Author Topic: AX160 No Oil pressure  (Read 2566 times)

Valleyordnance

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AX160 No Oil pressure
« on: August 07, 2017, 12:43:03 PM »
Hi Guys,

Finally got our M2 started up with our rebuilt AX160 in it.  Starts great - but no oil pressure.  Replaced the oil pump, removed and cleaned the oil cooler, Cleaned the check valve in the oil pump. Positive the pump is engaged on the cam gear.  Pulled oil filter housing to see if there is any blockage, that's is clean as well.  We did not have the block cooked out as it was pretty clean when we rebuilt it.  Absolutely stumped on this one....  Do I need to prime the oil pump?  I've never worked on a motor this old before so I don't know what else it could be.

Thanks for any help!

Chris

steve1973

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Re: AX160 No Oil pressure
« Reply #1 on: August 07, 2017, 01:18:55 PM »
Are you using an original fuel pump? There is a rod that goes between the pump and cam. This rod also plugs an oIL passage. If this rod is missing you will have no pressure. Hope this helps.

Steve A.

Darth_Kitten

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Re: AX160 No Oil pressure
« Reply #2 on: August 07, 2017, 02:29:10 PM »
Most definitely prime the oil pump. I've seen more than one horror story of someone cranking with the motor not primed, and crunch. 

steve-0

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Re: AX160 No Oil pressure
« Reply #3 on: August 07, 2017, 05:17:25 PM »
I haven't had a problem with a prime myself but I have heard the only way to prime is to pump oil through the oil gauge port.
I think I would try starting the engine with the oil line disconnected and see if there is any flow of oil at all.

Valleyordnance

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Re: AX160 No Oil pressure
« Reply #4 on: August 07, 2017, 06:43:34 PM »
Dropped the pan - Primed the pump.   Still no oil pressure. If I pull the port on the side of the block I get no oil squirting out (or even dripping out for that matter)

New fuel pump from Gary's  - original pushrod. 

Still stumped.   

steve-0

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Re: AX160 No Oil pressure
« Reply #5 on: August 07, 2017, 07:05:47 PM »
make sure the pick-up tube to the oil pump is sealed.. no cracks or other issues.

how did you prime it?

Valleyordnance

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Re: AX160 No Oil pressure
« Reply #6 on: August 07, 2017, 08:02:12 PM »
Removed pump from engine and primed in a pan of straight 30 - Pump works fine, pickup is fine,  blew oil all over the frickin shop. 

I've been beating my head against the dang thing for the last 3 days and probably can't see the forest for the trees.

Got it back in, engaged with the cam gear and aligned with distributor.  Can't turn the rotor by hand so I know it's engaged.

When I dropped the pan the whole bottom end was well lubed from the crank splash, but I don't want to toast the Cam bearings or lifters.

- The only funny thing I can think of is that the oil does not run back from the filter housing very fast at all.  I dumped a quart in there and it probably took an hour to run down to the pan with no filter installed. From my reading it runs down thru the timing case and lubes the gears on it's way back down (unpressurized)

Let me know if you guys can think of anything else it could be - I really could use the help

Checking out for the day

Chris

Outsider

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Re: AX160 No Oil pressure
« Reply #7 on: August 07, 2017, 08:26:13 PM »
Are you running the stock fuel pump? I have heard that if the fuel pump plunger shaft is not in the engine you will not have any oil pressure.

Steve
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woodwalker

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Re: AX160 No Oil pressure
« Reply #8 on: August 07, 2017, 09:27:29 PM »
Did you cut gaskets?

steve1973

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Re: AX160 No Oil pressure
« Reply #9 on: August 07, 2017, 10:29:48 PM »
Some of your oil passages could be blocked. Just an idea. Did you rebuild your engine?

Valleyordnance

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Re: AX160 No Oil pressure
« Reply #10 on: August 08, 2017, 08:00:43 AM »
Yes, Engine was rebuilt.  Stock fuel pump w/ pushrod in place (wouldn't run otherwise)   - I've checked the gaskets we made for the oil pump to see if any passages were blocked, all good.  Anywhere else on the motor anybody can think of where a passage could get blocked?  Like I said the motor was clean inside so we didn't bother having it cooked out. 

Thanks for all the replies so far,  will update with any success

Chris

HenryVIII

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Re: AX160 No Oil pressure
« Reply #11 on: August 08, 2017, 08:02:15 AM »
    I agree with Steve that some of your oil passages might be blocked because of what you described that the oil drains back so slowly from the filter housing. Until you can figure this out this is what I would do if I were you.
 
    remove the pump and take off the drive gear. Make an adapter so that you can drive the pump with a drill when it is installed in the engine. This way you can run the pump while not running the engine and chase down the problem without damaging your engine. If if is pumping it will pull harder on the drill and you will know it is making pressure. then you will have plenty of time to chase down the problem. I know this is a lot of work but at least you will not have to run engine to test it.
   
 I had the same problem on an old car engine I rebuilt. It turned out I forgot to reinstall a 1/8 plug in an internal oil passage. But it sounds to me like one or more of your oil passages might be blocked. An old engine builder told me that he always ran a gun cleaning brush down all the oil passages when he rebuilt engines because when you mess with them you might knock some stuff loose and this can block stuff up.

There is a row of small plugs on the left side of the block. These are oil galleys that go to the crank bearings each one should have oil pressure. try taking one or more out, if they are full of goo most likely you have plugged galleys.

Henry 
« Last Edit: August 08, 2017, 08:05:16 AM by HenryVIII »

steve1973

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Re: AX160 No Oil pressure
« Reply #12 on: August 08, 2017, 12:08:02 PM »
The only other thing I can think of is bad oil pressure gauge. Have you tried another gauge?

Outsider

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Re: AX160 No Oil pressure
« Reply #13 on: August 08, 2017, 03:30:41 PM »
There should be a pressure relief valve in one of the oil galleys to regulate the oil pressure. I don't know where it is located on a HT engine off the top of my head. I would check it to see if it is stuck open.

Steve
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8683jb

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Re: AX160 No Oil pressure
« Reply #14 on: August 08, 2017, 05:53:13 PM »
I don't know if this is any help but you verified the pump is working and the pickup is sealed when you put the pickup in oil it blew it all over the shop. You verified the pump gear is engaged on the cam, so the pump is being driven. If you've checked the relief valve and it's not stuck open, it sounds like the pump and its drive are doing what they're supposed to do and it seems to me that about all that's left is that you have a blockage or a huge internal leak (how's that for genius logic). If I was looking for a blockage, I'd try to find a way to pinpoint it. I haven't seen the oil flow diagram on this engine so I don't know where the closest pressure tap is to the pump. If it's the cooler then maybe you can pull it and confirm there's pressure that far and if so, then move on to the next gallery plug or next location where pressure oil should be and see if you have any there. If there is, keep going. I don't know how many places you could check this way, but at some point there won't be pressure oil present where there should be, and hopefully you'd be able to locate the blockage. If you have an internal leak you'd probably have no oil or very little oil at the first stop from the pump. Anyhow, just trying to help.
Jon
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