Piston wear, advice required

[bruny 0]

Advice required regarding piston wear on a Vr6!

All bushes and bores seem ok but measurements still need to be taken!

Pistons seem to have suffered at some time for some reason, be it heat or lack of lubrication!

Question is should these be replaced or is it superficial considering the fact that they shouldn't come in contact with the bores?? :help:Engine strip right down 014.JPG[/attachment:2ev37n6l]

[iceviolet 0]

a familiar sight! I think if it is just surface marks they should be fine, the ones i am putting in my rebuild are used ones and two of them have a few marks on them similar to those. When i measured them with a mic, they were within tolerance. Think they can look worse than they actually are. Then again im no expert as this is my first rebuild.

[bruny 0]

Do you know what the tolerance is? were your's worse , I seem to remember you had piston issues :(

[iceviolet 0]

from bentley manual:

 

-measure approximately 6mm from lower edge of skirt, at 90 degrees to piston pin axis

 

- maximum nominal dimension tolerance 0.04mm

 

2.9 pistons should measure 81.985mm as standard

[bruny 0]

Thanks for that, will check tomorrow :notworthy:

[bruny 0]

Thats a relief, replacement pistons costing around the £100 mark I was fearing the worst.

Having measured all the pistons the one showing the most evidence of witness marks is still reading well within tolerance at 81.993 :)

Bores and crankshaft are very good , just a re-shelling and hone the bores, new rings, head skim and rebuild, few cosmetic improvements and the jobs a good'un :clap: