Technical 40 zephyr 12 low oil pressure, where to look

Ok, 40 Zephyr, very nice car. Runs ok, we have a tuning issue we'll get thru easy enuff. Cool pressure is fine, about 15-25 at idle, just under 40 revved up. When it gets to operating temp the idle is at a scary low 7-10, and about 20-25 at speed or revved up. I don't like it. Has no pushrod for a fuel pump, just the guide tube and bushing. Yes I did a HAMB search and some say yes, others say no. It is the early version 12 (1 and ½ flatheads). I want it to be on a mechanical pump and just use the electric to prime the system. If we have to we can drop the pan again (fixed leaks) but things looked very nice in there so worn out doesn't seem to be it. Already have a good pump to install and the manifold is off at the moment. Before I close it up and take the "let's hope that's it" approach some conversation about it would be welcome. If I had to we could drop the pan and replace or boost or rebuild the pump. It would be nice to not have to. For the record I was just an observer on the pan drop, I might have just done the pump for the fun of it. Whatcha got? And as always thanks in advance.

Oh yeah, to avoid being told to fk off without pics, well here ya go. Like said, nice car...

He's looking down off the cliff of longer shackles, I keep giving him a nudge now n then...

 

What weight oil? If the lifters aren't rattling and it's not leaking, I'd drive it. Does it have that real accurate 50lb guage? lol Lippy

 

I would put a known good mechanical gauge on it first to see if it's the gauge. 7 to 10 at idle is not going to hurt anything. Like Lippy said what weight oil is in it?

 

I would check it with another reliable guage to verify, and probably go the next step up on oil viscosity and see if it makes a difference. Probably fine

 

I think its 15-40 in it. Before we were to dig in I will flop in a test gauge. I'd like to see 10 and 30 hot at least.

 

Those old low rpm buggars are pretty happy with not too much. My 1950 Ford 8N, based on the car engine, has about 5lbs at idle hot and quickly follows rpm with more, with straight 30 wt- it has 1100 hrs on it. Funny to watch that old direct mechanical gauge's needle twitch at idle

 

Verify the oil viscosity, you could even send a sample off for ****ysis to verify, or drain it and put in fresh oil. 15W-40 should provide good oil pressure, especially this time of year.

 

My Motor manual says 30 psi at 30 mph. I also have an HV-12 engine manual I bought at a flea market (I've always wanted a '40 or '41 Continental); it doesn't say anything about oil pressure, but it does go through several measurements for the oil pump clearances, along with mentioning several different relief springs.

 

I'm old, and as a kid I remember that low oil pressure was a common Lincoln V12 complaint.

 

I don't recall which years, but some of the Crankshaft has "soft plugs" that would dislodge and cause low oil pressure. Just at thought.

VR&C.

 

I’ve seen 10 pounds hot at idle difference between two different manufactures of 20w 50 racing oils.
They were Valvoline and Lucas high zinc.
I’d verify your pressure and then consider a higher multi viscosity 50 weight.

 

I was told low oil pressure was the reason they stopped making that engine. there must an electric pump or dry sump or something that can solve the problem.

 

Here's a thread that suggests a special oil pump over at the AACA site:
https://forums.aaca.org/topic/115500-engine-oil-pressure-again/

 

Check the oil sending unit attached to the oil filter canister

 

Rule of thumb: 7 psi for every 1000 rpm, don't overthink it, those engines where pretty much "famous" for low pressure.

Frank

 

Good info here, but, also post this on "The Ford Barn". All flathead stuff there.

 

I'm pretty settled in to regular expectations. I'm also familiar with the 10 per 1000 RPM or speed ratings. Since the intake is off now is the time to get after any issue related to the fuel pump rod and pressure loss if that is indeed an issue. The original manifold cracked and we found an NOS replacement. It has another head scratcher going on as well but that's something else to babble about later.

 

You wrote: "I want it to be on a mechanical pump and just use the electric to prime the system."
I have seen a number of electric pumps installed at the tank to correct low or no fuel delivery. The source of the problem is the flexible fuel line that goes from the steel fuel line on the firewall to the mechanical fuel pump on the rear of the intake manifold. The ferrules start leaking and the pump ****s air and not fuel. Replace the flex fuel line with a new one and the fuel delivery problem is solved. Back in the day most Lincoln V-12s ran just fine on the original mechanical pump by itself.

 

Yup, I agree. You don't see newsreels with cars all broke down on the side of the road everywhere, right?

 

But a hell of a lot of photo evidence of overheating problems!