there before I start... if there is no history, then you will have to pop a main and rod cap to see what size the bearings are. replace what is in there....ie:
standard, .010,.020 etc....

You can put in a piece of plastigauge on the bearing to check clearance, but if going back with the same size bearings,, I doubt you will ever see a problem. most of the time you will know by feel if something isn't right.
 
Last edited:
Bigger pan isn't going to do much, if anything, for "low" oil pressure. Obviously more, cooler oil is going to increase pressure, but I wouldn't expect an extra quart of oil to make any noticeable difference.
 
You must log in or register to reply here.

Latest Posts

Top Bottom