MSefi.com read only forum (Jan.15,2018)

I am just fabricating my fuel rail, and have the fuel pressure regulator from a CBR929 fuel rail.

I have cut the regulator and mount off of the old fuel rail, and was planning on using JB Weld to attach it to the new rail.
Has anyone tried this, and would it hold?

Leo

Leo

You're a braver man than me....

John

That is a darwin-ian style question - right?? FI cars are by nature running high pressure fuel in and out of the engine compartment. I for one wouldn't use a product with unknown burst ratings (or burst ratings at least 2x).

The Fuel Pump on a car I restored for my son had JB weld on pressure relief valve -- to "stop" a leak. It may have worked for a while, but when it failed gas sprayed every where. Lucky for me it was in the shop and just starting testing, no hot exhaust, opposite end of the engine compartment.... still consider myself luck that the car didn't lightup & melt down.

LEs

Not a good idea. Could you post some pics? Lots of people have had to fab up the FPR mount point and you should get some good ideas. JB Weld is wonderful for an epoxy but definitely has a different thermal expansion rate than either Al or steel. Under stress (pressure) it will probably fail at a very inopportune time causing an extremely hazardous situation. Fuel pressurized at 43psi leaks in a very rapid and far reaching manner. Fire bad....

-Mike

The burst rating is known...

Properties (psi)
Tensile Strength: 3960
Adhesion: 1800
Flex Strength: 7320
Tensile Lap Shear: 1040
Shrinkage: 0.0%
Resistant to: 500° F

Can withstand a constant temperature of 500 degrees F. The maximum temperature threshold is approximately 600 degrees F for a short term (10 minutes).
J-B Weld has proven to maintain its characteristics to temperatures as low as -67 degrees F.
J-B Weld has a tensile strength of 3,960 psi.

Although I still have to leak test the fuel rail still, the regulator off of a CBR929 are usually set to about 60psi.

Here are some pics...

That's flat out crazy imho.

Mike

I have been a master auto tech for 20 years, DO NOT USE JB WELD ON ANYTHING IN THE FUEL SYSTEM!!!! please! Its been my expiriance that the fuel will eventually cause the epoxy to disintigrate or de-laminate. looking at the pics it seems as tough it would be easy to just drill and tap the fuel rail to accept that regulator. use the gold peice as a template.

[quote]Properties (psi)
Tensile Strength: 3960
Adhesion: 1800
Flex Strength: 7320
Tensile Lap Shear: 1040
Shrinkage: 0.0%
Resistant to: 500° F

Can withstand a constant temperature of 500 degrees F. The maximum temperature threshold is approximately 600 degrees F for a short term (10 minutes).
J-B Weld has proven to maintain its characteristics to temperatures as low as -67 degrees F.
J-B Weld has a tensile strength of 3,960 psi.[/quote]

This is all well and good, but what are its chemical compatabillity characteristics with reguards to modern fuels?? im tellin you, ive tried it several times to help someone out of a bind, its never lasted. the fuel seeps into microscopic cracks and starts to soften the epoxy. You may get lucky, but is it worth taking the chance? a local welder would probly charge you $20 or less to weld the thing on! Dont mean to harp i just see an accident waiting to happen and i would hate to hear about someone getting hurt! Joe

Thanks everyone, there is some very good feed back there. I will be looking at fabricating a new rail. Taking the regulator off of its base that has been JB welded on the old rail, and mounting the regulator right on the fuel rail using the bolts that currently attach the regulator to its base.

Leo

I'm very happy to see you redoing this.

-Mike

Me too , I've handled a few of those regulators and i think just attaching it to the fuel rail will work out ok. one note of caution though, try to put the threads in the thicker part of the rail if possible, would be even better it there is enough meat to install helicoils. that aluminum may be fairly soft, so easy does it both when tapping and torquing the bolts! while your at it throw up some more pics, love to see wors in progress.Joe

Either properly machine the rail to accept that regulator, or get a remote mount regulator and tap the rail for pipe threads and get an AN adapter.

I understand the concept of staying on budget, but pressurized fuel systems should be done correctly.