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24in of vacuum at idle too high for the 2.8L?


franklin2

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You are running the original carb setup correct? Look on the back of the carb, you should have a piece sticking out the back of the carb with a wiring plug on it. Unplug that plug. Did the tick go away?
 


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@19Walt93 @franklin2 @8thTon

I’ll be updating pretty soon with everything.

Meanwhile... I hate to open this can of worms.. however I’m considering Valvoline VR1 (high in zinc and conventional) 10w30 for my oil change, after I do a flush. I’m thinking of taking this engine back to something similar/ what it was designed for, hoping it will restore my oil pressure and fix the tick.. I don’t care if I burn out my cat In a few years, I don’t plan on driving it much.

I’m want y’all’s opinions.
 
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SgtDan94

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You are running the original carb setup correct? Look on the back of the carb, you should have a piece sticking out the back of the carb with a wiring plug on it. Unplug that plug. Did the tick go away?
Actually the second time I’ve heard of this... unfortunately did not fix the problem.
 

19Walt93

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I know it isn't what you want to hear but I'd want to tear it down and check everything, there's apt to be nasty looking stuff like that throughout the engine. If you want to try something else first, but some generic, inexpensive 10w30 and a few filters and change the oil multiple times- maybe every few hundred miles to see if the oil clears up- before dumping your high zinc oil in it. Zinc will ruin the cat if the engine burns much oil, if it doesn't burn oil great. Zinc in the oil won't fix wear and damage that's already been done, it's essential when breaking in a flat tappet cam, though.
 

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I know it isn't what you want to hear but I'd want to tear it down and check everything, there's apt to be nasty looking stuff like that throughout the engine. If you want to try something else first, but some generic, inexpensive 10w30 and a few filters and change the oil multiple times- maybe every few hundred miles to see if the oil clears up- before dumping your high zinc oil in it. Zinc will ruin the cat if the engine burns much oil, if it doesn't burn oil great. Zinc in the oil won't fix wear and damage that's already been done, it's essential when breaking in a flat tappet cam, though.
this is what happened..

I installed a mechanical oil pressure gauge and found out I was wrong. The electronic sender/ gauge is reading true. The oil pressure is good at a cold start, and then drops down to MAYBE 5-7psi after 10 minutes of running.. no matter what speed/ RPM I’m at, the oil pressure is low and the engine has this awful tick that makes it uncomfortable to drive.

Im trying hard to find what’s going to be most cost effective. The real issue is that I don’t have a garage to work in. If I did I would tear that engine out and strip it down. So Empty parking lots are my shop, until I get kicked out of them like this morning. I just want to get this thing on the road and not worry about it blowing up. I’m planning on doing an engine flush tomorrow, and then an oil change and new filter, hoping that will restore my oil pressure at minimum.
 
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19Walt93

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If you're in a warm area you could probably get away with using 15w40 diesel oil,it's thicker and sticky and might improve the pressure if the problem is worn bearings with excess clearance. Ford never used to have an idle oil pressure spec, it was usually 1500 rpm or so but I'd suspect 5-7 psi is too low. What are you flushing the engine with? If it breaks sludge loose and clogs the pick up screen it'll be tear down time. I'd rather see multiple oil changes instead, just to be safe.
 

19Walt93

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I looked it up, the oil pressure spec is 40-60 psi@2000 rpms. I still think 5-7 at idle is too low.
 

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If you're in a warm area you could probably get away with using 15w40 diesel oil,it's thicker and sticky and might improve the pressure if the problem is worn bearings with excess clearance. Ford never used to have an idle oil pressure spec, it was usually 1500 rpm or so but I'd suspect 5-7 psi is too low. What are you flushing the engine with? If it breaks sludge loose and clogs the pick up screen it'll be tear down time. I'd rather see multiple oil changes instead, just to be safe.
I’ve got a bottle of motor medic flush.

Im willing to try anything. Do you think diesel oil would be ok? I’ve heard this a few times.. It doesn’t get colder than 50 degrees American where I live. I don’t think this engine is as beat up as I’m letting on. The bronco only has 150,000 lite miles. The body and interior are in perfect shape, so I believe that they’re lite miles. It just sat for 15 years in a barn and built up a lot of junk Inside.

the oil pressure seems perfectly normal until the oil heats up.. then it just drops off to nothing
 

franklin2

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You can put thicker oil in it, and then just turn the radio up. But low pressure is a sign of a more serious problem. I would look for another engine, and run this one while you get the spare fixed up and ready to go in. For most engines, you should have 10 psi per 1000 rpm. Most idiot oil light pressure switches come on at 5 psi or below, so you would probably have a blinking oil light. Sounds like it's just wore out, it happens.
 

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You can put thicker oil in it, and then just turn the radio up. But low pressure is a sign of a more serious problem. I would look for another engine, and run this one while you get the spare fixed up and ready to go in. For most engines, you should have 10 psi per 1000 rpm. Most idiot oil light pressure switches come on at 5 psi or below, so you would probably have a blinking oil light. Sounds like it's just wore out, it happens.
Hey thank you for all your help. I’m just fortunate I’ve had time off work to work on this bronco so much. If everything was perfect with it, I wouldn’t be having any fun. If i had a garage I would be looking into a remanufactured engine or possibly a diesel to swap in. Meanwhile I just like expirementimg and dodging rent-a-cops in abandoned parking lots. Hopefully someone can find this thread someday and learn how to fix their old ford.
 

8thTon

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I ran 15W-40 diesel oil in some older gasoline engines for quite a long time, and it worked well. I thought at one time they still had some zinc in them, but I could be wrong about that.
 

19Walt93

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I've never had faith in those mechanic-in-a can "fixes". I would much rather see multiple changes with clean oil, maybe with one quart of atf mixed in to add detergents, instead of dumping mystery goo in there. It's correct that thicker oil won't fix a worn out engine but it might get the pressure up high enough to keep it running for a while. I've said before that I'd rather tear it down but you've said you're not in a position to do that right now. I just wouldn't drive it 500 miles on the highway until you know how it's going to act. Diesel oil will work fine, I use some of the leftovers from my Kioti tractor in my John Deere lawn tractor during the summer. I do consider 50 degrees to be warm, the first 50 degree day in the spring the techs will leave the overhead door on the shop open.
 

8thTon

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I've never had faith in those mechanic-in-a can "fixes". I would much rather see multiple changes with clean oil, maybe with one quart of atf mixed in to add detergents, instead of dumping mystery goo in there. It's correct that thicker oil won't fix a worn out engine but it might get the pressure up high enough to keep it running for a while. I've said before that I'd rather tear it down but you've said you're not in a position to do that right now. I just wouldn't drive it 500 miles on the highway until you know how it's going to act. Diesel oil will work fine, I use some of the leftovers from my Kioti tractor in my John Deere lawn tractor during the summer. I do consider 50 degrees to be warm, the first 50 degree day in the spring the techs will leave the overhead door on the shop open.
Kioti! I have an LK3054, great machine.
 

SgtDan94

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I've never had faith in those mechanic-in-a can "fixes". I would much rather see multiple changes with clean oil, maybe with one quart of atf mixed in to add detergents, instead of dumping mystery goo in there. It's correct that thicker oil won't fix a worn out engine but it might get the pressure up high enough to keep it running for a while. I've said before that I'd rather tear it down but you've said you're not in a position to do that right now. I just wouldn't drive it 500 miles on the highway until you know how it's going to act. Diesel oil will work fine, I use some of the leftovers from my Kioti tractor in my John Deere lawn tractor during the summer. I do consider 50 degrees to be warm, the first 50 degree day in the spring the techs will leave the overhead door on the shop open.
Well I didn’t end up running the flush. We did a full oil change with VR1 10w-30 since we had it and a motorcraft filter. Theres good news- the oil pressure is restored and is stable. To make sure, I made about a 7 mile trip up the freeway maintaining about 65mph, the pressure did not drop like it normally would. I’m really happy with the results. There’s still a slight tick but it seems to not be as bad. Over all I feel a lot better driving it around with proper oil pressure.

I know the zinc in VR1 is not great for the new cat. Now that I’ll be driving the bronco more, I’ll check to see if it burns oil. The compression was within spec, so it may not be so bad.

ide like to add that I yanked off the 255 sized tires that were misshapen from sitting for years, and Installed some 205s.. I believe a 2 inch difference in tire size. Accelerates and drives MUCH better.... looks worse however haha, still worth it
 
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19Walt93

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If those tires were old and had sat in one place for years they weren't safe anyway. Watch the oil to see how fast it darkens up, a couple of low mileage changes would be a good idea. Smaller diameter tires are cheaper and easier than a gear change, I prefer a vehicle that runs good to one that looks good.
 

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