A.I.R/Smog Question ...... (nickel tubes in manifold)

[Bill C.]

Was wondering if not having those nickel tubes in the manifold would cause problems?

In all my infinite wisdom, that was the one item I managed to miss when rebuilding the engine. The machine shop removed the tubes before bead blasting them and I never thought anything about it.


I am pretty sure I can get the tubes on the driver side in without taking the manifold off, but the passenger side (I have A/C) might be lucky if I can two of them in.

Input is appreciated.

[Joe L.]

Re: A.I.R/Smog Question ...... (nickel tubes in manifold)

Was wondering if not having those nickel tubes in the manifold would cause problems?

In all my infinite wisdom, that was the one item I managed to miss when rebuilding the engine. The machine shop removed the tubes before bead blasting them and I never thought anything about it.


I am pretty sure I can get the tubes on the driver side in without taking the manifold off, but the passenger side (I have A/C) might be lucky if I can two of them in.

Input is appreciated.

Bill-----


I don't think the lack of the inner extension tubes will cause any problem except, perhaps, reduce the efficiency of the system. However, if it were me, I'd want to have them installed. If you can remove the "trees", you can install the tubes; there's no need to remove the manifolds, at all. Just remove the "trees" and insert the tubes; that's all there is to it. I realize this might be tough on the right side with all the A/C stuff in the way, but if you can get the "trees" off, that's all you need. In any event, I would install as many of the tubes as I could even if it's not all 8.

[Clem Z.]

Re: A.I.R/Smog Question ...... (nickel tubes in manifold)

the outside tubing manifolds seat against the top of the inside exhaust manifold tubes so i am not sure you would not have a exhaust leak there without those tubes in the manifolds.

[Joe L.]

Re: A.I.R/Smog Question ...... (nickel tubes in manifold)

the outside tubing manifolds seat against the top of the inside exhaust manifold tubes so i am not sure you would not have a exhaust leak there without those tubes in the manifolds.

clem-----


Yes, without the extension tubes (or, appropriately sized washers installed in their place) it is possible that an exhaust leak can occur; the tubing nuts on the "trees" are a straight thread and will not seal at the threads. However, in most cases the ends of the "tree" tube will seat and seal against the machined surface at the base of the threads in the manifold. The tubing nuts will thread in further than when installed with the extension tubes in place, but there is enough thread to accommodate this.

[Dale S.]

Re: A.I.R/Smog Question ...... (nickel tubes in manifold)

My 67 AIR car has run for several years without them. I glass beaded the originals when I found them in the garage and put them in the glove box. I will reinstall them when I need to pull the tubes again.(hopefull never). Dale,

[Duke W.]

Re: A.I.R/Smog Question ...... (nickel tubes in manifold)

Those internal tubes are a significant restriction to exhaust flow. Based on SOTP removing them from my Cosworth Vega resulted in noticeably more top end power. I don't know what the effect would be on emissions, but in its last emission test before it got Historial Vehicle plates it would have passed current model field standards except NOx, which doubled due to cam reindexing that substantially reduced overlap, but it was still only half the limit for its year group.

The B-nuts seated sort of okay - no leaks, but it took a couple or three retorque before all of them held.

Duke

[Bill C.]

Re: A.I.R/Smog Question ...... (nickel tubes in manifold)

Thanks for all the great input

I am going to order a set of the tubes from Paragon, $150 DAMN expensive.
I will also get a new set of trees too. Figure if I have them off the car might as well replace the originals, plating is comming off, and there is rust on the tubes close to the exhaust manifold.
It will make the engine compartment look nicer too.

Bill

[Harmon C.]

Re: A.I.R/Smog Question ...... (nickel tubes in manifold)

The finish on replacement tubes many times is not the same as the original finish.

[Patrick H.]

Re: A.I.R/Smog Question ...... (nickel tubes in manifold)

The finish on replacement tubes many times is not the same as the original finish.

Nor the configuration.