Not sure if that is the correct name for them but they are all rusted out and are decrepit. These are a tin like material that fit around the exhaust manifolds. I believe they are only there to help send warm air to the carburator. Where can I buy replacements ? If I can find them, are they a hassle to replace ? How important are they ? Can I fashion something out of foil or something similar ?

thanks

 

Just unhook the hose and leave them off. Plug the vac line that runs to the flapper on the breather.

Its there to try to help with cold starts by sending heated air into the intake. I rarely see one that even works. I haven't had the one on my blazer for about 2 years and notice no difference.

 

Hose - how many ? Vac line - how many ? I take it, they are not one and the same ? "Flapper on the breather" is that what I am referring to as a carburator ? Should I just take those "heat exchangers" off so I can see what you are talking about ? They seem useless at this point anyways.

 

You are describing the heat shields which also function as a pre-heater for the intake air. IMO, the pre-heater function is not worth it. Just disconnect all of the vacuum lines from the air cleaner, gut the air cleaner baffle, and remove the tube that extends down to the heat shield. You will be all set. You can leave the heat shields on unless they are partially broke off and annoying...

 

There was an actual purpose for those heat risers. Inside the snorkle of the air intake is a flapper. The flapper is attached to a piece of spring steel. When the spring steel is cold it pulls the flapper closer to closed, as it warms up the flapper opens more until fully open. This helps the engine start on those cold mornings, however as already pointed out, after 20 years things tend to wear out.

Disconnecting the risers only increases the amount of time for the flapper to open fully, provided it moves at all. Will you notice a difference, I doubt it, however your fuel economy will. When you cut back on air your running more fuel. How much of a difference will it be, no idea? Oviously someone at GM thought it was worth teh effort to reduce fuel consumption.

 

If you remove the flapper (gut the air cleaner flapper), it should not impact your fuel mileage. I have done this on several older vehicles without issue even in the dead of winter. We also got rid of the exhaust valve on the passenger side after the manifold as well.

When these things work, they do help, but not enough to make them worth replacing with another one just like it just to wait for that one to fail as well.

 

on my 86 s-10 i took that whole assembly apart and mad a custom assembly for it. it really doesnt effect the mileage much. not enough to notice. but then again the 2.8 isnt a great motor either.

 

Maybe this is why my vehicle is so so very hard to start (lack of fuel). Once I get it started and warmed up then it runs fine.

That foil like hose runs into the EGR valve (I think ):

1) Is that where the flapper/baffle is ?

2) After I remove that hose do I have to do anything with that hole (duct tape it) ?

3) Disconnect all vac hoses going to air cleaner/EGR. Block the hole(s) also ?

 

So you guys are talking about removing the tin hose that runs from the intake to the exhaust manifold on the drivers side right? I always thought that thing looked wierd.

 

The EGR valve on these motors typically mounts directly to the side of the intake manifold and accesses an exhaust passage in the intake that is fed from a passage in the head... The large (~1.5" diameter) foil duct just connects to a tube on the bottom of the snorkel portion of the lower air cleaner housing. Where this connects is where the intake flapper valve is. You do not have to worry about the ports on the lower portion of the air cleaner where the small vacuum lines connect as far as blocking them off, however, you should plug the lines that you remove. Better yet, get some vacuum caps of the appropriate size and remove the lines at their opposite end, installing the caps to plug the ports.