Still working on elusive oil supply to valve train problem

[Forester Massey]

Several months ago I posted questions about why I am not getting oil pressure to my valve train. I have dug deeper into the issue but still cannot figure out what is going on. Here is what I do know.

1. I have oil pressure. 40lbs when running and 30lbs when just cranking over the motor.

2. I have the valve train set up correctly. I have removed the valve train and oil does not make it to the top of the motor.

3. I can easily blow air all the way to the cam. This tells me my head gasket is on correctly.

4. Oil holes in the cam are open.

This is a continental z-145 motor. The oil pump is bolted to the front main bearing. The oil pressure line is at the back of the motor. The machine shop guy speculates that I am bleeding out somewhere along the crankshaft, preventing the oil from making it to the top of motor but lubricating the crank.

Its that is the case, I cannot find where this could be occuring. He thinks there is a plug near the front of the block that was removed and needs to be replaced. I can find nowhere this plug could be. My oil pump was rebuilt when I rebuilt the motor.

If anyone can give me your opinion, I would welcome it. If there are any plugs inside these blocks, let me know where to look.

 

[Jerry/MT]

The Machine shop guy could be right but I'm not that familiar with that specific engine. Have you looked on the AGCO site to see if there is a plug that might have been left out. The puzzling thing is that you have high oil pressure and that's the opposite effect for large effective areas in the lube system (big bearing clearances , leakage, etc) Whats the spec oil pressure? I'm thinking it should be 25-30 psig.
Is your oil relief valve equipped with the correct spring or is the relief valve stuck partially open? Do you know if the cam bearing clearances are within tolerance? Does it have an oil filter?

If you have adequate oil pressure on the gauge than you should have oil to valve train if there is oil available at the rear of the engine the cam bearing is after the pressure tap, I believe. Blowing air and getting it past the cam bearing doesn't mean that you will have adequate clearance to get signifiant oil past that point since air has a much lower vicosity than oil and thus less resistance. If that clearance is too big, on the other hand, than you could be draining oil away at the cam bearing and it would test open when you blew air through.

 

[The kid]

I found this reply and solution on another site to a like problem on a Continental.
"Got it figured out. Pulled the rocker shaft off and blew air through the oil passage and everything was ok. Blew air down the oil passage in the head and nothing. Pulled the head off and found someone has put the wrong head gasket on it at some point in its life. There was no hole for the oil passage. Happened to have a gasket kit for one I got with another tractor and its got the hole in it."
-kid

 

[murphy1244]

I found this reply and solution on another site to a like problem on a Continental.
"Got it figured out. Pulled the rocker shaft off and blew air through the oil passage and everything was ok. Blew air down the oil passage in the head and nothing. Pulled the head off and found someone has put the wrong head gasket on it at some point in its life. There was no hole for the oil passage. Happened to have a gasket kit for one I got with another tractor and its got the hole in it."
-kid

Where did you get that? I swear I've seen the same quote.

 

[The kid]

Where did you get that? I swear I've seen the same quote.

It was found through Google search "no oil to valvetrain tractor"
The actual reply came from YesterdaysTractors
-kid

 

[Forester Massey]

Dear Jerry:

You mentioned the oil relief valve. I am not familiar with it. Kid, I can blow air down the head to the cam. This verifies my head gasket is correct. I have wondered if the clearance where the cam sits into the block is too big-allowing oil to spill out under pressure rather than pushed up to top of engine. When the cam was in place and I blew air down from the head, it would come out around the cam bushing. Its appears to fit snug and the machine shop guy says he has never seen one out of spec.

I will recheck cam tolerance again. Also, I have never found a diagram of the lubrication system for this motor. My shop manual does not have one. If you know of one, please send it my way. I really want to get this baby finished.

 

[murphy1244]

It was found through Google search "no oil to valvetrain tractor"
The actual reply came from YesterdaysTractors
-kid

Thanks Kid, I knew I seen that before

 

[The kid]

I'm sure it's a problem right under your nose. It always is.

 

[Forester Massey]

Its been under my nose for a while. Thinking aloud. The oil pump is attached to the front crankshaft bearing (cylinder #1). The oil pressure gauge line is at the end of the block (below cylinder #4). That tells me oil is being moved through crank to back. I am told I may be bleeding oil out somewhere between these locations. I know of no plugs or threaded holes in this area. Does anyone else?

 

[The kid]

Its been under my nose for a while. Thinking aloud. The oil pump is attached to the front crankshaft bearing (cylinder #1). The oil pressure gauge line is at the end of the block (below cylinder #4). That tells me oil is being moved through crank to back. I am told I may be bleeding oil out somewhere between these locations. I know of no plugs or threaded holes in this area. Does anyone else?

OK. Was it working in the beginning? What have you done to it? Retrace your steps and recheck those areas.