Oil pressure Question: What causes this?

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superdart

superdart

Shade Tree Tinker Gnome.....
Joined
Aug 26, 2004
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Location
DFW, Texas
Engine: 360 9:1 maybe 2000 miles on the engine

Pump - HV oil pump
Oil gauge: VDO Vision electric

Pressure use to be 30-40psi warm at idle, and 70-ish on the highway. I haven't driven it much this year due to other things going on. Now when I pulled it out two weeks ago, it only shows about 20psi warm and 40psi at highway. The scary thing is that when I lean on the throttle, the oil pressure goes down about 5-7psi.

I just hooked up a cheap Sunpro mechanical gauge, and it shows about 55psi at idle cold. The pressure looks better, but when I rev the motor up you can see the oil go back down the nylon tube toward the engine.

WTF??

The only thing I have ever changed was adding the roller rockers (with roller bearings) and installed my Amsoil bypass kit. After both of these mods the oil pressure seemed to be fine.

Now, what I DID do was change the oil. Now keep in mind the oil kit is mounted higher than the block adapter on the engine. I am assuming the oil is draining back down into the sump when the engine is not running. I added extra oil, but I think maybe I didn't add enough oil, and it is sucking a bit of air.

Never had this problem before...does it sound feasible? The car runs great, but I'm not driving it again until I'm confident I won't tear anything up.

I think I am going to disconnect my oil kit and just spin an oil filter on the block to prove/eliminate the kit as being the problem.
 
I have trouble with people using these remote oil filter things when a factory mount and a good filter is proven to work in almost all cases. If it aint broke, don't fix it.
 
I have a remote kit on mine and not only does it work perfectly it makes changing the filter a whole lot messy and faster. The factory angle adapter is prone to leak and has some awful ports inside for the oil to flow through so the remote filter kit (if plumbed in via fittings straight into the block) is a definite improvement.

Superdart it sounds like the pickup has came loose and swung up higher than the oil level and is sucking air. Maybe as a test try adding a couple more qts. of oil and see if it still goes down when you accellerate. If not there's your problem.

BTW: I added pics of my remote setup. Sure nice not to dump hot oil all over the headers when changing it.
 
Well, here is my setup. It's an Amsoil BMK-13 dual filter, ultra low micron filtration system. The oil passes from the engine, to the filter base, then to the B&M oil cooler that you can see at the bottom of the core support, then back the engine. Overkill? Yes...but that's the way I roll...unless of course it is going to cause problems.
 
Superdart Are you running the Dominator Racing Oil that Amsoil just came out with? According to their paperwork it's supposed to be heavily fortified in the zinc additive package.
 
Have u ever looked at the size if the ports in all the fittings u are using? It just looks like the lines may be a little restictive. Rule of thumb would be the more length-bends-fittings= need for bigger lines. Also the finer the filter the more pressure drop at the filter. With all the lines you show in the pic's I would be using at least 5/8" id lines then your restriction would be right at the block and no where else.
 
mod5v said:
Have u ever looked at the size if the ports in all the fittings u are using? It just looks like the lines may be a little restictive. Rule of thumb would be the more length-bends-fittings= need for bigger lines. Also the finer the filter the more pressure drop at the filter. With all the lines you show in the pic's I would be using at least 5/8" id lines then your restriction would be right at the block and no where else.
Click to expand...

Good point. Most of those hyd. JIC fittings have real small i.d. compared to the o.d. If I were using hyd JIC fittings I'd use no smaller than 3/4" fittings and drill out the adapters so they have at least a 7/16 i.d.
 
Well, we're going to find out. I have a Fram PH16 to screw on the block. I didn't get to it today since I spent most of the day welding on my buddies rice burner.

Maybe tomorrow.
 
I was also going to suggest the filters. And I agree, run Wix. Any filter you pay less than $5 now a days is a POS. Napa and Carquest sell the Wix line, but make sure you get teh good one, not the cheaper line. The air in the line is no big deal. It compresses and the gage reads, then when pressure drops, it expands again.
 
I run K&N oil filters on my 340, seem to work great! They are about 6-10 bucks but I am willing to pay more more for a performance filter. BTW, I have also heard Fram filters are junk, Wix ones are great too.
 
Generally oil pressure going DOWN as RPM increases indicates excessive rod bearing clearance.

That seems like a lot of plumbing for the oil to go through before it can actually reach any moving parts in the engine. Why?
 
Texas + Hot = oil cooler is good idea...so I figured I'd add the filters while I was at it. The system has been on the car over a year with no problems until now. But, this may be another case of simple is good.

Fishy68 - I agree Fram sucks, but it is just for testing. If this does resolve the issue, I'll put an Amsoil EAO42 on the block. I have that minimopar site bookmarked.:cheers:

Jefflock - I am currently using the (ATM) 10W-30, but am looking at changing to the Dominator in my next oil change.

I run Amsoil exclusively in everything I own. Hell, I did back to back dynoes with my Dakota and picked up 7hp at the tires after changing all my fluids to Amsoil. 8)

C130 - I usually cut my filters open and check for foreign materials, and haven't seen anything yet. I would think if I were shelling my bearings I would be seeing it in my filter or magnetic oil plug, correct?
 
DING DING DING....We have a winner.

I disconnected the oil kit and spun a block filter on, and drained about 1 qt of extra oil I had in the crankcase (to fill up the lines to the filter mount). Now the car is pushing proper pressure and the pressure increases with RPM.

So now the task is to find out if there is a problem with one of the oil filters I just installed during this oil change, or if I just didn't have enough oil in the crankcase to pressurize the lines when they drain back.

Either way, I'm comfortable driving it now knowing it's not an impending engine problem.
 
Glad you have a WINNER!!!!!!
 
Thanks, I actually just realized it might not be either of those items.

The Amsoil bypass mount uses a spring loaded restrictor to force a limited volume of oil through the (very high restriction) bypass filter. If this restricotr jams then it would be forcing ALL of the oil through the bypass filter..which is VERY bad. The bypass filter works down to about 1 micron in size, and is very restrictive. So, I'm gonna start by pulling that out (it's removeable) and making sure it is working.
 
I'm not positive, but you can also get a hydraulic system filter that should screw directly on the filter boss that filters down to 10 microns. Dump truck s and stuff use them to keep the spool valves and stuff in good shape. If you're really that concerned. You may try pre-filling your filters too.
 
Actually I always prefill the oil filters.

I have removed the plate style oil cooler and about 5 feet worth of line. Now I am running only the dual filter assembly with about 4.5 feet of hose.

I started the car and slowly added oil until the gauge was moving in the right direction when revving. I used a mechanical gauge with a magnet mount so it was right there in the engine bay, and I could monitor it while filling.

I needed to add a little over a quart to the sump, on top of the 2 quarts needed to prefill the filters. So that works out to about 7.5-8 quarts total with the added lines and filters (it's a 5 qt pan with windage tray).

Currently at operating temp I am running about 25-30 psi at idle and about 60psi at 2,000 rpms. Currently I am still using 10W-30 Amsoil.
 
What problems do you guys experience with Fram filters? I don't think I've ever had a problem with them.
 
They used to be (liek 20 years ago) decent. They now have little filtering media and plug fast, they have no drainback valve, the end is constructed of cardboard and can fall apart, and they can cause low or erratic oil pressure readings (not joking, I've seen it on several engines before). They are junk, like most filters selling for under $5-6.
 
superdart said:
Actually I always prefill the oil filters.

I have removed the plate style oil cooler and about 5 feet worth of line. Now I am running only the dual filter assembly with about 4.5 feet of hose.

I started the car and slowly added oil until the gauge was moving in the right direction when revving. I used a mechanical gauge with a magnet mount so it was right there in the engine bay, and I could monitor it while filling.

I needed to add a little over a quart to the sump, on top of the 2 quarts needed to prefill the filters. So that works out to about 7.5-8 quarts total with the added lines and filters (it's a 5 qt pan with windage tray).

Currently at operating temp I am running about 25-30 psi at idle and about 60psi at 2,000 rpms. Currently I am still using 10W-30 Amsoil.
Click to expand...

You should have not needed to add more than the 2 qts needed to compensate for the dual filter setup and a small amount for the hoses. Definitely sounds like the pickup has came loose and swung up higher so now it takes a higher level of oil in the pan to cover the pickup.
 
I didn't have the sump totally full before I started adding oil. It was above the add mark, but far below full. My total capacity is just about 7.5 qts...which should be correct accounting for lines, two filters, 5 qt pan, and the filter mount.

It was working perfectly with just the PH16 on the engine block and the oil being just above the add mark.
 
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