Which prechambers shims do I use?
 

For my om617, I have an 84 td head that I got when I found out my 85 was cracked. I have no knowledge on what was in there before, does anyone know what shims to use on an 84 turbo head for the prechambers? Is there a way to measure the correct depth? Thanks!

your prechamber should stick out 7.8mm - 8.4mm from the surface of the head.


there a 4 different thicknesses of sealing rings and their part numbers listed on page 6 of this pdf:


https://www.startekinfo.com/StarTek/outside/12265/disc_2/program/Engine/617/01-417.pdf

you should only need a thicker sealing ring if the head has been resurfaced

Thanks! I didn't know that was in there