Air injection nozzles, What size?

Can anyone tell me what size plug would be needed to eliminate the air injection nozzles? I have a 1980 308 GTSI.

 

For the 308 2-valve heads, the air injector nozzle thread size is M14 x 1.5P

Others have reported strange exhaust noises if you don't include the 8mm spud on the end -- I added that feature to protect the exposed web of Aluminium of the cyl head around the hole (so I've only "with spud" experience).

If you send me a PM with your email address, I can send you ~2MB of related information (and we'll assume that you've already searched on "air injection nozzle" here and at the old site -- lots of information and other approaches ).

 

I new as soon as I saw this response. This had to be a Mech Eng. Used Eng paper included name, date, and all dimensions for a machine shop. Looked at profile yep Mech Eng. I some times wonder if it is just obvious to people in the Eng field or does everone notice. Anyway great detail I hope if I ever need info on a part the response is this good.

 

Steve, or anyone,
Will that plug work on a qv head?
Perhaps we could send that drawing to Hill Engineering to make up a batch....
I'd also heard that oil drain plugs work.
best
rt

 

We, or at least I, don't say publicly "great job" very often on this forum. But here's one where, Steve, again, goes over and above. Detailed. Informative. Accurate. Reliable. A standard for us all. Thanks Steve.
Philip

 

Russ -- I don't know the QV nozzle design, but my guess would be "no" (just based on my foggy recollections of the SPC illustrations which aren't that clear). Your comment that "an oil drain plug works" would make me guess an M16 or larger thread size.

Perhaps Malcolm at FerrariUK can give us some information or a jpeg of the 83-84-85 QV air injector nozzle(s, if different,) and the(ir) placement. Does it/they protrude significantly into the exhaust stream?

Thanks for the kind words everyone. (This information used to be accessible here -- in a deep, dark corner-- but Rob took it down )

 

Steve,

I will have a look and see what I can find and will post on Monday if anything comes to light.

 

Steve and Malcolm

Many, many thanks. The injectors sitting in the middle of the flow must have some flow penalty - will look forward to any info.

Again, many thanks
rt

 

I just did this one.

One problem that I have with the 'square end' plug design is that it still represents a notable flow discontinuity in the exhaust port.

In my case the previous owner had disconnected the air pump belt, so the ends of all of the nozzles were warped and could not be removed intact. I took a Dremel and cut off each one. I then purchased a stainless steel bolt (see first picture), tapped the old nozzle, and then threaded it down into the business end of the nozzle (second picture). Then, insert the plug back into the head port and uniquely scribe the end of each one so to match the port configuration and trim to fit (last picture).

I think that this design is an improvement over the square-ended ones, and it is way inexpensive to do, as a bonus.

DM / Ohio

 

Here are some ready made. I bought a set for my '78 GTS. Beautiful work.


http://www.ferrariads.com/cgi-bin/classifieds/classifieds.cgi?search_and_display_db_button=on&db_id=1963&query=retrieval
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These are very similar to what I had made for my car (again, thanks to Steve M. who gave me the same info he provided here in this thread!! ).

I decided it would be easier to use existing bolts, cut down and re-threaded than to use hexagonal stock.
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By-the-way, my last photo does not show a copper gasket, but I did use them with the plugs. I can't remember, but I think it was a common, domestic oil-drain plug gasket that I used.

 

Here's what happens when the previous owner decides to disconnect the air pump belt.

Picture 1 shows the damaged air nozzles. I highlighted them with some yellow paint in order to aid picture clarity. Sort of blocks the port, don't they?

Picture 2 shows what you end up with once you cut it out of the port.

Picture 3 shows the 'business end' of the tapered end plugs which I made from the remnants of the damaged nozzles. Note the smooth flow at the port wall, which one would not be able to achieve with the square cut design as shown earlier in this thread.

Enjoy - DM

 

This is a brilliant photo post - many thanks for adding motivation to get mine out.
rt

 

I capped the heads of mine when I pulled off the manifold. Ditto Russ's comments. Time to get serious and get them out.
Philip

 

Man,

I can hardly wait to get this smog junk off of my car. I have one frozen smog pump and I hope the remainig one driven off of the back cam doesn't lock up and do the engine.

Just as soon as i am sure the seller has finally come through with the smog and the registration is really done all of this crap is going into a box and i can work on getting the car to run like it should.

To that end, what suggestions do any of you gents have for removing these crimes against nature???

Penetrating oil on the injector nozzles?



At what point do you begin to sense that the nozzles might have deformed or become impossible to remove without dropping the manifold?? What happens if you keep going with the attempted removal?? Do the nasty deformed nozzle clumps just break off and find their way into the muffler where they will rattle and fizz untill you go crazy, or is this like pasing a stone?? Or could you screw up the bosses in the manifold and have to pull them out to repair the fittings. How does it go.

All help is always appreciated,

chris

 

A rattle in the exhaust I could cope with. If a piece fell into the exhaust valve and ruined it or worse still went through and ruined the bore, now that would be annoying. Perhaps these should only be taken out when the manifold is coming off as well.

 

[QUOTE
Perhaps Malcolm at FerrariUK can give us some information or a jpeg of the 83-84-85 QV air injector nozzle(s, if different,) and the(ir) placement. Does it/they protrude significantly into the exhaust stream?
[/QUOTE]


The only nozzles we have are #118097, which are for a 1983 QV........

The protrusion measured from the underside of the face of the hexagon to the tip of the tube is 33mm

 

Malcolm -- Thanks for hunting that down and posting the picture. I checked that the 2-valve and QV use the same size Cu washer, but can you confirm that the thread size is M14 x 1.5P? And finally, would it be possible to get a jpeg of it as (loosely) installed in a QV head exhaust port like the 2-valve shot that DM posted to see the effective penetration of the tube portion? Putting your length measurement on DM's jpeg (and assuming the heads are machined the same) would indicate that the effective penetration into the port is not very large.

Russ -- Based on that jpeg (and assuming that the thread size is the same) I'd alter my opinion to "maybe/probably" -- or at least worth checking further.

 

Steve,

Yes the thread size is 14 x 1.5, for information the thread on the other end is 13 x 1.

I will search and see if I have a QV cylinder head for the requested picture

 

Steve,

Shots as requested

 

That's an interesting difference between the 2v and 4v air injectors. If the qv/3.2 use the short penetration injector, would it then be practically as much value added as the solid plug just to cap the existing injector off vs a solid plug? I must say I am impressed by Dave's per cylinder custom pieces as well.

Great thread.

 

Thanks again Malcolm -- very useful info.

Russ -- I think performance-wise there probalby isn't any super-strong need to remove the QV air injection nozzle if you can block it off by other means, but removal (and replacement with a dedicated plug) would still be the best preservation method IMO.

 

Malcolm and Steve
Many thanks! Terrific thread.

Are there any current good sources for a dedicated plug? Or can I use your drawing and get some done?
Group buy anyone?

best to all
rt

 

Russ -- All things are possible . Check the FerrariAds link in Spasso's previous message -- Peter B. had some sets made up using the SHCS approach. Additionally, if you had the access and wanted to add the refinement of custom machining the end of each plug to exactly match the exhaust port walls per DM's approach you could have the end spud portion made longer.

I've got one spare plug left over -- if you promise to send it back to me, I'd be glad to loan it to you for a test fitting. Shoot me a PM with your shipping address if interested.