Oil for boosting oil pressure in 1950s V8

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Many many people on the vintage Mustang forum are using Mobil 1 15w-50 on their vintage engines, worn or fresh. It’s not expensive, easy to find at any Walmart, and recommend by Mobil for our vintage engines. It has great wear protection as well. I’ve been using it for 20+ years on many different cars of mine, and customers cars too. After 85,000 miles on one Hi-Po 289 I checked the main bearing clearance when the oil pan was off to switch to a different pan. No measurable wear.

Z
 
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Oct 6, 2020
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Yes, and clocked correctly for FE engines. All bearings are new. Block steam cleaned, all oil gallery plugs removed and rodded/steamed and tapped and threaded plugs installed.

Oil pump is a 5 lobe rotor style. I inspected it prior to installing it in the engine.



Oil filter adapter and holes in the block were modified for increased oil flow as consistent with first generation FEs.



That was my reasoning for going with the standard output Melling as well. I did all the oiling mods typically dine to FEs but didn't restrict the passages to the rocker shafts as some guys do.

I've built a few Euro engines, but this is my first mid century V8.
Please elaborate on the oiling mods you've done.

If you increased flow, pressure will drop.
 
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I owned cars with those motors and manuals always listed 10-40 as ideal for them. I had 292's and 312 and father -in-law had 352 in his 65 Ford. We never had oil issues. Maybe you are over thinking this. If the oil pressure light doesn't come on at idle you are good. My VW 1600 air cooled uses a 3PSI oil light. Not sure what the old Ford V8 was but I can imagine it was quite low too.
 
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How does flow matter exactly? Flow lubricates?

Oil helps cool the valvetrain, as well as contributes to heat generation in the bearings by way of hydrodynamic friction. The better the flow, the better the valvetrain cooling, and lesser the bearing heat. You also get more oil splash onto the cylinder walls and bottom of the pistons.

His engine has clearances typical of a 20 grade but using 10W-40 and seeing only 10 psi at hot idle. The higher viscosity oil with the tighter clearance will show rather high pressure as the viscosity reduces flow a bit at the bearings and rockers. What his situation indicates to me is there's insufficient oil flowing to the rotating parts and with insufficient flow to backup against those restrictions, you get insufficient pressure. A stock oil pump could send 10W-40 at 4+ gpm and 30+ psi at hot idle without much issue against those clearances. Hence, I think something is killing off oil flow before it gets to the rotating parts.
 
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I owned cars with those motors and manuals always listed 10-40 as ideal for them. I had 292's and 312 and father -in-law had 352 in his 65 Ford. We never had oil issues. Maybe you are over thinking this. If the oil pressure light doesn't come on at idle you are good. My VW 1600 air cooled uses a 3PSI oil light. Not sure what the old Ford V8 was but I can imagine it was quite low too.

True for a stock engine. However, his engine has been rebuilt with tighter clearances than stock as well as other oiling mods. (it seems, awaiting response) Therefore, the factory recommendation no longer applies.
 
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Just checking my records of what i measured on assembly for bearing clearances. Mains were 0.0018"- 0.0023"
What were the rods? Is there a sloppy one?

390 and 428 Top oilers I've built have had low idle pressure on 30 grade oil I've used for wear in period. Main area to check on worn engines is a sloppy valvtrain - as someone mentioned. Remember the narrow bolts go where the oil feeds are to the rocker stand.
Also important If the pump was blueprinted and tightened up. Should have about 2 thousandths clear from rotor to cover. Over 3 thou you'll likely have low idle pressure; but you don't need much idle pressure.

Sounds like you got the engine brushed and cleaned well so you don't have machining junk dammed up in corners of the gallery drills.

Remember the pump is there to put the oil in the journals - the oil film thickness does the lubrication and part separation - not oil pressure. - Ken
 

Fabulous50s

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Those are not tighter clearances than stock. Actually what the shop manual calls for.

I am using Amsoil Z-Rod 10w-30.

Stock rocker shafts and arms. Stock 270/270 cam. I didn't want to risk the break in horror stories and this ain't no hotrod.

Oiling mods:

1.Drill out hole in block from oil pump supply to oil filter adapter from 5/16" to 3/8" to match the diameter of the rest of the passages.

2. Drill 3/8" drain hole in the valley toward the timing chain.

3. Remove the oil "jiggler" and install a plug in it'd place. Only early FEs have the jiggle pin, thus should increase oil pressure.

4. Gently ease (relieve) the holes in the block for the oil filter adapter toward the filter.

5. Relieve the oil holes in the main bearings to better line up with the offset oiling holes in the block. I didn't touch the block, just the bearings.
 
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Those are not tighter clearances than stock. Actually what the shop manual calls for.

I am using Amsoil Z-Rod 10w-30.

Stock rocker shafts and arms. Stock 270/270 cam. I didn't want to risk the break in horror stories and this ain't no hotrod.

Oiling mods:

1.Drill out hole in block from oil pump supply to oil filter adapter from 5/16" to 3/8" to match the diameter of the rest of the passages.

2. Drill 3/8" drain hole in the valley toward the timing chain.

3. Remove the oil "jiggler" and install a plug in it'd place. Only early FEs have the jiggle pin, thus should increase oil pressure.

4. Gently ease (relieve) the holes in the block for the oil filter adapter toward the filter.

5. Relieve the oil holes in the main bearings to better line up with the offset oiling holes in the block. I didn't touch the block, just the bearings.

I apologize. I misread your original post. (I seem to be doing that a lot lately.... might be time for another cat scan. lol)

The OEM tolerance was a ridiculous range of .0005-.0025" though I've known them to be on the wider side of that (.0022-.0025") for ease of assembly. I could be mixing that up. I've been off my game a bit lately.

Given we're talking about a 10W-30 and your oiling mods, I'm less concerned. 10 psi oil pressure isn't an issue so long as flow and film thickness are sufficient. You could try the 10W-40, but I think it would just increase bearing heat with no benefit.
 
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Those are not tighter clearances than stock. Actually what the shop manual calls for.

...

5. Relieve the oil holes in the main bearings to better line up with the offset oiling holes in the block. I didn't touch the block, just the bearings.
I forgot about this one - being a Chevy guy

Did you open the gasket window on the filter adapter gasket to match the channels in the block and pump? Possibly they are coming modified now like on the CJ motors. It really only an issue when the block is channeled to mirror the adapter. In the ex below it is NOT channeled - so no effect.
This is not your issue anyways :)

stock gasket:

19780045_fel_70135.jpg


Hi Po:

oil adapter.jpg
 
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How is this still a mystery that everyone is trying to solve???

Look at the mods he's done to improve flow. Everyone claims they've built this and that, yet doesn't see the red flag??? You guys are jumping to the most extreme mechanical issues. Just NO.

Op, you've answered your own question. You improved flow but you're expecting the same pressure??? That is not how any of this works.

Flow and pressure are INVERSELY PROPORTIONAL.

Want more pressure, install a higher pressure pump. Simple.
 

Fabulous50s

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Yes, I slotted the filter adapter gasket. I didn't take a lot of pictures when I was building the engine as I had oily hands and was in the groove.

I just picked up 2x 5qt Jugs of M1 15w-50. I didn't know M1 still made it. I used to run M1 15w-50 in my VWs.

Same price as Castrol GTX Classic, so I went for synthetic for the same price as GTX.
 

ZeeOSix

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If you increased flow, pressure will drop.
As long as the PD oil pump isn't in pressure relief, can't increase flow unless you change the oil pump (ie, pump volume per revolution).

And if all things were held constant, increasing the flow will increase (not decrease) the oil pressure.
 

ZeeOSix

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How is this still a mystery that everyone is trying to solve???

Look at the mods he's done to improve flow. Everyone claims they've built this and that, yet doesn't see the red flag??? You guys are jumping to the most extreme mechanical issues. Just NO.

Op, you've answered your own question. You improved flow but you're expecting the same pressure??? That is not how any of this works.

Flow and pressure are INVERSELY PROPORTIONAL.

Want more pressure, install a higher pressure pump. Simple.
An engine's oil pressure is mainly from all the journal bearings (crank, rods and camshaft), and of course the oil viscosity and oil pump performance (volume per rev). The oiling mods he's done won't really effect the oil pressure.
 

ZeeOSix

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Flow and pressure are INVERSELY PROPORTIONAL.
With a PD oil pump, it's more like flow is constant (at a constant RPM and oil viscosity), and the pressure is inversely proportional to the oiling system's total flow resistance. It takes more pressure to force the same oil volume and viscosity through the same flow resistance. If you held everything constant, then flow and pressure are directly proportional ... meaning if flow is increased, so is the pressure to make that flow go through the same flow resistance.
 
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As long as the PD oil pump isn't in pressure relief, can't increase flow unless you change the oil pump (ie, pump volume per revolution).

And if all things were held constant, increasing the flow will increase (not decrease) the oil pressure.
You are referring to the oil pump, I am referring to the rest of the mods he did to the oiling system after the pump. Pump will try to flow a certain amount at a certain rpm at a certain pressure. If you modify the oiling system enough, that pump will not be able to keep with with the flow.

Again, find me one engineer to disagree withe the statement "flow and pressure are inversely proportional" .
 
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