Air injection nozzles, What size?

Hey Guys

I am currently on this project as well. The plug size is indeed M14x1.5P for the QV engine. I think some one already posted that info. In my quest for finding a proper plug I did find an oil plug from Pepboys that fit perfectly. That was just the plug and no nipple on the end so there may be some whistling in the exhaust. I don't really care to find out if the car will whistle or not so I am planning on having some longer bolts turned down to size. On my adventure of trying to find a plug that would fit I think I found a nice S.S. bolt that could easily be turned down at ACE hardware. This seems to be the easiest way to go. Any machine shop guys out there with any ideas?

Bill

 

Hello again - Several folks, having read and viewed the info that I had posted here earlier, have sent me personal messages asking me about this detail or that. Thought that I'd simply post here and address all of the points raised at one time by reviewing the work that I did, step by step, per several requests.

As you all ought to be able to guess from my alias, mine is a USA spec 1980 2-valve 308 GTSi.

If the exhaust injection nozzles have been damaged by becoming flared at the ends as mine had, then unfortunately there's NO WAY to extract them intact by simply unscrewing them and pulling them out. The ONLY method available to remove them will be to cut the damaged flared ends off. Beware - if you blunder ahead and try to horse a damaged flared end nozzle out using the Brute Force technique, you are certain to enlarge and damage the hole in the aluminum cylinder head. I used a small Dremel cut-off wheel with rags stuffed behind the nozzle so to keep chips and grit from falling back in towards the exhaust valve. And, of course, the only way to get the Dremel wheel in there is thru the open exhaust ports, which will obviously require complete header removal. I had already planned on the removal of the headers anyways since I was also going to remove that funky damaged aluminum heat cladding around both headers in order to have the headers silver ceramic coated (a job well worth doing, by the way). The removal of the front header also requires the removal of the right side fuel tank (assuming the engine is in situ, that is), so you can see that, if your only goal is to remove your damaged nozzles while the engine is still in the car, you have a large amount of preparatory work facing ahead of you.

Since I was forced to cut out each of the eight (8) damaged nozzles in order to remove them, I used them as the basis to make up my new plugs. Simply clamp the threaded cut-off nozzle into a vice and tap the internal nozzle sleeve for the new filler bolt. I used a 1/4"-NC thread Stainless Steel bolt 2" long that I purchased at the local hardware store for the grand sum of 50 cents each. The 1/4"-NC was a perfect diameter for the inside of the nozzle, but of course you could use a 6 mm tap as an alternative if you prefer to work in the metric world.

As I stated earlier, since I had free access up into the exhaust ports, I wanted to scribe cut the end of each nozzle so to uniquely match the port wall. This avoids any flow disruption at that location within the port. Simply screw the nozzle up into the hole, scribe mark the plug to match the contour of the exhaust port, and then remove and trim the end of the nozzle to your mark using a bench grinder. Here's another picture showing the end result (you can still see traces of the yellow highlight paint) - nice and smooth!

If you are fortunate enough to have a set of intact and undamaged nozzles, then you are indeed very lucky as you will have saved yourself the need to remove the headers and fuel tank. Your best bet then will be to use the square-cut end plug design as other good folks have posted here since you will obviously have no opportunity to scribe match the ends as I did. I would recommend that the length of the unthreaded portion which protrudes beyond the end of the plug threads be 1/2" to 9/16" (13 to 14 mm) in length. Steve's excellent plug drawing shows this dimension to be 6 to 10 mm - based upon my work, I would offer the opinion that this is just a bit too short. Any shorter than 1/2", and you will needlessly increase the depth of the wedge-shaped divot that you are creating at the wall of the port at the end of the plug. Any longer than 9/16", and you will have the plug end protruding into the port. Even at best, this square-end plug divot will create some flow turbulence in the exhaust port, but it will certainly be dramatically better than the blockage due to the old nozzles. And, over time, this divot area might even fill up with carbon exhaust soot somewhat so to smooth out the flow a bit.

So ... there's my answers to the various points raised. All in all, a very satisfying job, and it did honestly improve the engine's throttle response based upon the old seat-of-the-pants Butt-O-Meter dyno.

Enjoy.

Cheers - DM / Ohio

 

Just thought I'd add some other information here if someone ever needs to "repair" their 108205 2-valve air injection nozzles. You guys have it too easy now -- I never really considered using the pieces of the old 108205 parts as the plugs because at the time I still needed a working set to swap in and out (and most of mine looked as bad as DM's). If you can buy the 108205 part for ~$40 or less I wouldn't hassle with this, but then (maybe as now -- since FerrariUK doesn't list them) they weren't available from Ferrari at any price.

The basic idea is to (silver) rebraze a new stainless steel cross-drilled tube portion into the existing threaded fitting per the drawings below:

 

Howdy guys, I've been off in Italy for a couple of weeks and finally I'm getting things sorted out at home...

My ad dropped off for my injection plugs that "Spasso" so kindly linked the photo onto this thread. The ad is back up (Ferrari Ads.com) for my ready made plugs that I had made using SteveM's design and Peter's cap screw idea. Here they are:v308 2V Air-injection Plugs

I got frustrated trying to find a solution, so I had 15 sets made...my problem is solved, now I hope to help other 308's coming off state mandated smog checks. I'm trying to recover my costs only on the plugs, they're not cheap, but you won't be disappointed. If you have a beer drinkin' buddy that is sharp on the lathe...go that route. Otherwise these will be a quick solution to filling the holes.

SteveM was kind enough to send me his information and article he wrote on the 308's air-injection system...I have copies, if anyone is interested I'll snail mail you one.

 

A somewhat cleaned up version of what Ferrari UK posted.

 

I would LOVE to take the air pump junk off of my car. But in California, Arnold just signed a bill requiring smog checks forever on cars newer than 1976.

I noted that "chrismorse" has a California location. Yet is looking to remove these nozzles. How are you going to handle the smog test????

Mark

PS Note that I have a posting question on the forum right now: topic is "red hot exhaust manifold". Am struggling with what to do with this whole problem.

 

Does this bill have any exemption language for classic cars/historic cars? I've been out of the state for 8 years now after having lived there for 11 years.
Are there any county variances or is it an all county blanket bill?

I think I'd "sell" the car out of state. Then "purchase it back" at a later "legal" date to try to loop-hole the bill. Then, as an out-of-state purchased, "used car exemptions," if any, might apply???

 

Interesting idea on selling rebuying out of state. Not sure if it would work.

The new law has no exemptions that I am aware of for classic or special cars. However, in the other post on this topic, there is a note that indicates if the smog equipment is no longer available anywhere, that you may be exempted through a refereeing process. Good grief!

I am going to try to make it all work with some of the recommendations from the other post. (hot exhaust post)

Mark

 

Does anyone know of a current source of plugs for a 2V ?

 

I have had excellent results with pipe plugs to close up the opening. 1/4" NPT, socket head (allen wrench type) in stainless are easily found in plumbing or hardware supply stores

 

Thanks, I've found the exact plug thread to be 14MM x 1.5 pitch but the 1/4"
will also work. Has anyone actually experienced the rumored "chirpping" or strange exhaust note produced by not filling the void beyond the threaded portion of the hole? I was about to install a standard plug when I was made aware of this possible problem and the comments have caused some concern.