Thread: Blocking heat cross-over passage

Tweet

Car won't be driven in cold weather and I want to block the head's heat cross-over passage.Whats the best method? I hear there are shims,core-fillers,new heat resistant gaskets,and was wondering if there is a method that works other than filling?

yes all of what you put down if aluminum intake you can plug it with aluminum i would not play with the cross ports in the heads. you block them with intake gasket with no cross over i have did this many times with big blocks and have not had any thing go bad from it there is some stuff called MANLEY MIRACLE SEAL EPOXY #40180 to repairing ex ports good up to 1350 you can use this

Originally Posted by shevy not heme

Car won't be driven in cold weather and I want to block the head's heat cross-over passage.Whats the best method? I hear there are shims,core-fillers,new heat resistant gaskets,and was wondering if there is a method that works other than filling?

don't use a heat riser in the manifold and the cross over won't or can't work no way.

Thanks guys.I am considering buying an intake(used) that has a notched area cut out at the heat crossover area ,not sure why,but I need to close that area in so my heads won't blow exhaust out.The center ex.ports on the heads are open to the manifold there.

shevy not heme, some yrs. chevy. put a heat riser in the right side only of their V8 so when the motor was cold the heat riser would close and force the right manifold exhaust through the intake to the left exhaust manifold and out of the tail pipe. this was to help, heat up the cold gas and get the choke off quicker, when the heat riser opened, then the exhaust would get out of both sides and i guess some exhaust would still cross over, but nut much. if you have headers or no heat riser i wouldn't worry bout it.

Thanks Mike but these heads have 2 openings at each middle ex.pocket,(with the heads upside down and valves out of the heads, looking into the ex.pocket you see two openings).Meaning that every time the ex.valve opens hot ex.is pushed #1.out into the ex.system,headers,mufflers,etc. #2.hot ex.is also pushed into the crossover port of the head which would connect to the intake manifolds crossover port to provide intake manifold/carb heat. And with the intake manifold that I want to buy having that section of the intake manifold cut out,the exhaust would just blow everywhere. So I need to block it off or fill the head crossover opening.

All it takes is a piece of tin over the port on the head with the intake gasket. Some of the gasket kits used to come with them... Maybe the Fel Pro perfomance gaskets? Can't remember the part number or anything......

go ahead a block them off, i always used them, but without the heat riser you want know the dif. we may be talking 2 dif. things, but the exhaust is gonna take the path of least resistance and that would be out of the tail pipe. the only reason the crossover is there is to heat the gas up on cold starts, and after the motor warmed up the exhaust goes out of the tail pipe. with the heat riser closed the exhaust had to go somewhere, so it crossed over to the left side.

Thanks guys.Dave I'll check for that part.It would be better than filling them in case I ever want to use the heads on a daily driver.
Mike,these are egr smog heads that allow the engine pistons to blow hot exhaust straight out toward the carburator(into the open air around the carb in this case with the intake notched).This is a race intake and I'm not familiar with the reason for this notch.Maybe it was on a turbocharged motor???
Mike I'm sure with your experience you've seen these,I must not be explaining very well.This intake doesn't have a heat riser,even the part of the intake where the heat riser would bolt to is notched out,,,gone,,,.I presume it is that way for some race application?

I have heard of guys using tin like Dave suggested, and I have also heard of guys just stuffing copper scrub pads in there.

Just block it off with a piece of tin. Like any gas or liquid (and most people I know) the exhaust gasses will follow the path of least resistanc and go out the headers. Even without plugging it, quite sure you would have to have the car on a dyno to see the difference in power and torque with or without the crossover passage plugged.........

is this what the top of your intake look like shevy ?

i am in the process of blocking my cast manifold too i got a piece of brass and am going to wittle down two pieces about 1 inch long and then i am going to make shure they fit really tight into the manifold and epoxy them up and take a hammer and drive them into the manifold hole so they wont ever move again. one could use a chunk of aluminum the same way also. if you still want soem heat one could them drill a 1/4 inch hole in them or whatever.

Mike,no I am using an open,single plane Holley intake that has the area where the crossover port is, cut out.But of course the cut out area is only the area where the manifold bolts to the head.The area I am talking about is down by the middle bolt holes(the mounting flange of the intake manifold is the area cut out).This leaves the crossover port of the head(intake side only)wide open.It's the head's crossover port opening(intake manifold side) that I'm dealing with.
canadianal,that's an idea that would work,but in my case it would be on the head crossover port.Thanks.

a gasket with no ex port will work or use the tin bock offs or cut two pices of 3/16 alum to fit in the cross ports if the take is alum and tack weld them in the intake a bit 1/4 seal with rtv hi heat so if you want the ex port latter on you can knock them out or weld them all the way up and then no rtv and use any intake gasket you like