Took the '77 over to a buddies today, we were chatting and the subject of oil pressures and effect on bearings in the 351M and 400 Fords came up. I had forgotten that he spent some time in a Ford dealership back in the '70s, before I knew him. He was looking over my truck with the idea he's gonna install some body stuff and paint her. He knew I had had this truck since the '80s at least and he asked it's mileage and if it had good oil pressure. I said it stayed between 60-70 psi on the way over, he asked if I ever had bearings go out. I told him what happened in '92 and that I put new bearings in and a high volume pump recommended by Brownie (he knew Brownie, he used to work in that shop too) . He said "You mean high pressure don't you?" I said "No, Brownie suggested high volume". ... and then my buddy went on to say that at the Ford garage, they told people to use a high pressure pump to get the oil past the top end in those engines to the bearings.

What say y'all ... how do you look at it? Which is more important, high volume or high pressure.

Later I found it was a standard oil pump I put in in 1992, all those years ago. Post 6 below. I chose to leave it.

 

Pressure is created by restrictions in the flow. An engine is full of leaks, rods, mains, cam bearings, lifters etc. When it's new those leaks are small and you have good pressure as the engine wears they get bigger to the point that the oil pump is supplying all the oil it's capable of suppling. In other words the engine is leaking more oil than the pump can pump. A high volume pump might correct this for a time. A high pressure relief spring in the pump won't change anything in a worn engine.

 

The stock pump in a Ford Cleveland is already a high volume pump in the sense that it uses the same rotors as the big block engines. If you use a Melling pump it is already high pressure too. Cut back the leaks in the system and it'll have so much pressure you won't believe it. Some 351m/400 engines suffered from low oil pressure issues. The reason for this is that many of the blocks have main housing bores that are too large. The fix would be to trim the caps and line hone the block but what many builders do is install a set of main bearings, measure and then grind a crank to fit with the desired bearing clearance. Often this ends up being a crank that's .009 or .019 under instead of .010, .020 or whatever.

If the engine is built with .002 clearance rods and mains the oil pressure will be nice hot with 10W-30 motor oil. You could even drop down to .0015 and be fine in most street applications.

Here's a video of a 384 inch Cleveland that I did about 5 years ago for a custom with a Pantera. He's run it in that Silver State Challenge out in NV and other stuff like that. It shows what the oil pressure looks like if you just get the leaks under control. It's a 351C block with bushings in the right side lifter bores and a restrictor feeding the left side. Solid roller lifters, Scat crank, rods and Probe pistons. It has an Aviad pan and a stock Melling pump. In this video I had run the engine a lot, probably at least one hour under load and had done many dyno pulls to 7000rpm. Revved up it would hold about 90psi and idle at 75 hot.

 

Totally agree with what Dave just said. I built a spare 351C for my truck around this time last year. With mostly left over parts I had laying around, .002 on mains .0025 on the rods. Lifter bushings in all 16 holes with restrictors at all 5 cam bearings. On my run stand @ 185 degrees, 85 PSI @ 2000 with Driven GP1 10-30.

 

Well ... I understand that trying to push a bigger volume through a hole in the same time will increase the effort required to do the push, or "raise pressure", I'm pretty satisfied that Brownie set me straight, 30,xxx on it and it still make good psi hot, even with just standard bearings on what was likely a slight worn crank in '92. I have a memory of using some plastigage on the bearings, but I may be recalling when I fixed up that 400 on my stand ... my notes tell me it's got between 2 and 2.5 thousandths bearing clearances. It's been a really long time since I put that together. I know Brownie went and pulled the pump off the shelf there when I did my 351m, I know it is a high volume pump and that the oil galleys create restriction. I did not then understand the oil routing so well on these engines though. I see several here do. Thank you all.

 

I meant to inquire, but forgot. The High Volume oil pump was in a box and just said high volume, not sure that it was a Melling pump then, it was off the shelf at my NAPA and was what they used in builds. Brownie has retired, but I remember him cautioning about HV/HP pumps. I had told him I didn't want to blow oil filters off.

Reason I'm even looking tonight is I think come Spring, might pull the pan and look at a couple bearings that I put in back in 1992, but maybe I should leave them alone? I do have a ARP oil pump driveshaft I thought I might put in and since the pump will be out, wondering if I should go back to a stock pump? The goal then was just to get a bit more time out of it, and it has certainly done that. Maybe best to just leave the HV in. It's been 30 years and over 30,000 miles now, and I still have great oil pressure (60 psi+ warm at cruise). I have taken to running 15w40 DeloLE in it.

updated 05-20-2023: Just finished my new bearing roll in and discovered that while worn, my 1992 bearings weren't all that bad and that I thought it had a HV oil pump, it really had a Melling M84A standard press and standard volume replacement oil pump. I know what Brownie told me, maybe was just boxed wrong. 351M/400 bearing "roll in" job plan. - Ford Truck Enthusiasts Forums (ford-trucks.com)

 

Not the best idea to run diesel oil in a gas motor
It is a detriment
Nice build Dave,

 

The deisel oils tend to have zinc etc in them. That's why to use them

 

It's not diesel or gas oil, it's just a high zinc motor oil. I bought a few of those boxed 6 "5 qt jug" cases of the Delo LE when I still had my two Gold Wings, was a great commercial sales promotion = good price, it worked, and slicked up the shifting like fresh snot. It's long been used by many for years with them. I had to let them go a few years ago ... it was a balance issue I did not then know was gonna be getting better (it is much better now, about gone actually) and it was awful tempting to go for a ride, but I knew then that it was dangerous for us to do so. On a MC, one must have the head on a swivel if they want to be safe ... and that's what would throw me in a twirl. It was bad. It was a tumor in my cerebellum. I would not / do not use it in anything with a cat.

 

The diesel oils have too many additives, that are not suitable for gasoline engines, and can plug up your catalytic converter
The books talk about heat generation and premature wear
Use at your own risk IMO
Some of the newer diesel oils can be used, mainly the 5-30 ones

 

I believe the additives that damage the converters is the same additive that has been taken away from most modern oils because the cause damage to converters. Zddp which is what he's looking for in the diesel oil, the zink for added protection on metal to metal wear surfaces. Cam/lifters I thought the issue with diesel oil was a foaming problem in gasoline engines.

I run VR1 but if in a bind and I have to Id drop a quart of rotella in to get me by. Is this something I need to rethink?

Maybe this is something I need to do more research about but that's the jist of what Ive gathered over time on this forum.

 

From the spec sheet: Chevron Delo 400 LE SAE 15W-40 | SCL (sclubricants.com) ... it looks to be API SM, CJ-4.

Anyway, moving right along, I believe when I get my ARP fatter shaft drive for the oil pump, I'll just drop the pan after draining the oil, pull the pump, swap the shaft, and pull the distributor to look at the drive gear, maybe replacing the roll pin, maybe with the next larger size. Think I should leave the rod & main bearing caps untouched since it's maintained oil pressure these past 30 years and 32,xxx miles so well. In 2004, even pulled a loaded two axle trailer of furniture to Alabama.

 

I don't think I'd worry about checking the bearings if pressure is good.

You could send some used oil out to lab testing to get an idea if there's abnormal amounts of metals in it. (I don't think I would worry about that either)

 

Oil with a C is for diesels (CD, CE, CF, up to CJ now) on the specs
Oil with an S is for gas engines
You won't catch me putting C oil in a gas motor (well except by mistake)

 

I run diesel oil, cat or no cat. No issues yet.