Ford 4.6 oil pressure update

Jeff NWOH · Dec 19, 2015

Ended up being the camshaft journals that were losing the most oil. Couldn't really verify it with air pressure in the oil system so I rigged up a way to push some oil into the motor. Didn't see much coming out of rods or mains, but it sure came down through the cyl head drain holes.

I replaced one cam with a better used one from a junk engine. Managed to hold the cam gear up with a couple screwdrivers wedged into it to keep tension on the chain as I didn't want to pull the timing cover.

There aren't any cam bearings in that engine so the caps were somewhat scored and worn like the cam. I cleaned the worst with some 400 grit and milled a couple thousandths off the caps to tighten them up somewhat. Not ideal, but better than replacing the head.

Holding 13-14 psi at hot idle now. I figure after I do the other cam I may get 20 or so. Unfortunately, the other cam gear has no holes in it so I am still stewing on how to hold it up while I swap cams.

Thanks for the input. Just wanted to let you all know what I found.

JimB2 · Dec 19, 2015

Hold the cam gear with 2 visegrips.

UncleTom · Dec 19, 2015

Or clamp on to the cam with 2 vicegrips.

billmart · Dec 19, 2015

why does the replacement cam look as clean as a new one? Bill

Jeff NWOH · Dec 19, 2015

Pretty much the way it looked out of the donor motor. Just rinsed it off in parts washer. Motor only had 100k on it. Bad head gasket and they ran it til it spun a bearing.

I don't think mine had regular oil changes. That motor shouldn't be that dirty inside. I've done head gaskets on a couple Northstar Cadillac motors with 150k that look every bit as clean as that upper cam in first pic.

Jeff NWOH · Dec 19, 2015

I thought about that. The issue is I can't lose any tension at all on the chain. The tensioner has a ratchet mechanism on it so it won't retract once it extends. There is a release but I don't know if it would be possible to access it.

With the screwdriver deal I wedged them in til they were tight and slid the gear off without losing anything.

Vise grip may work but if it doesn't I'm up a certain creek without a paddle. I'm going to have to play with it a bit and see if it looks doable before I commit.

Janicholson · Dec 19, 2015

Use 2 j hooks made from 5/16 rod, through a plate (or two) that sit on the opening to pull straight up on the bottom of the gear where the teeth are visible. Jim

Brian Jasper co. Ia · Dec 19, 2015

The timing chain tensioners have a gasket on them that is notorious for blowing out. You should pull the cover and have a look. When the gaskets on the tensioners blow out it reduces pressure to the cam bearings.

Hobo,NC · Dec 19, 2015

I looked around to see how common this was..

http://www.modularrevolution.com/forums/archive/index.php?t-731.html

One guy said he had seen 50 are so like yours but no explanation as to why... I would check crankshaft end play (thrust BRG) for the ell of it. If its excessive your days are numbered...

I do remember reading about oil pump issues but believe it was 95 down. You are a better man than me I would have stopped when I seen the camshaft journals worn out..

Jeff NWOH · Dec 19, 2015

Didn't really cost anything to try. Time will tell if it holds up.

A used junkyard engine would probably double my investment in the thing. Having done an engine swap on our other Explorer already, I know I don't want to do another.

ASEguy · Dec 20, 2015

Interesting that they wore like that. Did you plastic gauge or mic them before?

robgIN · Dec 20, 2015

That is exactly what I expected to see . That is what happens when the tensioners leak oil pressure and starve the cam. Sometimes the roller on the rocker arm seizes and damages the cam and usually falls off giving you a miss. As long as the bearings on the bottom end are ok leave them in and it will live a long time if you replace the tensioners, otherwise it will happen again. You may be able to rent a kit with the cam holders etc from a parts store.

Jeff NWOH · Dec 20, 2015

I didn't, but I would guess .020 - .030" clearance.

Jeff NWOH · Dec 20, 2015

I'm still thinking at least some of the timing parts have been replaced. I found a good sized chunk of chain guide in the pan that will only fit one spot on one guide. That piece is not missing in my engine.

I did pressurize the oil system with air and oil and didn't see or hear anything coming out of or around the tensioners. I definitely checked after my last post.

As far as I can tell there isn't a visible gasket in there. I looked on rockauto.com and see two styles of tensioner. A plastic one with a molded o ring style gasket and a cast iron with a smooth back which I assume seals metal to metal or maybe a dab of rtv. I've got the cast iron. I can definitely see where that plastic one could cause some problems.

My theory is it had issues before and the chains, guides, and/or tensioners were replaced. The damage was done to the cams and they finally wore to the point it couldn't make oil pressure with hot oil at idle.

Just curious....what would you say would be a "normal" oil pressure at hot idle for this engine?

robgIN · Dec 20, 2015

if it has the metal tensioners then someone has replaced them . The plastic ones are the ones that cause the issue. I would expect 20 psi at idle , if I remember right that is the min Ford wants, but not being a 3 valve version it can get by with less. I think you are right suspecting someone fixed most of the problem but the damage was already done on cams.I think what you are doing will work. Chunk of guide in pan , it probably broke a guide and one chain jumped time and they had to replace parts. With good cams and brg surfaces cleaned up as best you can I think you can get by with it .

robgIN · Dec 20, 2015

They make a wedge tool that goes down between the chain at tensioner area to hold the tensioner in, you unbolt the cam gear and swap out cam and away you go. I think it came out when they went to 3 valve engines with the variable cam timing phasers to cut warranty time paid for phaser replacement , as you no longer had to remove front cover . It works pretty well might see if you can get ahold of one somewhere.

Ford 4.6 oil pressure update

Jeff NWOH

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JimB2

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UncleTom

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billmart

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Jeff NWOH

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Jeff NWOH

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Brian Jasper co. Ia

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Hobo,NC

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Jeff NWOH

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ASEguy

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