Inliners International Forums General Discussion Hi Performance Wayne 12 port questions

I have a Chevy Wayne Cast iron 18 bolt 12 port head that I have owned for many years and never used because the water jackets were filled with some sort of "hardblock" type compound probably for drag racing. The package included all valve train, valve and side cover, 5 carb alum. manifold, 5 Stromberg 97's. Hilborn fuel injection and front cover pump, Cast iron headers and zoomie style headers. Moon 2 gal. fuel tank. 6 GMC connecting rods. 6 Venola pistons. Crane 330 cam. What would the value of this package be now if I wanted to sell it? I would like to clean out the "hardblock" and make it streetable, but I do not know if that is possible. Any thoughts? Thanks. I currently have the head mounter on a 235 Chevy block and have it running. It goes about 5 min. before the temp. climbs too much. I have removed some the of the "hardblock" and have some water flow through the head but not enough.

If the water jacket is filled completely with the hardblock then it will be near impossible to remove enough to circulate water thoroughly for street use.

That would be a sweet buy!

Perhaps a liquid of some sort that dissolves the filler?? That would warrant a little research!

"Once hard, it cannot be removed from the block." from: http://www.hardblok.com/

The above link says that it is iron particles with a cement binder. Anything that would eat hardblok would also eat cast iron (and aluminum).

My experience with it is its pretty much permanent. It really limits the use of the head to drag racing and limits the use of someone looking to buy it also.

I'm no expert but isn't block filler used on the engine block and not head? There might be a good reason for the block filler used in the head...

That's what I was thinking. We filled our brazed lump race heads for that reason. At least it won't leak now!

The head that 12 port tim describes sounds like it's head #1208 maunfactured by Bob Toros in ~1960. Look at the 12 Port Registry in the "Historical" tab in the sidebar. I purchased head #1207 in 1960 and had lots of water leaks through casting defects in the combustion chambers and spark plug threads. After two round trips between St. Louis and Burbank, California for repairs in 1961 and 1962 it appeared that the defects were repaired. By that time, I had gone back to school, got married etc. and put the head and the rest of my hot rod stuff in storage. I finally returned to my youth about ten years ago and got the engine and head running, with lots of Morosso stop leak, but no leaks.

If head #1208 was in as bad or worse shape as mine, it's not surprising that an exasperated owner just filled the head.

I took my roadster with the head, on a 261, to the Denver convention in 2014 and drove it on part the Hot Rod Power Tour in 2015. I'm planning on bringing it to Dayton in July.

Yes this is head 1208. I have had some luck recently removing the material in the water jackets with a cement remover with a sugar base. It does not seem to harm the cast iron and I can leave it in a long time. It turns the material in the head to mush and I can rinse it out. As I remove the material I can see some to the porous spots that will leak. I am not sure how to go about fixing these spots. I will pressure check the head once I feel I have removed most of the material. Muggy weld sells a arc welding rod for cast Iron that might work on the porous spots. What kind of moroso stop leak are you using? Thanks.

With the water jacket all cleaned up - you might consider taping off all the holes and then sloshing gas tank sealer around in there:
POR15 tank sealer

While this will surely make it water tight - it might act as insulator and impact heat transfer from the head to the coolant.

I used this in my gas tank - it cures hard as rock.

If you can find it, Sodium Silicate works especially well. I used to find it in the drug store. It is also known as Iron Glass.

Plug off all of the water jacket holes. I used to use a piece of flat steel for the block to head surface. Place the sealed up head in an oven and heat it up to about 275 degrees. let is stay in there for a couple of hours to insure that it is evenly heated all the way through.

Mix up the Sodium Silicate if needed. It usually comes in a liquid form in a glass jar.

Remove the head from the oven. You'll need a pair of oven mitts or something comparable. Pour the liquid into the head through the thermostat housing hole and plug it up. Slosh the liquid around in the head until it no longer shows any leaks and dump out the excess liquid.

I've used this stuff numerous times on leaky, porous heads and blocks. It works well and doesn't effect cooling. DO NOT let it stay in the head!!! Pour out the excess as soon as evidence of leakage has stopped!! It can harden in block passages that you can't clean out.

I learned this trick from Smokey Yunick. Again! It has always worked for me.

Does the water jacket have to be free of all rust before the sodium silicate is added?

It helps, but I've actually done the equivalent to a running engine. I had an old big block Chevy that I couldn't keep coolant in. I looped the hoses to eliminate the radiator and ran the engine with sodium silicate in it, then drained out the excess. I then loosened the belts and spun the water pump by hand for a while to keep it from locking up.

Worked great!! You need to remember to bypass the heater system as well or you COULD ruin a heater core or heater control valve.

That is with 100% sodium silicate correct? No water or coolant mixed in?

Correct!!

When looking on line for sodium silicate I see pure sodium silicate and 37-40% sodium silicate. Do you remember which you used. Should I try the pure stuff and dilute it down(if so about how much?) or just go with the 40%.

For the application you're intending, if you use the method I described, use the pure stuff. That is what I used.

I use sodium silicate for my casting core patterns. Its pretty easy for me to buy locally by the 5 gallon bucket from my foundry supply source. You may find it cheaper locally as well.