if its a '59-63 261 block with the 1/2"NPT connections and the pin in the "out" position, then yes. Both lines attach to the same galley, but if the pin is in the "in" position, then it blocks that galley and forces the oil out the front fitting and into the filter, then back into the block at the rear fitting.
Hey snarl, thanks for the info. I'm kind of lost on what you mean by pin? If its in or out? Could you explain to me how to tell if the pin is in or out or where to find that at? Its a 61 261 motor. Thanks jeff.
Its a new melling oil pumpthat I put in. I still have the old pump, should I drop the pan and put the old pump back in? I just figured if I tore it apart to clean, I might as well drop a new pump in at the same time. Thanks for any input.
Here is what my pin looks like currently.... Is that considered to be the IN position or OUT position?
It is in the out (flush with the end of the block) position, which is bypass filtration. Moving the pin in about 1/2" to get full flow filtration is a big PITA. I've heard of guys breaking the block trying to do it. Your call..... changing the oil pump isn't relevant to anything. There is nothing wrong anyway....
okay guys how about this, lets do this tech style. If you have gotten some proven hp out of your 261 post and itemize what you did! so that way we can have a clear cut list and we can compare what works best? I know someone earlier posted they can get 320 ft lbs of torque with out getting to radical.
Thanks Snarl for letting me know its in bypass filteration. Well, I could try to push the pin in, or what if I plugged the upper back oil line and then ran the line back into the pan, if I drilled and bun the pan to flow the oil back into the pan? I'd hope that the pin would move with ease....so that would make this less of a headache. But if worse comes to worse, I was thinking of option 2 with having the return line go into the pan.
I got as far as making a flow bench adapter plate and nozzle, cutting up a head thru several planes to determine wall thickness, milling various areas of the port and chamber with <?xml:namespace prefix = st1 ns = "urn:schemas-microsoft-com<img src=" /><st1:stockticker>CNC</st1:stockticker> repeatability, and testing results. Next is documenting the benefit of the larger powerglide intake valves along with chamber mods to improve exhaust flow and later see what a dyno shows. So far I can say with some certainty that the well known mod of plunging a shell reamer in from the manifold side does not help but reduces velocity and increases turbulence by making the sharp turn at the sides even worse. As well after cutting apart many different oil filters the full flow thing is not exactly true either as dirty oil will go on by without you knowing about it. Pics of head sectioning are in the album in my signature and I wish I had more time for it.
I would. On mine, I had to drill it out. I then tapped the hole for a pipe plug and made my own pin that didn't require a press fit. This way, I could take it apart if I ever needed to without issues. It's entirely up to you how you want to handle it.
There really isn't anything you would do to a 261 that is any different than what you would do to a 235 when talking about performance mods.
You're over thinking it. Having a line dump into the pan isn't going to get you anywhere. That's what a 235 does. 54-58 261 and all 235's are bypass oilers. These engines all have the small oil lines with one line pressurized to the filter, an orifice in the canister to control flow, and a return line that just dumps into the oil pan. 59-63 261's when setup for bypass filtration have basically both oil lines going into the oil galley. Whatever oil wants to go through the filter does, and the rest just continues on to the bearings. This is the better way to go than just dumping into the pan. what are you using for a filter setup? the stock unit or an aftermarket spin-on filter?
Just to clarify, this is the procedure for a 235 or a '54-58 261. '59-63 261's only need to have the pin pushed in for full flow.
Im using an aftermarket spin on filter. I do hand have the old original canister that bolted on my manifold but running a header now so I bought the oil filter relocation kit from summit or jegs. Thanks, jeff.
if you do move the pin in, the front line will hook up to the "in" side of your filter head. If you can, its best to mount it low. like off the frame, rather than up high. good luck!
Thanks Snarl, hoping for the best on having it move. I do have the filter mounted low on the frame right now, so thats a plus too. Worse case scenario, if the pin doesn't want to move, should the bypass setup still work the way it is with the pin the way it is?
I tried to move a pin in...no go....like how hard to you want to pound on it before you break the block???? I drilled the center of the pin to weaken it,then pulled it out and tapped the hole to 9/16 fine ( I have this tap for GMC oil filter conversion) Then cut off a bolt and threaded it in.I suppose I could have just driven in the pin after driiling it and tapping the pin for a plug.Just didn't think that way at the time....Duh
Thats some good info, thanks a lot. Im mainly concerned like you said, how hard do you hit it before something cracks or something? Ill be checking it in a little bit when I get there, see how hard or freely it will move.
Should I even bother trying to get it to move then? Or what would you reccomend doing? If left where it is, will there be to much pressure going to the screw on oil filter? Thats why I was thinking of plugging the upper one, so that oil came out the bottom line in to filter and back out to the oil pan. Or would it be better to drill and tap it like another guy did on here to restrict the oil that way? Sorry for all the questions, just trying to do this the right way the first time without causing any problems hopefully, and with me being the newbie, you guys are very helpful and i appreciate all the info you may have to share. Jeff
Must have gotten lucky, thing moved with ease, barley had to hit. Thanks for the info and help guys, im sure ill have more questions to come haha. Jeff
After breaking a couple blocks trying to move the pin years ago, I would do as "Cosmo49"s tech tip suggests. It has the advantage of being removeable during rebuilds to clean the oil passages.
It will work just fine with it where it is. Just change the oil a little more often. If I were to try and push it in, I'd have the pan off and make up some kind of c-clamp style press, and heat up the block around it beforehand. Like I and others have said, leave it alone or drill it out.... Since you got it to move, you won't need to worry about it!
First I have to say that this thread is great! After that I have some questions! I have a 54-55 261 from a 1st series 55 truck! If I want do put the 261 in my 55 chevy (car) what problems will I get? Motormounts will not fit, but I can make new ones Waterpump! , there is much info and parts to put a newer engine in older car, but no info about putting older engine in newer car! Can I make a spacer and use 55-235 pulleys and fan? Oilpan and oilpump! Can I use from 55-235?
Stuff that bolts to the outside of 235 all fits the 261.Early water pumps bolt on 55 and up blocks with an adapter,pay attention to pulley sizes to maintain proper water pump speed. The 261 block is on the stand in my shop.Zero decked Ross forged pistons,cam just sent off to Oregon Cam Grinding.Got a GMC oil pump I'm gonna install,maybe...Pump is longer so I need to modify the oil pan.The stock Chevy pump is ok,just messing with stuff. Block had to go .080 to clean up . Made a few crude tools to poke around through water passages trying to measure cylinder wall thickness.I suppose sonic testing is easier but 200 more bucks.....Appears at .080 the cylinder thinnest area is around .140 on non thrust surfaces.Should be just fine for a street engine.Taking these blocks .125 over like they used to do can be risky business I think
Here's the 261 and the Ross Pistons. Pistons are zero decked,the intake valve notch is about 4.5 cc's. 848 head I checked at 79 cc's comes out to an actual 8.9 compression..I put in the crank earlier.
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