Timingbelt 323i

[Atle_323i]

On the timingbelt for 110 tooth, you use the tension spring that is blue, and on the 127 tooth you use a metal color one.
What is the difference using blue vs metal color? Or why is there 2 type of springs?

[Jeroen]

As far as I know these are different sets, not just the belt. A 110 square tooth belt has its own tensioner with different measurements, therefore a different spring as well.

In the 1980's there as a factory recall where most of the M20's were converted to 127 round tooth as these ran smoother. Apart from belt, tensioner and spring, also the 3 cogwheels were replaced. However, I have already encountered several M20's myself that did not have this update, probably because these cars were not dealer-maintained anymore.

[Atle_323i]

As far as I know these are different sets, not just the belt. A 110 square tooth belt has its own tensioner with different measurements, therefore a different spring as well.

In the 1980's there as a factory recall where most of the M20's were converted to 127 round tooth as these ran smoother. Apart from belt, tensioner and spring, also the 3 cogwheels were replaced. However, I have already encountered several M20's myself that did not have this update, probably because these cars were not dealer-maintained anymore.

So would it be an idea to convert to 127 tooth instead of 110?

[Jeroen]

Also the one in between for the ignition. Not sure if these are all still available.

[Atle_323i]

Also the one in between for the ignition. Not sure if these are all still available.

Camshaft sprocket is not available anymore, but it should be possible to get one from Ebay or so.

[Jeroen]

Yup, no problem to fit a used example

[Atle_323i]

Will the camshaft pulley from M20 325i for E30 fit, are they the same as for E21?

And is it worth the hassle to change timingbelt system? Is the 127 system more reliable versus 110?

[Jeroen]

They did change things for a reason, but how serious the problems were, no idea. I tried to dig up the recall service bulletin but no luck sofar, so I can't tell for sure which parts are interchangeable. What I do know is that the 110-tooth parts were getting pretty scarce years ago already.