Filling water jacket in cast iron heads

Anyone do this successfully?  I want to attempt this run all filled. Block and heads.  Use Moroso block fill or Hard Blok ? Is there another product avail that will work with cast iron?

1) Why do you want to fill the jackets in the heads?
2) Exactly which iron heads?
2) How much horsepower are you targeting that makes you feel it's a good idea to fill the heads and how will you be making that power ( ie, blower, nitro, etc)?

I just can't think of a situation where filling the cast iron heads will provide any necessary structural integrity because of any level of power they might support...if structural integrity is what you are after.
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I'd like to eliminate cooling system hardware. 3 minute run time on\off throttle. 1000ish HP methanol\10psi. Just any of the 70's iron heads, I can choose.

This old video posted here a long time ago shows in the very beginning what looks like (too me anyway) the head's corner/end water jacket passages have been partially filled with what I'm assuming is grout.

https://www.youtube.com/watch?v=sTulqQZ822k

Kobelco wrote:I'd like to eliminate cooling system hardware.  3 minute run time on\off throttle.   1000ish HP  methanol\10psi.  Just any of the 70's iron heads, I can choose.

I don’t think they need to be filled for that—just run the heads open-air.

Were it not for the 3-minute run time I’d probably suggest the block doesn’t need to be filled either as I’ve known numerous blown alcohol stock block engines making more power and weren’t filled anywhere, but those engines weren’t running for 3 minutes at a time (except for warm-up in the pits).

On  the other hand, the heads will probably get hotter than the block so personally I might try it unfilled...but won’t make that recommendation outwardly without the personal experience first.

On that video looks like something is in the water ports but hard to make it out.

The thought of adding the filler to the heads is heat absorption. I have come across 2 different competitors that ran it dry one had the heads (iron) filled but not the block other had block filled but not heads (aluminum). Both wet sump. All run methanol so we can richen it up to help cool combustion (not sure if that has ever been proven).
I will run iron and iron w Copper head gaskets to keep the thermal expansion the same or almost.

Thoughts ???

Aside from cylinder wall support I don't see the need to fill anything.  That said, a short fill on the block (for said cylinder wall support) might be prudent...as would an oil cooler.

After that just run it.  Leave the heads alone.

P.S. Yes running on the rich side of the tuning window is a good idea.

3 minutes with a 1000hp without a cooling system? Doesn't seem doable. Will the meth. keep the temp. down? Maybe run coolant just in the engine only, leave enough room for expansion. Might be a good place to try some of that waterless coolant.

strokedmyford wrote:3 minutes with a 1000hp without a cooling system? Doesn't seem doable.

I disagree; have you tried?

OP says, "3 minute run time on\off throttle."  I think on methanol it just might be doable, especially with the iron heads. But I don't know the final application.

I once put a brick on a car's gas pedal, I drained the coolant, then I started the car.  The engine screamed for about ten minutes, on gasoline and with aluminum top end, but it wouldn't die. I shut it off at the key.

Now try the above again except this time leave the coolant in the engine and drain the oil instead.  How long do you think the engine would live this time...maybe 12 seconds?

So...I'm thinking iron block & heads, MeOH fuel, lots of engine oil, and an oil cooler.

10QTS of oil in a wet sump is what I am thinking. What type of Oil cooler? I am trying to reduce peripheral moving parts. I can weld on some fins on the oil pan.

Water in the heads and top of block might be good to try, add an expansion tank like old thunderbirds had...??

Keep the feed back coming I appreciate it.

Just wanted to add this, another competitor had a PG trans with a 10" hose looping the cooler in-out I was shocked that it didn't melt I did not get to ask him about longevity of it. Pan was aluminum looked like 5" deep.

There is a lot more to this than a few verbal exchanges on the internet; feel free to give me a call directly and have a pen and paper ready when you do.

I have no experience with this. But just thinking through it I agree with Paul. I don't see the benefit at that hp level. Just set the clearances loose. And run it. I am curious of what Paul would recommend for piston rings and skirt clearances. And would this change bearing clearances?