Still working on elusive oil supply to valve train problem

[Harry in Ky]

I don't think I buy your theory about oil flow through the crankshaft. I admit I can't remember ever having a Z145 apart, and don't consider myself any sort of authority on Continental engines at all, but that makes no sense to me. I would suspect there is a mating passage from the oil pump through the main bearing cap to another passage in the block to a main oil galley. I wonder just how do the cam journals lubricate? You mentioned at one point that you overhauled this engine yes/no? Did you have the crank and camshaft out? Does the engine have replaceable cam bearings? I've seen some older engines where only the front cam journal had a bushing, and even some engines with none at all. I don't see any listed in the parts book. What can you remember about the cam bore with the rocker lube passage when you had it apart?

 

[Forester Massey]

In the beginning I thought it was gummed up or that I had the valve train rod on incorrectly. I ended up buying a new rod and getting it right. Its not the rod orientation. As far as I can tell, I have never had pressure to the top. Remember, tractor was given to me with blown head gasket.

 

[Harry in Ky]

Sorry, but no, I don't remember how this all came about. So I take it you have NOT actually seen this engine torn down? At least not past the headgasket? I have seen older engines use pressure fed cam journals to supply rocker shafts. Some have a small groove either on the inside of the cam bushing or outside the cam journal to provide a pathway for a small flow of oil to flow around the cam and into the vertical bore to the rocker shaft. Others used a cross drilling in the cam journal that mates the pressure passage below to the feed passage above during the few degrees of rotation when the three drillings are matched up. I can't tell from the parts book if your engine might employ either of these methods.

 

[The kid]

I don't think I buy your theory about oil flow through the crankshaft. I admit I can't remember ever having a Z145 apart, and don't consider myself any sort of authority on Continental engines at all, but that makes no sense to me. I would suspect there is a mating passage from the oil pump through the main bearing cap to another passage in the block to a main oil galley. I wonder just how do the cam journals lubricate? You mentioned at one point that you overhauled this engine yes/no? Did you have the crank and camshaft out? Does the engine have replaceable cam bearings? I've seen some older engines where only the front cam journal had a bushing, and even some engines with none at all. I don't see any listed in the parts book. What can you remember about the cam bore with the rocker lube passage when you had it apart?

I have read if the main bearings are incorrectly installed will cause this problem. There is also a tube in the valve train if not properly aligned will do this. Since he has oil pressure below. I'd recheck that valve train assembly and double check the head gasket.

 

[namyessam]

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.

I responded to a prior post of yours on this subject and at first I thought there was a plug on the front side of the block under the timing cover that could be missing but looking at agcopartsbooks, it apears that it is outside the cover and would be leaking oil that could be seen, the same goes with the plug on the back side of the block in the clutch housing. I have run out of ideas and just throwing these out. Could it be the oil filter is not seated on the block inside the housing. There is supposed to be a spring and washer on top of the filter pushing the filter down against the block. These are often lost and never replaced I was told by my dealer. It is unavailable part through Massey. Do you have a spin on filter adapter that may have a missing orfice allowing too much oil through the filter and limiting it to the engine? I have no idea how these adapters work, I don't have one. Hope you find the problem, it sure is baffling.

namyessam

 

[The kid]

Taken from YesterdaysTractors
"I am not familiar with the TO30, however on a M.F. 65 (continental gas engine) the rocker shaft can be installed so no oil gets to the rockers. Rotate the shaft one half turn and you will get oil, but not what I would call a gusher.
I.T. service manual instructs readers to install the shaft so no oil is delivered.
The Massey service manual gives directions that yield flow to the rockers. "

 

[namyessam]

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

This quote is the most confusing part of the whole puzzle. If oil cannot make it to the top of the head, the oil will not get to the rockers whether it is correctly assembled or not. From the best of my memory the main oil channel runs from the front of the block to the rear and plugged on both ends with 1/4 npt plugs The mains are fed by a cross drilled hole from the main bearing bore to the main channel. the crank is cross drilled from the mains to the rods bearings feeding oil to the rods. The oil pressure sending fitting is in the rear of the block. The oil pump in on the front main feeding the main channel. The head is fed by a verticle line, I think it runs though the rear cam bearing to the main oil channel. I think there is a groove in the cam shaft bearing area that allows oil to flow up to the head. The only other outlet for the oil is to the oil filter. If there is not sufficient back pressue in the filter it may reduce the pressure enough to prevent oil to the head. I rebuilt my motor 4 years ago so memory is a little foggy. Pure speculation but possible.

namyessam

 

[namyessam]

2. The head is fed by a verticle line, I think it runs though the rear cam bearing to the main oil channel. I think there is a groove in the cam shaft bearing area that allows oil to flow up to the head.

namyessam

I've been thinking some more about this issue and the only other thing I can think that can be possibly wrong is if I am correct that the head is supplied by an oil line drilled through the rear cam bearing to the main oil channel is if the line between the cam bearing and the main channel is plugged. OP states that he can hear air coming out of the cam when he blows air down from the head. Can the plug in the main oil channel on the front of the block be removed and see if air comes out there. Air will go to the filter and the main bearings. The channel will be full of oil and make a mess but could elliminate that part of the problem. The channel could be probed with a long wire to see if any chunks of dirt can be removed. May save a teardown.

 

[The kid]

In the beginning I thought it was gummed up or that I had the valve train rod on incorrectly. I ended up buying a new rod and getting it right. Its not the rod orientation. As far as I can tell, I have never had pressure to the top. Remember, tractor was given to me with blown head gasket.

Forester, are you using the AGCO manual? Jensales, I&T? It really sounds like your going to have to split the tractor get inside to see if all is well as in clearance, pipe from oil pump to engine block o ring. You might have cam clearance problems. To check any of these your going to have to get inside. My manual shows two pipes coming off the oil pump. One going to the pickup screen. The other going directly to the block with o ring seal. Like I said, your going to have to get inside to find the problem. Bummer. -kid

 

[Jerry/MT]

The oil pressure relief valve is after the pump in the lube circuit.It's actually built into the pump It's a spring with special spring constant and there is a small piston that uncovers a return circuit to the crankcase. It maintains oil pressure between 25-30 psig. You can shim it up to get higher pressures and pull the hims to get lower pressures. if all your clearance are correct, ll the oil passages are clear and if the spring is the correct one and the piston is not stuck there should be flow to the rockers and your gauge should be between 25-30 psig, lower at higher pressure altitudes. When you checked the rear cam bearing, was there evidence of oiling?