Any inexpensive way to block ACV port in center iron?
 

Devcon 10110 is a standard, but I don’t need a pound and can’t justify the price. Any thoughts? I have seen silicon caulking used before. Not sure about reliability. Perhaps the fire rated silicon caulking . I have jb weld. Not sure about the 500degree rating. That said are the ports really getting that hot ?

I just looked at the Devcon 10110 and its high temp rating after cure = 250°F

Devcon 10110 Plastic Steel Putty 1 lb.

So maybe JB Weld is a better choice purely based on temp rating.

Would compacting some aluminum foil into the port and topping off / skimming with Jb weld work?

I wouldn't use aluminum. Over time it will heat up and break off.

What is the purpose of blocking these ports? Are you keeping the stock manifold but don't want the heat entering it? Sorry for the ignorance, I have 3 aftermarket intakes that all block the port just by being solid there.

if its a stock intake an Air Control Valve block off plate works fine, and they are cheap and reversible if needed

Yeah that's what I did when I still had the factory intake and stripped carb. All aftermarket aluminum intake manifolds block off the ports into the center iron. Why F up your motor with JBweld? That's what I don't get.

The guy who built my car just used a plate

On race engines we have always filled them in with aluminum foil and JB Weld. Make little aluminum foil balls and pack them in the hole. Then add JB Weld. Usually takes 2-3 rounds to get it full. Did the same thing on the 6th port activator ports on my GSL-SE 13B.

That's how my dentist does fillings.

OK, not true, but there is a method called gold foil inlay or compaction. You just keep pressing malleable gold into the area to be filled.

I would happy to do this to anyone's irons if they agree to pay me like a dentist!

But why do you do this? Is it for a class that requires the stock intake, and you're reducing heat in it?

Reducing heat. We are allowed to remove anything related to emissions, cold weather operation, etc.

On a 12A, we block off the water passages going into the intake manifold. On my car, I also filled the water passages in the manifold with foil and JB Weld to act as an insulator from the header even though I had a heat shield there too.

Moar....
Allot of guys will either duct outside air to the outside of the carb or put a blower that puts air on the outside of the carb to keep it cool in case there is a full course yellow or a black flag all situation during a race. Slower track speeds or having to come to the pits and stop during a race can lead to vapor lock. My current car's intake wrapped in gold reflective foil, the bottom of the air box has DEi insulation on it, the air box lid is covered by gold reflective foil and the air intake hose is covered in DEi insulation.

Heat is bad on a race car. Rotary engines make allot of heat.

Thank you.

Just saying, if for some reason you ever need to remove it, it's a pain (particularly with the motor still together). I had to chip out a JB welded ACV exhaust port in order to pass smog and man was that a nightmare. Took a few days of chipping (engine in the car still) away at that thing. Making sure nothing dropped down, trying to get around the abrupt corner with bent chisels and nails... It's not a fond memory.

If reducing heat is the goal then yeah, makes sense I suppose (I can't claim to have any experience with racing, yet). However on my daily driven, fat Nikki, ported 12A, leaving the water passage functional and only using an ACV block off plate seems to be working fine. When running the carburetor is actually cold due to all that air going through it/the venturi effect. Of course that probably wouldn't be the case if I was wide open all day, but it's a streetcar so that doesn't happen. The intake isn't usually too warm either, although I admit that it's not something I check often.

Guess I'd just leave it with this. Street cars and track cars are very different things. It really just depends on the goal, the downsides, and the return. If it were me - assuming this is for a consistently driven street car with a Nikki and stock style intake - I would not block the coolant or exhaust ports. If those factors change, my opinion may as well. Just my two cents.

Agree. I would never do this to my street car. On a track-only motor I see where every horse counts and you do whatever it takes. But I wouldn't ruin a street motor for the minimal gain this gives you. On a street motor being too cold of intake/engine temp will hurt your performance and mileage, especially in cooler months. This must be for track cars only, but that wasn't/isnt clear from the thread title.