1978 308GTS C02 test pipe broke off. Help!

Hello all.

The car is a 1978 308 GTS, and I lost one of the C02 test pipes from the number 4 cylinder on the rear (to the back of car) cylinder bank. I know i have to find this part, which looks like a brass tube with a bolt capping the top, but wanted to ask if there is any type of temporary fix? Such as a bolt with a very specific thread and depth?

I seem recall many other 308 owners creating some sort of custom plug for this very purpose.

Thank you for any advise.

 

This is not uncommon. Really, the thing to do is simply to just remove the rest and weld over them.

 

Don't laugh...

Go to your local plumbing store. They sell brass/copper plugs that are absolutely identical. You can recreate the piping with standard metal brake/fuel line, and rebraze the fittings on, if you want. They even have ones that will accept the pipe via a compression fitting. Cost: $1.50. Looks perfect, and functional.

Only downside, is they are not metric. You need to rethread it. I already had a rethread kit, which is extremely helpful. They are about $30. Greta for cleaning off rusty threads, etc.

Of course, Isuspect Ricambi has something suitable too .

 

Thank you kindly for the advice, but will this affect the tuning of the carburators using an gas analyzer?
Or does it not really matter.

 

Brian, do you not have the four loose tubes (for the rear bank) in your tools bag??
(Should be in jack bag....)

They would have the proper fitting to remake the fixed ones in the rear..

I can mail you one if you need it as a sample.....

 

Most 4 gas analyzers now just go up the exhaust tips, I haven't ever seen anyone use the individual tubes as a test point, no.....it must have been a period factory tool, to have such a small probe..


So as Dr. Tommy said you could remove and plug them all at the header but to weld the front one you'd have to remove it and even reaching them to plug with fittings won't be easy! I have seen both methods of abandonment used....

As you see, like the sir injection lines, it's about time for them all to corrode and fail....on our cars.

 

Thank you all! I do not have the loose tubes in my tool/jack kit, and I just emailed Trutlands to see if they have a replacement as all the other ones seem fine.

Thanks Bubba I'll keep your idea in mind if I have to make another one, and thank you BPU699 as well for the Harware Store Advice! I've gotten very lucky at the harwware store many times!

 

You mean your pipes are bolted in at the REAR of the car?

Those ARE the four loose ones! LOL!

Only the ones at the firewall side of the engine were to be permanently installed, the short straight ones for the rear bank are the ones from your tool bag!

 

The "custom plug" you are remembering is for another location it is to plug the cylinder head, when the air injection nozzle is removed from the exhaust port air stream...it needs a special shape on the end to avoid inducing a noise..

The four sampling ports on the rear header are normally capped with pipe plugs, when the sampling tubes are out, probably metric but not hard to find...you see the four front ones stubbed up by the front distributor? They have caps in them also but are permanent with more extensive downstream tubing.....

 

Yes the four loose pipes have been on the engine since I got the car. Let ask this:
Will the bolts at the top of the test pipes also block the hole where the test pipe screws into the head?

All I would have to do is buy another bolt, remove the broken pipe piece and fitting, and then plug it with the bolt? I guess what I'm really asking is the bolt the same thread size as the fitting base?

Sounds more complicated when you write it out!

 

oops

I am not sure. In fact I didn't even know a carbed car had those or needed them. What happens is the pipes rust and just go to pieces. Mine did and I know several other's that have as well.

 

When one of mine let go on the front bank I removed the header (not that hard) and had a machine shop get all the rusted metal out and retapped them to metric threads and used a short bolt with a copper washer. When the rear ones fell away one at a time I welded them closed. That is until the one under the fuel distributor went. Then I removed the rear header and I drilled out the welds and retapped to metric thread and plugged them as the fronts were done several years before. Hope this helps.

 

Let me get to my car and I'll just send you one....I don't think the top plug will plug the manifold fitting, but using mine as a sample I could find you four bolts that would. Then you'd have three loose ones! The Fca judge won;t notice if you flash the tool bag real fast....

I see no benefit from having them installed all the time, indeed as Tommy said, one of my used headers came in with all four ports neatly welded shut, must have been a friend of his! LOL!

 

Good point they may not be 'bolt thread' pitch at all, as they look more like brake line fittings!!!

A long barrel fitting on a flared tube end....I'll see if I can get some made from my loose ones Brian....

 

Ferrari makes a specific part for this -- "CO Plug" 110860 -- search on that number for the details if you want to find a generic substitute.

And if the tube broke off, the chances of getting the fitting out of the bung on the header tube without crumbling is nil

 

I thank you all! I have quite a nasty exhaust leak at the moment and with the hollowed out converters the car is loud as hell. There are worse things though!

Thanks again.

 

Thanks!

What does "M 12X1.25X8" translate to?

I'm guessing 12mm od, 1,25mm pitch, 8mm length?

 

Yes, that's correct (for a male hex head fastener), but the 8mm thread length seems a little short (although it would probably work OKish). I don't have a 110860 in hand to measure, but my recollection is that the thread length is more like 10mm (as the Copper sealing washer takes up 1.5 mm of that). What is your reference for the 8mm length -- or is it a generic part that you are considering using as a substitute?

 

Hi, and thanks!

I got that description, "MANIFOLD PLUG M 12X1.25X8", from Dennis McCann - http://www.allferrariparts.com/parts_list.php, which also specifies the "gasket", 10298460/93353, as "copper washer 12x18mm". I'm trying to source this from a nearby hardware shop so Brian doesn't have spend the weekend and into next week driving around with a beater-sounding exhaust leak, or worse.

Any thoughts on screw material, should I have a choice?

 

Fill the broken open with J.B. Weld........

 

JC Whitney's still in business, are they?

 

I was just sayin'.....desperate times call for desperate measures! LOL!

Someone lost his four plugs if the tubes are in there! LOL!

Probably why one of my headers was welded closed, at those points....with REAL welding..

 

Very possible I'm wrong on the length as I haven't seen the threaded end in the flesh since ~2000 (and it's better than great IMO that the McCann's F parts website gives some useful information other than just PN -- every F DIYer should thank them).

For the material -- long-term probably best to use a stainless steel with at least 10% Cr content since the temp is kind of high (any 3XX or 4XX series stainless would do), but for a temporary repair any reasonable metal would be OKish.

 

...And a Cucharacha air horn.

Never occurred to us it wasn't correct, until one got bent they seemed very sturdy.

 

Thanks again.

All I could find locally was 12x1.25x20, grade 8.8(?) serious looking screws. Didn't have time to get them cut down at lunch, Brian may have to bring them back tomorrow if a hacksaw won't do it.

Thanks to all for the help.