Fuel rail questions?

[mjr45]

I'm debating on making a new fuel rail(I'm convinced my rail has a couple of microscopic leaks) for my EFI Z and have a question.

1. Since on the stock rail fuel goes to thru the FPR prior to going to the injectors and CSV, shouldn't the FPR be mounted on the front of the new rail?

In looking at the rails built by some members, it appears the FPR is mounted on the firewall at the back of the aluminum rail. Am I just missing something regarding fluid dynamic's here? My idea is that if I mount an adjustable FPR to the front of the rail directly from the fuel hardline and then run the back of the rail to the fuel return line, I would better approximated what the stock rail is doing. Please correct my thinking on this. Thanks.

[Zed Head]

You might be looking at the ports on the FPR backward. The center port on the bottom of the FPR is the return port. Fuel is fed in to the rail directly, then the FRP acts as a pressure relief valve, bleeding excess pressure off through that center port.

If you have old hoses on the stock 1975 rail they might have longitudinal cracks that will seep or squirt fuel. I had an episode of a tiny three foot stream of fuel squirting out of an old injector hose once. A 1978 rail is solid steel (no connecting rubber hoses like on the 75-77 rails) and will bolt on directly, but it will need the FPR it came with also.

Attached a drawing...

Edited May 3, 2014 by Zed Head

[mjr45]

Zed, the fuel rail is off a 79, but one of the injector ports was bent and cracked at the base and I had it brazed to seal it, but I believe there are still some microscopic breaks. The reason I believe this, is that after any driving the car, there are small spots of sticky brown stuff on the heat shield directly underneath the #1 and 2 injector ports off the rail. After looking at the rail, I understand what you mean. Thanks for answering my question, now I can get on with making a new aluminum rail.

Mike

[Zed Head]

siteunseen's link has all of the relevant information. I assume you''l be using it as a guide? One area I made a mistake on mine that needed fixing, was I left it too long in front. There's only so much space available between the injector and the thermostat housing. I had to grind a corner on mine to get it to fit. I could have recut and retapped but I didn't even know if it was going to work. Future fix. Good luck.

[mjr45]

Yup I'm probably going to use the same as siteunseens' but also found one on the Zcar driver site by the name of Fubarrails, waiting to hear from him. Thanks for the advice.

Mike

[siteunseen]

My only mistake (:stupid:) is I didn't check the levelness and the up and down plumb? when I tapped the 6 injector holes. 4 are straight and 2 aren't, but they're separated so only a OCD person like myself would notice. I would, of course, not get in a hurry and check the levelness between each drilling. I guess the force of my drill press caused the rail stock to move in between holes. Clamp it with cardboard or luan wood works best on the press. Use plenty of oil or spray lube on the drill bits and the taps. This is the only thing that wouldn't melt down onto my heat shield, Permatex High-Temperature Thread Sealant (.2 oz) 59214: Get the best Pipe Sealer & Teflon Tape at Advance Auto Parts.

Let me know if I can help.

Cliff

Oh yeah, I didn't drill the ends just tapped the threads. The hole is already perfect from rossmachine.

Oh yeah again, I didn't do a barb for the CSV, just T'd out the back. One goes to the FPR the other side to the cold start valve.

Edited May 3, 2014 by siteunseen

[mjr45]

Site, I like the rail you did, but how did you get her to hold the fish?

Mike

[black gold man]

She now has good reason to smell like fish.

[FastWoman]

Geeez! Come on, guys!

Edited May 4, 2014 by FastWoman

[mjr45]

Black gold man that is sooooooo bad!

[siteunseen]

Site, I like the rail you did, but how did you get her to hold the fish?

Mike

She's the bait!

[CG240Z]

I am too having injector issues so I ordered 6 new injectors and the pallnet fuel rail. Hopefully I'll get the fuel rail in by the end of this week. It was reasonable priced and I can let you know how the fit and finish it. I also noticed how the FPR mounts on the backside and am not quite sure why or how that works.