I have recently helped a friend bore out his B18C throttle body to 64mm, but the one thing i can't get right is the butterfly plate, now my question is do they usually laser cut the plates or machine the plates down on the lathe, and i know there is some kind of a sealant you can buy for butterfly plates that have been worn due to wear that stops the vacuum leaks, much help would be appreciated.

 

The best way to get it to seal right is to cut it on a lathe.

You need to get a piece of bar stock, cut the end to the same angle as it sits in the body. Bolt the butterfly on to the bar a bit over sized. So when you cut the outter plate the edges are angled instead of 90deg to the face.

 

Thanks for the info, i will try that.

 

The butterfly will end up oval a bit.