P Clips, Fuel Lines & Brake Hoses

[GreatOldOne]

Hi guys,

Over the weekend I managed to get the front discs on and all of the calipers bolted on. In doing so, I've started to install some of the brake lines.

The rear ones have gone on OK, but more about that in a minute. The line that goes from the master cylinder through the transmission tunnel to the back will require clipping up - with P Clips. I ordered some with the chassis, but the internal diameter of them is too small (even taking the rubber off them) from the braided hoses, so I've got to get some others.

I've seen a few on eBay, but for the most part they're plastic. Are these OK? or should I get the metal type? I'd be getting several sizes, as I'd need some for the fuel lines as well... Which leads me to my next question.

I'm going to get some fuel hose and install the run from the rear of the car to the engine bay now, as it'll be easier to whislt the engine, box & prop aren't in the way. I assume that I'll need to run two pipes (supply & return), but what diameter pipe do I need? Will it be the same size for both runs?

Finally, back to those rear brake lines. I've got them all clipped in nicely, and run to the back bulkhead. I'm not entirely sure that they're long enough though (maybe due to the way I've run them, but they're following the path of the old lines...)

What I think I may have to do is run a piece of hard pipe from one side of the car to the other with connectors, like so:

                |
                |
                #
                #
----##========#####----

--  flexi
== coper / hard pipe
## connectors

The copper pipe would run under the prop shaft to the left hand side, and the have the correct connector on the end for the flexi to screw in to. The other end would have the correct connector to go into the three way union that I have.

I need to have a measure to be sure - but If I do need something like this to make the distance up, a) do you think it'd be OK, and b) Would someone be willing to make up the pipe for me? I know a lot of you have done you're own pipes so have things like brake flaring tools and fittings, and possibly a couple of feet of pipe spare. Obviously I'd reimburse anyone who can do this for me.

I'll try and take some pictures of the problem area later on so you can see what I'm going on about.

Cheers,

Jason

[MartinClan]

Originally Posted by GreatOldOne

I've seen a few on eBay, but for the most part they're plastic. Are these OK? or should I get the metal type?
Jason

I used stainless p-clips, you can get them from Namrick amongst other places.

Originally Posted by GreatOldOne

I'm going to get some fuel hose and install the run from the rear of the car to the engine bay now, as it'll be easier to whislt the engine, box & prop aren't in the way. I assume that I'll need to run two pipes (supply & return), but what diameter pipe do I need? Will it be the same size for both runs?

You will need 2 fuel lines. I used 8mm supply and 6mm return - both in copper. I thought that 6mm for the supply might not be big enough.

I made my own brake lines up - I have plenty of fittings and pipe left. The only thing I would say is the tool I used produces imperial flares. As far as I can see they look exactly the same as metric ones - but I haven't put any fluid in my system yet lol

BR

Robin

[GreatOldOne]

Thanks for the advice Robin.

I had a poke around when I got in from work, and by re-routing the brake lines (I had them going through the eyes in the arms and the brake shields that used to be the transition from the hard pipes to the flexi ones) I've got enough slack to join the pipes with the t-connector and fix it to the rear bulkhead.

Should have thought of fiddling with the pipes earlier... I'm as dumb as toast sometimes...

[jeremy]

Before you decide on you fuel line dimensions, have a look at your planned fuel set up.Check the width of pipes on your marlin tank;mine are 10mm.Next decide if you are using a facet low pressure pump at the back;if so this is supplied with 8mm inlet and outlet fittings;next look at the front setup; if you are using a marlin swirlpot, this has 10mm fittings; followed by a high pressure filter and pump which have 8mm fittings........you can see were i am going with this..try and draw you system on paper and minimise the amount of reducers and clips involved..reduce the risk of leaks.\europa have a great range of fittings for their pumps and car builder solutions have a great range of in-line fuel hose reducers. good luck!

[MartinClan]

Originally Posted by jeremy

Before you decide on you fuel line dimensions, have a look at your planned fuel set up.Check the width of pipes on your marlin tank;mine are 10mm.Next decide if you are using a facet low pressure pump at the back;if so this is supplied with 8mm inlet and outlet fittings;next look at the front setup; if you are using a marlin swirlpot, this has 10mm fittings; followed by a high pressure filter and pump which have 8mm fittings........you can see were i am going with this..try and draw you system on paper and minimise the amount of reducers and clips involved..reduce the risk of leaks.\europa have a great range of fittings for their pumps and car builder solutions have a great range of in-line fuel hose reducers. good luck!

Excellent advice!

Robin

[peterux]

Just to add my two pennies to all the excellent advice above.
I used 8mm copper pipe for both feed and return, metal p clips, a Marlin swirl pot upside down on the inlet side (i didn't like the idea of putting the fuel system just above the exhaust manifold) and a whole host of pipe fittings and reducers.

This is an area of the build you can use your right brain and invent your own solution!!

Oh and don't forget to use the proper high pressure rubber fuel injection hose for the high pressure sections. halfords actaully stock quite a good selection of sizes for low and high pressure. A bit more expensive but no postage and packing costs.

[GreatOldOne]

So, 8mm for both runs? Must be Ok, as you've got you're engine running!

I was planning on doing the long runs in flexible pipe, to cut down on the connections, and getting the pipe over long to give me room to sort out the connectors and routing at the other ends later on. I just wanted to get the fuel lines in whilst I've got the room and the gearbox and engine isn't in the way.

[Patrick]

Yup, I'm using 8mm copper too. I had to flare the ends a bit which helped the flow.

It becomes a complete PITA to work on those lines once you've got the engine in! I plan on doing the whole lot with braided flexible pipe at some point reducing the number of connections, but not until the engine comes out for a rebuild.

[peterux]

Originally Posted by GreatOldOne

So, 8mm for both runs? Must be Ok, as you've got you're engine running!

I was planning on doing the long runs in flexible pipe, to cut down on the connections, and getting the pipe over long to give me room to sort out the connectors and routing at the other ends later on. I just wanted to get the fuel lines in whilst I've got the room and the gearbox and engine isn't in the way.

Not sure I would want flexible pipe all the way down the transmission tunnel but must admit I just assumed that copper was the norm. Copper doesn't rust or deteriorate much over time and is reasonably robust to any stones kicked up underneath the car.
I soldered on some 8mm copper straight connectors on the ends for the rubber pipe to grip to.

Not sure what the SVA inspector would think of flexible pipes all the way unless they were covered in metal braid which could be expensive?

cheers
Peter

[Patrick]

I worked out £60-£80 to do the whole lot with braided pipe - another reason I'm using copper to start with. I don't see any reason why the sva folks would have a problem as long as the pipes are of suitable specification

[GreatOldOne]

Originally Posted by peterux

I soldered on some 8mm copper straight connectors on the ends for the rubber pipe to grip to.

Pete - where did you source the straight connectors from? And when you soldered them on, was it normal houshold plumming solder you used, or something more exotic (silver for example)?

Ta,

Jason

[peterux]

Jason,
I used standard microbore plumbing fittings from a large B&Q diy shop and used normal plumbing solder.

Peter

[GreatOldOne]

Thanks Peter!

[Will5]

Hi,

Peter mentioned going to halfords for flexi pipes. A few months ago they were promoting trade cards. I succeded in getting one, it invovled a few converastions with the local manager and proving that I was genuinely buying parts ie reciepts from GFS, scrapies etc... It is mainly tools and parts that get a discount, but it helps a little in curbing spirling costs.

Will

[GreatOldOne]

Only me again... (Please don't groan - I'll only be a minute )

Peter - you say you have straight microbore (8mm) fittings soldered onto the fuel pipe. what do these look like? (I tried looking at your Flikr site, but all the fuel pipe pics had something in the way of the transition)

I had a picture of them in my head that had a solder fitting on one end, coming to a 'barbed' or flared end on the other:

                'barbs'
       -------\\\
              |||
       -------///
Copper           Rubber 
end               end

The rubber pipe slipping over the barbs and then secured with a jubille clip - the barbs stopping the pipe from slipping off. Is this what you meant? Or am I barking up the wrong tree in the wrong forest?

I'm sure I'm stressing over nothing... But I can't help it.

[peterux]

Originally Posted by GreatOldOne

Peter - you say you have straight microbore (8mm) fittings soldered onto the fuel pipe. what do these look like? (I tried looking at your Flikr site, but all the fuel pipe pics had something in the way of the transition)

Hi Jason,
I've uploaded the best photo I can find, but didn't seem to photo the joint before fitting the hose.
http://www.flickr.com/photos/peters-...lin/417247262/
I think you've got the idea already.
I did this really to avoid another in-line reducer because I wanted 9.5mm hose to fit over the Marlin anti-surge tank connectors.

It's all still subject to road testing becuase I have made little further progress on the car due to other priorities

[GreatOldOne]

Peter - thanks for taking time out to take another photo - much appreciated.

I think I understand what you've done now...

you've used one of these (in the correct size):



...soldered on the end of the 8mm pipe, and have used the rings to stop the pipe from being forced off - in effect they become the 'barbs' I was talking about. A jubilee clip sat between the two solder rings finishes it off.

That right?

[GreatOldOne]

As a precaution, I mailed Marlin with a list of questions reguarding the fuel system. Here's the questions, and Marlin's replies:

Originally Posted by Marlin's Reply

Q: What diameter pipe should I be running? I have a 2.5ltr M20 engine from an E30 donor.
A: 8mm internal diameter

Q: Should I use copper piping, or can I use flexible hose all the way?
A: Your choice we use nylon

Q: If Copper, how are you managing the transitions from copper pipe to
flexible fuel line? (No answer supplied, as they use flexi all the way - see prev. question)

Q: Do I need to fit a swirl pot? I seem to remember something about a revised tank you're supplying now that should negate the requirement for a swirl pot.
A: We've found that using a swirl pot is the best and safest solution to any
fuel supply problems.

Q: Ideally, is there anyway you could provide a plumbing diagram for a
typical factory BMW Sportster fuel system? I don't want to get into the situation of running pipe only for it to be wrong and need redoing when I get the tank and other fuel system parts - especially once the engine has been installed.

A: Send me your fax no and I'll send you a diagram showing path to take.(I'll post up a copy of the Marlin Diagram as soon as I get it.)

I've also done a bit of googling on pipe transitions, and I found these two sites:

http://www.stevsonmotors.co.uk/fuelunions.htm
http://www.woolies-trim.co.uk/c-46-nuts-nipples.aspx (Suitable for work, even if the URL is suspect... )

They both do the barbed (or as the call it a nipple) ends for pipe that can be soldered on. The first link all seems to have compression fit versions as well.

[peterux]

Jason,
i'd stick to copper.
Joining rubber to nylon tubing sounds even more of a puzzle to me?

Peter

[GreatOldOne]

Here's the (very detailed ) diagram Marlin sent:

Tank ---> LP Pump ---> Swirl  ---> Filter ---> HP Pump ---> Engine
  ^                    |  ^                                   |
  |____________________|  |___________________________________|

They suggest the low pressure pump is mounted on the outside of the floor bulkhead behind the driver's seat, and the high pressure pump on the top of the drivers bulkhead.

Useful, eh?