XU10 bearing shells

[DamirGTI 362]

Anyone bought  std. XU10 main bearings lately with which you've been happy with clearances wise ?

 

 

Just tried a set of "King" , but the clearance ends up a bit on the loose side - between 0.063 and 0.076mm on the plastigauge strip , so on the very limit of the spec 0.069mm seems like .

 

Tried old shells , and those measure up bang on 0.050mm .. i'd use them instead , but a few of them do not look/feel that great , even after a bit of scotch brite polish .

 

Need to check the mains too tomorrow ... as i bought King as well . 

 

Glyco , Mahle , Kolbenschmidt , FAI (?!) and some other weird ones left to try out ...

[petert 636]

I fell for this 18 months ago. I thought I was going nuts. Everything I tried was loose. Here is a copy of a letter I wrote to Spoox, as I was looking for ACL bearings:

 

"I've been having a hell of time with bearings, which I'm going to share with you. I'm not sure how much of an engine builder you are, but you will find this interesting. My saga started with a set of Kolbenschmidt STD bearings that a customer purchased. These are from Germany. They gave a mains clearance of 0.004". I measured this three different ways, as I couldn't believe it. ie dial bore gauge, telescopic bore gauge and plasti-gauge. 

 

I couldn't wait for your ACL order to arrive, so I tracked down locally, a set of 5M1677 STD bearings. Again, 0.004" clearance. Now my head is spinning.

 

The tunnel bore is within tolerance and the crank measures Ø59.985. I have another six cranks and they all measure the same. 

 

I have sets of -0.3mm Glycol bearings so I've installed and measured those up. I will end of with 0.0022" after the crank is ground.

 

What does this mean? They only correlation between the two sets of dud bearings is that they're listed for XUD9 on the package and not XU10J4. This shouldn't make any difference however. In the ACL catalogue, the dimensions are identical."

 

I also purchased as the same time, two sets of King MB5129AM. They also had a clearance of 0.004".

 

I still haven't taken this up with ACL, but I will. It's too much of a co-incidence that all can be wrong. I suspect one company is making them and supplying them to the others.

 

Your 0.076mm (0.003") is at least tighter than my 0.004", but still out of spec.

Edited 2 minutes ago by petert