basic question.. I always installed my primary injectors with combination of o-rings that sealed fine, and I recently learned about the stock plastic piece with mesh that needs to be underneath the primary injectors. How do I install these parts in correct orientation and sequence? The block is 20b D-series which atkins rotary told me should use the FD style injector parts as seen.The primary injector holes are bare metal holes without any plastic or rubber sleeve. Thanks in advance.

 

I thought this would've been a very easy question

over 200 views, and no reply.....

found out those things are called the fuel injector diffusers. Do you guys even use them with rebuilt engine? or just skip them like I did from the beginning?

I was hoping this would help with low rpm cruise.

 

Diffuser first, then rubber grommet (aka insulator).
I think the outer face of the diffuser faces the center of the engine (if I can say so) so it can provide a more uniform fuel mist into the combustion chamber.

 

The diffuser is keyed so it will only go in the right way. The rubber seal goes around the end of the injector and basically seals it to the block so you don't have an air leak there.

Dale

 

When all else fails...



page F-106

 

You only need them for OEM injector and rail, as mentioned above the diffuser is keyed so it only goes in one way, then the rubber O-ring goes on the rail, it kind of sit between the rail and the block to fill that gap.

I see an EV14 in your picture, if you are running after market rail with EV14 then you don't need any of that.

 

And don't skip the diffuser on a stock fuel setup, you'll flood the engine and wonder why it's happening.

 

Grommet is not used with top feed injectors. You need to install injector spacers. I do use the diffusers.

 

man that's it. It just wouldn't fit with any combination of rubber stuff I have. thanks man. pm'd!

 

Ok. does your spacer go between the two as shown here?

 

because if I do this, it blocks that tiny air port on the side of the injector hole in the iron. and it doesn't keep the injector perfectly straight and centered.. there's really nothing to keep the end of the injector centered in the injector hole in the iron.. is there a thick o-ring that goes where the groove is at the bottom hat of the injector?

sorry... just never seen how it's supposed to look. I never used the diffuser before. thank you.

on the upside, the diffuser fit like a glove. thanks everyone!

 

You have some sort of spacer, looks like you need an o-ring on it to seal properly. There appears to be a groove for one.

 

What about ID 1000 in primary,
Better with or without diffuser ?

 

You only need diffuser for stock injector.

 

With a stock injector, the spacer fits perfectly around the end of the injector. It's pretty obvious where they should be when you're in there. With aftermarket stuff, all bets are off.