Bearing Seal Conrod fitment

[s_alt]

Hello,
Im currently rebuilding the heads on my R100T 81' and was curious if anyone had any insight on how to how to size for a new set of bearing shells on my connecting rods? I see on Max Bmw that you can size up +.25 and so forth. I noticed a little bit of side play on my left con rod and wasnt sure if maybe it just needed to get tightend down to torque spec or maybe needed new bearings.
Any help is much appreciated!

Thank you.

 

[robsryder]

Many years ago I learned about Plastigage when rebuilding an old British sports car. This stuff is used to determine clearances, i.e., proper fit, of bearings for connecting rods and such. Following is a link illustrating its use -

http://www.plastigaugeusa.com/how.html

A special tool is needed to remove the con rod caps. It is available here -

http://northwoodsairheads.com/tools-and-t-shirts.php


Following is a video illustrating replacement of bearing shells (hint: if an old bearing shell is dropped into engine during removal, you will likely need to remove the oil pan - at least I had to do so)

<iframe width="560" height="315" src="https://www.youtube.com/embed/9EdohXyY6Yc" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>


And yet another bit of info -

https://www.hotrod.com/articles/crankshaft-rod-bearing-install/

 

[s_alt]

Many years ago I learned about Plastigage when rebuilding an old British sports car. This stuff is used to determine clearances, i.e., proper fit, of bearings for connecting rods and such. Following is a link illustrating its use -

http://www.plastigaugeusa.com/how.html

A special tool is needed to remove the con rod caps. It is available here -

http://northwoodsairheads.com/tools-and-t-shirts.php


Following is a video illustrating replacement of bearing shells (hint: if an old bearing shell is dropped into engine during removal, you will likely need to remove the oil pan - at least I had to do so)

<iframe width="560" height="315" src="https://www.youtube.com/embed/9EdohXyY6Yc" frameborder="0" allow="accelerometer; autoplay; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>


And yet another bit of info -

https://www.hotrod.com/articles/crankshaft-rod-bearing-install/

That's right! The plastigauge. Thank you for the info. Ill start there and see what I find!

Much appreciated!

 

[1074]

Side play

Side play is allowed. It's the end play that you need to be concerned about!