Air injection ports

[Dombrockt]

Wanting to know if anyone has worked on sealing off the air injection ports found in the exhaust ports of the head. It appears that they would impact the flow pretty substantially. It looks like they could be welded shut, and smoothed out without too much headache. I would post a picture of what I'm talking about, but I would have better luck launching the space shuttle. Any thoughts?

[131]

I've done it twice, 1st time I had them welded, but ended up with a crack into the coolant gallery, the steam out the exhaust was like something from a cartoon. The 2nd time I did it, I threaded the holes, then made some sheer bolts by reducing the diameter of the bolt, leaving enough threaded section to fill the hole. When I tightened them into the head, they snapped of at the reduced section and I cleaned the rest up with the porting tool.

[Dombrockt]

Mick, did you feel like it was worth the effort to do anything to them? I've got the opportunity to do something now, but don't want to make a problem.

[131]

That was a few years ago, I haven't bothered with it since. If I was serious about porting and trying to get as much flow as I could for a race motor I'd probably go down that path, but for something I drive to work I wouldn't bother.

[vandor]

I doubt if would make much difference in flow, the exhaust is not nearly as important as the intake. If it's important to you then just get a head that does not have air injection. A 1592cc head if you have an 1800, a fuel injected head if you have a 2000.

[Dombrockt]

Thanks for the info! I wasn't aware there were heads that wouldn't have it. I think I'll leave my existing had as it sets. It's in good shape. If it's still bothering me next winter, I may build a head at that point.

[bradartigue]

I doubt if would make much difference in flow, the exhaust is not nearly as important as the intake. If it's important to you then just get a head that does not have air injection. A 1592cc head if you have an 1800, a fuel injected head if you have a 2000.

Any of the 131/132 heads cross over; 1592=1800=2000 in every combination. If the goal is simplicity get a 2000FI or early 1800 or any 1592 head. They all fit the 2000cc.