Prop shaft tunnel and fuel pipes

[sam_no3]

Hi

Just wondering if anyone can let me know where their fuel pipes route from the fuel tank to engine, also is it a particuarly big job to enlarge the size of the prop shaft tunnel on the roadster. Having several BIG issues at the moment. Any repsonses will be extremely appreciated,

thanks, Sam.

[stevejgreen]

Re: Prop shaft tunnel and fuel pipes

Most people have run both brake and fuel lines within the transmission tunnel. They are slightly more protected there from road debris etc.
I had to reroute mine when I changed the gearbox type but managed without altering the tunnel.
Wondering why you want to enlarge the the tunnel and what your BIG isues are so difficult to advise. Most roadsters have the original 6" wide tunnel, tapering to fit the gearbox but this was intended for the Marina gearbox and bellhouse.
Obviously different engine gearbox combinations have different dimension issues. I have seen some roadsters where the tunnel has been modified to be extremely narrow, quite tight around the propshaft, in order to fit wider seats etc.
Pictures and or more info on problems would help.

[sam_no3]

Re: Prop shaft tunnel and fuel pipes

Broke down yesterday after the propshaft ripped through the fuel lines. Guy from the RAC said it was dangerously positioned, also started scarring the brake lines so these have to be replaced now. Just wondered if fuel pipes down that route is the norm. Can't get any pictures sadly as i'm without axle stands for the next week due to moving home

[stevejgreen]

Re: Prop shaft tunnel and fuel pipes

Thats one hell of a breakdown and a little close to where you were sitting. Could have been a lot more dramatic and pleased you are OK.

That could have been another Lee moment with a substantial fire.

Was is a prop shaft failure? I would guess there may have been a fair amount of vibration before it let loose, was it a weld, bolt or UJ that failed?

A timely reminder to all of us to check our propshafts, UJ's and possibly replace the dif flange bolts with high tensile ones and torque them up.

Brake and fuel lines can be run beneath the car but are very exposed to road debris unless encased. Running the pipes high up in the tunnel should be ok, I have sleeved mine with braided tube for a bit of extra protection.
Its worth remembering that the vertical travel on the back axle is quite large, the nose of the differential gets quite high in the tunnel so pipes must be kept high along the whole length.

Hope this helps.

[CABRIOBOB]

Re: Prop shaft tunnel and fuel pipes

Sam, It seems you had a lucky escape.

I am holding a Marlin Roadster database and I can not find you or your car details. Could you please see the info requested from the may/june M.O.C pitstop mag so I can keep the database updated.

[sam_no3]

Re: Prop shaft tunnel and fuel pipes

The prop shaft is still in fine working order. I was told that no fuel hose brackets were loose so the guess is its been rubbing for some time before its finally ripped through them. To be honest i did hear about Lee's car the other week and it did shake me up a bit with mine!

When i get chance i'll have a look myself and get them moved further up into the tunnel as it sounds like they've been positioned wrong. This is the last thing i need at the moment as i'm supposed to be moving to belfast in a few days haha!

Bob, sorry you won't find my details as i'm not yet a member but will be from october, i'm being a bit of a cheapskate and holding back until the membership renewal period,

cheers, Sam.

[stevejgreen]

Re: Prop shaft tunnel and fuel pipes

Sam, that sounds a lot less catastrophic and explains why it was only a breakdown and not a total disaster.

I am assuming Marina based roadster.
FYI the diff is offset from center to allow for equal half shafts. If your tranny tunnel is central and has been narrowed from the standard 150mm the larger, safer, space for pipework is on the nearside.
It sounds as though you are up against it timing wise,if you had more time I would suggest getting under the car and replacing the whole fuel line from tank to pump. Good luck.

[CABRIOBOB]

Re: Prop shaft tunnel and fuel pipes

Sam, You will have policeman Tim the Membership sec after you as the forum input is for MOC members only and the club needs all the funds it can get to keep the website going.

[b_caswell]

Re: Prop shaft tunnel and fuel pipes

If you refix the fuel and brake lines high in the tunnel the propshaft will miss every thing as long as plenty of fixings are used along the pipes.
On my car I have also installed a strap across the tunnel under the prop shaft. Should the prop shaft fail IE break at either end it will not drop onto the road and then thrash about next to your thigh. Think about it!

[stevejgreen]

Re: Prop shaft tunnel and fuel pipes

Good advice Ben, I had not thought of that as a safeguard but I would like a little more than just ally on the side walls. I wonder if I could fit my now unused gearbox mount to do the job. It ought to be strong enough. Failing that line the tranny tunnel sides with 16swg steel.
Remember though that the propshaft drops alot lower than when the car is on level ground. Jack the car so the back axle hangs free and then add a bit for those big bumps on the country roads when the axle may be moving at a fair vertical speed. The top travel is governed by the bump stops if you still have them, the bottom travel is only limited by the deflection of the springs unless you have retaining straps fitted.
One thing I had to check when I replaced the top of my transmission tunnel after the gearbox swap, was to make sure that when drilling for fixings, you dont accidentally drill or screw through the pipes if they are at the very top.
I am still curious as to how wide the tranny tunnel on Sams car is and just where the fuel and brake lines have been run.

[trevor_ford]

Re: Prop shaft tunnel and fuel pipes

I have just put the Marlin back on the road and have run the fuel pipe down the passenger side of the cockpit rather than under the car, exiting in the footwell. Seemed a safer option as it can't get damaged and is easier to fit. Brake pipe is still in the tunnel. I also ran the speedo cable into the passenger footwell as I kept snapping them at the bend out of the gearbox. Made a sleeve to cover the hole.

[sam_no3]

Re: Prop shaft tunnel and fuel pipes

Right, after a very rushed and frantic effort i've sorted the fuel pipe for the mean time. Found out that the prop shaft donut had actually been snagging against the fuel pipe and rubbing it away, not the prop shaft itself. This has happened due to the fuel pipe being mounted on the same height horizontally as the prop shaft rather than right up in the tunnel, The brake lines have also been contacted by the donut but not as extreme, they will need replacing in the near future though. Matters aren't helped by the fact the top of the tunnel is a shorter than the bottom resulting in a trapezoid type shape which is making it very cosy for the donut.

For a temporary fix i've routed the fuel pipe underneath the passenger side floor until winter where i'll be fully stripping it down to bits and rebuilding her. I think in terms of safety wise, Trevor is totally bang on with the idea of routing the fuel pipe through the passenger footwell, i will be doing the same thing when i rebuild her over winter. If the prop shaft did fail there'll be a lot of sparks and shrapnel that can easily cut through the fuel pipe, quite a sobering thought really. Anyway on that happy note i've got some more packing to do!

Cheers, Sam.

[stevejgreen]

Re: Prop shaft tunnel and fuel pipes

Ok a narrower tunnel and perhaps poor installation.
As you have said donut I am guessing a ford gearbox.
A couple of comments.
There are two versions of the ford prop, one with and a donut the other with a UJ.
The donut was originally fitted to eliminate noise, the prop had a centre support, limiting the deflection angle that the donut had to cope with. With a short prop on the Marlin, the donut quite probably is being taken through angles that were not intended and may well be getting soft with age and use, hence your problem.
A prop with UJ's at both ends, giving more space in the tunnel, so perhaps no need to reroute the pipework, should cost less than £120.00.
Just something else to consider.

[cameronfurnival]

Re: Prop shaft tunnel and fuel pipes

Im going to pick up this thread again as what I would like to know fits in quite neatly with it

Im looking under my car (a ford based romero) and am thinking that although my pipe clips are 12" apart (I measured them!) the IVA man may want them closer so Im redoing them. The pipe currently goes near the top of the tunnel and then drops down at the rear before cutting diagonally across the rear floor and then up the rear bulkhead to a flexi-hose. Im assuming this is similar for all roadsters? I want to get rid of that diagonal traverse and get it more safely positioned - any ideas?

[b_caswell]

Re: Prop shaft tunnel and fuel pipes

I clicked on this thread and thought I had gone into a time warp.

My tank is fitted set tight to the right with the filler on left. The fuel line runs high in the left side of the tunnel and carries straight on through over the axle and up over the end of the tank.