Lubrication problem

I have a 70 F250 with a fe390 engine. Suddenly I get a rough idle followed a couple of days later by a distinct valve tick. My oil pressure gauge is running at the low end at idle. I pulled the valve covers and have no oil flow from the rocker arm holes. I started the engine and put a hose to my ear from each valve and about half of them are noisy to some extent. most of them can't be heard except by the hose method. What could have suddenly caused this lack of oil flow? The engine has less than 100,000 miles and is really clean inside. I know the prior owner and he changed oil like clockwork. I did have occasion to let the engine idle for long periods to charge the camper battery. Could this have caused irregular wear on the crank or cam bearings? I'm not familiar with this type of engine and have had no success in learning how the oil flows throughout the fe engine. Non of my manuals including the factory manual gives a decent description of the lubrication system. Any help is appreciated.

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Originally Posted by swcash

I have a 70 F250 with a fe390 engine. Suddenly I get a rough idle followed a couple of days later by a distinct valve tick. My oil pressure gauge is running at the low end at idle. I pulled the valve covers and have no oil flow from the rocker arm holes. I started the engine and put a hose to my ear from each valve and about half of them are noisy to some extent. most of them can't be heard except by the hose method. What could have suddenly caused this lack of oil flow? The engine has less than 100,000 miles and is really clean inside. I know the prior owner and he changed oil like clockwork. I did have occasion to let the engine idle for long periods to charge the camper battery. Could this have caused irregular wear on the crank or cam bearings? I'm not familiar with this type of engine and have had no success in learning how the oil flows throughout the fe engine. Non of my manuals including the factory manual gives a decent description of the lubrication system. Any help is appreciated.

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Welcome to the forum.
Denny will have a diagram.
I'm sure he will be along very soon.

I'd drop the pan, clean it out, and replace the oil pump and screen. Oil pumps do wear out, and your motor is 37 years old. That would be a good starting point, then you will know if it is something internal like excess clearances, etc.

I've always had a policy of pulling the pan and putting in a new oil pump anytime I use an engine from a wreck or junk yard. The one time I didn't do it was when it bit me.

Oh, and welcome to the forum.

Don

Here is a cutaway of the engine. I've seen better drawings, but this will give you some idea.
Don

Sounds like the engine has done very good!!!! A 37 year old engine with less then 100,000 miles that is still in running condition is great!!! Could be a variety of things, at that age with those miles it obviously spent a lot of time just sitting. The older oils had a nasty habit of building up sludge throughout the engine and in your case it sounds like some of it has made it into the oil passages that feed the rocker arms. A clean out and new pump like Don suggested may remedy the problem. Or perhaps the lack of lube to the rockers has already done the damage and it's also going to require some repairs on the rocker arms... Lots of old parts in there that have been sitting for awhile, perhaps it's just time to freshen everything up?

Great schematic Denny!!!! My guess is the lines from the cam bearing to the rocker shafts are clogged..... What's yours?

You guys have beeen a great help so far. Pulling the pan seems inevitable, but I think maybe I should try to get a REAL oil pressure reading with a REAL gauge first. This way I'll have some sort of base to work from. Do you think all the idleing caused this problem? I know 100,000 seems like a lot of miles but another friend had 250000 on his fe 390 and it was still running strong. Like I said before the oil was changed religiously and inside the valve covers is spic and span.
The drawing is exactly what I was looking for. I now can see where the oil comes from. I could pull the one bolt on each rocker shaft and blow compressed air down through. I know I still need to pull the pan no matter what. When I pull the pan and say the screen is clean, then what should I check next? Check pump clearances? Use Plasticgauge on the bearings? Just my luck, it hasn't rained in 6 months here in California, today it has to rain.
I really appreciate all the input, as I was stalled out on this problem, being a chevy guy all my life not familiar with this engine. This forum rocks.

I'd just go ahead and replace the pump, they are cheap enough. Change the oil, maybe throw in a quart of Marvel Mystery Oil and see what happens. You either have something that can be fixed easily or a problem. By doing the new pump routine you will start eliminating the easy stuff first.

Don

Two things common on those engines

The oil passage to the rockers plug up in that short horizonal area where it goes sideways toward the bolt in the hollow rocker stand

Those engines had the rubber umbrella valve stem seals and they when they got old and brittle they would crumble up in zillions of rubber bits and eventually get down into the pan and plug the pickup screen---there generally is evidence along the edge of the head under the valve cover and/or you can see that the seals aren't on all the valvestems
These were one of the first engines to get fit with PC type seals on the engine

Jerry

I dont have a fix Denny and the pro's here will help with that but thru some research i found some oil mods that this guy says helps a 390 or fe by means . Just searching because i too have a 390 that will need refurbished . This guy shows some good mods to create the best oil flow . The link to his oil mods is on the left once open click on pages they will enlarge .. Once enlarged you can save them and print out later .

http://home.comcast.net/~gtscode/gtscode/

I think Denny and the guys nailed it. The bypass spring in the oil pump can get weak over time. That and the screen on the pickup clogged. Also on the rocker shafts....they too can clog sometimes. But I've only seen that in real heavy sludge cases. I'd be RR'ing the pickup and pump as advised.

Denny looks like some vintage paper also . I figured you or someone may be able to add to it with more tech also.

Wow, I'm getting quite an education on this fe lube system. I'm going to do my best to get to "wrenchin" today, I'll let you guys know what I come up with. Again, thank you all for all of the technical information.

Denny did a search for paul found no site but i did find him at a ford forum so im close

Well, I pulled the bolts on the rocker shaft and blew compressed air down through the oil passages. I then hooked up a 0-100 psi gauge at the oil filter adapter. Zero psi at idle. Changed out the gauge to verify. Zero psi at idle. I do get oil pressure as I increase the rpm. It goes as high as 80 psi and I eventually get oil from the rockers and the engine smooths out and the lifters quiet down. As soon as I let her idle the lifters get noisy and back to zero oil pressure. Next move is to drop the pan and see what is going on with the screen and the pump. Are there end clearances I can check on the pump gears? When I do get a new pump should I consider a high volume or a high pressure pump? I've seen them advertised high volume, and I've seen them high pressure, whats the difference. It seems like a high volume would have the potential of high pressure. I read that the 427 has a bypass spring set at 100 psi. Does anyone know what the normal setting is on the 390? I was surprised to see the pressure go as high as 80 today. Could that be my spring pressure?

Quote:

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Originally Posted by swcash

Well, I pulled the on the rocker shaft and blew compressed air down through the oil passages. I then hooked up a 0-100 psi gauge at the oil filter adapter. Zero psi at idle. Changed out the gauge to verify. Zero psi at idle. I do get oil pressure as I increase the rpm. It goes as high as 80 psi and I eventually get oil from the rockers and the engine smooths out and the lifters quiet down. As soon as I let her idle the lifters get noisy and back to zero oil pressure. Next move is to drop the pan and see what is going on with the screen and the pump. Are there end clearances I can check on the pump gears? When I do get a new pump should I consider a high volume or a high pressure pump? I've seen them advertised high volume, and I've seen them high pressure, whats the difference. It seems like a high volume would have the potential of high pressure. I read that the 427 has a bypass spring set at 100 psi. Does anyone know what the normal setting is on the 390? I was surprised to see the pressure go as high as 80 today. Could that be my spring pressure?

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With those miles, best thing to do is just replace the pump with and OEM rated volume and pressure pump. In an old engine, a hi volume pump will put too much oil in the top of the engine and too slow to drain back without some rework on the oil returns. Hi pressure isn't necessary on a stock engine, would do more harm then good. Pull the pump, take the pickup tube off and clean it thoroughly, reinstall it on the new pump.

Dave is right, just pick up a good quality stock oil pump and use that. Anything we say now is pure conjecture, you won't know what you really have til you pull the pan and look inside. You say the valve covers are clean, but the pan is the lowest point in the motor and sludge and crud always accumulate there.

Unless you have already done damage, I'm betting you find a clogged pickup and a weak pump and changing/ fixing those items helps. Post some pictures of the inside of the pan and all when you pull it down. We are curious. :3dSMILE: :3dSMILE:

Don

My Ford 400 lost it's oil pressure yrs ago. It turned out to be a lifter issue.
Some Fords feed the lifters first and will lose pressure from that point.
Ron

All good advice above. Before you get to far along however, give some serious consideration to pulling the front cover and replacing the timing set. If it still has the stock phenolic cam gear and it's worn enough that the fibers have plugged the pick up screen then it's done. There a couple of ways to verify a worn cam gear. Remove the fuel pump, turn the crank counter clockwise and reach in through the pump arm hole and check for chain tension. Another way is to use your timing light and check for smooth mechanical advance from about 10 to 12 degrees initial up to about 30 degrees total advance. If the timing advance is irratic the cam gear is worn or the mech. advance is worn or dirty. The bottom line is that in an engine that old the factory cam gear is almost certainly worn out. Steel replacement timing sets are quite reasonable and cheap insurance. Don't forget a new front crank seal.