I HAVE HEARD OF A METHOD OF SEALING A CRACKED CYLINDER HEAD OR BLOCK BY MEANS OF IMPREGNATING WITH SOME FORM OF RESIN. DOES ANYONE KNOW ANYTHING ABOUT THIS ?
its in the auto parts store, the coolant sealant that is. seals blocks heads and radiators, and actually works too. cant remember the name, check the chemicals section.
I use a product used for plugging the holes in bowling balls. Absolutly the best sealer I have ever found for race type cylinder heads that have problems beyond normal repair principals. This stuff is tough. Flows well and pours eaisily. You will have roughly twenty minutes to flow the product around the casting before it's time to pour out the excess. Check with any bowling supply outlet for the two part epoxy. It will run around $100. for two quarts.
There are several "two part" epoxy systems available for sealing low pressure cracks. I have seen a couple advertised claiming to seal combustion chamber cracks but the ones I tried in my youth (still on the market in 2003) FAILED miserably.
As to the red pepper---Come on guys let's not go off on that bent again. We all know that pepper, sawdust, copper powder, aluminium powder, egg whites, ---- on and on and on, ad infinitum, can seal up the "45 caliber hole" in the radiator. That stuff would get you home in a Model A but boy, did you have a clogged up radiator. Todays radiators are quite intolerant of these old time "cures". Unless you have a "need" to experiment and a deep pocket, stick to the "repair or replace" doctrine on the new stuff. It is not at all uncommon to put some magic potion in the radiator to stop a leak "temporarily" and forgetting until the thing costs you an engine or worse.
I have used a product called Seal All which is a liquid polymer you pour into the water jackets of a head and roll around until the entire inside of the head is coated then pour the remainder back into the bottle. I have used it on a couple of heads with cracks in hard to fix places that would be junk otherwise and it has definately worked. This has been in ports though, I dont know if it would work in a combustion chamber crack, but then, if the crack is in the chamber it could be fixed by other methods like plugging or welding. A good idea is to seal up the head once it is filled and pressurise it with air to push the seal all out into a crack or porosity.
The thing is though, it isnt cheap and its a bastard of a job to do so you would really have to have no other option.
Hope this helps, there is a bit of a website,
On a car with a slight external coolant leak at the head gasket it worked fine and never gave anymore troubles for several years. The engine never overheated neither, even at full load and speed for hours on European highways.
On a second identical case, I tested first another brand of sealant and it didn't work at all. Then I put in the cooling circuit a can of Bar's Leaks sealer, but I didn't flush the system properly to get rid of all the traces of the other stuff before, as advised on the Bar's instructions leaflet. It didn't work perfectly; the leak was reduced but was still there.
Then I sealed the leak with Araldite 2-components epoxy resin and up to now it doesn't leak anymore.