Bearing Shell measurement leaving marks

[The Black Flash]

Refitting crank and rods now. I've put the new bearing shells in place, torqued them up, and used a dial gauge to measure that each one is in spec. Doing this leaves small marks on the bearing shells where the spring loaded gauge runs on the surface - I've run the tension on the gauge as light as possible. I wouldn't call it a scratch, but it seems to have worn through the top white coating. Is this anything to worry about, or just polish off with an oily paper towel before fitting?
I'm guessing it's ok, but I've never seen anyone mention it so thought I'd check!

[Pumaracing]

Well at least it'll teach you not to do it again. You don't measure the internal i/d of bearings, you measure the housing and the journal. If those are in spec so is the whole assembly. The shells are made to tolerances of a tenth of a thou or two and are about the last thing you want to worry about. If you're desperate to check them then you measure the thickness, not the internal i/d once they're fitted.

If you don't have a ball end micrometer then zero a dial gauge on the surface of a crank journal, slide the shell in and there you go. Then you calculate your bearing clearance by subtraction.

[The Black Flash]

Oh, Arse.
Ah well, cock ups are how we learn I guess.

Would you advise replacing the affected shells? I don't want to do all this work and ruin it for the sake of a couple of bearings.

[Pumaracing]

The shells will be ok. No paper towels though or you'll do even more damage. Just oil them and fit them.

[The Black Flash]

Got it, cheers

[Steve_D]

Puma
What are your thoughts on Plastigauge?

Steve

[eliot]

Steve_D said:

Puma
What are your thoughts on Plastigauge?

Steve

IIRC, he doesn't like it. But would be interested to hear the reasons again.

[Pumaracing]

Never used it. For someone who doesn't have their own measuring equipment it might be useful. As someone who does I see no need for it.

[Pumaracing]

How does plastigauge tell you your conrod big end housing has 2 thou ovality and needs recircling or whether it's the housings or journals out of spec?

There isn't really any substitute for measuring each component separately, and in at least 2 planes, with micrometers and bore gauges.

[eliot]

Pumaracing said:

How does plastigauge tell you your conrod big end housing has 2 thou ovality and needs recircling or whether it's the housings or journals out of spec?

There isn't really any substitute for measuring each component separately, and in at least 2 planes, with micrometers and bore gauges.

/devils advocate/
By placing the plastiguage around the circumfrence of the journal?

[Pumaracing]

You can't use plastigauge other than at the 6 and 12 o'clock position in a housing.