The Stovebolt Site Forums The Shop Area Engine Shop 261 Full flow oil "plug". Is it in or out? Pics

Hi All,
This is a 1961 261 and I'm wondering if my full flow oil galley plug is pushed in or not. What do you think?
I don't know how to post pics, so here is a link to them.
http://joes41chevy.blogspot.com/
Thanks.
Joe

A 1961 261 should would have been full flow from the factory. Should have 1/2 pipe fittings for the oil filter lines.

Has the block been tampered with?

From what I understand, if you try to do away with the full flow filter and block off the lines, you will starve the engine of oil.

That plug will need to get pushed in for full flow filtering. I had a very hard time with mine and never got it done. I bashed on it so hard I was afraid I'd break the block, will drill it out if I ever get the motor out of the truck again. Seen lots of these with plug still out, why the factory set these up this ways is a mystery, you'd think they would ALL be full flow.

I know most of the posters aren't likely dealing with Canadian production engines but Canadian Pontiacs used the 261 for a few years with bypass filtration in the early 60's.

Maybe someone who reads this thread has first-hand experience moving that plug on a 1958-1963 USA truck 261. I have seen people describe moving the plug "back" or moving the plug "aside - to the side". Which is it?

After the plug has been moved, can it be moved back to the "no filter" position?

Did the 58-62 Canadian truck 261 have the full-flow filtration?

The plug per a manual I saw needs to be pushed in 0.63". Way to get it back out would be to drill it out.

If it is flush with the block as pictured it is out and a full flow filter is not used.

On my 261 the plug was the "out" position. (it must have been a service short block) Anyhooo A LOT OF PATIENCE AND A LOT OF PB BLASTER WILL DO THE TRICK !!!!!!!!!!!!!!! It took me about 3 weeks. With the block on its side, fill the plug recess with PB blaster and keep it soaked. Then each day tap the plug a few times with a ball peen hammer and a drift punch. The plug is installed with an interference fit. The benefits are enormous but the consequences of a rush job are dreadful. good luck

Thanks for all the replies. The block is currently bare and on its way to the machine shop. Should I just drill it out, tap the hole and put a long pipe plug in it?

When the pin is pushed in it blocks the passage between the oil pump and main galley and diverts oil pump output to that square, 1/2" NPT pipe plug just below the pin in your picture. Filter output needs to intersect the main oil galley which can be identified as a bulge down the entire length of the block with the oil pressure fitting right on top of it. Do some more research before taking cutting tools to this part of the block.

My 2 cents:

That pin is likely hardened steel which may not drill easily. If the pin is drilled successfully going too far can ruin the block.

There is a possibility that the multi decade interference fit will result in a cracked block attempting to move the pin if patience is absent that day.

And finally why bother with any of this considering there is a distinct possibility that using it as is with a finer element bypass filter than is available in a spin on will result in cleaner oil altogether.Full flow filtering is truly at the discretion of the spring/disc inside the spin on filter that can and will let dirty oil go on by.

Thanks ryanz. 24 hour soak of PB Blaster and the plug went in. I guess I'll have to wait and see if I did any other damage....
Here's two pics for your viewing pleasure.
https://picasaweb.google.com/lh/photo/vHDkrlwuB71QjG2P8lPawyngzqMAZC0BxUID73ICC4I?feat=directlink
https://picasaweb.google.com/lh/photo/xG1qaLQUeKd-OOEQHIZIAyngzqMAZC0BxUID73ICC4I?feat=directlink

I gots "dial-up so it will be tomorrow before the picture will download. But, I will offer this two cents worth, if you change the oil regularly you dont need a filter, (they are nice to have-dont get me wrong -but not absolutely necessary), so dont fret if the plug is "out" and not plugging the passage, use detergent oil (which is about all you can find these days) and change it at say 2000-3000 miles oil change increments if it is daily driven-shorter intervals if "short tripped". We had a '54 pass car with no filter and non-detergent oil and tore it down (after installing a rebuilt 261)for curosity sake at 83000 mi (3.70 rear gear) and it had a half thou wear on rod journals with NO FILTER and original insert bearings. Them big old bearings have a light load on them as they were originally sized as a soft babbit material to hold up to heavy cast iron piston loads with low pressure lubrication. If I had another late 261 I would prefer it to NOT have to use the full flow filter or a bypass loop as the fittings and location of them are a royal pain to run exhaust around. Not to mention emer brake,clutch linkage, column shift mechanism,steering box, etc. just another object to dodge.
The old Chevy partsman that sold me the 261s, also raced 1/8th over 261s and said you just cant pull the plugs out and should just live with the pain of working around them. The plumbing looks like Power Steering hoses. Does anyone have any problems waiting for the oil pressure to fill up those huge lines and start showing pressure on the oil pressure gauge?

AH-HAH the picture came up-- I'd say the plug is not pressed in. Mine were clearly pushed in much more, it seemed that at least a quarter inch or more depth of the reamed hole was visible.