Drilling an injector bung

[24OZ]

Hi there,

 

Need some advice, I am working on a project which requires me to drill a recess for the stock 280ZX Turbo injectors to sit in, I need to know whether a tool is available which can drill the hole as well as make the seat for the rubber washer to sit in so the edge of the injectors can rest on it.

 

I do not want to install injector bungs but rather drill them in. I am happy, more then willing in fact, to enlist the help of a machine shop, but seek your guidance on how it would be done and what tools will be required.

 

I did a search on drilling injector bungs but didn't find anything.

 

Thanks.

[ovenfood]

A gun barrel drill bit has a almost flat cutting edge and does not have cutting edges on it's flutes. So you should (given that you dill correctly) get a perfectly round hole. I don't know the best way to do what you are asking I only suggest a gun barrel because I was thinking of using a reamer to get the hole and a gun barrel to get the seat (just because I have the lying around and I am quite good at precision free hand drilling).

[Tony D]

There are dimensions for this somewhere...I saw it.

 

I think I used a Letter "O" drill... Then something like a 16th fractional for the injector seat. I made the same sort of clamped connectors inside a carburettor float bowl for 'hidden injection' some time ago. I may have had to use that "O" drill to enlarge the stock EFI injector recesses to accept standard O-Ringed injectors which were body-clamped like the originals and then had a rail attached above that separately... It's been a while.

 

If you have an EFI manifold and a caliper, I'd probably do as ovenfood suggests and step drill two holes about 1mm undersize, and then finish-ream them with a reamer of the proper diameter using dimensions taken from the stock manifold. Did you look on the Megasquirt Yahoo Forums, or their new forum? They had a lot of those kind of dimensions listed since a lot of guys had to drill bungs into existing carbie manifolds. I mean, they built a Turbo-Imp in 2002! There wasn't a manifold for THAT!

 

Somewhere I have a drawing...you can see portions of the hand written dimensions in the back of this photo---the solenoid drawing was on top of a full-size drawing of injector mounting to adapt to an SU Manifold... where that drawing is now is somewhere...at the house...somewhere...moved by others from my drawing board...somewhere You can even see my engineer's scale in the right corner!

Edited May 24, 2011 by Tony D

[24OZ]

Thanks for the input guys. Tony don't you just hate it when people tidy our stuff, it may look like a mess to the untrained eye but I know where everything is!

 

Price aside, is this the tool that would do it all in one? http://www.rossmachineracing.com/injectortool.html

Edited May 25, 2011 by 24OZ

[Tony D]

yep, don't even have to look at the link. They do make a 'one step' injector drill that does the hole and the injector step...but BEWARE there's not a SINGLE one of them available that I've seen that is for the STOCK injector. They are all for the 14mm O-Ring style Bosch Configuration injector.

 

The Nissan/Bosch injector has a smaller pintle, and seals with a flat o-ring against the body in axial crush. Standard O-Ring injectors use an O-Ring on the pintle in a configuration that seals in a radial crush circumferentially about it and the body is left to float freely between o-rings on either end. You can adapt the Nissan OEM style pintles by putting on a different 14mm compatible pintle cap, or an adapter that slips over the existing one to take the 14mm sealing o-ring (Nissan is more like 10mm)

Edited May 26, 2011 by Tony D

[24OZ]

Thanks Tony for the insight, really useful info.

 

Is there a way of converting the stock injector top end to fit an O-ring fuel rail. Reason - I'd like the injectors to sit against the fuel rail tightly and not for there to be any length, thus I want to make the injector and fuel rail as compact as possible.

 

Thanks.

[Tony D]

There is a Mitsubishi 550CC injector which has a very short body length. All dimensions standard O-Ring spec, but the top portion above the electrical wrappings is VERY short. It was for a TBI application. I was going to stuff them in a float bowl, but when I saw the price Mitsu wanted....

 

You want a little space there for thermal growth.

 

The "Stock" Nissan Barbed Injector...Go look at the Megasquirt forums, or Dunebuggies.com (I think) they had a lot of 'conversion' parts either made or that you could order from a Bosch Stocking House to convert from various configurations.

 

For the effort, buying remanufactured, or new injectors may be the most expedient route.