DIY - M20 throttle body vacuum fittings

[128keaton]

Sorry to add to a very old thread but just thought I would add for anyone who might not be able to figure out what to use for the ICV side, I bought a 21/32 drill bit, m18x1.5 tap and m18x1.5 male to 19an male fittings with a female 10an to whatever barb size you desire, I picked 5/8 as the hose ID was about .68in I believe.

I tried this out, but it doesn’t seem possible. There is not enough room for an elbow or anything after the m18x1.5 to 10an!

[zinc]

I managed to find a fitting that works for the ICV side. There is an o-ring and a nut on the M18 side so you can align it correctly and get it tight without needing PTFE tape. The other side is billed as 1/2" male JIC which AFAIK is the same as 3/4-16 & 8 AN.



(link to eBay)

M18x1.5 appears to be the correct size, but no drilling is required, just a HS tap. The hole is 17mm, so M18x1.5 gives 50% thread engagement. The next closest I found is 3/4-16 with 100% thread engagement which comes to 16.986mm but I don't like the sound of 100% thread engagement.

Comparison with original fitting:



M18x1.5 HS tap on a Lisle 70900 #11 Tap Socket

[zinc]

The 1/2" JIC/8AN threads appears to be a good size where you can screw the fitting into a new rubber hose (part no 13411718777). If it doesn't seem to be sealing will maybe put some RTV or JB Weld on the threads to make it into more of a barb that will take a hose clamp.

[litu]

Cool, thanks for reminding me this. Need to upgrade my with this