Topic: Clearing out oil galleys in block/head??

[markreimer]

I was in the process of cleaning some heavy carbon deposits off the top of my pistons, while the block is still in place. I was using a brass wheel, careful not to hit the aluminum next to the sleeves. I had removed the head to take it in for a valve job.

What I realized after cleaning the tops of the pistons is that I forgot to tape up the oil galleys that run up from the bottom end and through the head to the cam shaft. 

I have no clue if any carbon crud made its way into the galleys, but given I was cleaning the pistons with a wire wheel, it seems almost guaranteed some dust got in there. I've heard enough horror stories of engine rebuilds gone wrong after one of the galleys gets plugged and the camshaft seizes up. So... How can I be sure that those galleys are clear of any junk before I put the new gasket and cleaned head back on the block?

I've heard of knocking out the main galley plug behind the alternator cover and blowing compressed air into it. Are there any other techniques?

thanks!

[MCRider]

74k4? The oil orifices are removable and so will blow out with compressed air maybe. That's OK you just want to be sure to catch them as they are NLA.

[markreimer]

74k4? The oil orifices are removable and so will blow out with compressed air maybe. That's OK you just want to be sure to catch them as they are NLA.

Yes, '74 cb750K. That is great news!

Also... what does NLA stand for?

[wrenchmuch]

No longer available. These jets would be in the head under the cam bearing assemblies.

[markreimer]

Ah I understand which orifices you are referring to now. I'll make sure to check them when I get the head back from the shop. I'm more concerned about having junk in the oil passages in the block, not the head. I'd like to make sure the block passages are cleaned out before I put the head back on. Is there a way to clean that out without removing the block?

[MCRider]

ITs at these orifices that the cam shearing bottleneck in oil flow occurs. Up to that point its hard to slow the oil down, pasaages are too big.  But the debris must be in the larger passageways first before it can be forced up and block the orifices.

Bottom line, everything has to be clean to avoid disaster.

ITs not uncommon for one or both of these to fall out while handling the head and be lost