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1980 F350 4X4 C6 Project

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Gary Lewis

Re: 1980 F350 4X4 C6 Project

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Is your engine new? It is on break-in of the cam that the most concern is for additives. But you still need to run some zinc for the cam even after break-in.

I’m running Brad Penn oil, but that’s probably overkill. However, since I have quite a bit of it that’s what I’m running. I think many others are running diesel oil, but I’ll let them speak to that.

On the oil pressure, if you are building a 351M or 400 there are mods that can be made to bring the pressure up. Go to Documentation/Engines/351M & 400 in the menu for a discussion of that.

Gary, AKA "Gary fellow": Profile

Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker & 10.25 Sterling/Trutrac, Blue Top & Borgeson, & EEC-V MAF/SEFI

Atlas75

Re: 1980 F350 4X4 C6 Project

The engine is not new. Supposedly rebuilt but I have no idea how long ago, what was done to it in the rebuild, or who did it. I just remember reading you need a certain level of zinc in the oil if you have flat tappet lifters?? I’m not sure what type of cam and/or lifters are in this engine.

Carl

1980 F-350 4X4; 400 C6; Dana 61 rear, Dana 50 TTB front
1984 F-250 4X4; 6.9L T19; Dana 70 rear, Dana 44 TTB front

ArdWrknTrk

Re: 1980 F350 4X4 C6 Project

Administrator

This post was updated on .

Be glad you don't have solid lifters!

I can't speak to a 400* specifically, but I always use diesel oil.
It has more detergent and a longer OCI.
Now that diesels too are using catalytics you aren't going to find the same elevated lives of ZDDP in CI oils that you used to.
But if you are that concerned you can add some (as long as you don't have a catalytic converter)
Because replacing those every six months when they get poisoned will get expensive quickly.

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

Gary Lewis

Re: 1980 F350 4X4 C6 Project

Administrator

In reply to this post by Atlas75

The biggest problem on the oiling system of the M-block engines is that it puts way too much oil to the #1 main bearing, thereby leaving too little for the lifters, and especially those on the driver's side which get their oil after the #5 main.

Tim Meyer told me he's turned an engine on his dyno w/o a pan and he could see lots of oil escaping from the #1 main, but not nearly as much from the others. So he came up with some mod's that make a big difference. The first mod is to the oil passage to #1 main, as shown below. The second is his own cam bearings that restrict the flow to the cam, thereby leaving more for the lifters.

The combo of those two works well. He built my engine and then ran it on the dyno. After warming it up and then doing six pulls to 5500 RPM it idled at 20 PSI of oil pressure.

Gary, AKA "Gary fellow": Profile

Atlas75

Re: 1980 F350 4X4 C6 Project

Well I finally had a chance to change the oil today. What came out was definitely dark in color. I’m concerned about the oil pressure though...and not in the way you might think. There are two oil pressure gauges in this truck. The factory one in the dash and an aftermarket one mounted under the dash. Before the oil change the factory needle was between the “R” and the “M” and the aftermarket read 60 psi. After the oil change the factory needle is between the “M” and the “A” and the aftermarket now shows 70 psi. Is that even possible? That seems really high. If something is wrong...what would it be?

Carl

1980 F-350 4X4; 400 C6; Dana 61 rear, Dana 50 TTB front
1984 F-250 4X4; 6.9L T19; Dana 70 rear, Dana 44 TTB front

Gary Lewis

Re: 1980 F350 4X4 C6 Project

Administrator

Yes, that's possible for a couple of reasons. First, if you went back with a heavier weight oil than was in it. Do you know what was in it and did you put a heavier weight oil back in?

Second, because a multi-viscosity oil will give higher oil pressure when it is new. The reason for that is that the high end of the viscosity range is achieved with long polymers and they tend to get sheared over time as they pass through the oil pump, so the viscosity then comes down.

Gary, AKA "Gary fellow": Profile

Atlas75

Re: 1980 F350 4X4 C6 Project

I have no idea what was in it or when it was possibly changed last. The only thing I know is that it was pretty dark and the oil filter had some rust on it (and it was a pain to get off

).

I put in a 10w-40.

70 psi just seemed high to me, especially at idle after it warmed up a bit. I guess we'll see what happens over time.

Carl

1980 F-350 4X4; 400 C6; Dana 61 rear, Dana 50 TTB front
1984 F-250 4X4; 6.9L T19; Dana 70 rear, Dana 44 TTB front

Gary Lewis

Re: 1980 F350 4X4 C6 Project

Administrator

70 PSI is high, especially for a 351M or 400 as they are notorious for having low oil pressure. Do you know the history of the engine? Like, how many miles are on it? From the early pics you posted it doesn't look to have been rebuilt.

As said, the M-block engines are notorious of low oil pressure. That has to do with the way the system was designed, which you can read about on the page at Documentation/Engines/351M & 400 and then the Oiling System tab, which is where the drawing below came from.

Dad's well-worn 351M idled at 10 psi after being truly warmed up. Rusty's was a bit higher as it had been rebuilt recently, but was still only like 15. So 70 is quite high, and I don't know why. But I worry that the engine might be full of gunk and that may be blocking some passages. However, as you can see in the drawing, the oil pressure pickup point is after everything but the lifters on the driver's side, so if you have that much pressure there everything else must be getting oiled quite well.

But I'd watch the color of the oil to see if it turns black very quickly as you may be cleaning up the engine. And watch the oil pressure as it will naturally come down as the oil gets used some.

Gary, AKA "Gary fellow": Profile

Atlas75

Re: 1980 F350 4X4 C6 Project

I don’t know the history of the engine. The guy I bought the truck from said it was rebuilt before he got it and he hadn’t owned it very long. With no receipts or documentation, who knows what rebuilt means. I did manage to find out who owned it before the guy that I bought it from. Maybe I should try to contact him and see what he knows...

Carl

1980 F-350 4X4; 400 C6; Dana 61 rear, Dana 50 TTB front
1984 F-250 4X4; 6.9L T19; Dana 70 rear, Dana 44 TTB front

Gary Lewis

Re: 1980 F350 4X4 C6 Project

Administrator

I would ask. It can't hurt. All he can say is "I don't know". But he might have some good info.

Gary, AKA "Gary fellow": Profile

Atlas75

Re: 1980 F350 4X4 C6 Project

Well...I had a humbling moment today.

I was trying to remove the rear tires and I couldn't get the lug nuts off on the drivers side. I thought they were just froze good so I hit them with PB Blaster and waited...but still they would not budge. Then I thought...let's try tightening them and see if I can work them back and forth. So I turned the nut to the right. Needless to say I figured out pretty quick that the drivers side has reverse threads!

Carl

1980 F-350 4X4; 400 C6; Dana 61 rear, Dana 50 TTB front
1984 F-250 4X4; 6.9L T19; Dana 70 rear, Dana 44 TTB front

ArdWrknTrk

Re: 1980 F350 4X4 C6 Project

Administrator

Yep, the Dana rear axles have LH nuts on the LH side. 💡
I just pointed this out in another thread.

Don't the nuts have little dots stamped in the apex's of the hex?
Do your studs have an 'L' stamped in the end?

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

Atlas75

Re: 1980 F350 4X4 C6 Project

I cleaned up the ends of the studs and sure enough the letter L was stamped in the end. Couldn’t see them with all the dirt. I also found a small letter L stamped on the lug nut also. Unless you were looking for it, you probably wouldn’t see it.

Carl

1980 F-350 4X4; 400 C6; Dana 61 rear, Dana 50 TTB front
1984 F-250 4X4; 6.9L T19; Dana 70 rear, Dana 44 TTB front

Atlas75

Re: 1980 F350 4X4 C6 Project

While wrestling with the lug nuts this past weekend (see post above) I took a few photos and I am wondering what they are. First off...what is this?

It looks like an old fuel filter but is that what it really is? Also, what is the module behind it with the wire coming out of it? My current fuel filter is located right up at the carb.

Second question is with the brake lines. In this photo you can see the hard line coming from the front of the truck and transition to a soft line to the splitter. At the bottom of the splitter there is a soft line that comes out and runs up and over that bracket and just ends there. It looks like there is something plugged in the end of the line. What is the purpose of that?

Carl

1980 F-350 4X4; 400 C6; Dana 61 rear, Dana 50 TTB front
1984 F-250 4X4; 6.9L T19; Dana 70 rear, Dana 44 TTB front

ArdWrknTrk

Re: 1980 F350 4X4 C6 Project

Administrator

The second thing is the rear axle breather.
The bolt that secures the brake hose splitter is hollow and allows the rear axle to relieve pressure as the gears and bearings heat things up.
Otherwise gear oil would be forced past the hub seals into the brake drums.

The first photo surely looks like an abandoned fuel pump and filter.
Can you tell where the red wire goes?

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

Atlas75

Re: 1980 F350 4X4 C6 Project

Is that some sort of screen in the end of the axel breather hose? Or is it just plugged with gunk and I need to clean it out?

I’ll trace the wire on that fuel stuff and report back. Maybe get a better photo or two as well. It certainly looks like it has been there for a while.

Carl

1980 F-350 4X4; 400 C6; Dana 61 rear, Dana 50 TTB front
1984 F-250 4X4; 6.9L T19; Dana 70 rear, Dana 44 TTB front

ArdWrknTrk

Re: 1980 F350 4X4 C6 Project

Administrator

There should be a little vent cap with a clip that attaches to the top frame rail.

Someone else was saying that a mud dauber had plugged theirs up, so it couldn't hurt to check.

I really don't know anything about the pump, which seems to be outside the frame rail, below your cab.

Could it be that someone rigged it up until proper replacement parts for a dead fuel pump were found?

Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with a Holley 80508 and Performer intake.
Too much other stuff to mention.

Gary Lewis

Re: 1980 F350 4X4 C6 Project

Administrator

I like to use a small fuel filter on the end of the vent hose. That way yuk can't get into the axle. But it doesn't stop a mud dobber or some such from plugging the end of the hose.

Gary, AKA "Gary fellow": Profile

Atlas75

Re: 1980 F350 4X4 C6 Project

I finally had a chance to bleed the brakes today thinking that should be step one in figuring out the soft pedal. I would first like to thank the brake gods for allowing all 4 bleeders to loosen without breaking off! I was using a hand vacuum bleeder and started at the rear passenger side. After just a min or so the fluid was flowing clean but had lots of bubbles. No matter what I tried, I could not get the bubbles to go away. I finally gave up and moved to the rear drivers side. Again the fluid flowed clear after 30 seconds or so but this time, no bubbles! I then moved to the front and both sides bleed fine with no bubbles.

So back to the rear passenger side...are the bubbles an indication of a bad wheel cylinder? I haven't noticed it leaking. But...being a Dana 60, I don't have easy access to inspect it either. If it is the wheel cylinder, has anyone rebuilt one or is it not worth it and just buy the unit complete?

Carl

1980 F-350 4X4; 400 C6; Dana 61 rear, Dana 50 TTB front
1984 F-250 4X4; 6.9L T19; Dana 70 rear, Dana 44 TTB front

Gary Lewis

Re: 1980 F350 4X4 C6 Project

Administrator

My experience is that the bleeder valves leak at the thread and introduce air into the stream, creating bubbles. You might try packing a heavy grease around the base of the bleeder valve to seal it.

Gary, AKA "Gary fellow": Profile

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