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Discussion Starter · #1 ·
I have spent the past few months rebuilding my 302. I finally got it to run but my oil pressure gauge read 0. At first thought it was the guage so I replaced sender and guage cluster, still nothing. Today I put a mechanical gauge on and primed the oil pump with a drill (counterclockwise) and still no oil pressure. I looked with a scope camera down the distributor hole and could see that the pump shaft was engaged and turning in the pump. I also noticed that if I switched the drill to clockwise I could hear the pump blowing air and could hear the oil do a pretty loud bubbling. I’m confused as to why the pump does not seem to pump any but does seem to blow air in the opposite direction. Any ideas would be greatly appreciated.

Also, I have run the engine a few times because I thought I had oil pressure but I now know I did not (I know this is a big mess up) I had found metal shavings on the dip stick but they were magnetic, so I was under the impression that was fine with a fresh engine on initial start. BUT today I noticed some large metal shaving stuck to the distributor drive gear, and they were NOT magnetic. How bad is that and do you think the bottom end is junk or if I get the oil pump working will I be okay? A little nervous about having months of work ruined

thanks
Jacob
 

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I have spent the past few months rebuilding my 302. I finally got it to run but my oil pressure gauge read 0. At first thought it was the guage so I replaced sender and guage cluster, still nothing. Today I put a mechanical gauge on and primed the oil pump with a drill (counterclockwise) and still no oil pressure. I looked with a scope camera down the distributor hole and could see that the pump shaft was engaged and turning in the pump. I also noticed that if I switched the drill to clockwise I could hear the pump blowing air and could hear the oil do a pretty loud bubbling. I’m confused as to why the pump does not seem to pump any but does seem to blow air in the opposite direction. Any ideas would be greatly appreciated.

Also, I have run the engine a few times because I thought I had oil pressure but I now know I did not (I know this is a big mess up) I had found metal shavings on the dip stick but they were magnetic, so I was under the impression that was fine with a fresh engine on initial start. BUT today I noticed some large metal shaving stuck to the distributor drive gear, and they were NOT magnetic. How bad is that and do you think the bottom end is junk or if I get the oil pump working will I be okay? A little nervous about having months of work ruined

thanks
Jacob
just on a wild azz guess... sounds like a gallery plug is out somewhere... yes you need to tear down and inspect and fix.. running without oil pressure is hell on bearings. i dunno about months of work... to pull, disassemble, clean, replace bearings, reassemble, and stab back in the car shouldn't take you more than a day if you get everything set up before hand
 

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If it ran with zero oil circulating, it would probably need to be gone through again. That’s why you always, always prime it before starting and make sure oil is coming through every rocker.

Sucks to hear. I’m also banking on a gallery plug is missing.
 

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Discussion Starter · #5 ·
How challenging is it to redo the crank bearings. Have never worked on bottom end of an engine, and am definitely willing to do it, but wondering if it is a safer bet to send it to builder to be done properly. Could I do it just by watching videos online or am I likely to mess up without experience?
 

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In my most humble opinion, it depends on your budget and/or willingness to learn - I am far from an engine builder, but I can assemble - my trial & error over the past 40 years has gained me much needed experience in what to look for during assembly & along the way, a truck load of broken parts when I "missed something"- the conundrum you are facing is tearing it apart, fix what you see & try it again...or buy a crate engine & learn nothing...either way you choose, best of luck with your build !
 

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How challenging is it to redo the crank bearings. Have never worked on bottom end of an engine, and am definitely willing to do it, but wondering if it is a safer bet to send it to builder to be done properly. Could I do it just by watching videos online or am I likely to mess up without experience?
It’s really not something that’s all that difficult. The average guy who is capable of putting an engine in a car and getting it running can do a set of bearings. Putting bearings in is easy, as long as the main and rod journals are still in good shape. I’d start by pulling the oil pan and seeing what it looks like first though - and finding the hole where all your oil is going as well.

It’s not a guarantee the metal you saw is coming from the bottom end as the cam and lifters can make metal too.
 

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Update:
I have taken off the upper intake manifold and the timing cover. All the gallery plugs and still in place. Any other ideas as to why I would be getting no oil pressure?
How many plugs did you count? There’s the 2 behind the timing cover, one inside behind the distributor (you have to remove the distributor to see), and one under the rear of the intake manifold. There are also some on the rear of the block, but you’d probably know if those were out.
 

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Discussion Starter · #11 ·
I took the timing cover off, saw the two to the left of the camshaft and the one to the right (behind where the distributor would be). Also took the intake off and the one there is in place. I would imagine if any of the rear ones were missing it would be pretty obviously spitting oil out right? That’s not the case for me. I would have to imagine that it’s something with the pump or pickup. I just dropped the oil pan and nothing looks out of wack. All the gaskets are in place. Really stumped here
 

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could be a broken ear on the pump ive seen that numerous times

thats assuming the pickup is at the bottom of the pan
 

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You have to spin the pump pretty fast for about 20-30 seconds before it picks up oil. How long did you try to prime the pump and how fast did you turn the oil pump shaft while trying to prime the engine?
 

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That would be good to know, wouldn't it?
That it would.

We had this come up with a sbc a couple weeks ago. We were about to do a cam break in on an engine that hadn’t been ran yet, and we spun the oil pump drive with a drill and got nothing on the mech gauge. Then we got another gauge with a fresh line and got 50psi. Must’ve been trash in the line, or the compression fitting was choking it off. Top end was soaked so we knew oil was getting up there.
 

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If you are using the stock oil pump drive rod it could be broken. The distributor drives the oil pump with this rod and if it breaks no oil pressure. I've broken one and there is a HD one available for this reason.

ks
 

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My concern when the issue is figured out would be a reassembly contamination issue. Make sure that block is clean clean clean before throwing new bearings in it if it comes down to that. A past failure can lead to a future one. Check pickup to pump as suggested. You wouldn’t hear bubbling if the driveshaft was broken.
 

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Discussion Starter · #19 ·
For anybody wondering the issue turned out to be much less significant. I have a remote oil filter relocated to the fender well. The hoses running to the filter were flipped flopped (in and out to filter) and the oil was basically getting caught up in the filter and not allowing pressure to build. Flipped the hoses and immediately got pressure by priming with the drill, even with the oil pan and front cover not attached. Luckily it was still getting oil the to the bottom end so the crank was fine, just was getting cut off at the filter. I guess sometimes the answer if way simpler than you think. Anyway dumb thing on my part but hey you live and you learn. Thanks for all the help
 

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For anybody wondering the issue turned out to be much less significant. I have a remote oil filter relocated to the fender well. The hoses running to the filter were flipped flopped (in and out to filter) and the oil was basically getting caught up in the filter and not allowing pressure to build. Flipped the hoses and immediately got pressure by priming with the drill, even with the oil pan and front cover not attached. Luckily it was still getting oil the to the bottom end so the crank was fine, just was getting cut off at the filter. I guess sometimes the answer if way simpler than you think. Anyway dumb thing on my part but hey you live and you learn. Thanks for all the help
If the filter has an anti drain back, it wouldn’t go anywhere once it reached the filter. So more than likely no oil was going through the engine at all.
 
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