The good ol' clutch shudder

[Garry]

A number of early US market NB8A's had excessive crank endfloat due to incorrect machining of the thrust bearing. This would lead to major engine damage and failure. The symptoms start with the idle speed changing as the clutch was pushed in. As the clutch was pushed in the crank would move forward and the big end would start to wear it's way through the block causing the idle speed to drop a little. Nasty.

If you were lucky it happened within the warranty period and Mazda gave you a new engine, if not, tough cookies. Gotta love Mazda's customer service. Rule of thumb was if your engine was still going OK after 70k km then you got a good one.

Strange that a similar problem continued into the NB8B. You'd think Mazda would have been a bit more careful with their thrust bearings in the later model.

[Hammer]

In the short term, probably no damage. But longterm (insert six figure klm here) the crank float will skew the conrods causing axial wear to the cylinders relative to crank. By this stage the motors will be showing a marked decrease in oil pressure due to increased bigend bearing wear and we will eventually see quite a few of these throwing rods or siezing pistons....

We'll I've bent a conrod on my SP late last year with about 79,000 kms on it. Do you think Mazda would have fixed this issue when they rebuilt the engine?

[Bevan]

When I first got my NB8B (60,000km) it had the shudder quite bad. About 18 months ago (80,000km), I went to do a flick turn U-Turn but the clutch just didn't grip. It slipped badly and my car stank like burnt clutch for a day, but the clutch shudder went away totally. It's just starting to come back very slightly the last couple of months (110,000km).

The clutch feels like it's going soon, maybe another 5000km in it. Hopefully, the problem will go away totally when it's replaced.