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No oil pressure post oil change (with pics). Any ideas on what happened?

Gsmopar

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The engine has been together for several years with no issues. I did the annual oil change and no pressure on start up. Pulled the distributor and tried priming the pump manually. Pulled the oil filter (dry). Tried partial fill of the oil filter, no luck. Pulled the pick up line and filled the pump, no luck. Pulled the pump apart and found this. Milodon single line pump. Had good pressure before the oil change. Any ideas as to what caused this?

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Untitled by Greg Ault, on Flickr

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Untitled by Greg Ault, on Flickr

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Untitled by Greg Ault, on Flickr

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Untitled by Greg Ault, on Flickr
 
All I can think of is you had the airlocked new oil filter and the oil pump ran without oil during startup and got trashed.

But man that’s a stretch. And burping the filter can be a mess, but I’ve seen fire ups after oil changes that result in no oil pressure, but were always corrected by burping the filter.

Someone smarter than me may have seen that before.
 
Sounds like the pump just lost it's prime? Trying to re prime the engine and nothing happens?
 
Looks to me like metal has been present in the pump. ruffcut
 
I dug a little deeper. Milodon cover, unknown pump. Bronze gear also showing significant wear.. I agree on the set up issue. I ordered a new Milodon billet pump and cover, and correct shaft with new bronze gear.

oil looked normal. I will cut apart the old filter. Second oil change on this engine. I remember that it was slow to prime the last time, but primed and held good pressure. The first filter likely had most of the aluminum.
 
Wonder if there was a nylon button on the shaft to keep rotor from heavy contact with cover face. Just thick enough to hold rotor .0001/.0002 off cover. How many miles on pump?
 
Wonder if there was a nylon button on the shaft to keep rotor from heavy contact with cover face. Just thick enough to hold rotor .0001/.0002 off cover. How many miles on pump?


<1000 miles.
 
Sorry to say,,,,dump the oil again,if there is metal in the pan the engine is contaminated and must be taken out. It could be ugly,don't ask how I KNOW!
 
Negative. No button. Thats a normal setup. I've experienced this also when a roller lifter malfunctioned. From the looks of this, I would say it was caused by steel fragments. Seems too aggresive for aluminum or such from bearings. I would suggest some searching to find the problem before adding a new pump and cover. JMO. ruffcut
 
Any chance the bushing under the cam gear is shot and the hex stuffed itself into the pump, pushing the 4 lobe gear into the cover? It’s not made for that force. I don’t see how it could be connected to the oil change but certainly a possible cause.
 
Just throwing this out there.... when you primed it... by chance did you lean on the drill (push down on it out of habit)
Just thinking maybe when it was cavitating and the pump was dry, would it be possible that leaning on the drill caused it.
Reason I'm bringing it up is Bob George, who's built hundreds of motors warned me about doing that when priming.
 
Just throwing this out there.... when you primed it... by chance did you lean on the drill (push down on it out of habit)
Just thinking maybe when it was cavitating and the pump was dry, would it be possible that leaning on the drill caused it.
Reason I'm bringing it up is Bob George, who's built hundreds of motors warned me about doing that when priming.


No lean/push when I primed, and it didn’t prime on initial start up. I used an intermediate shaft with no distributor gear and a drill extension with a secured flat head bit. It makes you be careful.
 
The oil coming out of the pump goes thru the filter. Most, if not all the metal should be in the filter. A few years ago my race car broke a valve spring and chewed up the spring seat. Fixed it at the track. Ran it to the end of the season. Never had any pressure issues. On tear down I found some pieces had been drawn into the pump. Chewed up the rotors pretty good. No other metal grit showed up anywhere. Bearings looked new.
Doug
 
The oil coming out of the pump goes thru the filter. Most, if not all the metal should be in the filter. A few years ago my race car broke a valve spring and chewed up the spring seat. Fixed it at the track. Ran it to the end of the season. Never had any pressure issues. On tear down I found some pieces had been drawn into the pump. Chewed up the rotors pretty good. No other metal grit showed up anywhere. Bearings looked new.
Doug
This highly depends on the filter used and if it has a by-pass or not. I was using a fram HP1 with bypass and everything was contaminated. Now I use a system one filter.
 
Mine was a Wix. The bypass should only open if the filter is clogged. Otherwise the bypass is closed.
Doug
 
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