Engine: 259 engine boring and sleeving one cylinder

[Milaca]

Received a call today from the machine shop. The bores cleaned up nicely at .030 over, however a cavity opened up in one of the cylinders. The machinist described it as an air pocket, and said the only way to repair it would be to bore it .125 over and then insert a sleeve. I told him to go ahead and sleeve the one cylinder.
Is such an occurrence (a cavity or air pocket in the casting) at all common? Just curious.
My next step is to bring him an oversized piston so that he can hone the cylinders to size, bring an intake and exhaust valves so that he can machine the valve seats to the proper height (is this a common procedure?) and bring him the camshaft so that he can verify that the cam bearings are properly installed/aligned.

That's all for now!

Cheerio,
Brent

[DEEPNHOCK]

Could also be caused by cavitation erosion.
Something that happens in diesel engines quite often without special coolant protection measures.
But... It could happen to any engine under certain conditions.
Anything is possible..

Here's some info...

http://www.passagemaker.com/channels/cavitation-erosion/

[Mike Van Veghten]

A sleeve is fine...IF done correctly. DON'T put an odd sized piston in..!
Unless you are running Nitromethane, then the fuel will make up for a "multitude" of sins..!
Like Jeff says, could be a hand full of reasons for your problem.

Mike

[swvalcon]

Brent if you are having him run the seats in the head what do you plan to do on the valves? He should be grinding the valves as well at the same time he does the rest of the work on the heads. You could put the seals on and the springs if you want but there again I would just have him do it so all you have to do is bolt them on. A sleeve in a block is no big deal. At my dads shop we did a lot of them. Steve.

[Milaca]

If I understood the machinist correctly, the cavity doesn't extend into the cooling passages.
As for valves, I have decided to order new valves because of the wear that I can see and feel in the valve stems. I want to reduce the chances of oil consumption. I had new guides installed by the machine shop also.

[Mike Van Veghten]

I didn't answer the valve question.
If your shop knows their stuff, (your comment sounds like it), grinding the valves and seats to the same height is a VERY good thing. Most shops don't understand this. You can actually loose power by not having the valve tips at the same place height wise.

Yes, have them set the seats, valves so they all end up at the same place, stem / retainer wise. Possibly a little more money, but money well spent.

Mike

[swvalcon]

I think I would still give him the valves even if new and let him run them one pass on the grinder. I've seen even new valves that if you just let them touch to grinder wheel would have a slight out of round.

[RadioRoy]

A freshly rebuilt Champion six, purchased from the International meet in Las Vegas back in 90 or 91 went into my 51 business coupe. After putting about 30 miles on it, the power fell off. Got it home just before the engine locked up. Pulled out the plugs, had an assistant hit the starter and did a great three stooges imitation as a geyser of coolant shot out of number 2 cylinder, hit me in the face and knocked me on the ground.

Pulled the head and there was a kidney bean sized/shaped hole in the cylinder wall that had broken into the water jacket. There were NO vertical scratches, like would occur if the rings or piston pin scratched or caught on something.

So yes... it does happen. My engine was cast at the foundry with a bubble time bomb in it, just waiting for the next re-bore to set it off.

[t walgamuth]

Brent if you are having him run the seats in the head what do you plan to do on the valves? He should be grinding the valves as well at the same time he does the rest of the work on the heads. You could put the seals on and the springs if you want but there again I would just have him do it so all you have to do is bolt them on. A sleeve in a block is no big deal. At my dads shop we did a lot of them. Steve.

i agree with this. i thought a cavity could be a casting flaw. sounds like he knows what he is doing.

[Skybolt]

It all depends on where the hole is. I found a hole in the bore but down at the oil galley. Core shift was the culprit. The block was sonically checked and the bores were thick enough to bore. We just didn't consider the oil galley during the check. It is a 63 block and I had it bored 0,100" over. One cylinder at the bottom below the where the rings would go but would lose oil pressure. That cylinder was bored some more and sleeved.

I have the engine in place but have not started it yet. I'm waiting for the slacker to finish the head porting, it's been far too long. Yes, I'm doing the porting. At least with it in place I can finish all the other stuff while I wait to finish the heads, like putting the dog house back on etc...

Len

[Dan Timberlake]

"My next step is to bring him AN oversized piston...."

Someone should be measuring ALL the piston skirts.
And the wrist pin bores, and the wrist pins, and the piston ring to groove side and back clearances, and the compression heights, and ......

regards,

Dan T

[TWChamp]

I agree with Dan, and be sure the machinist knows what he is doing. I was rebuilding a Wisconsin engine, which had a very slightly worn wrist pin. I bought a new rod bushing and took it to the formerly good machine shop to have it honed for a .0005" fit. The good older guys were retired, and the new guy honed it to the same looseness as the old worn bushing.