How to block EGR ports on intake manifold

[rocklaurence]

Hey Guys, I have an Edelbrock intake and I want to block the Exhaust runners that Heat the manifold. I was thinking of using and epoxy or high temp' RTV but I don't want it to chunk off and clog the exhaust. What do you guys recommend?

[babywag]

fill with molten aluminum brazing alloy or weld holes
I saw someone once have them machined and they installed plugs
sounds like you want to diy

[Tatsadasayago]

Lead works great also--has a low melting temp. Block with clay etc. about an inch or so into the runner, pour molten lead in almost flush with the flange and allow to cool.

[rocklaurence]

OK, if I were to go with led [melting point of 621*] where would be the best place to purchase a few ounces? Fishing tackle store?

[acct21]

Cut open a box or two of cheap Winchester white box 12 gauge field loads. About an ounce in each one...

[Tatsadasayago]

Downrigger fishing weights are a quick source. Tire weights are another, but are often a mixture of tin and antimony.

[candymancan]

go to a plumbing shop. they will have 50.50 solder on spools

[Nikkormat]

Places that sell reloading gear sell lead by the ingot.

[REDONE]

Hey bud! Are you trying to block off all the passages? Any particular reason? If you use a block off plate on the EGR boss and get rid of the flapper on the bottom of the manifold there won't be any differential pressure to push exhaust gasses through the intake manifold. If you want the EGR in place but non functional for appearances you could just plug the vacuum port. If you're dead set on blocking the cross over passage I'd weld plugs in them.

[rocklaurence]

Hey bud! Are you trying to block off all the passages? Any particular reason? If you use a block off plate on the EGR boss and get rid of the flapper on the bottom of the manifold there won't be any differential pressure to push exhaust gasses through the intake manifold. If you want the EGR in place but non functional for appearances you could just plug the vacuum port. If you're dead set on blocking the cross over passage I'd weld plugs in them.

Im assuming that exhaust pulses from either side will flow back and forth between the two sides through the intake passage. Does this process require that the flapper be closed on the exhaust maninfold?

[REDONE]

Yeah, when the flapper is closed (it works on a thermal spring, the colder it is, the more force the spring applies to keep it closed) it causes more back pressure on that side so some of the exhaust goes through the intake to the other side (some defeats the spring tension and pushes the flapper open, but still at greater pressure that the other Bank).
When you think about how fast the exhaust pulses happen it's pretty easy to see they are negligible regarding flow through the crossover. 4 exhaust stokes per revolution, times 600rpm for a low idle, divided by 60 seconds in a minute gives you 40 exhaust stokes per second at low idle. Since only half of these pulses apply to the crossover (3-4-5-6) we can cut that into 20, BUT they also over lap. 4 starts, but before if finishes 3 starts. But before it finishes 6 starts. But before it finishes 5 starts. While this may allow for some movement of gas in the crossover, it takes differential pressure to make gas flow through the crossover.

Edit>>> for a fun segue, 20Hz is the infrasonic frequency often believed to be the "brown note", so with the proper exhaust design it may be possible for your Jeep to create a whole new pucker factor at idle!

[440sixpack]

For Mopar Fel-pro makes a valley gasket that blocks them off. they don't for AMC so I've cut sheet metal to fit the hole and put copper silicone around it to seal. seems to be working fine 5 year later.

This is easily reversed if you chose to.

[Charles Kline]

Thanks for the info on the Flapper REDONE, I've wondered about it.

So in a case where that flapper is stuck closed does ALL the exhaust go through the intake to exit out the driver side exhaust manifold?

When that flap is open how does the EGR get its pressure to open (internal valve on EGR doesn't seal unless back pressure is present)


The flapper seems hoky. do most folks take it out or force it to be open at all times? what are the downside of doing that?


Thanks!

-Charles

[tgreese]

A stuck flapper forces the exhaust gases from the flapper side of the engine to go through the intake manifold and out the other exhaust manifold. So not all the exhaust gas goes through the manifold, only one-half of it.

The exhaust pressure is enough to power the EGR, without the added back pressure of the flapper. The EGR is closed when the engine is cold, so the flapper should be irrelevant once the engine reaches operating temperature and the EGR starts working. Regarding the back pressure sensor, I would expect back pressure changes in normal operation without the flapper being involved. The back pressure should be higher when the engine is working hard, and lower when the throttle is closed and there is less fuel burned. More fuel/air means higher temperatures and expanding gases, with higher back pressure.

Forcing exhaust gas through the intake manifold heats the manifold and helps to keep the gasoline from pooling on the inside of the manifold passages in cold temperatures. Keeping the gas atomized helps the engine to run when the air and engine are really cold.

if you live in a warmer climate, or can allow the engine to warm up so you don't have cold-weather drivability problems, you can disable or remove the flapper.