The Stovebolt Site Forums The Shop Area Engine Shop Installing bypass oil line

I am currently not getting much oil to my rockers so this weekend I'm planning to install a bypass oil line to the threaded plug on the passenger side of the head. My plan was to put a T in the line between the pressure port in the block and the inlet port in the filter. The line would run toward the firewall, where I would have another T so it could branch off to the gauge in one direction and then on to the rockers in the other. I read in another thread that if you tap in between the pressure port and the filter inlet, your gauge will only measure how dirty the oil filter is. If this is so, how would you recommend installing an oil line to the rockers?
PS: I've disassembled and cleaned the entire rocker assembly, including the inside of the shafts. Also cleared out the supply tube behind the pushrod cover, the passage in the hollow head bolt, the passage in the head. All is clear.

I just had a 54 in my shop today that had the return line from the oil filter attached to the center head port, instead on the normal block return port, and it seems to work OK.
Just an idea.

So oil that would normally exit the filter and dump into the crankcase is being routed up to the rockers?

That is correct.

After thinking about this a bit and reading through the archives, I think what I'm going to do is pull the push rod cover again, remove the oil supply tube, and see if blowing compressed air through the fitting above the rear camshaft bearing will solve the problem. I know the tube itself is clear, as is the drilled bolt and the passage through the head. I suppose it's possible I have the wrong head gasket. Is there any way to tell without pulling the head? (Ha-ha).

What year 235 are you working on again?
I thought it was a 1958-62 engine and they would not have a tube behind the side cover.
If it does have a tube, have you ever pulled the rear fitting that the tube screws into out?
That fitting is a restrictor fitting with a 1/16" hole which is known to plug up.

Dave, it's a '56. It does have the tube behind the push rod cover and no, I did not pull the fitting you mention. That's my next step, though, because I suspect the blockage is either there or further back. Interesting that you mention the restrictor. That would explain a lot. Thanks for the tip.

I had a customer that insisted on running Amsoil. She would not change oil, only the filter, as Amsoil recommends.
The restrictor on her engine was always plugging up to the point I drilled the restrictor oversize so it would not.

If you don't find the fitting plugged(which you will) try running the engine with the fitting out to see if oil comes out of the hole.
If no oil there then the cam bearing is in wrong, or in very bad condition.

OK. Will do that and report back.

My 1951 pickup has a by pass line on the drivers side teed from the pressure gauge. I was wanting to install a filter but I was afraid I would not get enough oil to my top end with out drilling out the hole in the inside of my filter case.

It's stuff like that has made me decide to dig back into it and see if I can find the cause of the blockage so I don't have to resort to the bypass.

Well, this afternoon, I took the push rod cover off and started the investigation. Here is the oil tube to the rockers:

[IMG]http://i7.photobucket.com/albums/y261/bohon/56%20Chevy%20truck/Blockage001.jpg[/IMG]

I removed the tube and it had no oil in it. Then I used compressed air to make sure the drilled out head bolt was clear, and also the passage in the head:

[IMG]http://i7.photobucket.com/albums/y261/bohon/56%20Chevy%20truck/Blockage007.jpg[/IMG]

[IMG]http://i7.photobucket.com/albums/y261/bohon/56%20Chevy%20truck/Blockage010.jpg[/IMG]

[IMG]http://i7.photobucket.com/albums/y261/bohon/56%20Chevy%20truck/Blockage006.jpg[/IMG]

[IMG]http://i7.photobucket.com/albums/y261/bohon/56%20Chevy%20truck/Blockage005.jpg[/IMG]

Once I was sure all these passages were clear, I went after the spot I really suspected: The rearmost fitting for the oil tube:

[IMG]http://i7.photobucket.com/albums/y261/bohon/56%20Chevy%20truck/Blockage012.jpg[/IMG]

Here is what I found:

[IMG]http://i7.photobucket.com/albums/y261/bohon/56%20Chevy%20truck/Blockage016.jpg[/IMG]

[IMG]http://i7.photobucket.com/albums/y261/bohon/56%20Chevy%20truck/Blockage019.jpg[/IMG]

There didn't seem to be much sludge in the fitting itself, but you couldn't see clear through. Here it is after cleaning:

[IMG]http://i7.photobucket.com/albums/y261/bohon/56%20Chevy%20truck/Blockage017.jpg[/IMG]

Here is the hole after cleaning:

[IMG]http://i7.photobucket.com/albums/y261/bohon/56%20Chevy%20truck/Blockage021.jpg[/IMG]

So the hole was about 90% blocked. I'll put everything back together tomorrow morning and see what happens.

Joe,

Thanks for posting the excellent photos. Looks promising. Let us know the outcome, so we can hopefully celebrate with you.

I'll do that. I was a little disappointed when I saw the fitting because there didn't seem to be much sludge in it. But when I saw that the hole was packed almost full of it, I figured I'd found the problem.

While the fitting is out, give the hole in the block it came out of a good shot of air. That should dislodge any built-up crud in the block passages. You might even crank up the engine for a few seconds to see if you get oil flow out of the block.
Jerry

OK Jerry. I shot some solvent down there to get as much crud out of the hole as I could. Will do the air too. I might change the oil again after this even though it's fresh. I shot a lot of solvent on the rocker assembly and through the passages while trying to figure out the oil flow and there's probably quite a bit of it in the crankcase now.

The solvent will evaporate as soon as the oil gets up to operating temperature. In fact, if you run the engine at a fast idle for 15-20 minutes with a quart of Kerosene or Diesel fuel added, then change the oil while it's hot, you'll get a good running cleanup. Just don't drive the truck- - -diluted oil doesn't have much film strength and the rod bearings might get damaged.
Jerry

I did that procedure a while ago with a 50/50 mix of oil and automatic transmission fluid.

This morning I cranked the engine to see if oil would come out of the hole. No oil. Lots of cranking and no oil. I'm thinking maybe the engine is shot. I decided to get it running and see if any oil would start coming out. So I fired it up and anxiously watched. No oil.
At this point, I'm thinking I need to find a place to store this truck. It was intended to be a quick (ha!) detour from another project I'm working on. I'm standing there, watching the hole, wondering who I can convince to let me store the truck at their place when all of a sudden the oil comes bubbling up. I nearly started singing the theme song from the Beverly Hillbillies.
It started off intermettent, then got steady. There's not a lot of force behind it but I suppose that's the way it's supposed to be. I have oil coming out of the holes in the top of every rocker except the front one, but maybe it will get up there when I accelerate. Here's a picture:

[IMG]http://i7.photobucket.com/albums/y261/bohon/56%20Chevy%20truck/oilflow001.jpg[/IMG]

Sounds like you hit gold!