The Stovebolt Site Forums The Shop Area Engine Shop 261 External Oil line?

Hi Group, Does anybody have some know as to where to run the external oil lines of a 55 261 engine without an oil filter?

Thanks

Let me clarify what I am going after: Some have said that when you bypass an oil filter on a 261, you should still run a hard line from the send and return on the drivers side of the block. Some say you just plug them. What should I do here? Patrick's in AZ says plug them and Carter's website says run it. Who's right? Does it matter?

If your 261 was equipped with a FULL FLOW external oil filter, you MUST NOT plug up the holes. This will completely cut off oil flow to the engine....dead engine. This is when you need to route an external line from send to return.

If your 261 is equipped with a PARTIAL FLOW external oil filter, you can simply plug the holes.

Someone will pipe up, and let you know what year the partial/full flow filter change-off happened.

Someone needs to post a pic of the oil galleries on the driver's side, showing the plug that gets driven in to make the 261 a full flow system. My 261 engine is in storage where it would be difficult to get a good picture. If the plug is in the "out" position, it's a bypass setup, but if it's been driven "in" the filter ports need to be connected.
Jerry

How about this link right from the Tech pages?
And didn't full flow start with '58?

http://www.stovebolt.com/techtips/full_pressure.htm

Full-flow canister oil filters were available on truck 261 engines from 1958-1963 (most likely both USA and Canadian truck 261s).

Someone posted a picture of the factory plug/dowel in the oil passage of a 58-63 261 but I cannot find the thread.

blowing a 261 by just plugging the holes

http://1954advance-design.com/Web%20images/261-engine/index.htm

If you are ABSOLUTLY sure it's a 55 then you can either plug the lines or run the old style cannister filter. If the block has been modified for full flow filtering then you cannot plug the lines.

And make sure you use the 1/2" lines not the tiny bypass oil lines. I screwed up my motor once with the wrong lines so I know it happens!!!

Look at the photo at the top of this page: oil lines 261 motor

Thanks guys. So, there are two blocks for a 261, I guess I didn't know this. I pulled the engine out of an old truck and the engine already had a rebuild on it. When I look up the code on the block, it's a 55, but now you guys have me a little leary and I want to be able to tell by looking because I don't want to blow up my fresh motor! How can I tell by inspection?

From the various casting codes and the engine serial number.

From the diameter of the oil filter ports/holes in the block.

TC, thanks again as always. I took some photos and have some answers for you. Here is a link to the photos of the block. From what I can tell, one port has a plug in it, and the other doesn't.

http://gallery.me.com/patrick.plummer#100361

The engine code is 3836340, which I think is an early 55-57 motor, but if somebody could help, it would be greatly appreciated. Also, I couldn't find a dowel anywhere on the engine to push in / out. I guess this wasn't an option for this year? Anyway, some oil line routing would surely help. Os should I just plug them?

Scroll down to the bottom of the page... If you desire to tap yours for full flow you'll do it just like the 235 in this excellent article.

Patrick,

It looks like you have a 1955 block (the photo of the block date code is a little dark). That engine would have a by-pass oil filtration system.

If the holes on your block are in the same location as on a 1953 block, this diagram might show you where the oil lines attach to the block.

Here are oil line locations for a 1954 235 block.

There is no dowel to push in or out in an engine that uses a by-pass oil filter. That is only pertinent if you have a 58-63 261.

Tim

Tim,

Thanks for the clarificaiton. This is great news. So I should be able to plug the holes right?

As long as you do not have a 1958-1962 261 engine (with 1/2" NPT oil lines), and your 216/235/261 engine has not been converted to a full-flow oil filtration system, you can run your engine with or without a by-pass oil filter.

Tim

It seems that pplummer's question has been answered, but here are images of the oil filter connections for the
early 261, with provisions (but no hoses) for a bypass filter, and the Late 261, showing the pin in the "in" position. I have another late 261, also with the full-flow factory filter, with the pin in the "in" position. How would the pin be pulled to the out position if one wanted no filter, but without an external shunt tube or hose?

Hoyt

It would be necessary to drill and tap the plug for a threaded stud or a bolt, and use washers and a nut to pull the plug to the "out" position. Just don't drill all the way through, or you'll need to make a new plug!
Jerry