Engine Block Water Passages

[peterw]

My story starts with a valve stuck open.....sounds like a terrible re-run. Anyway, with the head removed I found the elongated openings in the block nearest the manifold to be completely jam packed, plugged full of stuff. The pack is so tight you really have to work at removing all the junk. But I have a question...where is the passage way leading into or out of these holes? I assume there is a passage way from the elongated holes toward the center of the block, but I don't know and I can't find it by poking around in the pocket. Any ideas? Thanks so much.

[Dave Neptune]

peterw, first welcome to the forum. Not sure exactly which holes you're speaking of, can you post a pic. Many years ago when mine engine was siezed I pulled the head and had to dig out an incredible amount or rust. After I got it running I di an acid flush to finish up. I used a bent piece of stainless welding rod with a kink in the end with a drill motor to get the deep stuff at the bottom of the block.

Dave Neptune

[CalebD]

Having recently removed the late model head off our early model engine block to replace the gaskets I happen to have a picture (or 2). Our engine block is 45 years old but the head is probably more like 30 years old.

I was fairly pleased with how unclogged the cooling passages into the head were. The block seemed fairly clean also. Vinegar acid flushing must have helped a bit. There are some threads about doing an acid flush of the cooling system using Muriatic acid to clean out the cooling passages. This thread describes the procedures: http://www.moyermarine.com/forums/showthread.php?t=127

What looks like rust on top of the pistons is really more of a carbon buildup. No rust in the combustion chamber.

The cooling water passages are the elongated slots near the manifold as you describe. They connect the cooling passages in the head to those in the engine block. You need to clean the water passages in both the head and the block if you can, at least so cooling liquid (or acid) can get through.

[peterw]

Dave and CalebD - Thanks for your quick reply. CalebD hope it's ok to borrow your pic. I've circled a couple of the cooling holes I am talking about. I've dug out a lot of rust and now have basically closed pockets at the bottom of the hole. I have not uncovered a connecting passageway that would allow water to flow through the hole. I just don't know which way to continue to dig. Thanks

[Marian Claire]

I am not positive about this but I believe the channels run horizontally between the elongated holes, looping around the studs, and towards the round holes in the center of the block similar to the flow in the head. Try probing horizontally. The round holes on the cylinder side run thru to the water jacket area. Dan S/V Marian Claire

[Dave Neptune]

peterw, when I dug mine out it was a bit easier with the side plate removed. And if your beastie is that plugged up I'd pull it to check it's integrity and the diverter on the inside of the cover. Don't worry about getting it spotless just dig out the looser stuff and then clean the surfaces for reassembly. After you get it running it would be easy to acid or vinegar flush then the cooling system will be ready for years of service before needing another flushing.

While apart try soaking the water jacket in the manifold with vinegar overnight and see what comes out.

Dave Neptune

[Al Schober]

Those slots go down about 5/8" - then you'll hit solid metal. Each slot has a passage fwd and aft into the block cooling chambers. Use a 1/4" drill bit to clean out the passages.

[CalebD]

PeterW,

No problem borrowing my pic. It wasn't so pretty to begin with!

Using the picture as you did helps keep the discussion focused on to problem at hand.

Good luck with your digging and unclogging.

[peterw]

ok, success. Thanks Dave and Al. Holes are fore and aft, not quite at the bottom of the pocket and directed downward at about 45 deg angle.