The Stovebolt Site Forums The Shop Area Engine Shop Cracked Cylinder wall

I enjoyed my 261 stroker for 2 days before disaster. #3 cylinder wall is cracked. Is it worth trying to get it repaired/[img]https://www.stovebolt.com/ubbthread...umber/28564/filename/20210228_114439.jpg[/img]sleeved?

Looks to me like your 261 stroker has transformed itself into a boat anchor. Not sure if it can be sleeved. Hopefully Jerry will offer his opinion.

John

bigmacdaddy, it don't look good for the home team.

bigmacdaddy Unless there is worse damage below,that can easily be repaired with a sleeve,if its an overbore may take a 1/8th sleeve. They used to take the hood off and do it right in the truck,saved a lot of disassembly !

If the crack does not extend to within 1/2" of the top or bottom of the cylinder, installing a sleeve will not be a problem. Use a 1/8" wall repair sleeve to add more rigidity to the repair than a 3/32" thick one will provide. Leave a step at the bottom of the cylinder approximately 1/4" tall for the sleeve to bottom out against and trim the top flush with the head gasket sealing surface. I have sleeved cylinders on small block Chevy race engines with connecting rod sized holes in them without a problem, and run a full season of 1/4 mile dirt track competition with them. That's a tougher environment than your engine is ever likely to encounter.
Jerry

Any idea what caused this problem?

Pre68 Dave That is a factor to be sure of what happened so it wont happen again,if something pounds the piston ring groove closed on the ring it will split the cylinder. Usually up higher than that. That one has crosshatch but may still have taper.

What oversize were the cylinders bored when the engine was machined? The damage is approximately 45 degrees away from the thrust face of the piston skirt, so I'm guessing there was a casting flaw from the back side that did not show up until the cylinders were bored. A small coolant leak from a pinhole or a small crack could partially fill the cylinder with coolant, and the next startup could produce the displacement of the cylinder wall that shows up in the picture due to hydraulic locking of the cylinder.
Jerry

It was so long ago that I had the motor built. I vaguely remember having to bore larger, due to cylinder wall pitting. I think I originally had .050 over pistons, and had to go to .080. I also can't remember if we sleeved, or just talked about it as an option. Either way, this sucks. Still trying to get ahold of builder, and trying to figure out what we did. This is what I get for dragging my feet.

bigmacdaddy, great project but bad luck for sure. A couple minutes with Search produced a post of yours from '07 that I've copied below. In it you provide details on your build, mentioning the block was bored .050 over. You do mention .080 over if you had used .030 over Cadillac pistons, an option you didn't use if I read your post correctly.

Best of Luck
RonR


Re: balancing
#7307012/02/07 10:56 PM
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As far as I know, the original idea came from Tom Langdon of Stovebolt Engine Co. He wrote an article about it a year or so ago for 12 Port News which is the newsletter that accompanies another online club -Inliners International.
The basics are that it is a 261 block. Mine has been bored .050 over. The pistons are standard size from an 84 cadillac 365 V-8. One could also use .030 over caddy pistons and bore the block .080 over. The crank is offset ground to work with the 292 rods which will increase the stroke. Exactly how much I would have to look up. Beyond that, I will be using a mild cam with hydraulic lifters, a 2X1 Edelbrock intake and 2 Rochester single bbls. The 848 head from a 235 will be decked and milled slightly with 261 springs and powerglide intake valves with a 4 angle valve job. And of course, a split manifold with duals and HEI. My transmission is an SM420 mated with a Gear Vendors Overdrive. It is basically a 7 speed. I still have my granny gear and I can overdrive 4th. This gives me the equivilant of a 3:08 rear on the freeway without having to sacrifice low end torque - it is still there when I need it.

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Hey Moparguy, Thanks!
I was doing the same backtracking as you posted! I also discovered that I had the engine built in the summer of '13, but didn't post any details after all was said and done. I do believe I had to get the .030 over caddy pistons after discovering the pitts, meaning the block must have been re-bored at .080 over.

I'm building a similar stroker engine, but I've figured out a way to do it with regular 261 pistons- - - -not the scarce and pricey Cadillac ones. There's also a NASCAR-style H beam rod for a Nissan engine that can be adapted to take the stroke out to 4 5/16 ", also with stock 261 pistons. That one requires some whittling on the crankshaft counterweights and piston skirts to keep those parts from getting into contact with each other. With a .040 overbore that one comes out to 292 cubic inches.
Jerry