Bosch Thermo-Time-Switch replacement

[Yves]

Maybe you already know but in case ...

If you are in need of a new Thermo Time Switch for Bosch FI you probably know it is difficult to
find the original Bosch # 0280130214 (OEM Fiat # 4393600).

I found a PDF Bosch document specifically for the Thermo Time Switch.

The Bosch F026T03100 it is exactly the same electrical specification 35C 8Sec 40W
The only difference is the external body is longer but in our case it is not a real issue.

Now we have an alternative solution and easily available.

All detail in the PDF document.

 

[Dr.Jeff]

Nice job researching this Yves.

Several years ago Bosch went through a merger and as a result they streamlined many of their product lines significantly. New part numbers were created for the new lines, with each of the new numbers covering a whole bunch of old numbers and applications. In many cases that means the new part is slightly different from the old one but compatible as a replacement. For some components (e.g. FI fuel pumps) they also changed the design to a more modern one with very different appearances and dimensions. In those cases they include an adaptor to mount the new design in place of the older one.

The point being there are a lot of old Bosch parts that are no longer available, however newer replacement substitutes are. And the part number will be different now. Unfortunately Bosch hasn't been extremely generous is publishing cross over documents to help identify the new replacement components. Sometimes a lot of online researching will find it, other times you need to be more resourceful. To make things more confusing, those items with slightly different specs may seem incorrect as the proper replacement despite being suitable.

The TTS is only used during initial start up when cold so the actual specs are not that critical. Therefore something like that could be an example where the new part replacement item is slightly different from the original in terms of the specs. However the replacement you found is the same, so the physical dimension is the only difference here.

 

[maz124s]

I have this in my fuel injection X19 for over a year now after doing painstaking research myself also a small technical bit this new thermo time is made all with solid state electronics and no more bi-metallic strip that needs to be heated so i think will outlive the car, hence the longer design

Also one small technical difference this time switch will activate cold start injector for 1’second even if over 35 degrees - when i asked Bosch Classic in Germany they said this was by design to aid older cars in starting

 

[Larry]

Maybe you already know but in case ...

If you are in need of a new Thermo Time Switch for Bosch FI you probably know it is difficult to
find the original Bosch # 0280130214 (OEM Fiat # 4393600).

I found a PDF Bosch document specifically for the Thermo Time Switch.

The Bosch F026T03100 it is exactly the same electrical specification 35C 8Sec 40W
The only difference is the external body is longer but in our case it is not a real issue.

Now we have an alternative solution and easily available.

All detail in the PDF document.

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Thanks for posting this. The $137 cost makes me *very* glad I bought a used one from MWB for somewhat less money.

 

[Jefco]

I had a '74 Volvo with K-jet, and replaced the thermo-time switch with a button on the dash. Worked perfectly!

 

[Yves]

Thanks for posting this. The $137 cost makes me *very* glad I bought a used one from MWB for somewhat less money.

I agree with you Larry but it is sure a used one will cost less, but if used one is not available at the moment you need, now you know you have an alternative and this new Bosch product use a more recent technologie ... "solid state electronics" no bi-metal contact and probably will not fail before the futur owner of your X ;-)

 

[EricH]

I had a '74 Volvo with K-jet, and replaced the thermo-time switch with a button on the dash. Worked perfectly!

Something of a throwback to the days of manual chokes and hand throttles from a half-century ago and even manual spark advance from yet another fifty year older.... but still an elegant, simple, and practical answer for us who actually care about how our machines work.

 

[Jari]

Great info! Thanks.