Petrol pipes?

[york33]

Evening again all

It's silly question time :-) I had a dive through the archives and found mixed feeling on the subject, so thought I'd ask again....

Petrol pipe, what's anyone think to using copper for the long runs (supply+return) front to back? I just happen to have 10metres of random 8mm which would do the job nicely. Only trouble is, it's plumbing pipe and I've not a clue if this is likely to be a bad plan or not? Does MOT man require some approval marking on any fuel pipes?

cheers
Dave

[350matt]

As far as I know I think the only leglislation is for rubber pipes which have to be marked suitable for petrol and able to withsatnd 8Bar for injection.

So you should be fine with copper providing it doesn't have some odd reaction with petrol

Matt

[jchase]

If it's for the 280, I would be a bit wary, as the fuel system runs at 7 bar. You'd probably get away with it for a 2.5 bar v8 system. Still , what could go wrong ...

I used 8mm cunifer truck brake pipe for years on one of my Alfas, but again that was 2.5bar fuel pressure.

Also you need to really careful about the radii of the bends at 8mm - as the 280 fuel system works by varying the fuel pressure (Continuus mechanical injection) and if the return flow resistance changes, the engine will go out of tune.

-Jim

[Gerry Attrick]

Copper is a known catalyst for generating deposits in fuel injection systems (along with zinc). If you use it, you'll find your injectors will foul up, and you'll lose power and driveability. I suggest you stick with the standard 8-10 bar flexible stuff.

[leorest]

Gerry Attrick said:

Copper is a known catalyst for generating deposits in fuel injection systems (along with zinc). If you use it, you'll find your injectors will foul up, and you'll lose power and driveability. I suggest you stick with the standard 8-10 bar flexible stuff.

So, if copper is not good, what material is the best if you want solid lines for the long runs?
Leo

[Number 7]

One of the runs along the o/s sill of my 400 is in small bore copper pipe (poss. 8mm), joined to rubber hoses at either end. I assume that's how it left the factory (?) and have had no discernable problems with it.

7.

[Gerry Attrick]

Current fuels are more susceptible to oxidation than the older ones, and injector design in the late '80s tended to take account of a small amount of deposits being formed. (Emissions legislation wasn't as stringent as it is now!) The amount of deposit is also dependent on how you drive the car and how hot the fuel gets. I'm not saying you'll stop at the side of the road by using copper pipe, but if there is an alternative to using it, I'd go that route. With the number of problems related to the injection system, reported on the site, I'd try to remove as many causes as possible.

[york33]

Odd reactions with petrol were something I was worried about. Now, my Astra certainly had solid lines. There doesn't seem to be much else on offer that I can find, unless I go with steel tube, so I might have to run rubber hose. Just thinking that a solid run would be a neater solution.

thanks all so far
Dave

[chassis 33]

jchase said:

Also you need to really careful about the radii of the bends at 8mm - as the 280 fuel system works by varying the fuel pressure (Continuus mechanical injection) and if the return flow resistance changes, the engine will go out of tune. -Jim

What should the return pipe bore be, just wondering if this is why i cant get my Tasmin to run well?

Regards
Iain

[york33]

Ah, this will do the job nicely, not bad price too.

FYI:

www.demon-tweeks.co.uk/catalogue/product_detail.asp?CLS=MSPORT&TLGRP=M003&CODE=KRNROHR&PGRP=MC047&GRP=MC047&PCODE=KRNROHR-8

[grady]

I was watch a bit of Monster Garage last night and they were using solid stainless steel.

It was for a custom street rod so it was all polished up, very nice look .... with the body off.

[Gerry Attrick]

Stainless steel is the way to go. All the engine test beds use it - especially those testing fuel quality.