Plugging the YICS

[Incubus]

I am going to install an XJ head on a 1979 XS bottom end. I need to plug the YICS. Not having a schematic of the head I am looking for the best way to do that. I can see the a hole for the YICS in the head just below and beside each intake manifold. These ports lead to galleys in the head. I can't tell if the galleys go anywhere but this small port. Can I effectively plug the YICS just by sticking a rubber stooper in each of these four galleys?

I am open to suggestions.

Patrick

[trbig]

Just my opinion here, but I wouldn't trust a rubber plug over the course of time. I would hate the thought of having to take the head off again just to fix that again.... or be messing with the carbs trying to get it running and synch'd right, only to find out those rubber plugs had been leaking.
I have the same situation as you... XJ head on a '78 motor. What I did was bought a tap, and threaded those holes, then... I don't know the name of them, (Galley Plug maybe??) but I got them at the local hardware store... screwed 4 plugs into them with lock-tight. They are basically a short, headless screw with a hole on top for an allen wrench. You can counter sink them that way.




Find the plugs first, then get the right tap for them. I used a 3/8-24 tap. It fit well and the plugs were readily available. I feel confident that they will stay there permanently, and if I decide to put the XJ motor back in, I can pull the plugs out and slap the head on.
If you look up inside the YICS holes of the head with a flashlight, you can see a very small hole that exits into the intake chamber on top of the valve. You can't see it very well from this picture, but they are there. That's what you are trying to keep closed off.







Just another option, but seems to have worked well for me and was pretty cheap.

Tod

[Incubus]

Thanks, Tod. Before you drilled out the hole by the intakes to tap it and put the plugs in, did it appear to have some type of copper obstruction in the hole or was it just a hole? If the copper or brass obstruction was there, how deep does it go?

Thanks,

Patrick

[trbig]

I didn't drill anything out. I simply used that tap with some oil. It cut the threads nicely in the aluminum head. There was no copper or anything, it was just the aluminum stained by fuel/rust/ etc. If you look at that last little pic with the small orifice hole, you can see the bottom of that YICS hole if you look. I don't see why couldn't tap it all the way until it bottoms out, but I just did mine deep enough to countersink the plugs a bit. Make sure to clean all the shavings and oil out with a couple shots of carb cleaner when you're done (if you are going to do this) so the lock-tight will hold.

Tod

[red bandit]

I don't know the name of them, (Galley Plug maybe??)

socket head set screws cup point. set screws for short.

[Incubus]

I think that is what is confusing me. I look at the picture you posted with the arrow pointing at what I assume is the intake for YICS. The closeup, i assume of the same point, shows a hole. On my head, however, there is no hole. Perhaps someone already has plugged the YICS. I don't know how to insert a picture into a message. But I don't have a hole there in my XJ head. Instead of a hole, it looks like the end of a brass rod.

Patrick

[Incubus]

The rings are there, but there is no opening. I assumed it was some type of one-way valve....

[posthuman]

if you look NEXT to the head intakes, on the intake side of the head, you will see a round flat spot smaller than a dime.

in the middle of this is is a brass plug or pin in a sleeve of some kind a bit smaller than a BB.


on the underside of the head there is a passageway that you cant see unless you remove the head, these are the other side of these brass plugs.


the pics above are showing the head upside down, from the bottom.

[Incubus]

OK, now I see. Just because I'm a bit slow doesn't mean I won't eventually get there. So I was looking at the correct place to plug, but my proposed method of plugging was in question. I've seen those set screws in my local hardware store. I wonder if they come in metric, since my tap and die set is metric. At least now I know I was looking in the right place. I just wasn't sure if there were any other ports behind that BB plug and whether plugging that hole would be sufficient to deactivate the YICS.

Thanks, y'all.

Patrick

[trbig]

One other thing... don't quote me, but if I remember right, I had to take off these two studs also....





They're back there to help keep the YICS tube mated between the head and the block. I don't remember if it would actually clear the back if you left them, but I didn't want them just hanging there even if they did

Just for anyone curious... here's the difference in the back of the XJ motor with the YICS tubes versus the XS...







Different angles, but you get the idea.

Tod