how to fix this (exhaust manifold)?

dan58

I'm pulling all the emissions garbage off the new to me 86 Waggy 360. It's hopefully a direct replacement for my 73 with leaky valves and junk exhaust manifolds. What the heck are these tubes that are attached to the manifold? I assume it's some sort of EGR. How do I remove them or block them? They're heavily rusted, and I'm not so sure they're even worth it.

ironman_gq

they're air injection. the system uses an air pump to inject air into the exhaust to reduce emissions and it helped the catalytic converter work more efficiently. most people just cut the tubes off or remove the tubes entirely and plug the holes in the manifolds with threaded plugs. :mrgreen: I have a set of manifolds that came off my 304 that the PO just cut the tubes off at the plugs and put a screw in the end of em with some silicone.

The PIG Smith

The holes in the manifold for the those fittings are tapped for 9/16 Fine Thread. Yup, it is a goofy size. Autozone/Advanced Auto replacement Oil Pan Drain plugs can come in 9/16 Fine Thread.

dan58

Ah, okay. I soaked the bejeezus out of them with pb blaster tonight, and they barely budge. I'll keep after them and try to get them out and plug 'em. How do these manifolds flow compared the the dogleg ones?

tufcj

Those are high flow doglegs, all the exhaust manifolds since 1971 are. They changed the dump on the drivers side from just behind center to the rear in the late 80s, make sure you have the correct driver side manifold. Those fittings might free up if you know someone with an oxy/acetylene torch to heat the fittings red hot. Bob tufcj

mrtazwrench

tufcj wrote
Those are high flow doglegs, all the exhaust manifolds since 1971 are. They changed the dump on the drivers side from just behind center to the rear in the late 80s, make sure you have the correct driver side manifold.

Those fittings might free up if you know someone with an oxy/acetylene torch to heat the fittings red hot.

Bob
tufcj

on FSJ's the dump on the driver's side changed in 80 when they went to driver drop front axle, If you can get oxy/acetylene or a MIG welder, just trim the tubes off and weld the holes shut where the tubes attached, had to do it on vehicle on one of mine.

ironman_gq

Yep heat will be your best friend. get em good and hot and soak em in PB let it sit and repeat. Might take several days of soaking and heating to get em to break free but they will come loose.

dan58

Just to bump and update. All but two came out with no problems at all. PB Blaster did the trick. The other two actually twisted off inside, so they'd get welded solid.