MSefi.com read only forum (Jan.15,2018)

anybody drilled fuel rails w/ 17/32 bit? seems to be alittle loose to me. works good for the intake side but don't think it will hold the fuel pressure. just dont want to ruin my rail stock.

or 13,5 mm will do just fine , in fact that is the correct size.
But you have to have a good surface finish and also make a 45 degree chamfer dia 14,5 mm so the part will be easy to enter.

Heribert

you really nee da reamer. you need to predrill the hole to .313 with a drill and then finish drill to .500, then ream to .535-.540. oh yeah then chamfer the end. this will give you a nice sealing surface.

I am a machinist and no you do not want to just drill an o-ring sealing surface. depending on your equipment drill undersize and leave .01 thousands per side then ream to so size. this is based on having a bridgeport or similar. what are you working wih for equipment?

I have a drill press and that is it, the last set I did I made from scratch out of round stock, for the injector holes I drilled to 1/2 inch and then reamed slowly with a cut down spade bit, ghetto I know but it worked and never leaked. this time I bought the fuel rail stock and just need to drill the injector fittings out, I'm thinking about just grinding a few thousandths off of my 17/32 bit to tighten the fit some and then first drilling to 1/2. if I had the proper equipment I would use it believe me but I do all my own work.

I drilled 17/32 then used sandpaper to smooth out the bores. I used a Dremel to bevel the edge a bit to make it easier to insert the injector and o-ring. No problems and no leaks.

I got a cutter from Kinsler Fuel injection (rental) for my rail , I'm using Oring boss but they have other cutters to