261 rebuild

[Dongray]

I picked up a 261 that had sat for several years and upon opening it found some pitting in some of the cylinders.
I have read we're some people suggest if the pitting is minor to leave it alone. Some claim it fills in with carbon deposits and it won't be noticed. Others say to sleeve it since it is already bored out by 0.080.

I'm curious to see what this forum thinks?
Thanks,
Don
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[Speedbumpauto]

Just looked at Egge Machine and they show a .100 piston. If those pits will clean at that, I'd bore the .020 and have a fresh engine. It will run with the pits but being that close to the top(and compression) it will have some blow by. I'll bet, by looking the .100 pistons is giving you a good solution....maybe not cheap but good almost never is.

[Dongray]

Originally Posted by Speedbumpauto

Just looked at Egge Machine and they show a .100 piston. If those pits will clean at that, I'd bore the .020 and have a fresh engine. It will run with the pits but being that close to the top(and compression) it will have some blow by. I'll bet, by looking the .100 pistons is giving you a good solution....maybe not cheap but good almost never is.

Thanks , I could only find upto .080. new pistons would be cheaper than sleeving ($850). I actually found some one selling a 1960 261 wth a mild cam, and triple intake with carbs asking 800. Claims it was rebuilt 3 years ago but isn't running....he said we could scope it too look for over bore but I don't want another engine I need to pour money into, ones enough
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[dsraven]

was that engine gone through before it was put away dry? looks like crosshatch in the bore like a home rebuild. if so, are the bearings etc redone as well or was it a simple clean and paint? rebuilt cyl head? reconditioned con rods, check the valve stems and seats for rust pitting a well?
if all the other stuff was done already and checks out good, how about picking up another block and bore it to fit the .080 pistons? use the crank, rods, head etc from this block after a thorough check?
how about an nice new ls engine and auto trans. that would start the snowball rolling down hill.......

before spending money on this engine's parts make sure to disassemble everything and have the parts checked for sizes and clearances before finding out, upon assembly of the rest, that some parts were just cleaned up, not rebuilt. better safe than sorry.

[dsraven]

the reason I ask if the engine was home done is because the cross hatch is not really to spec. it looks like the crosshatch intersect angles are too horizontal compared to a normal 45degree angled pattern that a rebuild would show.

[mr48chev]

I'm thinking someone did a rereing job on that engine and let it sit. You can see where the ridge was cut out in the one photo and the rust spots show to be above where the pistons sat in each cylinder.

I'd do as DSraven said and pull it down and see exactly what I had. You may have a good crank and fresh set of bearings you can reuse or you may even be able to run a hone though the cylinders and clean things up enough to run it. I don't buy the holes filling up with carbon and sealing up though.

You could probably run it for a while but your buddies will probably nicknaming you Diesel after following the smoking truck own the road.

A set of 100 over pistons from Egge runs 288.40 https://egge.com/part/egg-1000-l2033-6/

[Mac the Yankee]

Considering the fact that your current block will need boring and/or sleeving, new pistons, etc, it might be wise to take a look at that other engine you mentioned, buy it if the price is right (and it's in better shape) and sell your block.

Even if you lose money on reselling your current block, you could be miles ahead!

[Dongray]

Thanks for the input everyone. I took a look at the other engine and it looked good with the triple carbs and all but....it was a 235 not a 261 as advertised, bummer.
I'll tear the engine apart as recommended and make a decision from there.
Any thoughts on sleeveing and using the Current pistons or just boring out to 0.100 and using new pistons? I have read where these engines were capable of .125 overbore but I would think that would be for the strip back in the day. I predominantly want a weekend drive with some punch and don't plan on long hauls.
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[Speedbumpauto]

IMO, don't even consider the sleeves. I will do them for people on rare or semi rare blocks but it's expensive and, in your plan, you end up with used pistons. The next oversize is, by far, your best bet. Cheaper/easier to bore and your money buys new pistons for the new rings and cylinder walls.

[dsraven]

are you trying to keep everything stock, thats why the no go with the good used 235?
like speedbump says, if you want a good rebuilt engine then bore it out and get NEW pistons, rings, cyl walls with proper crosshatch for break in, NEW bottom end as well and also go through the head at the same time. it's gonna cost you, that why the comment about staying stock.
here is ,at least, a partial list of things toi consider for a rebuild. I suggest to take the engine to a shop for cleaning and quote before pulling the trigger, then compare that with what your end use is going to be.

dissassemble and clean/hot tank/inspect all parts
check for cracks and gasket surface imperfections, line bore trueness etc
rebore
pistons and rings
cam brgs and timing components
check/replace cam and lifters
frost plugs, block heater
check/rebuild con rods big end
check/grind/polish crankshaft
new main and con rod brgs
rebuild gasket set
rebuild cyl head
check/replace pushrods
check/replace rockers and shaft
replace oil pump if applicable on that unit (can't remember but some are splash oiled? install oil filter
speedi sleeve for the front pulley
new water pump
flush/replace rad
replace coolant hoses and clamps
new fluids, oil and coolant
resurface flywheel
replace clutch assy
drain and fill trans,possibly replace trans output joint seal
check/replace u joint
check/rebuild starter
check/rebuild floor activator mechanism for "step on" starter lnkage

if not staying stock then why not upgrade to something mainstream, with parts readily available at any tom dick and harry corner parts place. that would be a small block v8 or an LS ot even a v6 engine swap, something with an overdrive trans behind it for highway cruising. that is a slippery slope though. you might as well do an IFS front end with disc brakes and power steering, then a better diff because the torque tube will be gone anyway, and so on, and so on.

[Dongray]

The thought of going with a sbc is very appealing but I am really after the straight six with an old hot rod feel without too many modern amenities except for a t5 tranny and newer rear axle. The IFS would be nice but I went with a dropped axle for old school approach and cost.
I really appreciate the checklist of rebuilding tasks it will definitely help me out when talking to the machine shop and making sure I don't skip something. I have rebuilt a 289 and a VW engine in the past but that was decades ago so it's pretty much like doing it for the first time again.
Thanks for all the input everyone I think y'all have given me some great insight into what I'm dealing with and helped me get off center.

Anyone know a good engine shop here in North Texas?

[dsraven]

if you are gonna be rebuilding the engine then maybe you wanna look at the newer chevy inline 6 that would have a normal chevy bell housing and readily available parts. decent oiling system etc etc. it would need some new engine mounts built due to side mounts but may be worth a look. if you're gonna spend money anyways.