Jump to content
persof

1951 Ford 8N - low oil pressure

Recommended Posts

I rebuilt the engine for a 1951Ford 8N tractor for a friend.  MANY new internal parts and lots of machine shop work.  It started up no problem but no oil pressure????.

 

If anybody has any experience with this kind of project then I will go into the details of what was done -And- ask how to troubleshoot this problem.

 

Thank You in advance

 

Fracis

Share this post


Link to post
Share on other sites
 

I'm not sure if it could be the problem but a long time ago in the service I helped rebuild a GM 6-71 diesel. Someone installed the oil pump gasket wrong. The rounded-diamond gasket for the pump had a hole for flow on one side but not the other. The blank side ended up covering the holes so there wasn't any flow. 

  • Like 1

Share this post


Link to post
Share on other sites
 
 

I'm with Terry,  Prime the oil pump.  There is a pressure relief valve on the front of the engine, Remove the hex head cap, pull out the plunger and spring.  Squirt in some 90wt oil.  Replace the plunger, spring, and hex head cap.  Now try again.

 

When the engine was rebuilt, was the oil pump overhauled?  The 8N didn't have the greatest pump to begin with and as these pump get well worn, the clearances reduce the oil pressure and make priming hard.  My 8N with a rebuilt engine and oil pump can barely hold 5 psi at idle when it is hot.

 

 

  • Like 1

Share this post


Link to post
Share on other sites
 

All,

This engine has new: pistons, rings, bearings, valves, ground crankshaft, milled block, milled head, rebuilt oil pump, new gauges, new oil pressure relief spring and lots of other things.

I did poor some oil into the pickup while the engine was inverted on my engine stand.  I also squirted lots of 30W into the opening at the rear of the engine where one pipe goes to the oil gauge and the other goes to the oil filter as it looks to me like oil is pumped from the front main bearing/oil pump assy through a tube that runs length wise feeding the bearings and then exiting this port.  See the photo with the exhaust port.  I have included some other photos that you can refer to with reply's.

I have spent lots of $ and time on this; this is the last major snag (and its critical)    

 

engine front.jpg

engine.jpg

govener.jpg

oil port.jpg

Share this post


Link to post
Share on other sites
 

 I know that when you rebuild some of these old Ford engines....The last issue is usually getting the oil pump primed. This can also happen if the tractor sits for an extended period.  Some guys fill what they can with oil during final assembly , and I've heard of guys using engine assembly lube in the pump to help it prime.   I know on the 53 ford NAA red tiger  engine(like on the tractor I have) theres a trick you can do with a drill and I think a socket extension through the distributer hole..I think.    But I'm not sure on your 8n's flat head engine.  try googling ford / fordson collectors club.  or  www.Ntractorclub .   Someone there might point you in the right direction.   

 

Although sounds like Kurt-NEPA  may already have the answer for you. 

Edited by Terry M

Share this post


Link to post
Share on other sites
 

Hey, not for nothing but how are you verifying that there's no pressure?  I ask only because I've had gauges go bad or the cap tube feeding them clogged with junk.  

Is there a way on that engine that you can at least confirm you are oiling, meaning, that although you're not seeing any pressure, is oil circulating?

Share this post


Link to post
Share on other sites
 

+1 on the NTractorClub.com  -  Great resource.

 

On your first picture, The open hole just below the water pump is where the oil pressure relief valve resided.  Did you replace it?

 

 

 

Edited by Kurt-NEPA

Share this post


Link to post
Share on other sites
 

On your last picture, the taped hole in the block should go into a tee.  One line goes to the oil filter (I think it is the return line) and the other to the oil pressure gauge.  You can check for flow by cracking the line to oil pressure gauge.  You should get flow with the engine running.  I've seen more than one bad oil pressure gauge, so this a quick check.

 

I would post your problem on the NTractorClub.com.  Great bunch of guys there that know more about these old N's than I do.  Friendly too!

 

BTW.  That engine looks great!  Nice job!

Share this post


Link to post
Share on other sites
 

Kurt & everyone else who has chimed in,

 

The oil pump was rebuilt by the same machine shop that did all the other work.

 

Yes I opened the pressure relief valve to see what I can see, maybe some gasket rtv is blocking?

 

the first test was to disconnect the pipe to the oil pressure guage...nothing came out.

 

I verified that all pipes were clear before reassembly 

 

to preserve the bearings, as much as I can, I have removed the spark plugs and only spin with the starter.

 

Is it OK to prime the oil pump with gear lube...I have a bottle of Amzoil 85W-??

 

 

FYI -- the tractor sat, uncovered with a vertical exhaust, in the woods for 10 years.

 

Thanks

Francis

Share this post


Link to post
Share on other sites
 

Amzoil 85W should work just fine.  Any of the heavier oils are perfect.

Share this post


Link to post
Share on other sites
 

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now

  • Recently Browsing   0 members

    No registered users viewing this page.

×