Pfc. Parts

Hello all -

I've searched this forum enough to know I should contact Roger Rest assured I have, however Roger isn't always in and I need a solution quickly.

I need to go from the fuel rail on my '85 to something that will connect to an off the shelf fuel pressure gauge. I know I could use a rubber hose and clamps but would rather not if I don't absolutely have to.

I believe what I need is a M12x1.5 female to thread onto the rail after removing the ball bearing. A standard fitting on the other side would be 1/8" NPT, though I think I might prefer a 6AN fitting? Maybe something machined from aluminum? Extra points given for an adapter that seals the M12 side without requiring a bearing?

Any clues?

Thanks,

Pfc. Parts

While we're on this subject, anyone have ideas about what I'd like to call "reverse offshoring" for parts like this?

I have a lathe/mill in my garage (it isn't installed yet but it will be someday). If I designed a part like the one I described I wouldn't be able to sell it in the US for the application described because I'd end up being liable if it got installed wrong and burned up someone's car. Of course, if the part were shipped to the US from Taiwan for example, this problem would likely go away. Anyone ever tried that?

FLYVMO

I think most 928 owner's would find it a great resource. You can always add a disclaimer like those silly ones on irons that say "don't put your hand on a warm iron, it will burn your hand"...

I guess there is never enough protection from the Darwin Award applicants, but if the part is dimensionally the same with equal or better materials, I'm sure you could sell quite a few. I think the 928 community needs people like you and Greg and Roger and...the list goes on.

Cheers!
Carl

ROG100

Because of all the potential issues with fuel gauges on our cars and the opportunity for them to be misused we stopped selling them. The fitting is pretty special and the thread size and pitch are easy. The ball face to the fuel rail being the hardest part and that is what cost the most $.
I am always in - just mega busy 8>)

michaelathome

This is what I have used.

http://www.lindseyracing.com/LR/Pors...-FPGK-968.html

People have had problems with some of the liquid fronts in the past FWIW.

Michael

dr bob

I tapped a used factory end cap with 1/4-20 threads, and used the GM adapter hose in the H-F fuel pressure gauge kit. In place of the ball bearing, I use a 1/4" tube compresion sleeve in brass. The sleeve fits nicely over the end of the 1/4" threaded end on the adapter hose inside the cap, enough to hold it until the cap is on the end of the rail snugly enough to get the ferrule/sleev to seal. I put an o-ring on the outside of the cap but I don't think it does much. There's Teflon thread past on the adapter hose threads and the threads on the end of the rail.

Most plain threaded adapters make no provision for sealing on the end of the rail. The rail end is flared and expects the ball bearing to do the hard work. Obviously the bearing would block the passage through an adapter to a gauge so you can't put the original back in. Using the brass compression sleeve/ferrule solves the problem handily, plus they are available at Home Depot in the plumbing/tube fitting aisle.

Having this adapter opens the door to connecting the injector flushing cannister, using the same hose and adapter. I added quick-connect fittings to the 1/4-NPT end, and can push cleaner, fuel or air in from the front if needed. It's been handy a few times.

Pfc. Parts

Thanks Dr. Bob, I hadn't thought of using a standard brass ferrule, makes perfect sense. One solution I had heard of involved drilling a hole through the bearing, which didn't sound all that easy to do. I also considered replacing the metal bearing with an off the shelf plastic bead that had been drilled for a necklace, but there would be problems making sure whatever plastic it was made of was compatible with gasoline. Jewelry supply stores don't list those characteristics

Sounds like drilling and tapping a used rail cap might be my only choice. I was hoping for something simpler since I'm not planning a permanent installation, I just need to check the pressure going to the rail to see if my fuel pump is OK.

Pfc. Parts

Thanks Michael, that's the fitting I need. I hate to buy the gauge too just to get the fitting though since I already have a gauge, but then no one said 928's were cheap.

Pfc. Parts

I sort of figured that might be the case. Sigh.

Pfc. Parts

Or maybe just make the part but don't suggest an application. Here's a M12x1.5 to 1/8" NPT adapter. We have no idea what it's used for but we sell them for $12 a piece.

GregBBRD

Besides that, who needs a permanent fuel pressure gauge, anyway?

It's not like the fuel pressure "jump" around and change. Even if you have an "adjustable regulator"......set and forget.

Pfc. Parts

Just to be clear; I'm looking for an adapter so I can hook up a standard fuel pressure gauge to the rail. The gauge isn't permanent, it has a 3 foot hose on it but it isn't set up for Porsche's strange test fitting.

This shouldn't be nearly as difficult as it is.

Pfc. Parts

To wrap up this thread, I ended up buying the adapter and gauge from 928 Motorsports. After pricing the adapter parts that *might* have gotten me from a M12x1.5 on the fuel rail to the GM standard female Shrader fitting on my pressure test gauge I gave up and just bought the kit.

If anyone wants to try piecing together an adapter without machining a fuel rail cap I suggest Discount Hydraulic Parts ( www.discounthydraulichose.com ). They seem to have the right stuff but 928 Motorsports has them beat on price and you get a spare gauge out of the deal.

Mrmerlin

well there is another way,
get a spare fuel rail cap and a few sealing washers to fit over the rail threads .
Drill out the end of the cap and tap it to fit the NPT threads of the gauge put some PTFE sealing paste on the gauge threads screw it into the cap add the two sealing washers to the rail then put the cap on

85euro928

In chasing a FPR problem over the weekend I wound up making an adapter by drilling a 1" diameter plug with a hole saw from a 1" thick piece of aluminum and then drilling and tapping each side with the appropriate sized threads. I assembled the pieces using PTFE and no leaks, but I don't plan on leaving the adapter or FP gauge in place and will remove it as soon as im I'm done. Cheap, easy, and it took about an hour.