What Did I Just Break By The Oil Filter?

Cut off valve for the air injection.

 

Part number 121751 (item 1):

https://www.ferrariparts.co.uk/diagram/ferrari/308-quattrovalvole-usa/009-air-injection

The way it works is:

During cold-running = coolant thermoswitch closed = electrovalve 2 actuated = intake vacuum reaches the cutoff valve 1 = cutoff valve open = air is drawn into the exhaust stream by the exhaust pulses.

During warm-running = coolant thermoswitch open = electrovalve 2 not actuated = intake vacuum does not reach the cutoff valve 1 = cutoff valve closed = no air is drawn into the exhaust stream.

So with that broken (or glued shut ) you'll have no air injection during cold-running, but warm-running will be normal (i.e., just leave it like it is with the broken piece blocking the hose until you get a new cutoff valve).

 

Well, it will be the same as it has been ever since that poor repair was made -- so another 500 miles won't really matter. Long-term, you should fix it as it will keep the cat in better working order and extend its life.

 

I would give that a "probably would" if the various hose fitting diameters are the same (but I'm a stickler for looking stock -- although I agree that the metal case and metal port fitting would be much more rugged).

 

Tommy, its a SAAB part. It fits 92-98 900s.. #4228011 or 42-28-011

Several places are showing it as back ordered or NLA. It might be out of production

 

They are pretty buried so not easy to see. Metal looks like a good idea to me.

 

If the Porsche part fits the air hoses I see no reason not to use one of those. I'd keep it working. It helps the other parts from degrading but if you block it off go to the manifolds, take off the check valves and replace with pipe caps you can get at Lowes or Home Depot.

 

This part crosses to one for Mercedes of the period. The Mercedes one is all black, rather than the black and ivory of the OEM Ferrari item.

It is just a vacuum actuated check valve which as noted regulates airflow as determined by the electrovalve that turns on and off the vacuum.

This is what the non OEM one looks like, many F parts suppliers would likely be providing this one as the supresession part.

 

You might be able to repair the old one, drill out the old vacuum hose stub and epoxy a 1/8 brass hose barb into the hole. Assuming the internal diaphragm is still ok.

If you do put in a new one, put a little silicon lube on the plastic hose stub, so the vacuum hose doesn't heat weld itself to the plastic and makes it prone to breaking off.

 

And all the usual suppliers I checked show then as backordered, or discontinued. If you have a source who shows them as in stock let us know.

 

https://www.ital-spares.com/brand/ferrari/8728/cut-off-valve/rueckschlag-ventil?c=103

 

I never use offshore suppliers except in very rare cases for vintage cars. I have a business to run.

 

Pelican shows 5qty for porsche unit.
https://www.pelicanparts.com/search/?q=993%20113%20245

$100 less for the Mercedes one... Hahahaha
https://www.pelicanparts.com/More_Info/0001407760.htm?pn=000-140-77-60-M22&bc=c&SVSVSI=2225

 

Valve, secondary ventilation - 7.20605.71.0 PIERBURG - 4228011, 7700863034, 9146656

This is the actual Pierburg part for those who want to track one down.

 

The first part number is the Peirburg number. The next one is the Saab pn, the Renault pn and the Volvo pn.

 

Indeed, part of the problem is these cars are now on the cusp of being vintage cars. These cut off valves were available about 3 years ago for about $30. Now more like $200, plus shipping. At least they are still available, sort of.

 

Various Volvo dealerships still seem to have these in stock, I ordered a spare one from a Toronto dealership. The price was reasonable, and since local no ship charge for me. Volvo pn 9146656 on the various Volvo parts web sites, the part itself came in the Pierburg box with pn 7.20605.71.0

 

Here is a link for those who source in the US...
https://usparts.volvocars.com/p/42833809/9146656.html