The Stovebolt Site Forums The Shop Area Engine Shop mystery petcock

So I am prepping my cracked block for the JB-Weld miracle to come, and having a problem with coolant still seeping out of the crack. I drained the radiator two months ago, still I have this seepage. So I opened a petcock that sits alongside this crack, expecting it to be a drain for the water jacket. Petcock is low on the block, driver's side far back, maybe 3 inches above the oilpan. Nothing comes out at all. So I take off the petcock, which is pretty well thick with black gunk, and clean out the hole which is also full of black gunk. Still no coolant runs out of that hole, but my cracked block still seeps. So what is this petcock for? and how do I thoroughly drain the water jacket?

Organbuilder,

I saw the picture you posted of the crack. It appears to be right smack dab at the bottom of the water jacket. The petcock drains the water jacket, but remember, this could be a swamp of goop and rust. I would try to cook as much moisture out of the crack area as I could with a small torch. It will probably boil the water and gunk on the other side of the crack.


Stuart

What about blowing through the petcock with compressed air to get the junk out of the way?

"What about blowing through the petcock with compressed air to get the junk out of the way?"

You could do that but it still doesn't get the crud out of the block. It would likely just re-deposit itself there again or somewhere else anyway. The only way I know of to get rid of it for certain is to tear it down to the point where you can dip the block in cleaning solution (some call it boiling it)and then run long spiral brushes throught the jacket. There may be some commercial solvent you can run through the cooling system that will help loosen it but I am unaware of it. Perhaps someone else might know.

53moneypit, what I was thinking was that even if I can clear the petcock temporarily, I could then drain the waterjacket until I get the repair finished. The gunk will slide on back later I suppose.
Karl

Organbuilder,

There is a soft plug (freeze plug) near your crack. If you are thinking about flushing some of the crud out so the crack will stop weeping, you could knock the plug out and flush from this hole to the petcock or vice versa! The crack area is right at the bottom of the cavity and is probably a swamp.

You drilled some stop holes in the crack so when the gunk is washed out, clear water should drain from these holes. You can buy a expanding type freeze plug to replace the hammer in type and it should be fine.

Stuart

I cleaned mine by running water into the block and wiggling a length of piano wire into the petcock hole.That way everything I loosened up came out the hole.

why not go another way with this,,,if you have a 216 or 235 engine rather than try to repair the block replace it with a good one and have something that will last and service you down the road...216 and 235.s are not costly,,try to get into a 235 if you can...doc

why not go another way with this,,,if you have a 216 or 235 engine rather than try to repair the block replace it with a good one and have something that will last and service you down the road...216 and 235.s are not costly,,try to get into a 235 if you can...doc

Well doc, there might be a bunch of 216s lying around in Iowa, but they are more rare here in Sweden. And I do want to stick with a 216, being the stingy type, I just invested in a rebuilt head I want to stick on the next engine. Long term plan is a new block, but short term is that I want the truck on the road by Easter. The worst that can happen is that the motor dies, and I won't be so much worse off than if it sits waiting in the garage.
I just blew out through all available holes. The drain hole has not opened up yet, but the two holes I drilled in the crack started to gush finally. So I seem to have drained some of the extra coolant. All I really want to do is get the best possible (driest) surface to glue to.
I've got a line on two 216s sitting in Minnesota, and I hope to be able to bring one back as a reserve. The shipping will cost 5 times the cost of the engine.
Karl

I believe you have a point,,what I take for normal here I have a small salvage yard close to me and it is full of older treasuresso sometimes I wonder why someone is doing what you are trying when I can get it with ease and very little cost..So sorry if I offended just living in my own small world and no offense was intended...doc

Organbuilder Grind a groove in the crack just like you would if you were to weld crack. You don't want it smooth.The rougher the better. Use a 4" grinder with new wheel. Grind eash side of crack for 1/4".If possible have wheel off center to make rough cuts. Several coats, smallest first, Don't spread whole area at once,layer away from crack at 1/16 lapps.

Thanks Beaver, good ideas, I need all the help I can get. I have no grinder and I don't see how one would fit in that cramped space without a lot of part removal. But I do have a Dremel, and I plan to wear down a lot of Dremel grinder heads before I do the gluing. The glue equivalent I found here is a loctite product, 2-part metal glue, called "chemical metal" (in Swedish) - it hardens in 10 minutes. Let me know if I should bury this glue and special order Devcon B instead. I sure envy you guys that can just run down to Napa and pick up simple stuff like freeze plugs!
No offense taken, Doc, I'd like to do the fix proper and expect to sometime, but even if I were back in the states it would take me a number of months or more to rebuild and switch an engine. There are guys on this site that swear by JB weld, and if I just get the prep work right I have hopes that it could hold a number of years.
Karl

I've done a lot of crack patching, and the most effective stuff I've found is a product called Devcon Epoxy Steel. It's similar to J-B Weld, but it's for industrial use. Try drying the block out with a propane torch in the area of the crack. If any water seeps under the patch while the epoxy is curing, it will keep it from bonding to the block properly. Ditto on leaving a rough surface, and get the block ground down to clean bare metal for 1/2" or more on all sides. If you want to hide the repair, press a piece of 40 grit sandpaper onto the surface of the patch when it's about halfway cured. The sandpaper will leave a rough surface that resembles the texture of cast iron. Good luck!
Jerry

I addition to heating the block with a propane torch to evaporate the water, how about jacking up the entire side truck (since the engine is still in it), to tilt the water away from the crack in the block? I would think that one cinder block under each of the tires on the side where the crack would be enough gravity to keep the water away.

Have you tried liquid glass from the drug store ?
In my youth it was a common practice for used car dealers to fix a cracked head/block/head gasket with egg keep... (think its called silca -something )I did it once and ran the car for a couple of years
there were and still are tricks to raise oil pressure and with a well placed small nut and quiet a noisy trans or diff with a little sawdust ...my pappy taught me more than just about the birds and the bees

Use a wax type substance to "temporarily" plug the crack. I use the stuff electricians use around fittings and pipes that come through walls. It's the black stuff that they pack around the opening to pipe gap. Then use brake cleaner to clean the prepped crack and apply the epoxy. I would also get some of those magic GM coolant pellets and throw them in too,
Scott