Bonze Main Bearings

[Bad bug]

Ah! so this is the center main then. I do hope that they will be made with the correct crush. Who knows maybe later they will produce an entire set.

[Type4Unleashed]

Originally Posted by Bad bug

Ah! so this is the center main then. I do hope that they will be made with the correct crush. Who knows maybe later they will produce an entire set.

No, the thrust bearings on the Type lV are on the flywheel end and are where the end play is set between the flywheel and bearing with flywheel shims, the center mains are already steel backed so no need to do those in bronze, center thrust are installed on Type 1 motors when flanged cranks are used.

But you have to be careful now, the I think it's Mahle bearings that have been coming out for the Type lV are no longer steel back center mains.

It's not only the correct crush, but the materials expansion rates, a bronze thrust bearing was made and the wrong combination of materials were used and the bearing expanded too much and sized on the crank.

So it's a matter of finding the right combination of materials to get the correct expansion rate. For example valve guides are made of bronze, actually silicon bronze.

[effvee]

Originally Posted by Type4Unleashed

No, the thrust bearings on the Type lV are on the flywheel end and are where the end play is set between the flywheel and bearing with flywheel shims, the center mains are already steel backed so no need to do those in bronze, center thrust are installed on Type 1 motors when flanged cranks are used.

But you have to be careful now, the I think it's Mahle bearings that have been coming out for the Type lV are no longer steel back center mains.

It's not only the correct crush, but the materials expansion rates, a bronze thrust bearing was made and the wrong combination of materials were used and the bearing expanded too much and sized on the crank.

So it's a matter of finding the right combination of materials to get the correct expansion rate. For example valve guides are made of bronze, actually silicon bronze.

Me again, I now have heard another way to go is with BMW bearings. Can you shed some light on this? From what I have heard all of the bearing will be halves and using BMW steelbacked bearings; as an update/better mouse trap.

When I had my case done, my bearings cam all Alum.

[effvee]

Originally Posted by effvee

Me again, I now have heard another way to go is with BMW bearings. Can you shed some light on this? From what I have heard all of the bearing will be halves and using BMW steelbacked bearings; as an update/better mouse trap.

When I had my case done, my bearings cam all Alum.

Ok, now I have learned that, only a type IV case using stadard bearing, can use the BMW bearings. I was told that I will need to stick with stock 20 over bearing.