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To the OP, what year and cu block?
 

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Its a 289. when I get home I'll go thru all my pictures I took during the build. Spoke to my builder. He wants me to take the long tube off that holds the oil ending unit and see if that clogged. I'll put the gauge directly into the block and crank it up. he also said he's seen Melling pumps that may not work correctly. Something about a bypass within the pump. So I'll pull the dizzy out and see how much pressure I get spinning it. If all that checks out, he wants the engine back. he asured me all the oil plugs are installed in the front but he didn't think there was a plug under the manifold......soooo I think I will pull the manifold off also. i know I have apicture of the top of the engine before the manifold went on. I'll check.

Stay tuned!
Hooking a gauge directly into the block is a good idea, eliminate as many variables as possible.

The oil pump for the all of the Windsor based engines has a pressure regulator that bypasses back into the inlet side of the pump. It's a dumb design. If you have a restriction in the pickup tube, it can create negative pressure on the back side of the shuttle valve, which can cause it to bypass at too low of a pressure. When I was at Canton in the late 90's, we had some Fox body customers that were having major oil pressure issues at high RPM. We tried a bunch of the usual tricks, but they still had problems. I was staring at a 302 pump one day and I had an epiphany about the internal bypass. I modified a pump and sent it to one of our customers to test and low and behold, problem solved. We then did a batch and sent them out to the others we knew of and problem solved there as well. They went into the next year's catalog and we couldn't make them fast enough. Unfortunately, Melling eventually figured out what we were doing and incorporated our mods into the 10688/10833 pumps.
 

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Hooking a gauge directly into the block is a good idea, eliminate as many variables as possible.

The oil pump for the all of the Windsor based engines has a pressure regulator that bypasses back into the inlet side of the pump. It's a dumb design. If you have a restriction in the pickup tube, it can create negative pressure on the back side of the shuttle valve, which can cause it to bypass at too low of a pressure. When I was at Canton in the late 90's, we had some Fox body customers that were having major oil pressure issues at high RPM. We tried a bunch of the usual tricks, but they still had problems. I was staring at a 302 pump one day and I had an epiphany about the internal bypass. I modified a pump and sent it to one of our customers to test and low and behold, problem solved. We then did a batch and sent them out to the others we knew of and problem solved there as well. They went into the next year's catalog and we couldn't make them fast enough. Unfortunately, Melling eventually figured out what we were doing and incorporated our mods into the 10688/10833 pumps.
What's your best guess on the low pressure @Hemikiller?

Allen
 

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Turn, no, I don't think the old plug is a cause of low pressure. But it takes 10 seconds to remove it, and it really should be removed to allow adequate cleaning. I really can't imagine trying to do an engine without proper cleaning. It looks dirty. Did the block get baked and blasted ? Boiled in sodium hydroxide ? of just a quick spray wash ? And even if just a spray wash, I can't believe it wasn't taken out for cleaning. I would have sent it back as soon as I noticed the dirty original plug. Its just not how this is supposed to be done. I have to wonder what else isn't done, or isn't done properly. I'd be taking it out and sending it back. I wouldn't even check anything else. It should come out, disassemble, remove ALL plugs, clean everything, start over with new rings, bearings & oil pump & pickup. The new build is contaminated with stuff that should have been cleaned the first time. As to low pressure, I'm betting some of the plugs behind the timing cover are missing or crazy loose. I wonder if the originals were replaced ? Maybe an original plug popped out in the new assembly. LSG
 

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Another thing to check beside the gauge is the actual sending unit for the oil pressure. I was getting low pressure readings on mine and causing some concern. Someone here suggested that I remove the sending unit and replace it with a cheap mechanical style oil pressure gauge, which I did. My pressure jumped back up to a normal range, so that narrowed it down to the tube or sending unit. I pulled the tube and cleaned it out pretty well, and then shot some carb cleaner into the very small orifice of the sending unit where it screws into tube. Put it all back together and pressure stayed within the normal range. Over time, the pressure started going back down, so I pulled the sending unit again, gave it a few squirts of carb cleaner, and pressure at the gauge jumped back up to where it should be. It's doing it again....I think it's time for a new sending unit, or some more blasts with carb cleaner.
 

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HV pump you say ? I won't again
 

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Discussion Starter #28
I really appreciate everyone input with all of this. I agree with LSG, that plug should have been replaced. I will ask about it. i remember looking at the oil galley plugs in the front and the back and they all were tapped and had new thread sealant on them, but I will inquire on the one under the intake. If it wasn't replaced, I will let him know I'm not happy. That's just lazy!

On a good note, oil pressure is now fine!

I took the extension tube off and blew it out. Some frothy looking oil came out. I then hooked my oil pressure gauge up to my air line and it read 90 psi like my air line, so the gauge is working correctly. I then hooked the gauge directly into the side of the block, took the dizzy off and spun the oil pump and got 55 psi. The oil pump had some resistance on it. Having never done this before, I assume that's what I was supposed to feel like. It wasn't super easy to spin. I then put the extension tube back on the block and hooked up my gauge and again got 55 psi when i spun the dizzy.

Pulled a valve cover off while spinning the oil pump and there was definitely oil going up there.

Started it right up and was getting 45 psi of oil pressure at idle.

Thanks again for everyone's help. I've said it before and I'll say it again, this is a great collection of people with such a huge amount of knowledge. For someone like me just learning about this hobby, I am always amazed at the willingness to share what you all know. Working on an old car like this has been on my bucket list for a long time. I'm thrilled I have been able to accomplish that with all your help.

If any of you find yourself up here in eastern MA, PM me. I owe you a burger and a beer!
 

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I am glad it was such an easy fix! However I would still talk to the builder about the oil plug and how he cleaned the engine.
 

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Fresh rebuild and 15W/50?... The 289 was designed for 10W/40. 15W/50 is too heavy when cold, and too heavy when hot. I broke mine in (351W - also designed for 10W/40) with 5W/30, then switched to 10W/40. Only thing I'd put 15W/50 in is an engine with 200K miles that hasn't seen an oil change in 20 years... parts are so worn you need the really thick oil to fill the gaps.
 

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Fresh rebuild and 15W/50?... The 289 was designed for 10W/40. 15W/50 is too heavy when cold, and too heavy when hot. I broke mine in (351W - also designed for 10W/40) with 5W/30, then switched to 10W/40. Only thing I'd put 15W/50 in is an engine with 200K miles that hasn't seen an oil change in 20 years... parts are so worn you need the really thick oil to fill the gaps.
I could be wrong ,but I think original spec was a straight 30 weight
 

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Fresh rebuild and 15W/50?... The 289 was designed for 10W/40. 15W/50 is too heavy when cold, and too heavy when hot. I broke mine in (351W - also designed for 10W/40) with 5W/30, then switched to 10W/40. Only thing I'd put 15W/50 in is an engine with 200K miles that hasn't seen an oil change in 20 years... parts are so worn you need the really thick oil to fill the gaps.
What a stock one requires and what a new build, with different tolerances require, are unrelated. Always run what the builder tells you.

glad you got it figured out without tearing it down.
 

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And now the wet blanket on your nice new firebreather,.......

Ophthos, okay, you have pressure. Thats good. BUT, I still think you ought to take it out and send it back and start over. I would want it cleaned, new rings and new bearings, and a new camshaft and lifters, dissemble & clean oil pump. Heres why. SO, there was gunk in the fitting that reads the pressure, and we know that there were plugs left in and oil passages not cleaned. So cleaning the channel to the gauge got some crap out. What do you suppose is in the oil galleries that your guy DIDN'T clean ? And the block just looks dirty in the picture. Somebody went to the effort to paint glyptal in the valley but didn't clean the block first ?! You saw the guy putting sealer on some plug,.....which ones ? The plugs in the back face on the bell get sealant, the ones at the front do not. The plug behind the distributor should have a hole drilled in it, does yours ? Are you certain ? Think of the trash & gunk that was in those uncleaned galleries. That gunk is now contaminating your new build. As it gets pumped into the lifters, crap gets trapped there. Lifters can be disassmbled and cleaned, but its time consuming, its usual to just replace lifters with crap in them. And lifters are mated to the cam, so that gets replaced too. I hope your guy gives one hellava warranty, I would not be happy. Sorry. LSG
 

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EXACTLY what LSG said ^
 

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Allen T, yes, there are plugs at the end of the galleries that feed the lifters. One of those plugs is right behind the distributor gear, you can't get to it unless the dizzy is out. The place I retired from puts a plug with an .060 hole there. What this does, after all of the driverside lifters have had oil, the dizzy gear is sprayed with oil. Frequently we also put the bleeder plug on the other side lifter gallery as well. Sometimes lifters are noisey if there are air bubbles trapped in the system, and the oil that comes from the oil plug lubricates the dizzy gear, and the other one sprays the back of the timing gear. I wonder how many people who think that their HV oilpump ate the cam & dizzy gears actually have a solid plug and don't know they shouldn't ? The assembly room at the shop had a boxfull of the bleeder plugs for whenever they were needed. LSG
 

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You could drain the oil through a strainer and cut the oil filter open and see what’s in there l 100% agree with Lsg your broke the motor in at 2000 for 20 minutes with 20psi the oil tube had junk in don’t anything pull the motor send it back to the engine builder and let him go through it like Lsg stated above good luck hope it all works out
 
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