Update on my oil pressure. Time to get dirty I guess

As long as the motor is not ratteling and as long as the OP comes up with engine rpm it should be OK. My old Mopar manual says 5-8 lbs at idle and 10 lbs per 1,000 rpm is enough.

If a change in the weight of the oil did not change anything, there may be a posibility an oil pressure relief spring is weak or broken? Maybe your motor doesn't have a relief spring? I also have heard that some brands of oil filters (Fram is one) have had a problem causing low oil pressure. Seems the build in byp*** valve is too weak in those filters. May or may not be your problem, just a thought.

If you have already tried all of this stuff, I'm sorry, I'll just climb back under my rock. Gene

 

not being a flathead guru or anything, I have heard that they tend to have low oil psi sometimes. I know my dads 8BA does the same thing and it has ran fine for many miles. many many miles. just my 2 cents......

 

I also don't know much about flatheads. If there is another place to check the pressure you may try there.

It kind af depends where the low pressure starts .The pump may be putting out 50 lbs and it is dropping at the rods or mains. Then again the crankshaft may be getting 50 lbs and the drop is further up the line.It may be dropping right before the gauge so the engine may be fine.

I don't know if flatheads have a plug that could have pushed out internally.

I know from working with Chebby's that rod side clearance will dump oil pressure real quick.Also will make them tend to smoke as the oil bled off the rods goes on the cyl. walls and the oil rings can't handle it all.

 

I've just heard from Ron H that the current aftermarket oil pumps are sloppy and can dump pressure. Is your pump new or old??
The newly discovered problems involve the diameter of the upper casting where it goes into the block--the pressure can be dumped right here, before it even gets to the galleries! Check fit in block by just shaking it for the lower part of this, measure the upper bore fit since that can't be felt separately. Then pull the lower cover plate, shake the gears, and CHECK ENDPLAY. Most recent Chevy aftermarket pumps have waytoomuch end play, and I'd expect the same here.
How far has engine been apart??
If everything you can easily get to is OK and engine is a happy runner, especially since it's a temp employee until you can do a build, I'd certainly consider overwhelming the problem with a high volume pump, either aftermarket Melling or the big Lincoln one.

 

is it possible the galleries may be "gunked up"? Can you use the old trick of one qt of oil to 3 qts of ****** fluid to clean it up a bit? Is there another brand of "cleaner" that you can run in your flatty to break up and clean out that "gunk" or most of it for better oil flow?

The 8BA I have starts at 50 psi oil, then drops to about 15 at idle....I guess its good considering what I keep reading about this topic.

 

I would pull the front cover and check the gallery plug (to see if it's installed) and also pressurize the oil system to see how much is getting past the cam bearings. Then I would pull the pan and check clearances on the mains, then the rods. You can use an old flathead oil filter can for a pressure test. Run the bottom outlet to the hole in the block where the gauge line goes, install an air fitting with a regulator or on/off valve in the top cover of the can, fill it with oil, apply about 30-50 PSI, and watch which bearings squirt the most. (Also good for pre-oiling a fresh motor). If you hear air, you've used all of the oil in the can and will have to start over. It's a matter of timing unless you can find a gl*** sight gauge for the rig also. I did this last night to prime a new motor. Works good; lasts a long time.

pigpen

 

What are you running for an oil filter ?

 

I wouldnt even run an oil filter on a flathead.

 

Are we talking about a new engine or a "once rebuilt good running flatty when pulled engine". I started this internet thing on the old flathead board and I was embarr***ed to mention the oil pressure that my unknow flatty was carrying at hot idle. About 5lbs, 30 at 50 MPH it's been doing that since 1997 I got a complex listening to all the fresh engine bragging goin' on. I put on a new oil pump but it didn't change much. I've got a fresh engine I could drop in there but it won't die so I just live with it. Maybe us low pressure guys could form a support group to keep our egos up? You aren't alone.

 

Yeah--oil pressure is for goldchainers, not trad at all...
But I'm still curious about whether the pump is Ford or a recent repro.

 

Oil... Pressure... Flathead...

Those are three words I recognize, but I don't understand when strung together.

Sort of like: McDonalds... Breakfast... Burrito...

Oh, well. All I know is that a flathead will be OK under even unreasonable conditions, and Grimlock's doesn't seem to have unreasonable conditions. Also, answering Bruce's questions will get anyone where you want to go.

--Matt

 

Air in the line shouldn't make any difference. The air bubble will compress to the pressure within the system.

I'm with Unkl Ian as well. What kind of oil filter setup do you have?
If a full time filter system are there hoses involved like you'd have with a remote system?
Get the hoses reversed and you'll see a lower pressure, but only about 15-20%. Did that trick once and oil pressure at all rpm levels was down, but within reason.

If you're gonna get dirty - although you shouldn't with a fresh car, that's one of the pleasures about working on a hot rod, specially one that's only been running a short while because they are usually very clean.
Anyway, get some Plasti-Gage and shoot the bearing clearances on one rod and one main journal. As well as noting the condition of the bearings.

I know that some don't like Plasti-Gage, but it has it uses and this is one place where the product shines.

Even though you got a new gauge, was it electric or mechanical?
You can take a common run of the mill pressure gauge and plug it into the oil system and see what's happening.
My dad borrowed an old 100# air pressure gauge of mine to check the oil pressure on his Turbo Buick. The gauge came back with a little oil in it, but no big deal. One of the few times I could help him out in the world of engines and mechanics....

 

I agree !!!!

 

On an olde engine that hasn't beem apart, you doubtless have a real pump made to proper clearances. FIRST check the screen on the pickup--it might just be ****ing through an inch of slag. Next test spring on relief valve--I haven't checked to see if there's a published spec. Mebbe give it the vise test with one from a new pump. Check endplay in pump. I kinda doubt the trouble is bad stuff.

 

Looks like Melling M-15 or M-19 depending on what you have.

The M-19 is listed in the book as 32-48 std volume (if screen is fabricated)

The M-15 is for 32-53 high volume.

Then they list the M-19 for the 49-53 8BA engine.

I'm kinda flathead illiterate. And I have stuff for a lot of engines... just not a flatty.

 

Good plan. Always check the cheap stuff first, and the obvious, like a clogged pickup screen or loose tube. A high volume oil pump will more than likely necessitate a pan modification for clearance. I tried one in one of my 8BA's and it didn't work with the stock pan. I'm now using the standard M19 from Speedway on both of my 8BA's with good results. I also tried the full flow system from Motor City Flathead. That system did not build pressure on start up as quickly as I thought it should. I was afraid of premature bearing wear so I went back to the stock style system which builds 50 lb. right away (cold, no filter). The other motor has the old can style filter which doesn't seem to hinder the pressure.

pigpen

 

Also, a HV pump should only be necessary as a kludge on an engine with lots of very sloppy bearings. I'm currently betting on a clogged pickup. Drop pan, check that first. Try to buy a new pressure valve spring while you're at it, or borrow one from someone with a new pump. Vise test, crude but a way to ballpark estimate if old spring is good:
Figure out a way to corral the two springs so they are together in series end to end and can't go flying--I'd say wire the ends together, perhaps. Put the ***embly in a vise and tighten--if old spring collapses much before the new, it's weak.
If this is a quiet and happy engine except for the pressure, I'd suspect a real failure involving bearings is unlikely--I bet you'll find two inches of crud in the pan and a pickup screen that is completely clogged. Check gear condition AND ENDPLAY while in there. Go read Ron's Ford Barn posts on new pump problems with fit in blocck too--if you need a new pump, make sure you check this fit.

 

Not sure how difficult it would be to do with a flathead oil pump, but once't upon a time little brother and I set up a 455 Olds with Milodon pump by making a bracket and drive adapter so we could test the pump on the bench.

We had a gauge plugged into the system and the pickup was immersed in a shallow pan of oil which also picked up the oil that'd gone through the pump.
We tried several spring/shim setups till we got where we wanted to go.
Keeping in mind that pressures would be down a bit once the engine was hot.

One flat washer of the right diameter under the relief spring can crank the pressure up quite a bit in some cases.

If you're digging through a stack of new washers you'll find them in varying thicknesses.
You can also find fairly thin flat washers in stainless.
Very minor adjustments can be made with shim stock cut to shape.

 

We used to do the old "washer trick" on the '47 Chrysler flathead six, back in the day. You could do it from the outside; the oil pump was exposed externally. Got to 100lb. one cold morning and had to back off on the thickness for fear of blowing something. That was even before I got that awful name, many moons ago.

pigpen

 

Are you using an electric fuel pump? Was the old stock pump removed? If it was removed did you or anyone else plug the pushrod hole? When I installed the blower on my 8BA I had to do away with the old pump and go electric. When I did I had a lot of oil vapor coming out of the old fuel pump stand breather. I removed the breather stand and started the engine; looked in the intake/pumpstand hole and saw a lot of oil pumping out of the pushrod hole. I bought a 7/16" Welch (freeze) plug and glued it with RTV to a piece of 3/8" all thread; stuck it down through the intake and tapped it home with a light hammer. I then broke the RTV loose and pulled the all thread back out. Breather problem solved!

Perhaps this could have been your problem since day 1 and it just got worse through cam bearing wear.

If you're still using the stock fuel pump then my solution won't help!

 

all flatties run more then enough volume of oil . and flatties are known too run very low oil pessure . my 296 run 3 psi hot at an idle . they still have lots of volume and volume is needed to float the crank on a oil wedge . the idea is to flow oil thru fast in volume which one floats the crank , and two doesn`t give the oil time too get as hot . so i wouldn`t be too concerned it is a flat head not an over head !

 

Ive been preaching for years that one of the first things to do with an old unknown flatty (any old engine that ran straight weight for that matter) is to drop the pan and clean out the crud in the screen. Pre 50 8BA pumps were low pressure and wouldnt do much over 30# even new. Ford went to the Melling M19 in mid-50 and that is the same pump sold today. The early pump had square cut gears, the M19 is helical.

Ive had no QC problems with the M19 and all builds easily hold 30# hot using Castrol 20W50. I wont use a straight weight except for the initial 500 mile break-in.

It doesnt take long for a pump to wear and loosen up the gear mesh, especially on non-modern multi grade oils that have the best anti wear additives. In the old days a pump was often replaced around 30K miles, about the same time a valve job was needed.

 

3 psi....whoa is right. mine got between 15-20 and I kept reving the motor in fear of it locking up.....

Crazy

 

Grim, If you pull the pan and find gunk and stuff, I would change the pump just for good measure. When you go to put the new pump in you'll find a groove in the part that slides up into the engine block. This groove will accept an O ring, find one that gives ya about .010 to .015 crush when you push the pump into the hole. That done will give you about 5 more pounds and helps on any pump and solves the problem Bruce was talking about. I have it on all my Flatheads and works great. --TV

 

Grim, red circle, and yes all pumps have this groove. I know this works I've seen it many times.--TV Also run 20 /50 it seems to do a better job.

 

What are "red circle" and "blue circle" O-rings? All of the ones I have ever seen are black.