It seems quite a few of you are using 850cc primaries what rail injectors are you using or can the fd injectors be made to fit the stock 20b primary rail?
Kevin

 

the fd ones should fit straight in

 

THe FD3S 850cc Secondary injectors do not fit the stock 20B primary fuel rail. If you want 850cc primaries, send me the 3 stock 20B primary 550cc injectors and I will have them modified into 850cc. It cost about $175.00 per injector to do this but, then you can still use the stock 20B primary fuel rail.. 20B and cosmo Re use a different style sidefeed primary injector and the standard oval port topfeed 550cc secondary which is easily upgraded with any topfeed injector

 

+1

I recently tried to use FD 850s in an RE primary rail. Although they "fit" the same there are issues that can't be overcome easily.

 

Yes, the primary Cosmo Re and 20B injectors can be modified to whatever you want up to 1300cc. I have done this many many times and they work great..

 

I test fitted my FD 850cc injectors into the 20b primary rail the other day, they fit in but sit much higher up in the fuel rail, since they are a shorter injector.

Can you run them like this or will the spray pattern be affected too much?

Can I just cut the rail shorter? Not saying I would do this, but curious.

Is there a 20B primary rail available to fit the FD 850 injectors?

 

I would rather buy/modify a rail them modify my injectors at a cost of $175 each

 

KGParts.com sells both a primary and secondary rail for the 20B which accepts Bosch style top-feed injectors.

 

I suggest you use 83lb top feed injectors with an aftermarket top feed rail. In my experience they are more responsive to changes in millisecond levels at low duty levels than (at least) the stock high impedance FD secondaries.

One thing re the KG rails, the primary rail does not fit without washers under the bracket. Don't let that deter you though; it's easy enough to take care of.

 

I had no such issue with my KG primary rail. Are you sure you installed the metal spacers properly? I was also using a spacer until I realized I hadn't driven the metal spacers into the irons deep enough.

 

First I tried installing them without injector diffusers. The body of the injectors overlapped with a cast lump of metal for an intake manifold bot hole on the intermediate housing. I then installed them with the injector diffusers so that they would sit up higher and clear the piece they were interferring with. This left the rail bracket a couple MM above the bolt holes. Once I got all that sorted out I installed the sleeves. I had a set made for the primary ports and the secondary ports (as the depth is slightly different).

 

Hmm, maybe it's injector specific. I used Siemens 850's which fit fine, but the Rochester 1000's I originally intended to use had the problem you describe.

 

Interesting. Siemens doesn't make 850s; they make 83lb injectors that are ~872cc. That is what I have. Someone else on here had the same problem several months ago.

 

Yea, I am using the same 872's (call them 850's for simplicities sake!). How weird! My iron has D096 stamped on it for whatever thats worth, I wonder if there were any minor variations between the codes.