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Discussion Starter · #1 ·
So I just had a motor built. On first start up it took longer than I liked to build oil pressure. Right when I was about to shut it down the gauge went up to about 70 psi. After about 20/30 minutes of idle time the pressure fell slowly to about 5psi. I had to pull the motor and take it back to the builder. I bought a new oil pump and he put it in, the old pump was on my last motor that blew up. The builder says the motor is ready. I really don’t want to put everything back together to have the same issue. Is there anything else I should have them look at before picking my motor up?
 

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Discussion Starter · #5 ·
Who’s decision was it to reuse the old oil pump? If your engine builder made the call to re use the old oil pump then that fuck up is on him.
At the very least, I would inspect the oil pan for bearing material or other metal fragments.
I guess both of ours. It was the gt500 pump with boundary billet gears. It was on my previous motor for 4 years. That motor blew up on the dyno.
 

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Discussion Starter · #6 ·
There is nothing wrong with reusing an old oil pump unless something is wrong with it. Was something wrong with your old oil pump? Who assembled the engine, the builder or you?

On a new build it is always a good idea to prime the oil system prior to start up. There are a number of threads on the site about how to do this. Do a search and read them.
I don’t know if there was or not. Just figured with the motor losing pressure it’d be best to change it. When the builder swapped pumps he said the pressure relief valve was sticking a little on the old pump. The builder assembled the motor. I have read many threads on new motor builds and some people say prime and some say just fire it up. When I get the motor back in the car I’ll prime the oil system.
 

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Discussion Starter · #8 ·
I have built and rebuilt many different types of race engines for more than 50 years. I have never seen an oil pump that had worn out. I have seen oil.pumps that have been damaged because the pan was pumped dry or mechanically induced failures from foreign particulate matter being drawn through the pump but I have never seen one that wore out.
The old pump was on the previous motor that blew up on the dyno. I cleaned where the gears go but didn’t think to take the relief apart. Maybe something was in there? Is there any other reasons I was losing so much oil pressure?
 

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Discussion Starter · #12 ·
Water Liquid Drinkware Fluid Plumbing fixture

Got my motor back for the second time and decided to check some things and found that the pickup was bottomed out in the pan. So the builder obviously never checked the pickup depth and this was the problem from the beginning, not the oil pump.
 

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Discussion Starter · #15 ·
Well after the 2nd time the builder checked the motor, put in a new oil pump and the pickup depth fixed, the motor is still losing oil pressure….
 

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Discussion Starter · #19 ·
Called L&M and talked to mike and he said without hesitation that my problem was bearing clearance. When I get the motor pulled I’ll be sending it to L&M. Obviously shops in my area can’t build a modular motor.
 
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