Greetings to all Cats. I am still restoring my old 77 XJ6, and was about to install the rebuilt carbs when I noticed that those 6 small heat riser tubes (is there a better name?) which come up from each of the 6 cylinders......well, the main horizontal tube has some small rust holes in it. Pics:





In the pic below, you can see where a prior owner had cut the pipe going to the "air pump" and just crimped it. My question is: Do these 6 small pipes run down to the 6 engine cylinders to pick up gas fumes/emmissions from the combustion process? So, if the pipes have small rust holes, then the engine will be losing compression, right?

Even this crimp was "jerry-rigged".....would have been better to solder a metal cap to the end of it, as this crimp could also be leaking:



So, I sanded the pipe down, and used some ole JB Weld on the holes:




Any replies would be appreciated......whether cylinder compression is lost through this tube or not.
Thanks.

 

No compression loss. The air injection pipes go to the exhaust ports, not the combustion chambers.

Cheers
DD

 

DD.......Thanks for that bit of information. With the small pipes being fitted down beside the spark plugs, it seemed that it was going straight down to the cylinders. Way better that they go down to the exhaust ports, I suppose before the exhaust manifold.

So, those rusty pipes were only leaking a bit of healthy carbon dioxide and unspent gas fumes, and no compression loss. Good news. On with the carb install...............

 

Since it is useless anyway, why not remove it and plug the resulting holes in the head?
I plugged mine with these:
https://www.ebay.com/itm/10PCS-304-S...MAAOSwHHFY~ZQi

 

Nanonevil......I was just thinking the same thing.....just remove the unnecessary pipeing and put plugs in. Will be on my "to do" list. Thanks for the link.

 

Only exception might be if VA.or any possible market state emsion law would apply.


In, CA, a no/no!!! but, some have done it so skillfully that the inspector did not detect the absence of the pump and the requisite plumbing.


Tis a greatly inefficient set up.


Carl

 

JagCad......I use antique car insurance and do not need inspections......so, I still have the freedom to do as I please. They are trying to take my guns and my freedom of speech, but damn them if they come after my antique rides.

 

Solved, so long as you keep it and not choose sell it to a buyr ina "nanny" state.


I figured out a loop hole in the registration of two past critters to "ditch" the pump and it's plumbing. In another, I "dummied" the rotten pipes well enough to pass...


Carl

 

Carl......I love the idea of those "dummied" rotten pipes.....kinda like catastrophic converters gutted out and put back on. Anyone in those "nanny" states dont qualify for one of our fine Jaguar Custom Modification Jewels.