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I thought I'd start a new thread on this subject. I need a check list of things to go over.

History. Fresh complete tear down a rebuild by professional engine builder. 0.60 pistons. All new bearings. Crank mice'd out to standard size and new standard bearings used. New Milling HV oil pump. Builder assembled entire engine except for water pump. I did that. Break in oil was Driven BR 15W50. Put 4 qts in and then pressurized the oil system with another qt thru the block via the sending unit extension. I did not spin the oil pump.

For Break in I ran the engine for 20 minutes around 2000 rpm and varied the rpm's slightly. Kept getting readings of just under 20 PSI hot. At idle, PSI dropped to under 10.

So It could be the gauge. It's my cousins mechanical oil pressure reading gauge. He's used it many times and trusts it's readings. Yesterday I put the original sending unit on and started the car. After 10-20 seconds the needle didn't move so I shut the motor down.

So what is my check list going forward? What can I do without taking the engine out and pulling things apart? I was thinking of pulling the dizzy off and spinning the oil pump and seeing what pressures I get and how much comes out of the rockers. @LSG said to look at the oil jacket plugs behind the timing cover. That's a bit more work but easy enough. I have no reason not to trust my sending unit. it worked before I broke the engine down. new ones a cheap enough, so I can get another one just to be sure.

Appreciate any input on how to trouble shoot this. I tried to call my engine builder but af course, the phones are down around Boston. Go figure!

Peter
 

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Ophthos, Red is correct, there is a plug under the intake in the back, and if you didn't get it in there, pressure will be very low. There are also several plugs behind the timing cover that could be missing or loose, but would not show leaks on the floor. Did your builder leave the plugs to you, or did he put them in ? The place I retired from put them in, because we didn't know if the customer knew where they all where, or had the drivers to put them in. My guess is that some of yours are missing or loose. LSG
 

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A buddy of mine had a similar issue, but it was caught during priming of the engine prior to first startup. Barely any oil was coming up to the rockers during priming. The plug under the intake was missed during reassembly from the builder.
 

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Anyone have a pic of the galley area where these plugs are located? I know there are a one or two near the cam sprocket. Are we talking 289/302?
 

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Here is a pic (stolen from another thread on here) of the Oil Gallery Plug hole under the intake. You need a 3/4" press plug for it. They have been known to pop-out if not installed correctly.

744186
 

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Discussion Starter #8
Ophthos, Red is correct, there is a plug under the intake in the back, and if you didn't get it in there, pressure will be very low. There are also several plugs behind the timing cover that could be missing or loose, but would not show leaks on the floor. Did your builder leave the plugs to you, or did he put them in ? The place I retired from put them in, because we didn't know if the customer knew where they all where, or had the drivers to put them in. My guess is that some of yours are missing or loose. LSG
He did all the plugs. I recall before I put the fly wheel on that he threaded two maybe three plugs in the back. Just remember they were threaded. I assume he put all of them in up front, but as you know assumptions can be wrong. I know I'm heading towards pulling things apart. Still waiting for the phones to come back on line.

Is my thinking good? Pull the dizzy first and spin the pump with the rocker covers off and see how much is coming out and what the pressure is. If both are inadequate, pull the manifold off first and check the plugs, if those are good, pull the timing cover off and check those. As a last resort pull transmission off and fly wheel off and look at plugs in the back.

Do I need to pull the engine out? I just gave the engine hoist back to my patient i borrowed it from!

Also I rent a new pressure gauge from Autozone and double check things.
 

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Discussion Starter #9
Anyone have a pic of the galley area where these plugs are located? I know there are a one or two near the cam sprocket. Are we talking 289/302?
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!
 

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When I pulled my dizzy recently out of the block, I could see a treaded plug down in the hole with a flashlight. It was a 1971 302 block.
 

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Check the easy things first. My 289 had low pressure and it turned out to be a clogged fitting at the sending unit.
 

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Discussion Starter #12
Check the easy things first. My 289 had low pressure and it turned out to be a clogged fitting at the sending unit.
That was the first thing my engine builder told me to check. Going to pull it off tonight and see. Thanks
 

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The front ones underneath the cam retainer plate maybe? Helpful video showing location. You have a picture of the front of your engine without timing chain on before install?


.
 

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The front ones underneath the cam retainer plate maybe? Helpful video showing location. You have a picture of the front of your engine without timing chain on before install?
I do and there isn't a plug there but I don't know if he put one in. I spoke with him today and he said he put the oil galley plugs in the front. Tomorrow I'll check the oil sending unit extension and if that isn't clogged, he wants the engine back. He'd rather I didn't take anything apart. He wants to do that and see whats going on.

Is there anyother place on a 289 block I can crew in an oil pressure guage?
 

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Ophthos, post #13 shows us alot. Yes, the plug is there, but it appears to be the original. This is NOT a good sign. The plug should be removed for cleaning before the engine is even bored, and then a new one installed before assembly. Yours looks original AND dirty. ALL of the plugs are supposed to be OUT during boring and honing. If yours was not,.......who knows what kind crap was trapped in that gallery, and that crap is now circulating in your new engine. This is not good. Can't imagine why it wouldn't get replaced. The whole bag of plugs, all that the engine needs, is less that $10, final customer cost. Sorry. LSG
 

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Ophthos, post #13 shows us alot. Yes, the plug is there, but it appears to be the original. This is NOT a good sign. The plug should be removed for cleaning before the engine is even bored, and then a new one installed before assembly. Yours looks original AND dirty. ALL of the plugs are supposed to be OUT during boring and honing. If yours was not,.......who knows what kind crap was trapped in that gallery, and that crap is now circulating in your new engine. This is not good. Can't imagine why it wouldn't get replaced. The whole bag of plugs, all that the engine needs, is less that $10, final customer cost. Sorry. LSG
You seriously think that the "original" plug being there is the cause of his low oil pressure issue?

Allen
 

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Just an indication of the quality of work performed.
Understood, but I think that is giving the OP a serious misunderstanding of what is going on. To not change that one plug is not an indication of why his oil pressure is low (and in my opinion not an indication of the quality of work performed). Again, I say give it back to the builder.

Now we won't know why the pressure is low until the Op informs as to why. IF it turns out that plug is to blame, then I will gladly say l concur, but until then, I'm not jumping on the bandwagon that a plug not being replaced is the cause.

Allen
 
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