Hi everyone, On my 1988 Swiss 328 there are two thermostats located next to the oil dipstick connection to the sump. Part numbers 125857 and 127155 related to the blow-by system. What is their purpose? Is there any relation to the air-injection system, ECU as well? I would like to replace them if nessesary, they are old. Thanks.
They are not related to the blow by system, its just where they are mounted. Not very familiar with the function of the second one but one alters frequency valve operation and as I recall ignition timing when oil gets to a specific temperature. I am not sure age by itself is a reason to replace them. They are a pretty reliable part.
As Brian said, they are shown on the SPC Blow By page, but are not part of that system. They are both associated with the air injection system, and are better called a "bimetallic thermoswitch" in English (rather than a "thermostat"). 125857 disables the air injection system when the engine oil is very cold (less than 5 deg C), and 127115 disables the air injection system when the engine oil is very warm (higher than 105 deg C). Do you have a copy of the OM supplement 434/87 for Swiss 328? If not, give a shout back, and I'll get you a DropBox link for it. PS You say that your 328 CH is "1988" (and I know the "year" often gets a little mixed up in Europe (due to the paperwork), but the Swiss C7 version (usually thought of as a 1987) has these two thermoswitches; whereas, the Swiss C8 version (usually thought of as a 1988) does not. Could you please post a picture of your engine to see if it is a C7 (K-Jet without Lambda) or C8 engine (KE3-Jet)?
Some same, some not same: On a C7 328 (with these two oil thermoswitches), there is no FV nor injection ECU. On the US 328, the single (different) oil temp thermoswitch is still used to disable the air injection when the oil temp has gone below 15 deg C, but has not yet reached 25 deg C. This oil thermoswitch signal is also connected to the injection ECU as you mentioned (so must be used by it). The 328 SPC indicates a C8 328 does not use the same oil themoswitches as a C7 328, but it also doesn't indicate what it uses or if it even has one. My guess would be it uses the same single oil thermoswitch as a US 328 to disable the air injection with cold oil, and is connected to the injection ECU -- so my guess would be the injection ECU changes the EHA operation on a C8 328 in a manner similar to what you indicated a US 328 does with the FV operation. I've never seen an OM supplement for a C8 328, so if someone has one, please post. Since the OP indicated his 328 has two oil thermoswitches, it must be a C7 328 (but would still like to see the engine to confirm/deny that).
I have only ever even seen one of those. I am still unclear why they went to a totally different system on them. I have a lot of Ferrari books that fell off a truck but have nothing on the C8. I hear there is due to be another truck accident soon. If I see any I'll let you know.
Thanks for the comments Steve and Brian. This is very helpfull. This engine has no Lambda (non catalist), no frequency-valve. (There is no copy of the 434/87 supplement in this OM). This engine has no injection ECU, just a mechanical K-jet. The only ECU I see is in the boot and controls the ignition timing. So, it must be a C7 Steve. If 127115 disables the air injection by switching off the solenoid and so the vacuum to the shutoff valve, does that mean the air injection is always active as long as the engine oil temperature stays between 15 and 105 Celsius? The oil temperature sits normally around 80 Celsius, so it is active all the time? I will post a picture of the engine later.
These are the two actual switches on my 328 engine, Photo 2003. They are not immersed but live outside the sump, so actual reading of the real oil temperatures should be off? p.s A good functioning air injection system is important to me because the exhaust emissions will become more clean. Times are changing, environmental issues are very actual these days. Classic cars are "dirty stinkers" today and have become more in dislike over here. Classic cars banned in the future? I hope not.. . Image Unavailable, Please Login
This link should get you a pdf copy of the Swiss 328 C7 OM 434/87: https://www.dropbox.com/s/ad72ms8mmgllj1x/MUM_328GtbGtssuisse%20434_87.pdf?dl=0 It is written in the way that "Everything in the euro 328 OM applies except for these things which are different". Yes, it's at least a C7 or maybe even an earlier 85/86 CH. C7 328 have a cat (but no O2 sensor) and insulated exhaust headers with exhaust sampling tubes -- if you don't have these items I think it's a 85/86 CH 328 (which they just called "CH" version at the time). If your exhaust system looks like this, it is an 85/86 CH: https://www.ricambiamerica.com/car-diagrams/ferrari/v6-v8/328-group/328-1985/exhaust-system-not-for-u-s-and-sa-version.html The C7 328 exhaust system looks like this (but with a threaded plug replacing the O2 sensor): https://www.ricambiamerica.com/car-diagrams/ferrari/v6-v8/328-group/328-1988/exhaust-system-for-us-sa-ch87-and-ch88-version.html Yes, electrically, the air injection system will be active whenever both oil temp switches are closed. However, at large throttle opening under heavy load, the intake manifold vacuum may be so reduced as to not be enough to open the cutoff valve (even though the electrovalve is open and applying intake vacuum to the cutoff valve). Both 85/86 CH 328 and C7 328 have the two oil thermoswitches so work the same in this regard. (Note: the schematic in the 434/87 OM is shown with a cold oil condition so one of the oil thermoswitches is shown open. At an oil temp of 80 deg C both oil thermoswitches would be closed = electrovalve energized and open and applying intake vacuum to the cutoff valve = cutoff valve open if intake vacuum enough = air injection system active). No, the metal is such a good thermal conductor, and they are close enough to the oil volume, that they will give a very close reading to the actual oil temperature. This isn't a thing looking for a super-high accuracy anyway.
Steve, thank you very, very much for taking the effort to explain the air injection system to me! Appreciate! The electric schematics are different to my car since there is no slow-down light present. No extra relais boxes also. Just the ignition box in the boot, and the relais board in the dash. So I don't know where the 12V is coming from to energise the bimetallic switches. This supplement explains the system clearly, thanks! There are heat shields around the exhausts. No test ports unfortunately. So, maybe a 85/86 car. I will test the system soon. Last year I replaced the injectors. Since then I think the mixture has changed a bit. (slightly more smoke). Or the air injection has stopped working. Have to investigate that. The smoke-non-return valves were replaced back in 2003. First I will check for 12V on the electrovalve with ignition ''on". Outside temp is 15 degrees now, so the switches should both be closed.
Needs more than the ignition "on" -- needs to have the fuel pump running. Also, these thermoswitches have hysteresis -- so the cold switch opens at 5 deg C, but doesn't close again until 15 deg C. If it's been to below 5 deg C, but not yet 15 deg C it might not be reclosed. Also, the accuracy of these thermoswitches is not great -- something like +/- 3 deg C or +/- 5 deg C for each switching point wouldn't be unusual. But you've got the right idea: when the the engine is at warm idle, the voltage between the two terminals of the electrovalve should be +12V (if both oil thermoswitches are working).
Checked the system today. With the fuel pump running (safety switch disconnected) there is 10,5 V at the vacuum solenoid. I disconnected the vacuumhose to the vacuum operated shutoff valve. This vacuum line to the inlet manifold was open (mouth testing). Connector at the solenoid disconnected: vacuum line closed. So, vacuum solenoid is working correctly. Disconnected the air feeding line (coming from the air filter) to the shutoff valve and replaced it with a test hose. By mouth testing (blowing); blocked. Using a Mitivac the valve opened and I was able to blow air into the air injection pipes. By sucking on the test hose it was impossible to draw air back, so the non-return valves are operating fine. Letting the vacuum out from the shutoff valve; blocked again. So, the air injection system works perfectly.
